# Common Portability Library C API

## cpl_conv.h

Various convenience functions for CPL.

Defines

CPLFree

  Alias of VSIFree()

Typedefs

typedef const char *(*CPLFileFinder)(const char*, const char*)

  Callback for CPLPushFileFinder.

Functions

const char *CPLGetConfigOption(const char*, const char*)

  Get the value of a configuration option.

  The value is the value of a (key, value) option set with CPLSetConfigOption(), or CPLSetThreadLocalConfigOption() of the same thread. If the given option was no defined with CPLSetConfigOption(), it tries to find it in environment variables.

  Note: the string returned by CPLGetConfigOption() might be short-lived, and in particular it will become invalid after a call to CPLSetConfigOption() with the same key.

  To override temporary a potentially existing option with a new value, you can use the following snippet :

  See also

  CPLSetConfigOption(), http://trac.osgeo.org/gdal/wiki/ConfigOptions

  Parameters

    - pszKey – the key of the option to retrieve

    - pszDefault – a default value if the key does not match existing defined options (may be NULL)

  Returns

    the value associated to the key, or the default value if not found

const char *CPLGetThreadLocalConfigOption(const char*, const char*)

  Same as CPLGetConfigOption() but only with options set with CPLSetThreadLocalConfigOption()

void CPLSetConfigOption(const char*, const char*)

  Set a configuration option for GDAL/OGR use.

  Those options are defined as a (key, value) couple. The value corresponding to a key can be got later with the CPLGetConfigOption() method.

  This mechanism is similar to environment variables, but options set with CPLSetConfigOption() overrides, for CPLGetConfigOption() point of view, values defined in the environment.

  If CPLSetConfigOption() is called several times with the same key, the value provided during the last call will be used.

  Options can also be passed on the command line of most GDAL utilities with the with ‘&#8212;config KEY VALUE’. For example, ogrinfo &#8212;config CPL_DEBUG ON ~/data/test/point.shp

  This function can also be used to clear a setting by passing NULL as the value (note: passing NULL will not unset an existing environment variable; it will just unset a value previously set by CPLSetConfigOption()).

  See also

  http://trac.osgeo.org/gdal/wiki/ConfigOptions

  Parameters

    - pszKey – the key of the option

    - pszValue – the value of the option, or NULL to clear a setting.

void CPLSetThreadLocalConfigOption(const char *pszKey, const char *pszValue)

  Set a configuration option for GDAL/OGR use.

  Those options are defined as a (key, value) couple. The value corresponding to a key can be got later with the CPLGetConfigOption() method.

  This function sets the configuration option that only applies in the current thread, as opposed to CPLSetConfigOption() which sets an option that applies on all threads. CPLSetThreadLocalConfigOption() will override the effect of CPLSetConfigOption) for the current thread.

  This function can also be used to clear a setting by passing NULL as the value (note: passing NULL will not unset an existing environment variable or a value set through CPLSetConfigOption(); it will just unset a value previously set by CPLSetThreadLocalConfigOption()).

  Parameters

    - pszKey – the key of the option

    - pszValue – the value of the option, or NULL to clear a setting.

char **CPLGetConfigOptions(void)

  Return the list of configuration options as KEY=VALUE pairs.

  The list is the one set through the CPLSetConfigOption() API.

  Options that through environment variables or with CPLSetThreadLocalConfigOption() will not be listed.

  Since

    GDAL 2.2

  Returns

    a copy of the list, to be freed with CSLDestroy().

void CPLSetConfigOptions(const char *const *papszConfigOptions)

  Replace the full list of configuration options with the passed list of KEY=VALUE pairs.

  This has the same effect of clearing the existing list, and setting individually each pair with the CPLSetConfigOption() API.

  This does not affect options set through environment variables or with CPLSetThreadLocalConfigOption().

  The passed list is copied by the function.

  Since

    GDAL 2.2

  Parameters

    papszConfigOptions – the new list (or NULL).

char **CPLGetThreadLocalConfigOptions(void)

  Return the list of thread local configuration options as KEY=VALUE pairs.

  Options that through environment variables or with CPLSetConfigOption() will not be listed.

  Since

    GDAL 2.2

  Returns

    a copy of the list, to be freed with CSLDestroy().

void CPLSetThreadLocalConfigOptions(const char *const *papszConfigOptions)

  Replace the full list of thread local configuration options with the passed list of KEY=VALUE pairs.

  This has the same effect of clearing the existing list, and setting individually each pair with the CPLSetThreadLocalConfigOption() API.

  This does not affect options set through environment variables or with CPLSetConfigOption().

  The passed list is copied by the function.

  Since

    GDAL 2.2

  Parameters

    papszConfigOptions – the new list (or NULL).

void CPLLoadConfigOptionsFromFile(const char *pszFilename, int bOverrideEnvVars)

  Load configuration from a given configuration file.

  A configuration file is a text file in a .ini style format, that lists configuration options and their values. Lines starting with # are comment lines.

  Example:

      [configoptions]
      # set BAR as the value of configuration option FOO
      FOO=BAR

  Starting with GDAL 3.5, a configuration file can also contain credentials (or more generally options related to a virtual file system) for a given path prefix, that can also be set with VSISetCredential(). Credentials should be put under a [credentials] section, and for each path prefix, under a relative subsection whose name starts with “[.” (e.g. “[.some_arbitrary_name]”), and whose first key is “path”.

  Example:

      [credentials]
      [.private_bucket]
      path=/vsis3/my_private_bucket
      AWS_SECRET_ACCESS_KEY=...
      AWS_ACCESS_KEY_ID=...
      [.sentinel_s2_l1c]
      path=/vsis3/sentinel-s2-l1c
      AWS_REQUEST_PAYER=requester

  This function is typically called by CPLLoadConfigOptionsFromPredefinedFiles()

  Since

    GDAL 3.3

  Parameters

    - pszFilename – File where to load configuration from.

    - bOverrideEnvVars – Whether configuration options from the configuration file should override environment variables.

void CPLLoadConfigOptionsFromPredefinedFiles(void)

  Load configuration from a set of predefined files.

  If the environment variable (or configuration option) GDAL_CONFIG_FILE is set, then CPLLoadConfigOptionsFromFile() will be called with the value of this configuration option as the file location.

  Otherwise, for Unix builds, CPLLoadConfigOptionsFromFile() will be called with ${sysconfdir}/gdal/gdalrc first where ${sysconfdir} evaluates to ${prefix}/etc, unless the &#8212;sysconfdir switch of configure has been invoked.

  Then CPLLoadConfigOptionsFromFile() will be called with /home/even/.gdal/gdalrc on Unix builds (potentially overriding what was loaded with the sysconfdir) or /.gdal/gdalrc on Windows builds.

  CPLLoadConfigOptionsFromFile() will be called with bOverrideEnvVars = false, that is the value of environment variables previously set will be used instead of the value set in the configuration files.

  This function is automatically called by GDALDriverManager() constructor

  Since

    GDAL 3.3

void *CPLMalloc(size_t)

  Safe version of malloc().

  This function is like the C library malloc(), but raises a CE_Fatal error with CPLError() if it fails to allocate the desired memory. It should be used for small memory allocations that are unlikely to fail and for which the application is unwilling to test for out of memory conditions. It uses VSIMalloc() to get the memory, so any hooking of VSIMalloc() will apply to CPLMalloc() as well. CPLFree() or VSIFree() can be used free memory allocated by CPLMalloc().

  Parameters

    nSize – size (in bytes) of memory block to allocate.

  Returns

    pointer to newly allocated memory, only NULL if nSize is zero.

void *CPLCalloc(size_t, size_t)

  Safe version of calloc().

  This function is like the C library calloc(), but raises a CE_Fatal error with CPLError() if it fails to allocate the desired memory. It should be used for small memory allocations that are unlikely to fail and for which the application is unwilling to test for out of memory conditions. It uses VSICalloc() to get the memory, so any hooking of VSICalloc() will apply to CPLCalloc() as well. CPLFree() or VSIFree() can be used free memory allocated by CPLCalloc().

  Parameters

    - nCount – number of objects to allocate.

    - nSize – size (in bytes) of object to allocate.

  Returns

    pointer to newly allocated memory, only NULL if nSize * nCount is NULL.

void *CPLRealloc(void*, size_t)

  Safe version of realloc().

  This function is like the C library realloc(), but raises a CE_Fatal error with CPLError() if it fails to allocate the desired memory. It should be used for small memory allocations that are unlikely to fail and for which the application is unwilling to test for out of memory conditions. It uses VSIRealloc() to get the memory, so any hooking of VSIRealloc() will apply to CPLRealloc() as well. CPLFree() or VSIFree() can be used free memory allocated by CPLRealloc().

  It is also safe to pass NULL in as the existing memory block for CPLRealloc(), in which case it uses VSIMalloc() to allocate a new block.

  Parameters

    - pData – existing memory block which should be copied to the new block.

    - nNewSize – new size (in bytes) of memory block to allocate.

  Returns

    pointer to allocated memory, only NULL if nNewSize is zero.

char *CPLStrdup(const char*)

  Safe version of strdup() function.

  This function is similar to the C library strdup() function, but if the memory allocation fails it will issue a CE_Fatal error with CPLError() instead of returning NULL. Memory allocated with CPLStrdup() can be freed with CPLFree() or VSIFree().

  It is also safe to pass a NULL string into CPLStrdup(). CPLStrdup() will allocate and return a zero length string (as opposed to a NULL string).

  Parameters

    pszString – input string to be duplicated. May be NULL.

  Returns

    pointer to a newly allocated copy of the string. Free with CPLFree() or VSIFree().

char *CPLStrlwr(char*)

  Convert each characters of the string to lower case.

  For example, “ABcdE” will be converted to “abcde”. This function is locale dependent.

  Parameters

    pszString – input string to be converted.

  Returns

    pointer to the same string, pszString.

char *CPLFGets(char*, int, FILE*)

  Reads in at most one less than nBufferSize characters from the fp stream and stores them into the buffer pointed to by pszBuffer.

  Reading stops after an EOF or a newline. If a newline is read, it is not stored into the buffer. A ‘\0’ is stored after the last character in the buffer. All three types of newline terminators recognized by the CPLFGets(): single ‘\r’ and ‘\n’ and ‘\r\n’ combination.

  Parameters

    - pszBuffer – pointer to the targeting character buffer.

    - nBufferSize – maximum size of the string to read (not including terminating ‘\0’).

    - fp – file pointer to read from.

  Returns

    pointer to the pszBuffer containing a string read from the file or NULL if the error or end of file was encountered.

const char *CPLReadLine(FILE*)

  Simplified line reading from text file.

  Read a line of text from the given file handle, taking care to capture CR and/or LF and strip off … equivalent of DKReadLine(). Pointer to an internal buffer is returned. The application shouldn’t free it, or depend on its value past the next call to CPLReadLine().

  Note that CPLReadLine() uses VSIFGets(), so any hooking of VSI file services should apply to CPLReadLine() as well.

  CPLReadLine() maintains an internal buffer, which will appear as a single block memory leak in some circumstances. CPLReadLine() may be called with a NULL FILE * at any time to free this working buffer.

  Parameters

    fp – file pointer opened with VSIFOpen().

  Returns

    pointer to an internal buffer containing a line of text read from the file or NULL if the end of file was encountered.

const char *CPLReadLineL(VSILFILE*)

  Simplified line reading from text file.

  Similar to CPLReadLine(), but reading from a large file API handle.

  Parameters

    fp – file pointer opened with VSIFOpenL().

  Returns

    pointer to an internal buffer containing a line of text read from the file or NULL if the end of file was encountered.

const char *CPLReadLine2L(VSILFILE*, int, CSLConstList)

  Simplified line reading from text file.

  Similar to CPLReadLine(), but reading from a large file API handle.

  Since

    GDAL 1.7.0

  Parameters

    - fp – file pointer opened with VSIFOpenL().

    - nMaxCars – maximum number of characters allowed, or -1 for no limit.

    - papszOptions – NULL-terminated array of options. Unused for now.

  Returns

    pointer to an internal buffer containing a line of text read from the file or NULL if the end of file was encountered or the maximum number of characters allowed reached.

const char *CPLReadLine3L(VSILFILE*, int, int*, CSLConstList)

  Simplified line reading from text file.

  Similar to CPLReadLine(), but reading from a large file API handle.

  Since

    GDAL 2.3.0

  Parameters

    - fp – file pointer opened with VSIFOpenL().

    - nMaxCars – maximum number of characters allowed, or -1 for no limit.

    - papszOptions – NULL-terminated array of options. Unused for now.

    - pnBufLength – [out] size of output string (must be non-NULL)

  Returns

    pointer to an internal buffer containing a line of text read from the file or NULL if the end of file was encountered or the maximum number of characters allowed reached.

double CPLAtof(const char*)

  Converts ASCII string to floating point number.

  This function converts the initial portion of the string pointed to by nptr to double floating point representation. The behavior is the same as

  CPLStrtod(nptr, (char **)NULL);

  This function does the same as standard atof(3), but does not take locale in account. That means, the decimal delimiter is always ‘.’ (decimal point). Use CPLAtofDelim() function if you want to specify custom delimiter.

  IMPORTANT NOTE:

  Existence of this function does not mean you should always use it. Sometimes you should use standard locale aware atof(3) and its family. When you need to process the user’s input (for example, command line parameters) use atof(3), because the user works in a localized environment and the user’s input will be done according to the locale set. In particular that means we should not make assumptions about character used as decimal delimiter, it can be either “.” or “,”.

  But when you are parsing some ASCII file in predefined format, you most likely need CPLAtof(), because such files distributed across the systems with different locales and floating point representation should be considered as a part of file format. If the format uses “.” as a delimiter the same character must be used when parsing number regardless of actual locale setting.

  Parameters

    nptr – Pointer to string to convert.

  Returns

    Converted value, if any.

double CPLAtofDelim(const char*, char)

  Converts ASCII string to floating point number.

  This function converts the initial portion of the string pointed to by nptr to double floating point representation. The behavior is the same as

  CPLStrtodDelim(nptr, (char **)NULL, point);

  This function does the same as standard atof(3), but does not take locale in account. Instead of locale defined decimal delimiter you can specify your own one. Also see notes for CPLAtof() function.

  Parameters

    - nptr – Pointer to string to convert.

    - point – Decimal delimiter.

  Returns

    Converted value, if any.

double CPLStrtod(const char*, char**)

  Converts ASCII string to floating point number.

  This function converts the initial portion of the string pointed to by nptr to double floating point representation. This function does the same as standard strtod(3), but does not take locale in account. That means, the decimal delimiter is always ‘.’ (decimal point). Use CPLStrtodDelim() function if you want to specify custom delimiter. Also see notes for CPLAtof() function.

  Parameters

    - nptr – Pointer to string to convert.

    - endptr – If is not NULL, a pointer to the character after the last character used in the conversion is stored in the location referenced by endptr.

  Returns

    Converted value, if any.

double CPLStrtodDelim(const char*, char**, char)

  Converts ASCII string to floating point number using specified delimiter.

  This function converts the initial portion of the string pointed to by nptr to double floating point representation. This function does the same as standard strtod(3), but does not take locale in account. Instead of locale defined decimal delimiter you can specify your own one. Also see notes for CPLAtof() function.

  Parameters

    - nptr – Pointer to string to convert.

    - endptr – If is not NULL, a pointer to the character after the last character used in the conversion is stored in the location referenced by endptr.

    - point – Decimal delimiter.

  Returns

    Converted value, if any.

float CPLStrtof(const char*, char**)

  Converts ASCII string to floating point number.

  This function converts the initial portion of the string pointed to by nptr to single floating point representation. This function does the same as standard strtof(3), but does not take locale in account. That means, the decimal delimiter is always ‘.’ (decimal point). Use CPLStrtofDelim() function if you want to specify custom delimiter. Also see notes for CPLAtof() function.

  Parameters

    - nptr – Pointer to string to convert.

    - endptr – If is not NULL, a pointer to the character after the last character used in the conversion is stored in the location referenced by endptr.

  Returns

    Converted value, if any.

float CPLStrtofDelim(const char*, char**, char)

  Converts ASCII string to floating point number using specified delimiter.

  This function converts the initial portion of the string pointed to by nptr to single floating point representation. This function does the same as standard strtof(3), but does not take locale in account. Instead of locale defined decimal delimiter you can specify your own one. Also see notes for CPLAtof() function.

  Parameters

    - nptr – Pointer to string to convert.

    - endptr – If is not NULL, a pointer to the character after the last character used in the conversion is stored in the location referenced by endptr.

    - point – Decimal delimiter.

  Returns

    Converted value, if any.

double CPLAtofM(const char*)

  Converts ASCII string to floating point number using any numeric locale.

  This function converts the initial portion of the string pointed to by nptr to double floating point representation. This function does the same as standard atof(), but it allows a variety of locale representations. That is it supports numeric values with either a comma or a period for the decimal delimiter.

  PS. The M stands for Multi-lingual.

  Parameters

    nptr – The string to convert.

  Returns

    Converted value, if any. Zero on failure.

char *CPLScanString(const char*, int, int, int)

  Scan up to a maximum number of characters from a given string, allocate a buffer for a new string and fill it with scanned characters.

  Parameters

    - pszString – String containing characters to be scanned. It may be terminated with a null character.

    - nMaxLength – The maximum number of character to read. Less characters will be read if a null character is encountered.

    - bTrimSpaces – If TRUE, trim ending spaces from the input string. Character considered as empty using isspace(3) function.

    - bNormalize – If TRUE, replace ‘:’ symbol with the ‘_’. It is needed if resulting string will be used in CPL dictionaries.

  Returns

    Pointer to the resulting string buffer. Caller responsible to free this buffer with CPLFree().

double CPLScanDouble(const char*, int)

  Extract double from string.

  Scan up to a maximum number of characters from a string and convert the result to a double. This function uses CPLAtof() to convert string to double value, so it uses a comma as a decimal delimiter.

  Parameters

    - pszString – String containing characters to be scanned. It may be terminated with a null character.

    - nMaxLength – The maximum number of character to consider as part of the number. Less characters will be considered if a null character is encountered.

  Returns

    Double value, converted from its ASCII form.

long CPLScanLong(const char*, int)

  Scan up to a maximum number of characters from a string and convert the result to a long.

  Parameters

    - pszString – String containing characters to be scanned. It may be terminated with a null character.

    - nMaxLength – The maximum number of character to consider as part of the number. Less characters will be considered if a null character is encountered.

  Returns

    Long value, converted from its ASCII form.

unsigned long CPLScanULong(const char*, int)

  Scan up to a maximum number of characters from a string and convert the result to a unsigned long.

  Parameters

    - pszString – String containing characters to be scanned. It may be terminated with a null character.

    - nMaxLength – The maximum number of character to consider as part of the number. Less characters will be considered if a null character is encountered.

  Returns

    Unsigned long value, converted from its ASCII form.

GUIntBig CPLScanUIntBig(const char*, int)

  Extract big integer from string.

  Scan up to a maximum number of characters from a string and convert the result to a GUIntBig.

  Parameters

    - pszString – String containing characters to be scanned. It may be terminated with a null character.

    - nMaxLength – The maximum number of character to consider as part of the number. Less characters will be considered if a null character is encountered.

  Returns

    GUIntBig value, converted from its ASCII form.

GIntBig CPLAtoGIntBig(const char *pszString)

  Convert a string to a 64 bit signed integer.

  Since

    GDAL 2.0

  Parameters

    pszString – String containing 64 bit signed integer.

  Returns

    64 bit signed integer.

GIntBig CPLAtoGIntBigEx(const char *pszString, int bWarn, int *pbOverflow)

  Convert a string to a 64 bit signed integer.

  Since

    GDAL 2.0

  Parameters

    - pszString – String containing 64 bit signed integer.

    - bWarn – Issue a warning if an overflow occurs during conversion

    - pbOverflow – Pointer to an integer to store if an overflow occurred, or NULL

  Returns

    64 bit signed integer.

void *CPLScanPointer(const char*, int)

  Extract pointer from string.

  Scan up to a maximum number of characters from a string and convert the result to a pointer.

  Parameters

    - pszString – String containing characters to be scanned. It may be terminated with a null character.

    - nMaxLength – The maximum number of character to consider as part of the number. Less characters will be considered if a null character is encountered.

  Returns

    pointer value, converted from its ASCII form.

int CPLPrintString(char*, const char*, int)

  Copy the string pointed to by pszSrc, NOT including the terminating \0 character, to the array pointed to by pszDest.

  Parameters

    - pszDest – Pointer to the destination string buffer. Should be large enough to hold the resulting string.

    - pszSrc – Pointer to the source buffer.

    - nMaxLen – Maximum length of the resulting string. If string length is greater than nMaxLen, it will be truncated.

  Returns

    Number of characters printed.

int CPLPrintStringFill(char*, const char*, int)

  Copy the string pointed to by pszSrc, NOT including the terminating \0 character, to the array pointed to by pszDest.

  Remainder of the destination string will be filled with space characters. This is only difference from the PrintString().

  Parameters

    - pszDest – Pointer to the destination string buffer. Should be large enough to hold the resulting string.

    - pszSrc – Pointer to the source buffer.

    - nMaxLen – Maximum length of the resulting string. If string length is greater than nMaxLen, it will be truncated.

  Returns

    Number of characters printed.

int CPLPrintInt32(char*, GInt32, int)

  Print GInt32 value into specified string buffer.

  This string will not be NULL-terminated.

  Parameters

    - pszBuffer – Pointer to the destination string buffer. Should be large enough to hold the resulting string. Note, that the string will not be NULL-terminated, so user should do this himself, if needed.

    - iValue – Numerical value to print.

    - nMaxLen – Maximum length of the resulting string. If string length is greater than nMaxLen, it will be truncated.

  Returns

    Number of characters printed.

int CPLPrintUIntBig(char*, GUIntBig, int)

  Print GUIntBig value into specified string buffer.

  This string will not be NULL-terminated.

  Parameters

    - pszBuffer – Pointer to the destination string buffer. Should be large enough to hold the resulting string. Note, that the string will not be NULL-terminated, so user should do this himself, if needed.

    - iValue – Numerical value to print.

    - nMaxLen – Maximum length of the resulting string. If string length is greater than nMaxLen, it will be truncated.

  Returns

    Number of characters printed.

int CPLPrintDouble(char*, const char*, double, const char*)

  Print double value into specified string buffer.

  Exponential character flag ‘E’ (or ‘e’) will be replaced with ‘D’, as in Fortran. Resulting string will not to be NULL-terminated.

  Parameters

    - pszBuffer – Pointer to the destination string buffer. Should be large enough to hold the resulting string. Note, that the string will not be NULL-terminated, so user should do this himself, if needed.

    - pszFormat – Format specifier (for example, “%16.9E”).

    - dfValue – Numerical value to print.

    - pszLocale – Unused.

  Returns

    Number of characters printed.

int CPLPrintTime(char*, int, const char*, const struct tm*, const char*)

  Print specified time value accordingly to the format options and specified locale name.

  This function does following:

  - if locale parameter is not NULL, the current locale setting will be stored and replaced with the specified one;

  - format time value with the strftime(3) function;

  - restore back current locale, if was saved.

  Parameters

    - pszBuffer – Pointer to the destination string buffer. Should be large enough to hold the resulting string. Note, that the string will not be NULL-terminated, so user should do this himself, if needed.

    - nMaxLen – Maximum length of the resulting string. If string length is greater than nMaxLen, it will be truncated.

    - pszFormat – Controls the output format. Options are the same as for strftime(3) function.

    - poBrokenTime – Pointer to the broken-down time structure. May be requested with the VSIGMTime() and VSILocalTime() functions.

    - pszLocale – Pointer to a character string containing locale name (“C”, “POSIX”, “us_US”, “ru_RU.KOI8-R” etc.). If NULL we will not manipulate with locale settings and current process locale will be used for printing. Be aware that it may be unsuitable to use current locale for printing time, because all names will be printed in your native language, as well as time format settings also may be adjusted differently from the C/POSIX defaults. To solve these problems this option was introduced.

  Returns

    Number of characters printed.

int CPLPrintPointer(char*, void*, int)

  Print pointer value into specified string buffer.

  This string will not be NULL-terminated.

  Parameters

    - pszBuffer – Pointer to the destination string buffer. Should be large enough to hold the resulting string. Note, that the string will not be NULL-terminated, so user should do this himself, if needed.

    - pValue – Pointer to ASCII encode.

    - nMaxLen – Maximum length of the resulting string. If string length is greater than nMaxLen, it will be truncated.

  Returns

    Number of characters printed.

void *CPLGetSymbol(const char*, const char*)

  Fetch a function pointer from a shared library / DLL.

  This function is meant to abstract access to shared libraries and DLLs and performs functions similar to dlopen()/dlsym() on Unix and LoadLibrary() / GetProcAddress() on Windows.

  If no support for loading entry points from a shared library is available this function will always return NULL. Rules on when this function issues a CPLError() or not are not currently well defined, and will have to be resolved in the future.

  Currently CPLGetSymbol() doesn’t try to:

  - prevent the reference count on the library from going up for every request, or given any opportunity to unload the library.

  - Attempt to look for the library in non-standard locations.

  - Attempt to try variations on the symbol name, like pre-pending or post-pending an underscore.

  Some of these issues may be worked on in the future.

  Parameters

    - pszLibrary – the name of the shared library or DLL containing the function. May contain path to file. If not system supplies search paths will be used.

    - pszSymbolName – the name of the function to fetch a pointer to.

  Returns

    A pointer to the function if found, or NULL if the function isn’t found, or the shared library can’t be loaded.

int CPLGetExecPath(char *pszPathBuf, int nMaxLength)

  Fetch path of executable.

  The path to the executable currently running is returned. This path includes the name of the executable. Currently this only works on win32 and linux platforms. The returned path is UTF-8 encoded.

  Parameters

    - pszPathBuf – the buffer into which the path is placed.

    - nMaxLength – the buffer size, MAX_PATH+1 is suggested.

  Returns

    FALSE on failure or TRUE on success.

const char *CPLGetPath(const char*)

  Extract directory path portion of filename.

  Returns a string containing the directory path portion of the passed filename. If there is no path in the passed filename an empty string will be returned (not NULL).

  Parameters

    pszFilename – the filename potentially including a path.

  Returns

    Path in an internal string which must not be freed. The string may be destroyed by the next CPL filename handling call. The returned will generally not contain a trailing path separator.

const char *CPLGetDirname(const char*)

  Extract directory path portion of filename.

  Returns a string containing the directory path portion of the passed filename. If there is no path in the passed filename the dot will be returned. It is the only difference from CPLGetPath().

  Parameters

    pszFilename – the filename potentially including a path.

  Returns

    Path in an internal string which must not be freed. The string may be destroyed by the next CPL filename handling call. The returned will generally not contain a trailing path separator.

const char *CPLGetFilename(const char*)

  Extract non-directory portion of filename.

  Returns a string containing the bare filename portion of the passed filename. If there is no filename (passed value ends in trailing directory separator) an empty string is returned.

  Parameters

    pszFullFilename – the full filename potentially including a path.

  Returns

    just the non-directory portion of the path (points back into original string).

const char *CPLGetBasename(const char*)

  Extract basename (non-directory, non-extension) portion of filename.

  Returns a string containing the file basename portion of the passed name. If there is no basename (passed value ends in trailing directory separator, or filename starts with a dot) an empty string is returned.

  Parameters

    pszFullFilename – the full filename potentially including a path.

  Returns

    just the non-directory, non-extension portion of the path in an internal string which must not be freed. The string may be destroyed by the next CPL filename handling call.

const char *CPLGetExtension(const char*)

  Extract filename extension from full filename.

  Returns a string containing the extension portion of the passed name. If there is no extension (the filename has no dot) an empty string is returned. The returned extension will not include the period.

  Parameters

    pszFullFilename – the full filename potentially including a path.

  Returns

    just the extension portion of the path in an internal string which must not be freed. The string may be destroyed by the next CPL filename handling call.

char *CPLGetCurrentDir(void)

  Get the current working directory name.

  Returns

    a pointer to buffer, containing current working directory path or NULL in case of error. User is responsible to free that buffer after usage with CPLFree() function. If HAVE_GETCWD macro is not defined, the function returns NULL.

const char *CPLFormFilename(const char *pszPath, const char *pszBasename, const char *pszExtension)

  Build a full file path from a passed path, file basename and extension.

  The path, and extension are optional. The basename may in fact contain an extension if desired.

  Parameters

    - pszPath – directory path to the directory containing the file. This may be relative or absolute, and may have a trailing path separator or not. May be NULL.

    - pszBasename – file basename. May optionally have path and/or extension. Must NOT be NULL.

    - pszExtension – file extension, optionally including the period. May be NULL.

  Returns

    a fully formed filename in an internal static string. Do not modify or free the returned string. The string may be destroyed by the next CPL call.

const char *CPLFormCIFilename(const char *pszPath, const char *pszBasename, const char *pszExtension)

  Case insensitive file searching, returning full path.

  This function tries to return the path to a file regardless of whether the file exactly matches the basename, and extension case, or is all upper case, or all lower case. The path is treated as case sensitive. This function is equivalent to CPLFormFilename() on case insensitive file systems (like Windows).

  Parameters

    - pszPath – directory path to the directory containing the file. This may be relative or absolute, and may have a trailing path separator or not. May be NULL.

    - pszBasename – file basename. May optionally have path and/or extension. May not be NULL.

    - pszExtension – file extension, optionally including the period. May be NULL.

  Returns

    a fully formed filename in an internal static string. Do not modify or free the returned string. The string may be destroyed by the next CPL call.

const char *CPLResetExtension(const char*, const char*)

  Replace the extension with the provided one.

  Parameters

    - pszPath – the input path, this string is not altered.

    - pszExt – the new extension to apply to the given path.

  Returns

    an altered filename with the new extension. Do not modify or free the returned string. The string may be destroyed by the next CPL call.

const char *CPLProjectRelativeFilename(const char *pszProjectDir, const char *pszSecondaryFilename)

  Find a file relative to a project file.

  Given the path to a “project” directory, and a path to a secondary file referenced from that project, build a path to the secondary file that the current application can use. If the secondary path is already absolute, rather than relative, then it will be returned unaltered.

  Examples:

  Parameters

    - pszProjectDir – the directory relative to which the secondary files path should be interpreted.

    - pszSecondaryFilename – the filename (potentially with path) that is to be interpreted relative to the project directory.

  Returns

    a composed path to the secondary file. The returned string is internal and should not be altered, freed, or depending on past the next CPL call.

int CPLIsFilenameRelative(const char *pszFilename)

  Is filename relative or absolute?

  The test is filesystem convention agnostic. That is it will test for Unix style and windows style path conventions regardless of the actual system in use.

  Parameters

    pszFilename – the filename with path to test.

  Returns

    TRUE if the filename is relative or FALSE if it is absolute.

const char *CPLExtractRelativePath(const char*, const char*, int*)

  Get relative path from directory to target file.

  Computes a relative path for pszTarget relative to pszBaseDir. Currently this only works if they share a common base path. The returned path is normally into the pszTarget string. It should only be considered valid as long as pszTarget is valid or till the next call to this function, whichever comes first.

  Parameters

    - pszBaseDir – the name of the directory relative to which the path should be computed. pszBaseDir may be NULL in which case the original target is returned without relativizing.

    - pszTarget – the filename to be changed to be relative to pszBaseDir.

    - pbGotRelative – Pointer to location in which a flag is placed indicating that the returned path is relative to the basename (TRUE) or not (FALSE). This pointer may be NULL if flag is not desired.

  Returns

    an adjusted path or the original if it could not be made relative to the pszBaseFile’s path.

const char *CPLCleanTrailingSlash(const char*)

  Remove trailing forward/backward slash from the path for UNIX/Windows resp.

  Returns a string containing the portion of the passed path string with trailing slash removed. If there is no path in the passed filename an empty string will be returned (not NULL).

  Parameters

    pszPath – the path to be cleaned up

  Returns

    Path in an internal string which must not be freed. The string may be destroyed by the next CPL filename handling call.

char **CPLCorrespondingPaths(const char *pszOldFilename, const char *pszNewFilename, char **papszFileList)

  Identify corresponding paths.

  Given a prototype old and new filename this function will attempt to determine corresponding names for a set of other old filenames that will rename them in a similar manner. This correspondence assumes there are two possibly kinds of renaming going on. A change of path, and a change of filename stem.

  If a consistent renaming cannot be established for all the files this function will return indicating an error.

  The returned file list becomes owned by the caller and should be destroyed with CSLDestroy().

  Parameters

    - pszOldFilename – path to old prototype file.

    - pszNewFilename – path to new prototype file.

    - papszFileList – list of other files associated with pszOldFilename to rename similarly.

  Returns

    a list of files corresponding to papszFileList but renamed to correspond to pszNewFilename.

int CPLCheckForFile(char *pszFilename, char **papszSiblingList)

  Check for file existence.

  The function checks if a named file exists in the filesystem, hopefully in an efficient fashion if a sibling file list is available. It exists primarily to do faster file checking for functions like GDAL open methods that get a list of files from the target directory.

  If the sibling file list exists (is not NULL) it is assumed to be a list of files in the same directory as the target file, and it will be checked (case insensitively) for a match. If a match is found, pszFilename is updated with the correct case and TRUE is returned.

  If papszSiblingFiles is NULL, a VSIStatL() is used to test for the files existence, and no case insensitive testing is done.

  Parameters

    - pszFilename – name of file to check for - filename case updated in some cases.

    - papszSiblingFiles – a list of files in the same directory as pszFilename if available, or NULL. This list should have no path components.

  Returns

    TRUE if a match is found, or FALSE if not.

const char *CPLGenerateTempFilename(const char *pszStem)

  Generate temporary file name.

  Returns a filename that may be used for a temporary file. The location of the file tries to follow operating system semantics but may be forced via the CPL_TMPDIR configuration option.

  Parameters

    pszStem – if non-NULL this will be part of the filename.

  Returns

    a filename which is valid till the next CPL call in this thread.

const char *CPLExpandTilde(const char *pszFilename)

  Expands ~/ at start of filename.

  Assumes that the HOME configuration option is defined.

  Since

    GDAL 2.2

  Parameters

    pszFilename – filename potentially starting with ~/

  Returns

    an expanded filename.

const char *CPLGetHomeDir(void)

  Return the path to the home directory.

  That is the value of the USERPROFILE environment variable on Windows, or HOME on other platforms.

  Since

    GDAL 2.3

  Returns

    the home directory, or NULL.

const char *CPLLaunderForFilename(const char *pszName, const char *pszOutputPath)

  Launder a string to be compatible of a filename.

  Since

    GDAL 3.1

  Parameters

    - pszName – The input string to launder.

    - pszOutputPath – The directory where the file would be created. Unused for now. May be NULL.

  Returns

    the laundered name.

const char *CPLFindFile(const char *pszClass, const char *pszBasename)

  CPLFindFile.

const char *CPLDefaultFindFile(const char *pszClass, const char *pszBasename)

  CPLDefaultFindFile.

void CPLPushFileFinder(CPLFileFinder pfnFinder)

  CPLPushFileFinder.

CPLFileFinder CPLPopFileFinder(void)

  CPLPopFileFinder.

void CPLPushFinderLocation(const char*)

  CPLPushFinderLocation.

void CPLPopFinderLocation(void)

  CPLPopFinderLocation.

void CPLFinderClean(void)

  CPLFinderClean.

int CPLStat(const char*, VSIStatBuf*)

  Same as VSIStat() except it works on “C:” as if it were “C:".

FILE *CPLOpenShared(const char*, const char*, int)

  Open a shared file handle.

  Some operating systems have limits on the number of file handles that can be open at one time. This function attempts to maintain a registry of already open file handles, and reuse existing ones if the same file is requested by another part of the application.

  Note that access is only shared for access types “r”, “rb”, “r+” and “rb+”. All others will just result in direct VSIOpen() calls. Keep in mind that a file is only reused if the file name is exactly the same. Different names referring to the same file will result in different handles.

  The VSIFOpen() or VSIFOpenL() function is used to actually open the file, when an existing file handle can’t be shared.

  Parameters

    - pszFilename – the name of the file to open.

    - pszAccess – the normal fopen()/VSIFOpen() style access string.

    - bLargeIn – If TRUE VSIFOpenL() (for large files) will be used instead of VSIFOpen().

  Returns

    a file handle or NULL if opening fails.

void CPLCloseShared(FILE*)

  Close shared file.

  Dereferences the indicated file handle, and closes it if the reference count has dropped to zero. A CPLError() is issued if the file is not in the shared file list.

  Parameters

    fp – file handle from CPLOpenShared() to deaccess.

CPLSharedFileInfo *CPLGetSharedList(int*)

  Fetch list of open shared files.

  Parameters

    pnCount – place to put the count of entries.

  Returns

    the pointer to the first in the array of shared file info structures.

void CPLDumpSharedList(FILE*)

  Report open shared files.

  Dumps all open shared files to the indicated file handle. If the file handle is NULL information is sent via the CPLDebug() call.

  Parameters

    fp – File handle to write to.

double CPLDMSToDec(const char *is)

  CPLDMSToDec.

const char *CPLDecToDMS(double dfAngle, const char *pszAxis, int nPrecision)

  Translate a decimal degrees value to a DMS string with hemisphere.

double CPLPackedDMSToDec(double)

  Convert a packed DMS value (DDDMMMSSS.SS) into decimal degrees.

  This function converts a packed DMS angle to seconds. The standard packed DMS format is:

  degrees * 1000000 + minutes * 1000 + seconds

  Example: angle = 120025045.25 yields deg = 120 min = 25 sec = 45.25

  The algorithm used for the conversion is as follows:

  1. The absolute value of the angle is used.

  2. The degrees are separated out: deg = angle/1000000 (fractional portion truncated)

  3. The minutes are separated out: min = (angle - deg * 1000000) / 1000 (fractional portion truncated)

  4. The seconds are then computed: sec = angle - deg * 1000000 - min * 1000

  5. The total angle in seconds is computed: sec = deg * 3600.0 + min * 60.0 + sec

  6. The sign of sec is set to that of the input angle.

  Packed DMS values used by the USGS GCTP package and probably by other software.

  NOTE: This code does not validate input value. If you give the wrong value, you will get the wrong result.

  Parameters

    dfPacked – Angle in packed DMS format.

  Returns

    Angle in decimal degrees.

double CPLDecToPackedDMS(double dfDec)

  Convert decimal degrees into packed DMS value (DDDMMMSSS.SS).

  This function converts a value, specified in decimal degrees into packed DMS angle. The standard packed DMS format is:

  degrees * 1000000 + minutes * 1000 + seconds

  See also CPLPackedDMSToDec().

  Parameters

    dfDec – Angle in decimal degrees.

  Returns

    Angle in packed DMS format.

void CPLStringToComplex(const char *pszString, double *pdfReal, double *pdfImag)

  Fetch the real and imaginary part of a serialized complex number.

int CPLUnlinkTree(const char*)

  Recursively unlink a directory.

  Returns

    0 on successful completion, -1 if function fails.

int CPLCopyFile(const char *pszNewPath, const char *pszOldPath)

  Copy a file.

int CPLCopyTree(const char *pszNewPath, const char *pszOldPath)

  Recursively copy a tree.

int CPLMoveFile(const char *pszNewPath, const char *pszOldPath)

  Move a file.

int CPLSymlink(const char *pszOldPath, const char *pszNewPath, CSLConstList papszOptions)

  Create a symbolic link.

void *CPLCreateZip(const char *pszZipFilename, char **papszOptions)

  Create ZIP file.

CPLErr CPLCreateFileInZip(void *hZip, const char *pszFilename, char **papszOptions)

  Create a file in a ZIP file.

CPLErr CPLWriteFileInZip(void *hZip, const void *pBuffer, int nBufferSize)

  Write in current file inside a ZIP file.

CPLErr CPLCloseFileInZip(void *hZip)

  Close current file inside ZIP file.

CPLErr CPLCloseZip(void *hZip)

  Close ZIP file.

void *CPLZLibDeflate(const void *ptr, size_t nBytes, int nLevel, void *outptr, size_t nOutAvailableBytes, size_t *pnOutBytes)

  Compress a buffer with ZLib compression.

  Since

    GDAL 1.10.0

  Parameters

    - ptr – input buffer.

    - nBytes – size of input buffer in bytes.

    - nLevel – ZLib compression level (-1 for default).

    - outptr – output buffer, or NULL to let the function allocate it.

    - nOutAvailableBytes – size of output buffer if provided, or ignored.

    - pnOutBytes – pointer to a size_t, where to store the size of the output buffer.

  Returns

    the output buffer (to be freed with VSIFree() if not provided) or NULL in case of error.

void *CPLZLibInflate(const void *ptr, size_t nBytes, void *outptr, size_t nOutAvailableBytes, size_t *pnOutBytes)

  Uncompress a buffer compressed with ZLib compression.

  Since

    GDAL 1.10.0

  Parameters

    - ptr – input buffer.

    - nBytes – size of input buffer in bytes.

    - outptr – output buffer, or NULL to let the function allocate it.

    - nOutAvailableBytes – size of output buffer if provided, or ignored.

    - pnOutBytes – pointer to a size_t, where to store the size of the output buffer.

  Returns

    the output buffer (to be freed with VSIFree() if not provided) or NULL in case of error.

int CPLValidateXML(const char *pszXMLFilename, const char *pszXSDFilename, CSLConstList papszOptions)

  Validate a XML file against a XML schema.

  Since

    GDAL 1.10.0

  Parameters

    - pszXMLFilename – the filename of the XML file to validate.

    - pszXSDFilename – the filename of the XSD schema.

    - papszOptions – unused for now. Set to NULL.

  Returns

    TRUE if the XML file validates against the XML schema.

char *CPLsetlocale(int category, const char *locale)

  Prevents parallel executions of setlocale().

  Calling setlocale() concurrently from two or more threads is a potential data race. A mutex is used to provide a critical region so that only one thread at a time can be executing setlocale().

  The return should not be freed, and copied quickly as it may be invalidated by a following next call to CPLsetlocale().

  Parameters

    - category – See your compiler’s documentation on setlocale.

    - locale – See your compiler’s documentation on setlocale.

  Returns

    See your compiler’s documentation on setlocale.

int CPLIsPowerOfTwo(unsigned int i)

  CPLIsPowerOfTwo()

  Parameters

    i – - tested number

  Returns

    TRUE if i is power of two otherwise return FALSE

struct CPLSharedFileInfo
  #include <cpl_conv.h>

  Information on a shared file.

  Public Members

  FILE *fp

    File pointer.

  int nRefCount

    Reference counter.

  int bLarge

    Whether fp must be interpreted as VSIFILE*.

  char *pszFilename

    Filename.

  char *pszAccess

    Access mode.

namespace cpl

  Functions

  template<typename To, typename From>
  inline To down_cast(From *f)

    Use cpl::down_cast<Derived*>(pointer_to_base) as equivalent of static_cast<Derived*>(pointer_to_base) with safe checking in debug mode.

    Only works if no virtual inheritance is involved.

    Parameters

      f – pointer to a base class

    Returns

      pointer to a derived class

## cpl_csv.h

Enums

enum CSVCompareCriteria

  Values:

  enumerator CC_ExactString
  enumerator CC_ApproxString
  enumerator CC_Integer

Functions

const char *CSVFilename(const char*)

char CSVDetectSeperator(const char *pszLine)

  Detect which field separator is used.

  Currently, it can detect comma, semicolon, space or tabulation. In case of ambiguity or no separator found, comma will be considered as the separator.

  Returns

    ‘,’, ‘;’, ‘ ‘ or tabulation character.

char **CSVReadParseLine(FILE *fp)

char **CSVReadParseLine2(FILE *fp, char chDelimiter)

char **CSVReadParseLineL(VSILFILE *fp)

char **CSVReadParseLine2L(VSILFILE *fp, char chDelimiter)

char **CSVReadParseLine3L(VSILFILE *fp, size_t nMaxLineSize, const char *pszDelimiter, bool bHonourStrings, bool bKeepLeadingAndClosingQuotes, bool bMergeDelimiter, bool bSkipBOM)

  Read one line, and return split into fields.

  The return result is a stringlist, in the sense of the CSL functions.

  Parameters

    - fp – File handle. Must not be NULL

    - nMaxLineSize – Maximum line size, or 0 for unlimited.

    - pszDelimiter – Delimiter sequence for readers (can be multiple bytes)

    - bHonourStrings – Should be true, unless double quotes should not be considered when separating fields.

    - bKeepLeadingAndClosingQuotes – Whether the leading and closing double quote characters should be kept.

    - bMergeDelimiter – Whether consecutive delimiters should be considered as a single one. Should generally be set to false.

    - bSkipBOM – Whether leading UTF-8 BOM should be skipped.

char **CSVScanLines(FILE*, int, const char*, CSVCompareCriteria)

char **CSVScanLinesL(VSILFILE*, int, const char*, CSVCompareCriteria)

char **CSVScanFile(const char*, int, const char*, CSVCompareCriteria)

char **CSVScanFileByName(const char*, const char*, const char*, CSVCompareCriteria)

void CSVRewind(const char*)

char **CSVGetNextLine(const char*)

int CSVGetFieldId(FILE*, const char*)

int CSVGetFieldIdL(VSILFILE*, const char*)

int CSVGetFileFieldId(const char*, const char*)

void CSVDeaccess(const char*)

const char *CSVGetField(const char*, const char*, const char*, CSVCompareCriteria, const char*)

## cpl_compressor.h

API for compressors and decompressors of binary buffers.

Typedefs

typedef bool (*CPLCompressionFunc)(const void *input_data, size_t input_size, void **output_data, size_t *output_size, CSLConstList options, void *compressor_user_data)

  Callback of a compressor/decompressor.

  For a compressor, input is uncompressed data, and output compressed data. For a decompressor, input is compressed data, and output uncompressed data.

  Valid situations for output_data and output_size are:

  - output_data != NULL and *output_data != NULL and output_size != NULL and *output_size != 0. The caller provides the output buffer in *output_data and its size in *output_size. In case of successful operation, *output_size will be updated to the actual size. This mode is the one that is always guaranteed to be implemented efficiently. In case of failure due to insufficient space, it will be updated to the size needed (if known), or 0 (if unknown)

  - output_data == NULL and output_size != NULL. *output_size will be updated with the minimum size the output buffer should be (if known), or 0 (if unknown).

  - output_data != NULL and *output_data == NULL and output_size != NULL. *output_data will be allocated using VSIMalloc(), and should be freed by the caller with VSIFree(). *output_size will be updated to the size of the output buffer.

  Parameters

    - input_data – Input data. Should not be NULL.

    - input_size – Size of input data, in bytes.

    - output_data – Pointer to output data.

    - output_size – Pointer to output size.

    - options – NULL terminated list of options. Or NULL.

    - compressor_user_data – User data provided at registration time.

  Returns

    true in case of success.

Enums

enum CPLCompressorType

  Type of compressor.

  Values:

  enumerator CCT_COMPRESSOR

    Compressor.

  enumerator CCT_FILTER

    Filter.

Functions

bool CPLRegisterCompressor(const CPLCompressor *compressor)

  Register a new compressor.

  The provided structure is copied. Its pfnFunc and user_data members should remain valid beyond this call however.

  Since

    GDAL 3.4

  Parameters

    compressor – Compressor structure. Should not be null.

  Returns

    true if successful

bool CPLRegisterDecompressor(const CPLCompressor *decompressor)

  Register a new decompressor.

  The provided structure is copied. Its pfnFunc and user_data members should remain valid beyond this call however.

  Since

    GDAL 3.4

  Parameters

    decompressor – Compressor structure. Should not be null.

  Returns

    true if successful

char **CPLGetCompressors(void)

  Return the list of registered compressors.

  Since

    GDAL 3.4

  Returns

    list of strings. Should be freed with CSLDestroy()

char **CPLGetDecompressors(void)

  Return the list of registered decompressors.

  Since

    GDAL 3.4

  Returns

    list of strings. Should be freed with CSLDestroy()

const CPLCompressor *CPLGetCompressor(const char *pszId)

  Return a compressor.

  Since

    GDAL 3.4

  Parameters

    pszId – Compressor id. Should NOT be NULL.

  Returns

    compressor structure, or NULL.

const CPLCompressor *CPLGetDecompressor(const char *pszId)

  Return a decompressor.

  Since

    GDAL 3.4

  Parameters

    pszId – Decompressor id. Should NOT be NULL.

  Returns

    compressor structure, or NULL.

struct CPLCompressor
  #include <cpl_compressor.h>

  Compressor/decompressor description.

  Public Members

  int nStructVersion

    Structure version.

    Should be set to 1

  const char *pszId

    Id of the compressor/decompressor.

    Should NOT be NULL.

  CPLCompressorType eType

    Compressor type.

  CSLConstList papszMetadata

    Metadata, as a NULL terminated list of strings.

    Or NULL. The OPTIONS metadata key is reserved for compressors/decompressors to provide the available options as a XML string of the form <Options> <Option name=’’ type=’’ description=’’ default=’’/> </Options>

  CPLCompressionFunc pfnFunc

    Compressor/decompressor callback.

    Should NOT be NULL.

  void *user_data

    User data to provide to the callback.

    May be NULL.

## cpl_error.h

CPL error handling services.

Defines

CPLE_None

  No error.

CPLE_AppDefined

  Application defined error.

CPLE_OutOfMemory

  Out of memory error.

CPLE_FileIO

  File I/O error.

CPLE_OpenFailed

  Open failed.

CPLE_IllegalArg

  Illegal argument.

CPLE_NotSupported

  Not supported.

CPLE_AssertionFailed

  Assertion failed.

CPLE_NoWriteAccess

  No write access.

CPLE_UserInterrupt

  User interrupted.

CPLE_ObjectNull

  NULL object.

CPLE_HttpResponse

  HTTP response.

CPLE_AWSBucketNotFound

  AWSBucketNotFound.

CPLE_AWSObjectNotFound

  AWSObjectNotFound.

CPLE_AWSAccessDenied

  AWSAccessDenied.

CPLE_AWSInvalidCredentials

  AWSInvalidCredentials.

CPLE_AWSSignatureDoesNotMatch

  AWSSignatureDoesNotMatch.

CPLE_AWSError

  VSIE_AWSError.

CPLDebugOnly(...)

  Same as CPLDebug(), but expands to nothing for non-DEBUG builds.

  Since

    GDAL 3.1

CPLAssert(expr)

  Assert on an expression.

  Only enabled in DEBUG mode

CPLAssertAlwaysEval(expr)

  Assert on an expression in DEBUG mode.

  Evaluate it also in non-DEBUG mode (useful to ‘consume’ a error return variable)

VALIDATE_POINTER0(ptr, func)

  Validate that a pointer is not NULL.

VALIDATE_POINTER1(ptr, func, rc)

  Validate that a pointer is not NULL, and return rc if it is NULL.

Typedefs

typedef int CPLErrorNum

  Error number.

typedef void (*CPLErrorHandler)(CPLErr, CPLErrorNum, const char*)

  Callback for a custom error handler.

Enums

enum CPLErr

  Error category.

  Values:

  enumerator CE_None
  enumerator CE_Debug
  enumerator CE_Warning
  enumerator CE_Failure
  enumerator CE_Fatal

Functions

void CPLError(CPLErr eErrClass, CPLErrorNum err_no, const char *fmt, ...)

  Report an error.

  This function reports an error in a manner that can be hooked and reported appropriate by different applications.

  The effect of this function can be altered by applications by installing a custom error handling using CPLSetErrorHandler().

  The eErrClass argument can have the value CE_Warning indicating that the message is an informational warning, CE_Failure indicating that the action failed, but that normal recover mechanisms will be used or CE_Fatal meaning that a fatal error has occurred, and that CPLError() should not return.

  The default behavior of CPLError() is to report errors to stderr, and to abort() after reporting a CE_Fatal error. It is expected that some applications will want to suppress error reporting, and will want to install a C++ exception, or longjmp() approach to no local fatal error recovery.

  Regardless of how application error handlers or the default error handler choose to handle an error, the error number, and message will be stored for recovery with CPLGetLastErrorNo() and CPLGetLastErrorMsg().

  Parameters

    - eErrClass – one of CE_Warning, CE_Failure or CE_Fatal.

    - err_no – the error number (CPLE_*) from cpl_error.h.

    - fmt – a printf() style format string. Any additional arguments will be treated as arguments to fill in this format in a manner similar to printf().

void CPLErrorV(CPLErr, CPLErrorNum, const char*, va_list)

  Same as CPLError() but with a va_list.

void CPLEmergencyError(const char*)

  Fatal error when things are bad.

  This function should be called in an emergency situation where it is unlikely that a regular error report would work. This would include in the case of heap exhaustion for even small allocations, or any failure in the process of reporting an error (such as TLS allocations).

  This function should never return. After the error message has been reported as best possible, the application will abort() similarly to how CPLError() aborts on CE_Fatal class errors.

  Parameters

    pszMessage – the error message to report.

void CPLErrorReset(void)

  Erase any traces of previous errors.

  This is normally used to ensure that an error which has been recovered from does not appear to be still in play with high level functions.

CPLErrorNum CPLGetLastErrorNo(void)

  Fetch the last error number.

  Fetches the last error number posted with CPLError(), that hasn’t been cleared by CPLErrorReset(). This is the error number, not the error class.

  Returns

    the error number of the last error to occur, or CPLE_None (0) if there are no posted errors.

CPLErr CPLGetLastErrorType(void)

  Fetch the last error type.

  Fetches the last error type posted with CPLError(), that hasn’t been cleared by CPLErrorReset(). This is the error class, not the error number.

  Returns

    the error type of the last error to occur, or CE_None (0) if there are no posted errors.

const char *CPLGetLastErrorMsg(void)

  Get the last error message.

  Fetches the last error message posted with CPLError(), that hasn’t been cleared by CPLErrorReset(). The returned pointer is to an internal string that should not be altered or freed.

  Returns

    the last error message, or NULL if there is no posted error message.

GUInt32 CPLGetErrorCounter(void)

  Get the error counter.

  Fetches the number of errors emitted in the current error context, since the last call to CPLErrorReset()

  Since

    GDAL 2.3

  Returns

    the error counter.

void *CPLGetErrorHandlerUserData(void)

  Fetch the user data for the error context.

  Fetches the user data for the current error context. You can set the user data for the error context when you add your handler by issuing CPLSetErrorHandlerEx() and CPLPushErrorHandlerEx(). Note that user data is primarily intended for providing context within error handlers themselves, but they could potentially be abused in other useful ways with the usual caveat emptor understanding.

  Returns

    the user data pointer for the error context

void CPLErrorSetState(CPLErr eErrClass, CPLErrorNum err_no, const char *pszMsg)

  Restore an error state, without emitting an error.

  Can be useful if a routine might call CPLErrorReset() and one wants to preserve the previous error state.

  Since

    GDAL 2.0

void CPLLoggingErrorHandler(CPLErr, CPLErrorNum, const char*)

  Error handler that logs into the file defined by the CPL_LOG configuration option, or stderr otherwise.

void CPLDefaultErrorHandler(CPLErr, CPLErrorNum, const char*)

  Default error handler.

void CPLQuietErrorHandler(CPLErr, CPLErrorNum, const char*)

  Error handler that does not do anything, except for debug messages.

void CPLTurnFailureIntoWarning(int bOn)

  Whether failures should be turned into warnings.

CPLErrorHandler CPLSetErrorHandler(CPLErrorHandler)

  Install custom error handler.

  Allow the library’s user to specify an error handler function. A valid error handler is a C function with the following prototype:

  Pass NULL to come back to the default behavior. The default behavior (CPLDefaultErrorHandler()) is to write the message to stderr.

  The msg will be a partially formatted error message not containing the “ERROR %d:” portion emitted by the default handler. Message formatting is handled by CPLError() before calling the handler. If the error handler function is passed a CE_Fatal class error and returns, then CPLError() will call abort(). Applications wanting to interrupt this fatal behavior will have to use longjmp(), or a C++ exception to indirectly exit the function.

  Another standard error handler is CPLQuietErrorHandler() which doesn’t make any attempt to report the passed error or warning messages but will process debug messages via CPLDefaultErrorHandler.

  Note that error handlers set with CPLSetErrorHandler() apply to all threads in an application, while error handlers set with CPLPushErrorHandler are thread-local. However, any error handlers pushed with CPLPushErrorHandler (and not removed with CPLPopErrorHandler) take precedence over the global error handlers set with CPLSetErrorHandler(). Generally speaking CPLSetErrorHandler() would be used to set a desired global error handler, while CPLPushErrorHandler() would be used to install a temporary local error handler, such as CPLQuietErrorHandler() to suppress error reporting in a limited segment of code.

  Parameters

    pfnErrorHandlerNew – new error handler function.

  Returns

    returns the previously installed error handler.

CPLErrorHandler CPLSetErrorHandlerEx(CPLErrorHandler, void*)

  Install custom error handle with user’s data.

  This method is essentially CPLSetErrorHandler with an added pointer to pUserData. The pUserData is not returned in the CPLErrorHandler, however, and must be fetched via CPLGetErrorHandlerUserData.

  Parameters

    - pfnErrorHandlerNew – new error handler function.

    - pUserData – User data to carry along with the error context.

  Returns

    returns the previously installed error handler.

void CPLPushErrorHandler(CPLErrorHandler)

  Push a new CPLError handler.

  This pushes a new error handler on the thread-local error handler stack. This handler will be used until removed with CPLPopErrorHandler().

  The CPLSetErrorHandler() docs have further information on how CPLError handlers work.

  Parameters

    pfnErrorHandlerNew – new error handler function.

void CPLPushErrorHandlerEx(CPLErrorHandler, void*)

  Push a new CPLError handler with user data on the error context.

  This pushes a new error handler on the thread-local error handler stack. This handler will be used until removed with CPLPopErrorHandler(). Obtain the user data back by using CPLGetErrorContext().

  The CPLSetErrorHandler() docs have further information on how CPLError handlers work.

  Parameters

    - pfnErrorHandlerNew – new error handler function.

    - pUserData – User data to put on the error context.

void CPLSetCurrentErrorHandlerCatchDebug(int bCatchDebug)

  Set if the current error handler should intercept debug messages, or if they should be processed by the previous handler.

  By default when installing a custom error handler, this one intercepts debug messages. In some cases, this might not be desirable and the user would prefer that the previous installed handler (or the default one if no previous installed handler exists in the stack) deal with it. In which case, this function should be called with bCatchDebug = FALSE.

  Since

    GDAL 2.1

  Parameters

    bCatchDebug – FALSE if the current error handler should not intercept debug messages

void CPLPopErrorHandler(void)

  Pop error handler off stack.

  Discards the current error handler on the error handler stack, and restores the one in use before the last CPLPushErrorHandler() call. This method has no effect if there are no error handlers on the current threads error handler stack.

void CPLDebug(const char*, const char*, ...)

  Display a debugging message.

  The category argument is used in conjunction with the CPL_DEBUG environment variable to establish if the message should be displayed. If the CPL_DEBUG environment variable is not set, no debug messages are emitted (use CPLError(CE_Warning, …) to ensure messages are displayed). If CPL_DEBUG is set, but is an empty string or the word “ON” then all debug messages are shown. Otherwise only messages whose category appears somewhere within the CPL_DEBUG value are displayed (as determined by strstr()).

  Categories are usually an identifier for the subsystem producing the error. For instance “GDAL” might be used for the GDAL core, and “TIFF” for messages from the TIFF translator.

  Parameters

    - pszCategory – name of the debugging message category.

    - pszFormat – printf() style format string for message to display. Remaining arguments are assumed to be for format.

void _CPLAssert(const char*, const char*, int)

  Report failure of a logical assertion.

  Applications would normally use the CPLAssert() macro which expands into code calling _CPLAssert() only if the condition fails. _CPLAssert() will generate a CE_Fatal error call to CPLError(), indicating the file name, and line number of the failed assertion, as well as containing the assertion itself.

  There is no reason for application code to call _CPLAssert() directly.

## cpl_http.h

Interface for downloading HTTP, FTP documents

Typedefs

typedef CPLHTTPResult *(*CPLHTTPFetchCallbackFunc)(const char *pszURL, CSLConstList papszOptions, GDALProgressFunc pfnProgress, void *pProgressArg, CPLHTTPFetchWriteFunc pfnWrite, void *pWriteArg, void *pUserData)

  Callback function to process network requests.

  If CLOSE_PERSISTENT is found in papszOptions, no network request should be issued, but a dummy non-null CPLHTTPResult* should be returned by the callback.

  Its first arguments are the same as CPLHTTPFetchEx()

  Parameters

    - pszURL – See CPLHTTPFetchEx()

    - papszOptions – See CPLHTTPFetchEx()

    - pfnProgress – See CPLHTTPFetchEx()

    - pProgressArg – See CPLHTTPFetchEx()

    - pfnWrite – See CPLHTTPFetchEx()

    - pWriteArg – See CPLHTTPFetchEx()

    - pUserData – user data value that was passed during CPLHTTPPushFetchCallback()

  Returns

    nullptr if the request cannot be processed, in which case the previous handler will be used.

Functions

int CPLHTTPEnabled(void)

  Return if CPLHTTP services can be useful.

  Those services depend on GDAL being build with libcurl support.

  Returns

    TRUE if libcurl support is enabled

CPLHTTPResult *CPLHTTPFetch(const char *pszURL, CSLConstList papszOptions)

  Fetch a document from an url and return in a string.

  Alternatively, if not defined in the papszOptions arguments, the CONNECTTIMEOUT, TIMEOUT, LOW_SPEED_TIME, LOW_SPEED_LIMIT, USERPWD, PROXY, HTTPS_PROXY, PROXYUSERPWD, PROXYAUTH, NETRC, MAX_RETRY and RETRY_DELAY, HEADER_FILE, HTTP_VERSION, SSL_VERIFYSTATUS, USE_CAPI_STORE, GSSAPI_DELEGATION values are searched in the configuration options respectively named GDAL_HTTP_CONNECTTIMEOUT, GDAL_HTTP_TIMEOUT, GDAL_HTTP_LOW_SPEED_TIME, GDAL_HTTP_LOW_SPEED_LIMIT, GDAL_HTTP_USERPWD, GDAL_HTTP_PROXY, GDAL_HTTPS_PROXY, GDAL_HTTP_PROXYUSERPWD, GDAL_PROXY_AUTH, GDAL_HTTP_NETRC, GDAL_HTTP_MAX_RETRY, GDAL_HTTP_RETRY_DELAY, GDAL_HTTP_HEADER_FILE, GDAL_HTTP_VERSION, GDAL_HTTP_SSL_VERIFYSTATUS, GDAL_HTTP_USE_CAPI_STORE, GDAL_GSSAPI_DELEGATION

  Parameters

    - pszURL – valid URL recognized by underlying download library (libcurl)

    - papszOptions – option list as a NULL-terminated array of strings. May be NULL. The following options are handled :

      - CONNECTTIMEOUT=val, where val is in seconds (possibly with decimals). This is the maximum delay for the connection to be established before being aborted (GDAL >= 2.2).

      - TIMEOUT=val, where val is in seconds. This is the maximum delay for the whole request to complete before being aborted.

      - LOW_SPEED_TIME=val, where val is in seconds. This is the maximum time where the transfer speed should be below the LOW_SPEED_LIMIT (if not specified 1b/s), before the transfer to be considered too slow and aborted. (GDAL >= 2.1)

      - LOW_SPEED_LIMIT=val, where val is in bytes/second. See LOW_SPEED_TIME. Has only effect if LOW_SPEED_TIME is specified too. (GDAL >= 2.1)

      - HEADERS=val, where val is an extra header to use when getting a web page. For example “Accept: application/x-ogcwkt”

      - HEADER_FILE=filename: filename of a text file with “key: value” headers. (GDAL >= 2.2)

      - HTTPAUTH=[BASIC/NTLM/GSSNEGOTIATE/ANY] to specify an authentication scheme to use.

      - USERPWD=userid:password to specify a user and password for authentication

      - GSSAPI_DELEGATION=[NONE/POLICY/ALWAYS] set allowed GSS-API delegation. Relevant only with HTTPAUTH=GSSNEGOTIATE (GDAL >= 3.3).

      - POSTFIELDS=val, where val is a nul-terminated string to be passed to the server with a POST request.

      - PROXY=val, to make requests go through a proxy server, where val is of the form proxy.server.com:port_number. This option affects both HTTP and HTTPS URLs.

      - HTTPS_PROXY=val (GDAL >= 2.4), the same meaning as PROXY, but this option is taken into account only for HTTPS URLs.

      - PROXYUSERPWD=val, where val is of the form username:password

      - PROXYAUTH=[BASIC/NTLM/DIGEST/ANY] to specify an proxy authentication scheme to use.

      - NETRC=[YES/NO] to enable or disable use of $HOME/.netrc, default YES.

      - CUSTOMREQUEST=val, where val is GET, PUT, POST, DELETE, etc.. (GDAL >= 1.9.0)

      - FORM_FILE_NAME=val, where val is upload file name. If this option and FORM_FILE_PATH present, request type will set to POST.

      - FORM_FILE_PATH=val, where val is upload file path.

      - FORM_KEY_0=val…FORM_KEY_N, where val is name of form item.

      - FORM_VALUE_0=val…FORM_VALUE_N, where val is value of the form item.

      - FORM_ITEM_COUNT=val, where val is count of form items.

      - COOKIE=val, where val is formatted as COOKIE1=VALUE1; COOKIE2=VALUE2; …

      - COOKIEFILE=val, where val is file name to read cookies from (GDAL >= 2.4)

      - COOKIEJAR=val, where val is file name to store cookies to (GDAL >= 2.4)

      - MAX_RETRY=val, where val is the maximum number of retry attempts if a 429, 502, 503 or 504 HTTP error occurs. Default is 0. (GDAL >= 2.0)

      - RETRY_DELAY=val, where val is the number of seconds between retry attempts. Default is 30. (GDAL >= 2.0)

      - MAX_FILE_SIZE=val, where val is a number of bytes (GDAL >= 2.2)

      - CAINFO=/path/to/bundle.crt. This is path to Certificate Authority (CA) bundle file. By default, it will be looked for in a system location. If the CAINFO option is not defined, GDAL will also look in the the CURL_CA_BUNDLE and SSL_CERT_FILE environment variables respectively and use the first one found as the CAINFO value (GDAL >= 2.1.3). The GDAL_CURL_CA_BUNDLE environment variable may also be used to set the CAINFO value in GDAL >= 3.2.

      - HTTP_VERSION=1.0/1.1/2/2TLS (GDAL >= 2.3). Specify HTTP version to use. Will default to 1.1 generally (except on some controlled environments, like Google Compute Engine VMs, where 2TLS will be the default). Support for HTTP/2 requires curl 7.33 or later, built against nghttp2. “2TLS” means that HTTP/2 will be attempted for HTTPS connections only. Whereas “2” means that HTTP/2 will be attempted for HTTP or HTTPS.

      - SSL_VERIFYSTATUS=YES/NO (GDAL >= 2.3, and curl >= 7.41): determines whether the status of the server cert using the “Certificate Status Request” TLS extension (aka. OCSP stapling) should be checked. If this option is enabled but the server does not support the TLS extension, the verification will fail. Default to NO.

      - USE_CAPI_STORE=YES/NO (GDAL >= 2.3, Windows only): whether CA certificates from the Windows certificate store. Defaults to NO.

  Returns

    a CPLHTTPResult* structure that must be freed by CPLHTTPDestroyResult(), or NULL if libcurl support is disabled

CPLHTTPResult *CPLHTTPFetchEx(const char *pszURL, CSLConstList papszOptions, GDALProgressFunc pfnProgress, void *pProgressArg, CPLHTTPFetchWriteFunc pfnWrite, void *pWriteArg)

  Fetch a document from an url and return in a string.

  Parameters

    - pszURL – Url to fetch document from web.

    - papszOptions – Option list as a NULL-terminated array of strings. Available keys see in CPLHTTPFetch.

    - pfnProgress – Callback for reporting algorithm progress matching the GDALProgressFunc() semantics. May be NULL.

    - pProgressArg – Callback argument passed to pfnProgress.

    - pfnWrite – Write function pointer matching the CPLHTTPWriteFunc() semantics. May be NULL.

    - pWriteArg – Argument which will pass to a write function.

  Returns

    A CPLHTTPResult* structure that must be freed by CPLHTTPDestroyResult(), or NULL if libcurl support is disabled.

CPLHTTPResult **CPLHTTPMultiFetch(const char *const *papszURL, int nURLCount, int nMaxSimultaneous, CSLConstList papszOptions)

  Fetch several documents at once.

  Since

    GDAL 2.3

  Parameters

    - papszURL – array of valid URLs recognized by underlying download library (libcurl)

    - nURLCount – number of URLs of papszURL

    - nMaxSimultaneous – maximum number of downloads to issue simultaneously. Any negative or zer value means unlimited.

    - papszOptions – option list as a NULL-terminated array of strings. May be NULL. Refer to CPLHTTPFetch() for valid options.

  Returns

    an array of CPLHTTPResult* structures that must be freed by CPLHTTPDestroyMultiResult() or NULL if libcurl support is disabled

void CPLHTTPCleanup(void)

  Cleanup function to call at application termination.

void CPLHTTPDestroyResult(CPLHTTPResult *psResult)

  Clean the memory associated with the return value of CPLHTTPFetch()

  Parameters

    psResult – pointer to the return value of CPLHTTPFetch()

void CPLHTTPDestroyMultiResult(CPLHTTPResult **papsResults, int nCount)

  Clean the memory associated with the return value of CPLHTTPMultiFetch()

  Since

    GDAL 2.3

  Parameters

    - papsResults – pointer to the return value of CPLHTTPMultiFetch()

    - nCount – value of the nURLCount parameter passed to CPLHTTPMultiFetch()

int CPLHTTPParseMultipartMime(CPLHTTPResult *psResult)

  Parses a MIME multipart message.

  This function will iterate over each part and put it in a separate element of the pasMimePart array of the provided psResult structure.

  Parameters

    psResult – pointer to the return value of CPLHTTPFetch()

  Returns

    TRUE if the message contains MIME multipart message.

void CPLHTTPSetFetchCallback(CPLHTTPFetchCallbackFunc pFunc, void *pUserData)

  Installs an alternate callback to the default implementation of CPLHTTPFetchEx().

  This callback will be used by all threads, unless contextual callbacks are installed with CPLHTTPPushFetchCallback().

  It is the responsibility of the caller to make sure this function is not called concurrently, or during CPLHTTPFetchEx() execution.

  Since

    GDAL 3.2

  Parameters

    - pFunc – Callback function to be called with CPLHTTPFetchEx() is called (or NULL to restore default handler)

    - pUserData – Last argument to provide to the pFunc callback.

int CPLHTTPPushFetchCallback(CPLHTTPFetchCallbackFunc pFunc, void *pUserData)

  Installs an alternate callback to the default implementation of CPLHTTPFetchEx().

  This callback will only be used in the thread where this function has been called. It must be un-installed by CPLHTTPPopFetchCallback(), which must also be called from the same thread.

  Since

    GDAL 3.2

  Parameters

    - pFunc – Callback function to be called with CPLHTTPFetchEx() is called.

    - pUserData – Last argument to provide to the pFunc callback.

  Returns

    TRUE in case of success.

int CPLHTTPPopFetchCallback(void)

  Uninstalls a callback set by CPLHTTPPushFetchCallback().

  See also

  CPLHTTPPushFetchCallback()

  Since

    GDAL 3.2

  Returns

    TRUE in case of success.

char *GOA2GetAuthorizationURL(const char *pszScope)

  Return authorization url for a given scope.

  Returns the URL that a user should visit, and use for authentication in order to get an “auth token” indicating their willingness to use a service.

  Note that when the user visits this url they will be asked to login (using a google/gmail/etc) account, and to authorize use of the requested scope for the application “GDAL/OGR”. Once they have done so, they will be presented with a lengthy string they should “enter

  into their application”. This is the “auth token” to be passed to

  GOA2GetRefreshToken(). The “auth token” can only be used once.

  This function should never fail.

  Parameters

    pszScope – the service being requested, not yet URL encoded, such as “https://www.googleapis.com/auth/fusiontables”.

  Returns

    the URL to visit - should be freed with CPLFree().

char *GOA2GetRefreshToken(const char *pszAuthToken, const char *pszScope)

  Turn Auth Token into a Refresh Token.

  A one time “auth token” provided by the user is turned into a reusable “refresh token” using a google oauth2 web service.

  A CPLError will be reported if the translation fails for some reason. Common reasons include the auth token already having been used before, it not being appropriate for the passed scope and configured client api or http connection problems. NULL is returned on error.

  Parameters

    - pszAuthToken – the authorization token from the user.

    - pszScope – the scope for which it is valid.

  Returns

    refresh token, to be freed with CPLFree(), null on failure.

char *GOA2GetAccessToken(const char *pszRefreshToken, const char *pszScope)

  Fetch access token using refresh token.

  The permanent refresh token is used to fetch a temporary (usually one hour) access token using Google OAuth2 web services.

  A CPLError will be reported if the request fails for some reason. Common reasons include the refresh token having been revoked by the user or http connection problems.

  Parameters

    - pszRefreshToken – the refresh token from GOA2GetRefreshToken().

    - pszScope – the scope for which it is valid. Currently unused

  Returns

    access token, to be freed with CPLFree(), null on failure.

char **GOA2GetAccessTokenFromServiceAccount(const char *pszPrivateKey, const char *pszClientEmail, const char *pszScope, CSLConstList papszAdditionalClaims, CSLConstList papszOptions)

  Fetch access token using Service Account OAuth2.

  See https://developers.google.com/identity/protocols/OAuth2ServiceAccount

  A CPLError will be reported if the request fails for some reason.

  Since

    GDAL 2.3

  Parameters

    - pszPrivateKey – Private key as a RSA private key

    - pszClientEmail – Client email

    - pszScope – the service being requested

    - papszAdditionalClaims – additional claims, or NULL

    - papszOptions – NULL terminated list of options. None currently

  Returns

    a list of key=value pairs, including a access_token and expires_in

char **GOA2GetAccessTokenFromCloudEngineVM(CSLConstList papszOptions)

  Fetch access token using Cloud Engine internal REST API.

  The default service accounts bound to the current Google Cloud Engine VM is used for OAuth2 authentication

  A CPLError will be reported if the request fails for some reason. Common reasons include the refresh token having been revoked by the user or http connection problems.

  Since

    GDAL 2.3

  Parameters

    papszOptions – NULL terminated list of options. None currently

  Returns

    a list of key=value pairs, including a access_token and expires_in

bool CPLIsMachinePotentiallyGCEInstance()

  Returns whether the current machine is potentially a Google Compute Engine instance.

  This does a very quick check without network access. To confirm if the machine is effectively a GCE instance, metadata.google.internal must be queried.

  Since

    GDAL 2.3

  Returns

    true if the current machine is potentially a GCE instance.

bool CPLIsMachineForSureGCEInstance()

  Returns whether the current machine is surely a Google Compute Engine instance.

  This does a very quick check without network access. Note: only works for Linux GCE instances.

  Since

    GDAL 2.3

  Returns

    true if the current machine is surely a GCE instance.

struct CPLMimePart
  #include <cpl_http.h>

  Describe a part of a multipart message

  Public Members

  char **papszHeaders

    NULL terminated array of headers

  GByte *pabyData

    Buffer with data of the part

  int nDataLen

    Buffer length

struct CPLHTTPResult
  #include <cpl_http.h>

  Describe the result of a CPLHTTPFetch() call

  Public Members

  int nStatus

    cURL error code : 0=success, non-zero if request failed

  char *pszContentType

    Content-Type of the response

  char *pszErrBuf

    Error message from curl, or NULL

  int nDataLen

    Length of the pabyData buffer

  int nDataAlloc

    Allocated size of the pabyData buffer

  GByte *pabyData

    Buffer with downloaded data

  char **papszHeaders

    Headers returned

  int nMimePartCount

    Number of parts in a multipart message

  CPLMimePart *pasMimePart

    Array of parts (resolved by CPLHTTPParseMultipartMime())

class GOA2Manager
  #include <cpl_http.h>

  Manager of Google OAuth2 authentication.

  This class handles different authentication methods and handles renewal of access token.

  Since

    GDAL 2.3

  Public Types

  enum AuthMethod

    Authentication method.

    Values:

    enumerator NONE
    enumerator GCE
    enumerator ACCESS_TOKEN_FROM_REFRESH
    enumerator SERVICE_ACCOUNT

  Public Functions

  GOA2Manager()

    Constructor.

  bool SetAuthFromGCE(CSLConstList papszOptions)

    Specifies that the authentication will be done using the local credentials of the current Google Compute Engine VM.

    This queries http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/token

    Parameters

      papszOptions – NULL terminated list of options.

    Returns

      true in case of success (no network access is done at this stage)

  bool SetAuthFromRefreshToken(const char *pszRefreshToken, const char *pszClientId, const char *pszClientSecret, CSLConstList papszOptions)

    Specifies that the authentication will be done using the OAuth2 client id method.

    See http://code.google.com/apis/accounts/docs/OAuth2.html

    Parameters

      - pszRefreshToken – refresh token. Must be non NULL.

      - pszClientId – client id (may be NULL, in which case the GOA2_CLIENT_ID configuration option is used)

      - pszClientSecret – client secret (may be NULL, in which case the GOA2_CLIENT_SECRET configuration option is used)

      - papszOptions – NULL terminated list of options, or NULL.

    Returns

      true in case of success (no network access is done at this stage)

  bool SetAuthFromServiceAccount(const char *pszPrivateKey, const char *pszClientEmail, const char *pszScope, CSLConstList papszAdditionalClaims, CSLConstList papszOptions)

    Specifies that the authentication will be done using the OAuth2 service account method.

    See https://developers.google.com/identity/protocols/OAuth2ServiceAccount

    Parameters

      - pszPrivateKey – RSA private key. Must be non NULL.

      - pszClientEmail – client email. Must be non NULL.

      - pszScope – authorization scope. Must be non NULL.

      - papszAdditionalClaims – NULL terminate list of additional claims, or NULL.

      - papszOptions – NULL terminated list of options, or NULL.

    Returns

      true in case of success (no network access is done at this stage)

  inline AuthMethod GetAuthMethod() const

    Returns the authentication method.

  const char *GetBearer() const

    Return the access token.

    This is the value to append to a “Authorization: Bearer ” HTTP header.

    A network request is issued only if no access token has been yet queried, or if its expiration delay has been reached.

    Returns

      the access token, or NULL in case of error.

  inline const CPLString &GetPrivateKey() const

    Returns private key for SERVICE_ACCOUNT method.

  inline const CPLString &GetClientEmail() const

    Returns client email for SERVICE_ACCOUNT method.

  Private Members

  mutable CPLString m_osCurrentBearer = {}
  mutable time_t m_nExpirationTime = 0
  AuthMethod m_eMethod = NONE
  CPLString m_osClientId = {}
  CPLString m_osClientSecret = {}
  CPLString m_osRefreshToken = {}
  CPLString m_osPrivateKey = {}
  CPLString m_osClientEmail = {}
  CPLString m_osScope = {}
  CPLStringList m_aosAdditionalClaims = {}
  CPLStringList m_aosOptions = {}

## cpl_minixml.h

Definitions for CPL mini XML Parser/Serializer.

Enums

enum CPLXMLNodeType

  XML node type.

  Values:

  enumerator CXT_Element

    Node is an element

  enumerator CXT_Text

    Node is a raw text value

  enumerator CXT_Attribute

    Node is attribute

  enumerator CXT_Comment

    Node is an XML comment.

  enumerator CXT_Literal

    Node is a special literal

Functions

CPLXMLNode *CPLParseXMLString(const char*)

  Parse an XML string into tree form.

  The passed document is parsed into a CPLXMLNode tree representation. If the document is not well formed XML then NULL is returned, and errors are reported via CPLError(). No validation beyond wellformedness is done. The CPLParseXMLFile() convenience function can be used to parse from a file.

  The returned document tree is owned by the caller and should be freed with CPLDestroyXMLNode() when no longer needed.

  If the document has more than one “root level” element then those after the first will be attached to the first as siblings (via the psNext pointers) even though there is no common parent. A document with no XML structure (no angle brackets for instance) would be considered well formed, and returned as a single CXT_Text node.

  Parameters

    pszString – the document to parse.

  Returns

    parsed tree or NULL on error.

void CPLDestroyXMLNode(CPLXMLNode*)

  Destroy a tree.

  This function frees resources associated with a CPLXMLNode and all its children nodes.

  Parameters

    psNode – the tree to free.

CPLXMLNode *CPLGetXMLNode(CPLXMLNode *poRoot, const char *pszPath)

  Find node by path.

  Searches the document or subdocument indicated by psRoot for an element (or attribute) with the given path. The path should consist of a set of element names separated by dots, not including the name of the root element (psRoot). If the requested element is not found NULL is returned.

  Attribute names may only appear as the last item in the path.

  The search is done from the root nodes children, but all intermediate nodes in the path must be specified. Searching for “name” would only find a name element or attribute if it is a direct child of the root, not at any level in the subdocument.

  If the pszPath is prefixed by “=” then the search will begin with the root node, and its siblings, instead of the root nodes children. This is particularly useful when searching within a whole document which is often prefixed by one or more “junk” nodes like the <?xml> declaration.

  Parameters

    - psRoot – the subtree in which to search. This should be a node of type CXT_Element. NULL is safe.

    - pszPath – the list of element names in the path (dot separated).

  Returns

    the requested element node, or NULL if not found.

CPLXMLNode *CPLSearchXMLNode(CPLXMLNode *poRoot, const char *pszTarget)

  Search for a node in document.

  Searches the children (and potentially siblings) of the documented passed in for the named element or attribute. To search following siblings as well as children, prefix the pszElement name with an equal sign. This function does an in-order traversal of the document tree. So it will first match against the current node, then its first child, that child’s first child, and so on.

  Use CPLGetXMLNode() to find a specific child, or along a specific node path.

  Parameters

    - psRoot – the subtree to search. This should be a node of type CXT_Element. NULL is safe.

    - pszElement – the name of the element or attribute to search for.

  Returns

    The matching node or NULL on failure.

const char *CPLGetXMLValue(const CPLXMLNode *poRoot, const char *pszPath, const char *pszDefault)

  Fetch element/attribute value.

  Searches the document for the element/attribute value associated with the path. The corresponding node is internally found with CPLGetXMLNode() (see there for details on path handling). Once found, the value is considered to be the first CXT_Text child of the node.

  If the attribute/element search fails, or if the found node has no value then the passed default value is returned.

  The returned value points to memory within the document tree, and should not be altered or freed.

  Parameters

    - psRoot – the subtree in which to search. This should be a node of type CXT_Element. NULL is safe.

    - pszPath – the list of element names in the path (dot separated). An empty path means get the value of the psRoot node.

    - pszDefault – the value to return if a corresponding value is not found, may be NULL.

  Returns

    the requested value or pszDefault if not found.

CPLXMLNode *CPLCreateXMLNode(CPLXMLNode *poParent, CPLXMLNodeType eType, const char *pszText)

  Create an document tree item.

  Create a single CPLXMLNode object with the desired value and type, and attach it as a child of the indicated parent.

  Parameters

    - poParent – the parent to which this node should be attached as a child. May be NULL to keep as free standing.

    - eType – the type of the newly created node

    - pszText – the value of the newly created node

  Returns

    the newly created node, now owned by the caller (or parent node).

char *CPLSerializeXMLTree(const CPLXMLNode *psNode)

  Convert tree into string document.

  This function converts a CPLXMLNode tree representation of a document into a flat string representation. White space indentation is used visually preserve the tree structure of the document. The returned document becomes owned by the caller and should be freed with CPLFree() when no longer needed.

  Parameters

    psNode – the node to serialize.

  Returns

    the document on success or NULL on failure.

void CPLAddXMLChild(CPLXMLNode *psParent, CPLXMLNode *psChild)

  Add child node to parent.

  The passed child is added to the list of children of the indicated parent. Normally the child is added at the end of the parents child list, but attributes (CXT_Attribute) will be inserted after any other attributes but before any other element type. Ownership of the child node is effectively assumed by the parent node. If the child has siblings (its psNext is not NULL) they will be trimmed, but if the child has children they are carried with it.

  Parameters

    - psParent – the node to attach the child to. May not be NULL.

    - psChild – the child to add to the parent. May not be NULL. Should not be a child of any other parent.

int CPLRemoveXMLChild(CPLXMLNode *psParent, CPLXMLNode *psChild)

  Remove child node from parent.

  The passed child is removed from the child list of the passed parent, but the child is not destroyed. The child retains ownership of its own children, but is cleanly removed from the child list of the parent.

  Parameters

    - psParent – the node to the child is attached to.

    - psChild – the child to remove.

  Returns

    TRUE on success or FALSE if the child was not found.

void CPLAddXMLSibling(CPLXMLNode *psOlderSibling, CPLXMLNode *psNewSibling)

  Add new sibling.

  The passed psNewSibling is added to the end of siblings of the psOlderSibling node. That is, it is added to the end of the psNext chain. There is no special handling if psNewSibling is an attribute. If this is required, use CPLAddXMLChild().

  Parameters

    - psOlderSibling – the node to attach the sibling after.

    - psNewSibling – the node to add at the end of psOlderSiblings psNext chain.

CPLXMLNode *CPLCreateXMLElementAndValue(CPLXMLNode *psParent, const char *pszName, const char *pszValue)

  Create an element and text value.

  This is function is a convenient short form for:

      CPLXMLNode *psTextNode;
      CPLXMLNode *psElementNode;

      psElementNode = CPLCreateXMLNode( psParent, CXT_Element, pszName );
      psTextNode = CPLCreateXMLNode( psElementNode, CXT_Text, pszValue );

      return psElementNode;

  It creates a CXT_Element node, with a CXT_Text child, and attaches the element to the passed parent.

  Parameters

    - psParent – the parent node to which the resulting node should be attached. May be NULL to keep as freestanding.

    - pszName – the element name to create.

    - pszValue – the text to attach to the element. Must not be NULL.

  Returns

    the pointer to the new element node.

void CPLAddXMLAttributeAndValue(CPLXMLNode *psParent, const char *pszName, const char *pszValue)

  Create an attribute and text value.

  This is function is a convenient short form for:

      CPLXMLNode *psAttributeNode;

      psAttributeNode = CPLCreateXMLNode( psParent, CXT_Attribute, pszName );
      CPLCreateXMLNode( psAttributeNode, CXT_Text, pszValue );

  It creates a CXT_Attribute node, with a CXT_Text child, and attaches the element to the passed parent.

  Since

    GDAL 2.0

  Parameters

    - psParent – the parent node to which the resulting node should be attached. Must not be NULL.

    - pszName – the attribute name to create.

    - pszValue – the text to attach to the attribute. Must not be NULL.

CPLXMLNode *CPLCloneXMLTree(const CPLXMLNode *psTree)

  Copy tree.

  Creates a deep copy of a CPLXMLNode tree.

  Parameters

    psTree – the tree to duplicate.

  Returns

    a copy of the whole tree.

int CPLSetXMLValue(CPLXMLNode *psRoot, const char *pszPath, const char *pszValue)

  Set element value by path.

  Find (or create) the target element or attribute specified in the path, and assign it the indicated value.

  Any path elements that do not already exist will be created. The target nodes value (the first CXT_Text child) will be replaced with the provided value.

  If the target node is an attribute instead of an element, the name should be prefixed with a #.

  Example: CPLSetXMLValue( “Citation.Id.Description”, “DOQ dataset” ); CPLSetXMLValue( “Citation.Id.Description.#name”, “doq” );

  Parameters

    - psRoot – the subdocument to be updated.

    - pszPath – the dot separated path to the target element/attribute.

    - pszValue – the text value to assign.

  Returns

    TRUE on success.

void CPLStripXMLNamespace(CPLXMLNode *psRoot, const char *pszNameSpace, int bRecurse)

  Strip indicated namespaces.

  The subdocument (psRoot) is recursively examined, and any elements with the indicated namespace prefix will have the namespace prefix stripped from the element names. If the passed namespace is NULL, then all namespace prefixes will be stripped.

  Nodes other than elements should remain unaffected. The changes are made “in place”, and should not alter any node locations, only the pszValue field of affected nodes.

  Parameters

    - psRoot – the document to operate on.

    - pszNamespace – the name space prefix (not including colon), or NULL.

    - bRecurse – TRUE to recurse over whole document, or FALSE to only operate on the passed node.

void CPLCleanXMLElementName(char*)

  Make string into safe XML token.

  Modifies a string in place to try and make it into a legal XML token that can be used as an element name. This is accomplished by changing any characters not legal in a token into an underscore.

  NOTE: This function should implement the rules in section 2.3 of http://www.w3.org/TR/xml11/ but it doesn’t yet do that properly. We only do a rough approximation of that.

  Parameters

    pszTarget – the string to be adjusted. It is altered in place.

CPLXMLNode *CPLParseXMLFile(const char *pszFilename)

  Parse XML file into tree.

  The named file is opened, loaded into memory as a big string, and parsed with CPLParseXMLString(). Errors in reading the file or parsing the XML will be reported by CPLError().

  The “large file” API is used, so XML files can come from virtualized files.

  Parameters

    pszFilename – the file to open.

  Returns

    NULL on failure, or the document tree on success.

int CPLSerializeXMLTreeToFile(const CPLXMLNode *psTree, const char *pszFilename)

  Write document tree to a file.

  The passed document tree is converted into one big string (with CPLSerializeXMLTree()) and then written to the named file. Errors writing the file will be reported by CPLError(). The source document tree is not altered. If the output file already exists it will be overwritten.

  Parameters

    - psTree – the document tree to write.

    - pszFilename – the name of the file to write to.

  Returns

    TRUE on success, FALSE otherwise.

struct CPLXMLNode
  #include <cpl_minixml.h>

  Document node structure.

  This C structure is used to hold a single text fragment representing a component of the document when parsed. It should be allocated with the appropriate CPL function, and freed with CPLDestroyXMLNode(). The structure contents should not normally be altered by application code, but may be freely examined by application code.

  Using the psChild and psNext pointers, a hierarchical tree structure for a document can be represented as a tree of CPLXMLNode structures.

  Public Members

  CPLXMLNodeType eType

    Node type.

    One of CXT_Element, CXT_Text, CXT_Attribute, CXT_Comment, or CXT_Literal.

  char *pszValue

    Node value.

    For CXT_Element this is the name of the element, without the angle brackets. Note there is a single CXT_Element even when the document contains a start and end element tag. The node represents the pair. All text or other elements between the start and end tag will appear as children nodes of this CXT_Element node.

    For CXT_Attribute the pszValue is the attribute name. The value of the attribute will be a CXT_Text child.

    For CXT_Text this is the text itself (value of an attribute, or a text fragment between an element start and end tags.

    For CXT_Literal it is all the literal text. Currently this is just used for !DOCTYPE lines, and the value would be the entire line.

    For CXT_Comment the value is all the literal text within the comment, but not including the comment start/end indicators (“<–” and “–>”).

  struct CPLXMLNode *psNext

    Next sibling.

    Pointer to next sibling, that is the next node appearing after this one that has the same parent as this node. NULL if this node is the last child of the parent element.

  struct CPLXMLNode *psChild

    Child node.

    Pointer to first child node, if any. Only CXT_Element and CXT_Attribute nodes should have children. For CXT_Attribute it should be a single CXT_Text value node, while CXT_Element can have any kind of child. The full list of children for a node are identified by walking the psNext’s starting with the psChild node.

class CPLXMLTreeCloser : public std::unique_ptr<CPLXMLNode, CPLXMLTreeCloserDeleter>
  #include <cpl_minixml.h>

  Manage a tree of XML nodes so that all nodes are freed when the instance goes out of scope.

  Only the top level node should be in a CPLXMLTreeCloser.

  Public Functions

  inline explicit CPLXMLTreeCloser(CPLXMLNode *data)

    Constructor.

  CPLXMLNode *getDocumentElement()

    Returns a pointer to the document (root) element.

    Returns

      the node pointer

## cpl_multiproc.h

Defines

CPLMutex

CPLCond

CPLJoinableThread

CPL_MUTEX_RECURSIVE

CPL_MUTEX_ADAPTIVE

CPL_MUTEX_REGULAR

CPLMutexHolderD(x)

CPLMutexHolderExD(x, nOptions)

CPLMutexHolderOptionalLockD(x)

CPLLockHolderD(x, eType)

CPLLockHolderOptionalLockD(x)

CTLS_RLBUFFERINFO

CTLS_WIN32_COND

CTLS_CSVTABLEPTR

CTLS_CSVDEFAULTFILENAME

CTLS_ERRORCONTEXT

CTLS_VSICURL_CACHEDCONNECTION

CTLS_PATHBUF

CTLS_ABSTRACTARCHIVE_SPLIT

CTLS_GDALOPEN_ANTIRECURSION

CTLS_CPLSPRINTF

CTLS_RESPONSIBLEPID

CTLS_VERSIONINFO

CTLS_VERSIONINFO_LICENCE

CTLS_CONFIGOPTIONS

CTLS_FINDFILE

CTLS_VSIERRORCONTEXT

CTLS_ERRORHANDLERACTIVEDATA

CTLS_PROJCONTEXTHOLDER

CTLS_GDALDEFAULTOVR_ANTIREC

CTLS_HTTPFETCHCALLBACK

CTLS_MAX

Typedefs

typedef void (*CPLThreadFunc)(void*)

typedef struct _CPLLock CPLLock

typedef void (*CPLTLSFreeFunc)(void *pData)

Enums

enum CPLCondTimedWaitReason

  Values:

  enumerator COND_TIMED_WAIT_COND
  enumerator COND_TIMED_WAIT_TIME_OUT
  enumerator COND_TIMED_WAIT_OTHER

enum CPLLockType

  Values:

  enumerator LOCK_RECURSIVE_MUTEX
  enumerator LOCK_ADAPTIVE_MUTEX
  enumerator LOCK_SPIN

Functions

void *CPLLockFile(const char *pszPath, double dfWaitInSeconds)

void CPLUnlockFile(void *hLock)

CPLMutex *CPLCreateMutex(void)

CPLMutex *CPLCreateMutexEx(int nOptions)

int CPLCreateOrAcquireMutex(CPLMutex**, double dfWaitInSeconds)

int CPLCreateOrAcquireMutexEx(CPLMutex**, double dfWaitInSeconds, int nOptions)

int CPLAcquireMutex(CPLMutex *hMutex, double dfWaitInSeconds)

void CPLReleaseMutex(CPLMutex *hMutex)

void CPLDestroyMutex(CPLMutex *hMutex)

void CPLCleanupMasterMutex(void)

CPLCond *CPLCreateCond(void)

void CPLCondWait(CPLCond *hCond, CPLMutex *hMutex)

CPLCondTimedWaitReason CPLCondTimedWait(CPLCond *hCond, CPLMutex *hMutex, double dfWaitInSeconds)

void CPLCondSignal(CPLCond *hCond)

void CPLCondBroadcast(CPLCond *hCond)

void CPLDestroyCond(CPLCond *hCond)

GIntBig CPLGetPID(void)

  Contrary to what its name suggests, CPLGetPID() actually returns the thread id.

int CPLGetCurrentProcessID(void)

int CPLCreateThread(CPLThreadFunc pfnMain, void *pArg)

CPLJoinableThread *CPLCreateJoinableThread(CPLThreadFunc pfnMain, void *pArg)

void CPLJoinThread(CPLJoinableThread *hJoinableThread)

void CPLSleep(double dfWaitInSeconds)

const char *CPLGetThreadingModel(void)

int CPLGetNumCPUs(void)

CPLLock *CPLCreateLock(CPLLockType eType)

int CPLCreateOrAcquireLock(CPLLock**, CPLLockType eType)

int CPLAcquireLock(CPLLock*)

void CPLReleaseLock(CPLLock*)

void CPLDestroyLock(CPLLock*)

void CPLLockSetDebugPerf(CPLLock*, int bEnableIn)

void *CPLGetTLS(int nIndex)

void *CPLGetTLSEx(int nIndex, int *pbMemoryErrorOccurred)

void CPLSetTLS(int nIndex, void *pData, int bFreeOnExit)

void CPLSetTLSWithFreeFunc(int nIndex, void *pData, CPLTLSFreeFunc pfnFree)

void CPLSetTLSWithFreeFuncEx(int nIndex, void *pData, CPLTLSFreeFunc pfnFree, int *pbMemoryErrorOccurred)

void CPLCleanupTLS(void)

class CPLMutexHolder
  #include <cpl_multiproc.h>

  Object to hold a mutex.

  Public Functions

  explicit CPLMutexHolder(CPLMutex **phMutex, double dfWaitInSeconds = 1000.0, const char *pszFile = __FILE__, int nLine = __LINE__, int nOptions = CPL_MUTEX_RECURSIVE)

    Instantiates the mutex if not already done.

  explicit CPLMutexHolder(CPLMutex *hMutex, double dfWaitInSeconds = 1000.0, const char *pszFile = __FILE__, int nLine = __LINE__)

    This variant assumes the mutex has already been created.

    If not, it will be a no-op

  ~CPLMutexHolder()

  Private Members

  CPLMutex *hMutex = nullptr
  const char *pszFile = nullptr
  int nLine = 0

class CPLLockHolder
  #include <cpl_multiproc.h>

  Object to hold a lock.

  Public Functions

  CPLLockHolder(CPLLock **phSpin, CPLLockType eType, const char *pszFile = __FILE__, int nLine = __LINE__)

    Instantiates the lock if not already done.

  explicit CPLLockHolder(CPLLock *hSpin, const char *pszFile = __FILE__, int nLine = __LINE__)

    This variant assumes the lock has already been created.

    If not, it will be a no-op

  ~CPLLockHolder()

  Private Members

  CPLLock *hLock = nullptr
  const char *pszFile = nullptr
  int nLine = 0

## cpl_port.h

Core portability definitions for CPL.

Defines

GINTBIG_MIN

  Minimum GIntBig value.

GINTBIG_MAX

  Maximum GIntBig value.

GUINTBIG_MAX

  Maximum GUIntBig value.

GINT64_MIN

  Minimum GInt64 value.

GINT64_MAX

  Maximum GInt64 value.

GUINT64_MAX

  Minimum GUInt64 value.

CPL_FRMT_GB_WITHOUT_PREFIX

  Printf formatting suffix for GIntBig.

CPL_FRMT_GIB

  Printf formatting for GIntBig.

CPL_FRMT_GUIB

  Printf formatting for GUIntBig.

CPL_C_START

  Macro to start a block of C symbols.

CPL_C_END

  Macro to end a block of C symbols.

MIN(a, b)

  Macro to compute the minimum of 2 values.

MAX(a, b)

  Macro to compute the maximum of 2 values.

ABS(x)

  Macro to compute the absolute value.

M_PI

  PI definition.

STRCASECMP(a, b)

  Alias for strcasecmp()

STRNCASECMP(a, b, n)

  Alias for strncasecmp()

EQUALN(a, b, n)

  Alias for strncasecmp() == 0.

EQUAL(a, b)

  Alias for strcasecmp() == 0.

STARTS_WITH(a, b)

  Returns whether a starts with b.

STARTS_WITH_CI(a, b)

  Returns whether a starts with b (case insensitive comparison)

CPLIsNan(x)

  Return whether a floating-pointer number is NaN.

CPLIsInf(x)

  Return whether a floating-pointer number is +/- infinity.

CPLIsFinite(x)

  Return whether a floating-pointer number is finite.

CPL_SWAP16(x)

  Byte-swap a 16bit unsigned integer.

CPL_SWAP32(x)

  Byte-swap a 32bit unsigned integer.

CPL_SWAP64(x)

  Byte-swap a 64bit unsigned integer.

CPL_SWAP16PTR(x)

  Byte-swap a 16 bit pointer.

CPL_SWAP32PTR(x)

  Byte-swap a 32 bit pointer.

CPL_SWAP64PTR(x)

  Byte-swap a 64 bit pointer.

CPL_SWAPDOUBLE(p)

  Byte-swap a 64 bit pointer.

CPL_LSBWORD16(x)

  Return a 16bit word from a originally LSB ordered word.

CPL_MSBWORD16(x)

  Return a 16bit word from a originally MSB ordered word.

CPL_LSBWORD32(x)

  Return a 32bit word from a originally LSB ordered word.

CPL_MSBWORD32(x)

  Return a 32bit word from a originally MSB ordered word.

CPL_LSBPTR16(x)

  Byte-swap if necessary a 16bit word at the location pointed from a originally LSB ordered pointer.

CPL_MSBPTR16(x)

  Byte-swap if necessary a 16bit word at the location pointed from a originally MSB ordered pointer.

CPL_LSBPTR32(x)

  Byte-swap if necessary a 32bit word at the location pointed from a originally LSB ordered pointer.

CPL_MSBPTR32(x)

  Byte-swap if necessary a 32bit word at the location pointed from a originally MSB ordered pointer.

CPL_LSBPTR64(x)

  Byte-swap if necessary a 64bit word at the location pointed from a originally LSB ordered pointer.

CPL_MSBPTR64(x)

  Byte-swap if necessary a 64bit word at the location pointed from a originally MSB ordered pointer.

CPL_LSBINT16PTR(x)

  Return a Int16 from the 2 bytes ordered in LSB order at address x.

  Deprecated:

    Use rather CPL_LSBSINT16PTR or CPL_LSBUINT16PTR for explicit signedness.

CPL_LSBINT32PTR(x)

  Return a Int32 from the 4 bytes ordered in LSB order at address x.

  Deprecated:

    Use rather CPL_LSBSINT32PTR or CPL_LSBUINT32PTR for explicit signedness.

CPL_LSBSINT16PTR(x)

  Return a signed Int16 from the 2 bytes ordered in LSB order at address x.

CPL_LSBUINT16PTR(x)

  Return a unsigned Int16 from the 2 bytes ordered in LSB order at address x.

CPL_LSBSINT32PTR(x)

  Return a signed Int32 from the 4 bytes ordered in LSB order at address x.

CPL_LSBUINT32PTR(x)

  Return a unsigned Int32 from the 4 bytes ordered in LSB order at address x.

CPL_NULL_TERMINATED

  Null terminated variadic.

CPL_PRINT_FUNC_FORMAT(format_idx, arg_idx)

  Tag a function to have printf() formatting.

CPL_SCAN_FUNC_FORMAT(format_idx, arg_idx)

  Tag a function to have scanf() formatting.

CPL_FORMAT_STRING(arg)

  Macro into which to wrap the format argument of a printf-like function.

CPL_SCANF_FORMAT_STRING(arg)

  Macro into which to wrap the format argument of a sscanf-like function.

CPL_WARN_UNUSED_RESULT

  Qualifier to warn when the return value of a function is not used.

CPL_UNUSED

  Qualifier for an argument that is unused.

CPL_NO_RETURN

  Qualifier for a function that does not return at all (terminates the process)

CPL_RETURNS_NONNULL

  Qualifier for a function that does not return NULL.

CPL_RESTRICT

  restrict keyword to declare that pointers do not alias

CPL_OVERRIDE

  To be used in public headers only.

  For non-public headers or .cpp files, use override directly.

CPL_FINAL

  C++11 final qualifier.

CPL_NON_FINAL

  Mark that a class is explicitly recognized as non-final.

CPL_DISALLOW_COPY_ASSIGN(ClassName)

  Helper to remove the copy and assignment constructors so that the compiler will not generate the default versions.

  Must be placed in the private section of a class and should be at the end.

CPL_ARRAYSIZE(array)

  Returns the size of C style arrays.

CPL_FALLTHROUGH

  Macro for fallthrough in a switch case construct.

Typedefs

typedef int GInt32

  Int32 type.

typedef unsigned int GUInt32

  Unsigned int32 type.

typedef short GInt16

  Int16 type.

typedef unsigned short GUInt16

  Unsigned int16 type.

typedef unsigned char GByte

  Unsigned byte type.

typedef int GBool

  Type for boolean values (alias to int)

typedef long long GIntBig

  Large signed integer type (generally 64-bit integer type).

  Use GInt64 when exactly 64 bit is needed

typedef unsigned long long GUIntBig

  Large unsigned integer type (generally 64-bit unsigned integer type).

  Use GUInt64 when exactly 64 bit is needed

typedef GIntBig GInt64

  Signed 64 bit integer type.

typedef GUIntBig GUInt64

  Unsigned 64 bit integer type.

typedef int GPtrDiff_t

  Integer type large enough to hold the difference between 2 addresses.

typedef char **CSLConstList

  Type of a constant null-terminated list of nul terminated strings.

  Seen as char** from C and const char* const* from C++

Functions

template<class T>
static void CPL_IGNORE_RET_VAL(const T&)

static inline bool CPL_TO_BOOL(int x)

## cpl_progress.h

Typedefs

typedef int (*GDALProgressFunc)(double dfComplete, const char *pszMessage, void *pProgressArg)

Functions

int GDALDummyProgress(double, const char*, void*)

  Stub progress function.

  This is a stub (does nothing) implementation of the GDALProgressFunc() semantics. It is primarily useful for passing to functions that take a GDALProgressFunc() argument but for which the application does not want to use one of the other progress functions that actually do something.

int GDALTermProgress(double, const char*, void*)

  Simple progress report to terminal.

  This progress reporter prints simple progress report to the terminal window. The progress report generally looks something like this:

      0...10...20...30...40...50...60...70...80...90...100 - done.

  Every 2.5% of progress another number or period is emitted. Note that GDALTermProgress() uses internal static data to keep track of the last percentage reported and will get confused if two terminal based progress reportings are active at the same time.

  The GDALTermProgress() function maintains an internal memory of the last percentage complete reported in a static variable, and this makes it unsuitable to have multiple GDALTermProgress()’s active either in a single thread or across multiple threads.

  Parameters

    - dfComplete – completion ratio from 0.0 to 1.0.

    - pszMessage – optional message.

    - pProgressArg – ignored callback data argument.

  Returns

    Always returns TRUE indicating the process should continue.

int GDALScaledProgress(double, const char*, void*)

  Scaled progress transformer.

  This is the progress function that should be passed along with the callback data returned by GDALCreateScaledProgress().

void *GDALCreateScaledProgress(double, double, GDALProgressFunc, void*)

  Create scaled progress transformer.

  Sometimes when an operations wants to report progress it actually invokes several subprocesses which also take GDALProgressFunc()s, and it is desirable to map the progress of each sub operation into a portion of 0.0 to 1.0 progress of the overall process. The scaled progress function can be used for this.

  For each subsection a scaled progress function is created and instead of passing the overall progress func down to the sub functions, the GDALScaledProgress() function is passed instead.

  Example:

      int MyOperation( ..., GDALProgressFunc pfnProgress, void *pProgressData );

      {
          void *pScaledProgress;

          pScaledProgress = GDALCreateScaledProgress( 0.0, 0.5, pfnProgress,
                                                      pProgressData );
          GDALDoLongSlowOperation( ..., GDALScaledProgress, pScaledProgress );
          GDALDestroyScaledProgress( pScaledProgress );

          pScaledProgress = GDALCreateScaledProgress( 0.5, 1.0, pfnProgress,
                                                      pProgressData );
          GDALDoAnotherOperation( ..., GDALScaledProgress, pScaledProgress );
          GDALDestroyScaledProgress( pScaledProgress );

          return ...;
      }

  Parameters

    - dfMin – the value to which 0.0 in the sub operation is mapped.

    - dfMax – the value to which 1.0 is the sub operation is mapped.

    - pfnProgress – the overall progress function.

    - pData – the overall progress function callback data.

  Returns

    pointer to pass as pProgressArg to sub functions. Should be freed with GDALDestroyScaledProgress().

void GDALDestroyScaledProgress(void*)

  Cleanup scaled progress handle.

  This function cleans up the data associated with a scaled progress function as returned by GADLCreateScaledProgress().

  Parameters

    pData – scaled progress handle returned by GDALCreateScaledProgress().

## cpl_string.h

Various convenience functions for working with strings and string lists.

A StringList is just an array of strings with the last pointer being NULL. An empty StringList may be either a NULL pointer, or a pointer to a pointer memory location with a NULL value.

A common convention for StringLists is to use them to store name/value lists. In this case the contents are treated like a dictionary of name/value pairs. The actual data is formatted with each string having the format “<name>:<value>” (though “=” is also an acceptable separator). A number of the functions in the file operate on name/value style string lists (such as CSLSetNameValue(), and CSLFetchNameValue()).

To some extent the CPLStringList C++ class can be used to abstract managing string lists a bit but still be able to return them from C functions.

Defines

CSLT_HONOURSTRINGS

  Flag for CSLTokenizeString2() to honour strings.

CSLT_ALLOWEMPTYTOKENS

  Flag for CSLTokenizeString2() to allow empty tokens.

CSLT_PRESERVEQUOTES

  Flag for CSLTokenizeString2() to preserve quotes.

CSLT_PRESERVEESCAPES

  Flag for CSLTokenizeString2() to preserve escape characters.

CSLT_STRIPLEADSPACES

  Flag for CSLTokenizeString2() to strip leading spaces.

CSLT_STRIPENDSPACES

  Flag for CSLTokenizeString2() to strip trailaing spaces.

CPLES_BackslashQuotable

  Scheme for CPLEscapeString()/CPLUnescapeString() for backlash quoting.

CPLES_XML

  Scheme for CPLEscapeString()/CPLUnescapeString() for XML.

CPLES_URL

  Scheme for CPLEscapeString()/CPLUnescapeString() for URL.

CPLES_SQL

  Scheme for CPLEscapeString()/CPLUnescapeString() for SQL.

CPLES_CSV

  Scheme for CPLEscapeString()/CPLUnescapeString() for CSV.

CPLES_XML_BUT_QUOTES

  Scheme for CPLEscapeString()/CPLUnescapeString() for XML (preserves quotes)

CPLES_CSV_FORCE_QUOTING

  Scheme for CPLEscapeString()/CPLUnescapeString() for CSV (forced quoting)

CPLES_SQLI

  Scheme for CPLEscapeString()/CPLUnescapeString() for SQL identifiers.

CPL_ENC_LOCALE

  Encoding of the current locale.

CPL_ENC_UTF8

  UTF-8 encoding.

CPL_ENC_UTF16

  UTF-16 encoding.

CPL_ENC_UCS2

  UCS-2 encoding.

CPL_ENC_UCS4

  UCS-4 encoding.

CPL_ENC_ASCII

  ASCII encoding.

CPL_ENC_ISO8859_1

  ISO-8859-1 (LATIN1) encoding.

Enums

enum CPLValueType

  Type of value.

  Values:

  enumerator CPL_VALUE_STRING

    String.

  enumerator CPL_VALUE_REAL

    Real number.

  enumerator CPL_VALUE_INTEGER

    Integer.

Functions

char **CSLAddString(char **papszStrList, const char *pszNewString)

  Append a string to a StringList and return a pointer to the modified StringList.

  If the input StringList is NULL, then a new StringList is created. Note that CSLAddString performance when building a list is in O(n^2) which can cause noticeable slow down when n > 10000.

char **CSLAddStringMayFail(char **papszStrList, const char *pszNewString)

  Same as CSLAddString() but may return NULL in case of (memory) failure.

int CSLCount(CSLConstList papszStrList)

  Return number of items in a string list.

  Returns the number of items in a string list, not counting the terminating NULL. Passing in NULL is safe, and will result in a count of zero.

  Lists are counted by iterating through them so long lists will take more time than short lists. Care should be taken to avoid using CSLCount() as an end condition for loops as it will result in O(n^2) behavior.

  Parameters

    papszStrList – the string list to count.

  Returns

    the number of entries.

const char *CSLGetField(CSLConstList, int)

  Fetches the indicated field, being careful not to crash if the field doesn’t exist within this string list.

  The returned pointer should not be freed, and doesn’t necessarily last long.

void CSLDestroy(char **papszStrList)

  Free string list.

  Frees the passed string list (null terminated array of strings). It is safe to pass NULL.

  Parameters

    papszStrList – the list to free.

char **CSLDuplicate(CSLConstList papszStrList)

  Clone a string list.

  Efficiently allocates a copy of a string list. The returned list is owned by the caller and should be freed with CSLDestroy().

  Parameters

    papszStrList – the input string list.

  Returns

    newly allocated copy.

char **CSLMerge(char **papszOrig, CSLConstList papszOverride)

  Merge two lists.

  The two lists are merged, ensuring that if any keys appear in both that the value from the second (papszOverride) list take precedence.

  Parameters

    - papszOrig – the original list, being modified.

    - papszOverride – the list of items being merged in. This list is unaltered and remains owned by the caller.

  Returns

    updated list.

char **CSLTokenizeString(const char *pszString)

  Tokenizes a string and returns a StringList with one string for each token.

char **CSLTokenizeStringComplex(const char *pszString, const char *pszDelimiter, int bHonourStrings, int bAllowEmptyTokens)

  Obsolete tokenizing api.

  Use CSLTokenizeString2()

char **CSLTokenizeString2(const char *pszString, const char *pszDelimiter, int nCSLTFlags)

  Tokenize a string.

  This function will split a string into tokens based on specified’ delimiter(s) with a variety of options. The returned result is a string list that should be freed with CSLDestroy() when no longer needed.

  The available parsing options are:

  - CSLT_ALLOWEMPTYTOKENS: allow the return of empty tokens when two delimiters in a row occur with no other text between them. If not set, empty tokens will be discarded;

  - CSLT_STRIPLEADSPACES: strip leading space characters from the token (as reported by isspace());

  - CSLT_STRIPENDSPACES: strip ending space characters from the token (as reported by isspace());

  - CSLT_HONOURSTRINGS: double quotes can be used to hold values that should not be broken into multiple tokens;

  - CSLT_PRESERVEQUOTES: string quotes are carried into the tokens when this is set, otherwise they are removed;

  - CSLT_PRESERVEESCAPES: if set backslash escapes (for backslash itself, and for literal double quotes) will be preserved in the tokens, otherwise the backslashes will be removed in processing.

  Example:

  Parse a string into tokens based on various white space (space, newline, tab) and then print out results and cleanup. Quotes may be used to hold white space in tokens.

      char **papszTokens =
          CSLTokenizeString2( pszCommand, " \t\n",
                              CSLT_HONOURSTRINGS | CSLT_ALLOWEMPTYTOKENS );

      for( int i = 0; papszTokens != NULL && papszTokens[i] != NULL; ++i )
          printf( "arg %d: '%s'", papszTokens[i] );  // ok

      CSLDestroy( papszTokens );

  Parameters

    - pszString – the string to be split into tokens.

    - pszDelimiters – one or more characters to be used as token delimiters.

    - nCSLTFlags – an ORing of one or more of the CSLT_ flag values.

  Returns

    a string list of tokens owned by the caller.

int CSLPrint(CSLConstList papszStrList, FILE *fpOut)

  Print a StringList to fpOut.

  If fpOut==NULL, then output is sent to stdout.

  Returns the number of lines printed.

char **CSLLoad(const char *pszFname)

  Load a text file into a string list.

  The VSI*L API is used, so VSIFOpenL() supported objects that aren’t physical files can also be accessed. Files are returned as a string list, with one item in the string list per line. End of line markers are stripped (by CPLReadLineL()).

  If reading the file fails a CPLError() will be issued and NULL returned.

  Parameters

    pszFname – the name of the file to read.

  Returns

    a string list with the files lines, now owned by caller. To be freed with CSLDestroy()

char **CSLLoad2(const char *pszFname, int nMaxLines, int nMaxCols, CSLConstList papszOptions)

  Load a text file into a string list.

  The VSI*L API is used, so VSIFOpenL() supported objects that aren’t physical files can also be accessed. Files are returned as a string list, with one item in the string list per line. End of line markers are stripped (by CPLReadLineL()).

  If reading the file fails a CPLError() will be issued and NULL returned.

  Since

    GDAL 1.7.0

  Parameters

    - pszFname – the name of the file to read.

    - nMaxLines – maximum number of lines to read before stopping, or -1 for no limit.

    - nMaxCols – maximum number of characters in a line before stopping, or -1 for no limit.

    - papszOptions – NULL-terminated array of options. Unused for now.

  Returns

    a string list with the files lines, now owned by caller. To be freed with CSLDestroy()

int CSLSave(CSLConstList papszStrList, const char *pszFname)

  Write a StringList to a text file.

  Returns the number of lines written, or 0 if the file could not be written.

char **CSLInsertStrings(char **papszStrList, int nInsertAtLineNo, CSLConstList papszNewLines)

  Copies the contents of a StringList inside another StringList before the specified line.

  nInsertAtLineNo is a 0-based line index before which the new strings should be inserted. If this value is -1 or is larger than the actual number of strings in the list then the strings are added at the end of the source StringList.

  Returns the modified StringList.

char **CSLInsertString(char **papszStrList, int nInsertAtLineNo, const char *pszNewLine)

  Insert a string at a given line number inside a StringList.

  nInsertAtLineNo is a 0-based line index before which the new string should be inserted. If this value is -1 or is larger than the actual number of strings in the list then the string is added at the end of the source StringList.

  Returns the modified StringList.

char **CSLRemoveStrings(char **papszStrList, int nFirstLineToDelete, int nNumToRemove, char ***ppapszRetStrings)

  Remove strings inside a StringList.

  nFirstLineToDelete is the 0-based line index of the first line to remove. If this value is -1 or is larger than the actual number of strings in list then the nNumToRemove last strings are removed.

  If ppapszRetStrings != NULL then the deleted strings won’t be free’d, they will be stored in a new StringList and the pointer to this new list will be returned in *ppapszRetStrings.

  Returns the modified StringList.

int CSLFindString(CSLConstList papszList, const char *pszTarget)

  Find a string within a string list (case insensitive).

  Returns the index of the entry in the string list that contains the target string. The string in the string list must be a full match for the target, but the search is case insensitive.

  Parameters

    - papszList – the string list to be searched.

    - pszTarget – the string to be searched for.

  Returns

    the index of the string within the list or -1 on failure.

int CSLFindStringCaseSensitive(CSLConstList papszList, const char *pszTarget)

  Find a string within a string list(case sensitive)

  Returns the index of the entry in the string list that contains the target string. The string in the string list must be a full match for the target.

  Since

    GDAL 2.0

  Parameters

    - papszList – the string list to be searched.

    - pszTarget – the string to be searched for.

  Returns

    the index of the string within the list or -1 on failure.

int CSLPartialFindString(CSLConstList papszHaystack, const char *pszNeedle)

  Find a substring within a string list.

  Returns the index of the entry in the string list that contains the target string as a substring. The search is case sensitive (unlike CSLFindString()).

  Parameters

    - papszHaystack – the string list to be searched.

    - pszNeedle – the substring to be searched for.

  Returns

    the index of the string within the list or -1 on failure.

int CSLFindName(CSLConstList papszStrList, const char *pszName)

  Find StringList entry with given key name.

  Parameters

    - papszStrList – the string list to search.

    - pszName – the key value to look for (case insensitive).

  Returns

    -1 on failure or the list index of the first occurrence matching the given key.

int CSLFetchBoolean(CSLConstList papszStrList, const char *pszKey, int bDefault)

  DEPRECATED.

  Check for boolean key value.

  In a StringList of “Name=Value” pairs, look to see if there is a key with the given name, and if it can be interpreted as being TRUE. If the key appears without any “=Value” portion it will be considered true. If the value is NO, FALSE or 0 it will be considered FALSE otherwise if the key appears in the list it will be considered TRUE. If the key doesn’t appear at all, the indicated default value will be returned.

  Parameters

    - papszStrList – the string list to search.

    - pszKey – the key value to look for (case insensitive).

    - bDefault – the value to return if the key isn’t found at all.

  Returns

    TRUE or FALSE

int CSLTestBoolean(const char *pszValue)

  Test what boolean value contained in the string.

  If pszValue is “NO”, “FALSE”, “OFF” or “0” will be returned FALSE. Otherwise, TRUE will be returned.

  Deprecated. Removed in GDAL 3.x.

  Use CPLTestBoolean() for C and CPLTestBool() for C++.

  Parameters

    pszValue – the string should be tested.

  Returns

    TRUE or FALSE.

int CPLTestBoolean(const char *pszValue)

  Test what boolean value contained in the string.

  If pszValue is “NO”, “FALSE”, “OFF” or “0” will be returned FALSE. Otherwise, TRUE will be returned.

  Use this only in C code. In C++, prefer CPLTestBool().

  Parameters

    pszValue – the string should be tested.

  Returns

    TRUE or FALSE.

bool CPLTestBool(const char *pszValue)

  Test what boolean value contained in the string.

  If pszValue is “NO”, “FALSE”, “OFF” or “0” will be returned false. Otherwise, true will be returned.

  Parameters

    pszValue – the string should be tested.

  Returns

    true or false.

bool CPLFetchBool(CSLConstList papszStrList, const char *pszKey, bool bDefault)

  Check for boolean key value.

  In a StringList of “Name=Value” pairs, look to see if there is a key with the given name, and if it can be interpreted as being TRUE. If the key appears without any “=Value” portion it will be considered true. If the value is NO, FALSE or 0 it will be considered FALSE otherwise if the key appears in the list it will be considered TRUE. If the key doesn’t appear at all, the indicated default value will be returned.

  Parameters

    - papszStrList – the string list to search.

    - pszKey – the key value to look for (case insensitive).

    - bDefault – the value to return if the key isn’t found at all.

  Returns

    true or false

const char *CPLParseNameValue(const char *pszNameValue, char **ppszKey)

  Parse NAME=VALUE string into name and value components.

  Note that if ppszKey is non-NULL, the key (or name) portion will be allocated using CPLMalloc(), and returned in that pointer. It is the applications responsibility to free this string, but the application should not modify or free the returned value portion.

  This function also support “NAME:VALUE” strings and will strip white space from around the delimiter when forming name and value strings.

  Eventually CSLFetchNameValue() and friends may be modified to use CPLParseNameValue().

  Parameters

    - pszNameValue – string in “NAME=VALUE” format.

    - ppszKey – optional pointer though which to return the name portion.

  Returns

    the value portion (pointing into original string).

const char *CSLFetchNameValue(CSLConstList papszStrList, const char *pszName)

  In a StringList of “Name=Value” pairs, look for the first value associated with the specified name.

  The search is not case sensitive. (“Name:Value” pairs are also supported for backward compatibility with older stuff.)

  Returns a reference to the value in the StringList that the caller should not attempt to free.

  Returns NULL if the name is not found.

const char *CSLFetchNameValueDef(CSLConstList papszStrList, const char *pszName, const char *pszDefault)

  Same as CSLFetchNameValue() but return pszDefault in case of no match.

char **CSLFetchNameValueMultiple(CSLConstList papszStrList, const char *pszName)

  In a StringList of “Name=Value” pairs, look for all the values with the specified name.

  The search is not case sensitive. (“Name:Value” pairs are also supported for backward compatibility with older stuff.)

  Returns StringList with one entry for each occurrence of the specified name. The StringList should eventually be destroyed by calling CSLDestroy().

  Returns NULL if the name is not found.

char **CSLAddNameValue(char **papszStrList, const char *pszName, const char *pszValue)

  Add a new entry to a StringList of “Name=Value” pairs, (“Name:Value” pairs are also supported for backward compatibility with older stuff.)

  This function does not check if a “Name=Value” pair already exists for that name and can generate multiple entries for the same name. Use CSLSetNameValue() if you want each name to have only one value.

  Returns the modified StringList.

char **CSLSetNameValue(char **papszStrList, const char *pszName, const char *pszValue)

  Assign value to name in StringList.

  Set the value for a given name in a StringList of “Name=Value” pairs (“Name:Value” pairs are also supported for backward compatibility with older stuff.)

  If there is already a value for that name in the list then the value is changed, otherwise a new “Name=Value” pair is added.

  Parameters

    - papszList – the original list, the modified version is returned.

    - pszName – the name to be assigned a value. This should be a well formed token (no spaces or very special characters).

    - pszValue – the value to assign to the name. This should not contain any newlines (CR or LF) but is otherwise pretty much unconstrained. If NULL any corresponding value will be removed.

  Returns

    modified StringList.

void CSLSetNameValueSeparator(char **papszStrList, const char *pszSeparator)

  Replace the default separator (“:” or “=”) with the passed separator in the given name/value list.

  Note that if a separator other than “:” or “=” is used, the resulting list will not be manipulable by the CSL name/value functions any more.

  The CPLParseNameValue() function is used to break the existing lines, and it also strips white space from around the existing delimiter, thus the old separator, and any white space will be replaced by the new separator. For formatting purposes it may be desirable to include some white space in the new separator. e.g. “: ” or ” = “.

  Parameters

    - papszList – the list to update. Component strings may be freed but the list array will remain at the same location.

    - pszSeparator – the new separator string to insert.

char **CSLParseCommandLine(const char *pszCommandLine)

  Tokenize command line arguments in a list of strings.

  Since

    GDAL 2.1

  Parameters

    pszCommandLine – command line

  Returns

    NULL terminated list of strings to free with CSLDestroy()

char *CPLEscapeString(const char *pszString, int nLength, int nScheme)

  Apply escaping to string to preserve special characters.

  This function will “escape” a variety of special characters to make the string suitable to embed within a string constant or to write within a text stream but in a form that can be reconstituted to its original form. The escaping will even preserve zero bytes allowing preservation of raw binary data.

  CPLES_BackslashQuotable(0): This scheme turns a binary string into a form suitable to be placed within double quotes as a string constant. The backslash, quote, ‘\0’ and newline characters are all escaped in the usual C style.

  CPLES_XML(1): This scheme converts the ‘<’, ‘>’, ‘”’ and ‘&’ characters into their XML/HTML equivalent (<, >, ” and &) making a string safe to embed as CDATA within an XML element. The ‘\0’ is not escaped and should not be included in the input.

  CPLES_URL(2): Everything except alphanumerics and the characters ‘$’, ‘-‘, ‘_’, ‘.’, ‘+’, ‘!’, ‘*’, ‘’’, ‘(‘, ‘)’ and ‘,’ (see RFC1738) are converted to a percent followed by a two digit hex encoding of the character (leading zero supplied if needed). This is the mechanism used for encoding values to be passed in URLs.

  CPLES_SQL(3): All single quotes are replaced with two single quotes. Suitable for use when constructing literal values for SQL commands where the literal will be enclosed in single quotes.

  CPLES_CSV(4): If the values contains commas, semicolons, tabs, double quotes, or newlines it placed in double quotes, and double quotes in the value are doubled. Suitable for use when constructing field values for .csv files. Note that CPLUnescapeString() currently does not support this format, only CPLEscapeString(). See cpl_csv.cpp for CSV parsing support.

  CPLES_SQLI(7): All double quotes are replaced with two double quotes. Suitable for use when constructing identifiers for SQL commands where the literal will be enclosed in double quotes.

  Parameters

    - pszInput – the string to escape.

    - nLength – The number of bytes of data to preserve. If this is -1 the strlen(pszString) function will be used to compute the length.

    - nScheme – the encoding scheme to use.

  Returns

    an escaped, zero terminated string that should be freed with CPLFree() when no longer needed.

char *CPLUnescapeString(const char *pszString, int *pnLength, int nScheme)

  Unescape a string.

  This function does the opposite of CPLEscapeString(). Given a string with special values escaped according to some scheme, it will return a new copy of the string returned to its original form.

  Parameters

    - pszInput – the input string. This is a zero terminated string.

    - pnLength – location to return the length of the unescaped string, which may in some cases include embedded ‘\0’ characters.

    - nScheme – the escaped scheme to undo (see CPLEscapeString() for a list). Does not yet support CSV.

  Returns

    a copy of the unescaped string that should be freed by the application using CPLFree() when no longer needed.

char *CPLBinaryToHex(int nBytes, const GByte *pabyData)

  Binary to hexadecimal translation.

  Parameters

    - nBytes – number of bytes of binary data in pabyData.

    - pabyData – array of data bytes to translate.

  Returns

    hexadecimal translation, zero terminated. Free with CPLFree().

GByte *CPLHexToBinary(const char *pszHex, int *pnBytes)

  Hexadecimal to binary translation.

  Parameters

    - pszHex – the input hex encoded string.

    - pnBytes – the returned count of decoded bytes placed here.

  Returns

    returns binary buffer of data - free with CPLFree().

char *CPLBase64Encode(int nBytes, const GByte *pabyData)

  Base64 encode a buffer.

int CPLBase64DecodeInPlace(GByte *pszBase64)

  Decode base64 string “pszBase64” (null terminated) in place.

  Returns length of decoded array or 0 on failure.

CPLValueType CPLGetValueType(const char *pszValue)

  Detect the type of the value contained in a string, whether it is a real, an integer or a string Leading and trailing spaces are skipped in the analysis.

  Note: in the context of this function, integer must be understood in a broad sense. It does not mean that the value can fit into a 32 bit integer for example. It might be larger.

  Parameters

    pszValue – the string to analyze

  Returns

    returns the type of the value contained in the string.

size_t CPLStrlcpy(char *pszDest, const char *pszSrc, size_t nDestSize)

  Copy source string to a destination buffer.

  This function ensures that the destination buffer is always NUL terminated (provided that its length is at least 1).

  This function is designed to be a safer, more consistent, and less error prone replacement for strncpy. Its contract is identical to libbsd’s strlcpy.

  Truncation can be detected by testing if the return value of CPLStrlcpy is greater or equal to nDestSize.

      char szDest[5] = {};
      if( CPLStrlcpy(szDest, "abcde", sizeof(szDest)) >= sizeof(szDest) )
          fprintf(stderr, "truncation occurred !\n");

  Since

    GDAL 1.7.0

  Parameters

    - pszDest – destination buffer

    - pszSrc – source string. Must be NUL terminated

    - nDestSize – size of destination buffer (including space for the NUL terminator character)

  Returns

    the length of the source string (=strlen(pszSrc))

size_t CPLStrlcat(char *pszDest, const char *pszSrc, size_t nDestSize)

  Appends a source string to a destination buffer.

  This function ensures that the destination buffer is always NUL terminated (provided that its length is at least 1 and that there is at least one byte free in pszDest, that is to say strlen(pszDest_before) < nDestSize)

  This function is designed to be a safer, more consistent, and less error prone replacement for strncat. Its contract is identical to libbsd’s strlcat.

  Truncation can be detected by testing if the return value of CPLStrlcat is greater or equal to nDestSize.

      char szDest[5] = {};
      CPLStrlcpy(szDest, "ab", sizeof(szDest));
      if( CPLStrlcat(szDest, "cde", sizeof(szDest)) >= sizeof(szDest) )
          fprintf(stderr, "truncation occurred !\n");

  Since

    GDAL 1.7.0

  Parameters

    - pszDest – destination buffer. Must be NUL terminated before running CPLStrlcat

    - pszSrc – source string. Must be NUL terminated

    - nDestSize – size of destination buffer (including space for the NUL terminator character)

  Returns

    the theoretical length of the destination string after concatenation (=strlen(pszDest_before) + strlen(pszSrc)). If strlen(pszDest_before) >= nDestSize, then it returns nDestSize + strlen(pszSrc)

size_t CPLStrnlen(const char *pszStr, size_t nMaxLen)

  Returns the length of a NUL terminated string by reading at most the specified number of bytes.

  The CPLStrnlen() function returns min(strlen(pszStr), nMaxLen). Only the first nMaxLen bytes of the string will be read. Useful to test if a string contains at least nMaxLen characters without reading the full string up to the NUL terminating character.

  Since

    GDAL 1.7.0

  Parameters

    - pszStr – a NUL terminated string

    - nMaxLen – maximum number of bytes to read in pszStr

  Returns

    strlen(pszStr) if the length is lesser than nMaxLen, otherwise nMaxLen if the NUL character has not been found in the first nMaxLen bytes.

int CPLvsnprintf(char *str, size_t size, const char *fmt, va_list args)

  vsnprintf() wrapper that is not sensitive to LC_NUMERIC settings.

  This function has the same contract as standard vsnprintf(), except that formatting of floating-point numbers will use decimal point, whatever the current locale is set.

  Since

    GDAL 2.0

  Parameters

    - str – output buffer

    - size – size of the output buffer (including space for terminating nul)

    - fmt – formatting string

    - args – arguments

  Returns

    the number of characters (excluding terminating nul) that would be written if size is big enough. Or potentially -1 with Microsoft C runtime for Visual Studio < 2015.

int CPLsnprintf(char *str, size_t size, const char *fmt, ...)

  snprintf() wrapper that is not sensitive to LC_NUMERIC settings.

  This function has the same contract as standard snprintf(), except that formatting of floating-point numbers will use decimal point, whatever the current locale is set.

  Since

    GDAL 2.0

  Parameters

    - str – output buffer

    - size – size of the output buffer (including space for terminating nul)

    - fmt – formatting string

    - ... – arguments

  Returns

    the number of characters (excluding terminating nul) that would be written if size is big enough. Or potentially -1 with Microsoft C runtime for Visual Studio < 2015.

int CPLprintf(const char *fmt, ...)

  printf() wrapper that is not sensitive to LC_NUMERIC settings.

  This function has the same contract as standard printf(), except that formatting of floating-point numbers will use decimal point, whatever the current locale is set.

  Since

    GDAL 2.0

  Parameters

    - fmt – formatting string

    - ... – arguments

  Returns

    the number of characters (excluding terminating nul) written in output buffer.

const char *CPLSPrintf(const char *fmt, ...)

  CPLSPrintf() that works with 10 static buffer.

  It returns a ref. to a static buffer that should not be freed and is valid only until the next call to CPLSPrintf().

char **CSLAppendPrintf(char **papszStrList, const char *fmt, ...)

  Use CPLSPrintf() to append a new line at the end of a StringList.

  Returns the modified StringList.

int CPLVASPrintf(char **buf, const char *fmt, va_list args)

  This is intended to serve as an easy to use C callable vasprintf() alternative.

  Used in the GeoJSON library for instance

int CPLEncodingCharSize(const char *pszEncoding)

  Return bytes per character for encoding.

  This function returns the size in bytes of the smallest character in this encoding. For fixed width encodings (ASCII, UCS-2, UCS-4) this is straight forward. For encodings like UTF8 and UTF16 which represent some characters as a sequence of atomic character sizes the function still returns the atomic character size (1 for UTF8, 2 for UTF16).

  This function will return the correct value for well known encodings with corresponding CPL_ENC_ values. It may not return the correct value for other encodings even if they are supported by the underlying iconv or windows transliteration services. Hopefully it will improve over time.

  Parameters

    pszEncoding – the name of the encoding.

  Returns

    the size of a minimal character in bytes or -1 if the size is unknown.

char *CPLRecode(const char *pszSource, const char *pszSrcEncoding, const char *pszDstEncoding)

  Convert a string from a source encoding to a destination encoding.

  The only guaranteed supported encodings are CPL_ENC_UTF8, CPL_ENC_ASCII and CPL_ENC_ISO8859_1. Currently, the following conversions are supported :

  - CPL_ENC_ASCII -> CPL_ENC_UTF8 or CPL_ENC_ISO8859_1 (no conversion in fact)

  - CPL_ENC_ISO8859_1 -> CPL_ENC_UTF8

  - CPL_ENC_UTF8 -> CPL_ENC_ISO8859_1

  If an error occurs an error may, or may not be posted with CPLError().

  Since

    GDAL 1.6.0

  Parameters

    - pszSource – a NULL terminated string.

    - pszSrcEncoding – the source encoding.

    - pszDstEncoding – the destination encoding.

  Returns

    a NULL terminated string which should be freed with CPLFree().

char *CPLRecodeFromWChar(const wchar_t *pwszSource, const char *pszSrcEncoding, const char *pszDstEncoding)

  Convert wchar_t string to UTF-8.

  Convert a wchar_t string into a multibyte utf-8 string. The only guaranteed supported source encoding is CPL_ENC_UCS2, and the only guaranteed supported destination encodings are CPL_ENC_UTF8, CPL_ENC_ASCII and CPL_ENC_ISO8859_1. In some cases (i.e. using iconv()) other encodings may also be supported.

  Note that the wchar_t type varies in size on different systems. On win32 it is normally 2 bytes, and on UNIX 4 bytes.

  If an error occurs an error may, or may not be posted with CPLError().

  Since

    GDAL 1.6.0

  Parameters

    - pwszSource – the source wchar_t string, terminated with a 0 wchar_t.

    - pszSrcEncoding – the source encoding, typically CPL_ENC_UCS2.

    - pszDstEncoding – the destination encoding, typically CPL_ENC_UTF8.

  Returns

    a zero terminated multi-byte string which should be freed with CPLFree(), or NULL if an error occurs.

wchar_t *CPLRecodeToWChar(const char *pszSource, const char *pszSrcEncoding, const char *pszDstEncoding)

  Convert UTF-8 string to a wchar_t string.

  Convert a 8bit, multi-byte per character input string into a wide character (wchar_t) string. The only guaranteed supported source encodings are CPL_ENC_UTF8, CPL_ENC_ASCII and CPL_ENC_ISO8869_1 (LATIN1). The only guaranteed supported destination encoding is CPL_ENC_UCS2. Other source and destination encodings may be supported depending on the underlying implementation.

  Note that the wchar_t type varies in size on different systems. On win32 it is normally 2 bytes, and on UNIX 4 bytes.

  If an error occurs an error may, or may not be posted with CPLError().

  Since

    GDAL 1.6.0

  Parameters

    - pszSource – input multi-byte character string.

    - pszSrcEncoding – source encoding, typically CPL_ENC_UTF8.

    - pszDstEncoding – destination encoding, typically CPL_ENC_UCS2.

  Returns

    the zero terminated wchar_t string (to be freed with CPLFree()) or NULL on error.

int CPLIsUTF8(const char *pabyData, int nLen)

  Test if a string is encoded as UTF-8.

  Since

    GDAL 1.7.0

  Parameters

    - pabyData – input string to test

    - nLen – length of the input string, or -1 if the function must compute the string length. In which case it must be null terminated.

  Returns

    TRUE if the string is encoded as UTF-8. FALSE otherwise

char *CPLForceToASCII(const char *pabyData, int nLen, char chReplacementChar)

  Return a new string that is made only of ASCII characters.

  If non-ASCII characters are found in the input string, they will be replaced by the provided replacement character.

  Since

    GDAL 1.7.0

  Parameters

    - pabyData – input string to test

    - nLen – length of the input string, or -1 if the function must compute the string length. In which case it must be null terminated.

    - chReplacementChar – character which will be used when the input stream contains a non ASCII character. Must be valid ASCII!

  Returns

    a new string that must be freed with CPLFree().

int CPLStrlenUTF8(const char *pszUTF8Str)

  Return the number of UTF-8 characters of a nul-terminated string.

  This is different from strlen() which returns the number of bytes.

  Parameters

    pszUTF8Str – a nul-terminated UTF-8 string

  Returns

    the number of UTF-8 characters.

int CPLCanRecode(const char *pszTestStr, const char *pszSrcEncoding, const char *pszDstEncoding)

  Checks if it is possible to recode a string from one encoding to another.

  Since

    GDAL 3.1.0

  Parameters

    - pszTestStr – a NULL terminated string.

    - pszSrcEncoding – the source encoding.

    - pszDstEncoding – the destination encoding.

  Returns

    a TRUE if recode is possible.

CPLString CPLOPrintf(const char *pszFormat, ...)

  Return a CPLString with the content of sprintf()

CPLString CPLOvPrintf(const char *pszFormat, va_list args)

  Return a CPLString with the content of vsprintf()

CPLString CPLQuotedSQLIdentifier(const char *pszIdent)

  Return a CPLString of the SQL quoted identifier.

CPLString CPLURLGetValue(const char *pszURL, const char *pszKey)

  Return the value matching a key from a key=value pair in a URL.

  Since

    GDAL 1.9.0

  Parameters

    - pszURL – the URL.

    - pszKey – the key to find.

  Returns

    the value of empty string if not found.

CPLString CPLURLAddKVP(const char *pszURL, const char *pszKey, const char *pszValue)

  Return a new URL with a new key=value pair.

  Since

    GDAL 1.9.0

  Parameters

    - pszURL – the URL.

    - pszKey – the key to find.

    - pszValue – the value of the key (may be NULL to unset an existing KVP).

  Returns

    the modified URL.

class CPLString : public string
  #include <cpl_string.h>

  Convenient string class based on std::string.

  Public Functions

  inline CPLString(void)

    Constructor.

  inline CPLString(const std::string &oStr)

    Constructor.

  inline CPLString(const char *pszStr)

    Constructor.

  inline CPLString(const char *pszStr, size_t n)

    Constructor.

  inline operator const char*(void) const

    Return string as zero terminated character array.

  inline char &operator[](std::string::size_type i)

    Return character at specified index.

  inline const char &operator[](std::string::size_type i) const

    Return character at specified index.

  inline char &operator[](int i)

    Return character at specified index.

  inline const char &operator[](int i) const

    Return character at specified index.

  inline void Clear()

    Clear the string.

  inline void Seize(char *pszValue)

    Assign specified string and take ownership of it (assumed to be allocated with CPLMalloc()).

    NULL can be safely passed to clear the string.

  CPLString &Printf(const char *pszFormat, ...)

    Assign the content of the string using sprintf()

  CPLString &vPrintf(const char *pszFormat, va_list args)

    Assign the content of the string using vsprintf()

  CPLString &FormatC(double dfValue, const char *pszFormat = nullptr)

    Format double in C locale.

    The passed value is formatted using the C locale (period as decimal separator) and appended to the target CPLString.

    Parameters

      - dfValue – the value to format.

      - pszFormat – the sprintf() style format to use or omit for default. Note that this format string should only include one substitution argument and it must be for a double (f or g).

    Returns

      a reference to the CPLString.

  CPLString &Trim()

    Trim white space.

    Trims white space off the let and right of the string. White space is any of a space, a tab, a newline (‘\n’) or a carriage control (‘\r’).

    Returns

      a reference to the CPLString.

  CPLString &Recode(const char *pszSrcEncoding, const char *pszDstEncoding)

    Recode the string.

  CPLString &replaceAll(const std::string &osBefore, const std::string &osAfter)

    Replace all occurrences of osBefore with osAfter.

  CPLString &replaceAll(const std::string &osBefore, char chAfter)

    Replace all occurrences of osBefore with chAfter.

  CPLString &replaceAll(char chBefore, const std::string &osAfter)

    Replace all occurrences of chBefore with osAfter.

  CPLString &replaceAll(char chBefore, char chAfter)

    Replace all occurrences of chBefore with chAfter.

  size_t ifind(const std::string &str, size_t pos = 0) const

    Case insensitive find() alternative.

    Since

      GDAL 1.9.0

    Parameters

      - str – substring to find.

      - pos – offset in the string at which the search starts.

    Returns

      the position of substring in the string or std::string::npos if not found.

  size_t ifind(const char *s, size_t pos = 0) const

    Case insensitive find() alternative.

    Since

      GDAL 1.9.0

    Parameters

      - s – substring to find.

      - nPos – offset in the string at which the search starts.

    Returns

      the position of the substring in the string or std::string::npos if not found.

  CPLString &toupper(void)

    Convert to upper case in place.

  CPLString &tolower(void)

    Convert to lower case in place.

  bool endsWith(const std::string &osStr) const

    Returns whether the string ends with another string.

    Parameters

      osStr – other string.

    Returns

      true if the string ends with osStr.

class CPLStringList
  #include <cpl_string.h>

  String list class designed around our use of C “char**” string lists.

  Public Functions

  CPLStringList()
  explicit CPLStringList(char **papszList, int bTakeOwnership = TRUE)

    CPLStringList constructor.

    Parameters

      - papszListIn – the NULL terminated list of strings to consume.

      - bTakeOwnership – TRUE if the CPLStringList should take ownership of the list of strings which implies responsibility to free them.

  explicit CPLStringList(CSLConstList papszList)

    CPLStringList constructor.

    The input list is copied.

    Parameters

      papszListIn – the NULL terminated list of strings to ingest.

  CPLStringList(const CPLStringList &oOther)

    Copy constructor.

  ~CPLStringList()
  CPLStringList &Clear()

    Clear the string list.

  inline int size() const

    Return size of list.

  int Count() const
    Returns

      count of strings in the list, zero if empty.

  inline bool empty() const

    Return whether the list is empty.

  CPLStringList &AddString(const char *pszNewString)

    Add a string to the list.

    A copy of the passed in string is made and inserted in the list.

    Parameters

      pszNewString – the string to add to the list.

  CPLStringList &AddStringDirectly(char *pszNewString)

    Add a string to the list.

    This method is similar to AddString(), but ownership of the pszNewString is transferred to the CPLStringList class.

    Parameters

      pszNewString – the string to add to the list.

  inline CPLStringList &InsertString(int nInsertAtLineNo, const char *pszNewLine)

    Insert into the list at identified location.

    This method will insert a string into the list at the identified location. The insertion point must be within or at the end of the list. The following entries are pushed down to make space.

    Parameters

      - nInsertAtLineNo – the line to insert at, zero to insert at front.

      - pszNewLine – to the line to insert. This string will be copied.

  CPLStringList &InsertStringDirectly(int nInsertAtLineNo, char *pszNewLine)

    Insert into the list at identified location.

    This method will insert a string into the list at the identified location. The insertion point must be within or at the end of the list. The following entries are pushed down to make space.

    Parameters

      - nInsertAtLineNo – the line to insert at, zero to insert at front.

      - pszNewLine – to the line to insert, the ownership of this string will be taken over the by the object. It must have been allocated on the heap.

  inline int FindString(const char *pszTarget) const

    Return index of pszTarget in the list, or -1.

  inline int PartialFindString(const char *pszNeedle) const

    Return index of pszTarget in the list (using partial search), or -1.

  int FindName(const char *pszName) const

    Get index of given name/value keyword.

    Note that this search is for a line in the form name=value or name:value. Use FindString() or PartialFindString() for searches not based on name=value pairs.

    Parameters

      pszKey – the name to search for.

    Returns

      the string list index of this name, or -1 on failure.

  bool FetchBool(const char *pszKey, bool bDefault) const

    Check for boolean key value.

    In a CPLStringList of “Name=Value” pairs, look to see if there is a key with the given name, and if it can be interpreted as being TRUE. If the key appears without any “=Value” portion it will be considered true. If the value is NO, FALSE or 0 it will be considered FALSE otherwise if the key appears in the list it will be considered TRUE. If the key doesn’t appear at all, the indicated default value will be returned.

    Parameters

      - pszKey – the key value to look for (case insensitive).

      - bDefault – the value to return if the key isn’t found at all.

    Returns

      true or false

  int FetchBoolean(const char *pszKey, int bDefault) const

    DEPRECATED: Check for boolean key value.

    In a CPLStringList of “Name=Value” pairs, look to see if there is a key with the given name, and if it can be interpreted as being TRUE. If the key appears without any “=Value” portion it will be considered true. If the value is NO, FALSE or 0 it will be considered FALSE otherwise if the key appears in the list it will be considered TRUE. If the key doesn’t appear at all, the indicated default value will be returned.

    Parameters

      - pszKey – the key value to look for (case insensitive).

      - bDefault – the value to return if the key isn’t found at all.

    Returns

      TRUE or FALSE

  const char *FetchNameValue(const char *pszKey) const

    Fetch value associated with this key name.

    If this list sorted, a fast binary search is done, otherwise a linear scan is done. Name lookup is case insensitive.

    Parameters

      pszName – the key name to search for.

    Returns

      the corresponding value or NULL if not found. The returned string should not be modified and points into internal object state that may change on future calls.

  const char *FetchNameValueDef(const char *pszKey, const char *pszDefault) const

    Fetch value associated with this key name.

    If this list sorted, a fast binary search is done, otherwise a linear scan is done. Name lookup is case insensitive.

    Parameters

      - pszName – the key name to search for.

      - pszDefault – the default value returned if the named entry isn’t found.

    Returns

      the corresponding value or the passed default if not found.

  CPLStringList &AddNameValue(const char *pszKey, const char *pszValue)

    Add a name=value entry to the list.

    A key=value string is prepared and appended to the list. There is no check for other values for the same key in the list.

    Parameters

      - pszKey – the key name to add.

      - pszValue – the key value to add.

  CPLStringList &SetNameValue(const char *pszKey, const char *pszValue)

    Set name=value entry in the list.

    Similar to AddNameValue(), except if there is already a value for the key in the list it is replaced instead of adding a new entry to the list. If pszValue is NULL any existing key entry is removed.

    Parameters

      - pszKey – the key name to add.

      - pszValue – the key value to add.

  CPLStringList &Assign(char **papszListIn, int bTakeOwnership = TRUE)

    Assign a list of strings.

    Parameters

      - papszListIn – the NULL terminated list of strings to consume.

      - bTakeOwnership – TRUE if the CPLStringList should take ownership of the list of strings which implies responsibility to free them.

    Returns

      a reference to the CPLStringList on which it was invoked.

  inline CPLStringList &operator=(char **papszListIn)

    Assignment operator.

  CPLStringList &operator=(const CPLStringList &oOther)

    Assignment operator.

  CPLStringList &operator=(CSLConstList papszListIn)

    Assignment operator.

  CPLStringList &operator=(CPLStringList &&oOther)

    Move assignment operator.

  char *operator[](int i)

    Return string at specified index.

    Fetch entry “i”.

    Fetches the requested item in the list. Note that the returned string remains owned by the CPLStringList. If “i” is out of range NULL is returned.

    Parameters

      i – the index of the list item to return.

    Returns

      selected entry in the list.

  inline char *operator[](size_t i)

    Return string at specified index.

  const char *operator[](int i) const

    Return string at specified index.

  inline const char *operator[](size_t i) const

    Return string at specified index.

  inline const char *operator[](const char *pszKey) const

    Return value corresponding to pszKey, or nullptr.

  inline char **List()

    Return list.

    Ownership remains to the object

  inline CSLConstList List() const

    Return list.

    Ownership remains to the object

  char **StealList()

    Seize ownership of underlying string array.

    This method is similar to List(), except that the returned list is now owned by the caller and the CPLStringList is emptied.

    Returns

      the C style string list.

  CPLStringList &Sort()

    Sort the entries in the list and mark list sorted.

    Note that once put into “sorted” mode, the CPLStringList will attempt to keep things in sorted order through calls to AddString(), AddStringDirectly(), AddNameValue(), SetNameValue(). Complete list assignments (via Assign() and operator= will clear the sorting state. When in sorted order FindName(), FetchNameValue() and FetchNameValueDef() will do a binary search to find the key, substantially improve lookup performance in large lists.

  inline int IsSorted() const

    Returns whether the list is sorted.

  inline operator char**(void)

    Return lists.

  inline operator CSLConstList(void) const

    Return lists.

  Private Functions

  void MakeOurOwnCopy()
  void EnsureAllocation(int nMaxLength)
  int FindSortedInsertionPoint(const char *pszLine)

  Private Members

  char **papszList = nullptr
  mutable int nCount = 0
  mutable int nAllocation = 0
  bool bOwnList = false
  bool bIsSorted = false

## cpl_time.h

Functions

struct tm *CPLUnixTimeToYMDHMS(GIntBig unixTime, struct tm *pRet)

  Converts a time value since the Epoch (aka “unix” time) to a broken-down UTC time.

  This function is similar to gmtime_r(). This function will always set tm_isdst to 0.

  Parameters

    - unixTime – number of seconds since the Epoch.

    - pRet – address of the return structure.

  Returns

    the structure pointed by pRet filled with a broken-down UTC time.

GIntBig CPLYMDHMSToUnixTime(const struct tm *brokendowntime)

  Converts a broken-down UTC time into time since the Epoch (aka “unix” time).

  This function is similar to mktime(), but the passed structure is not modified. This function ignores the tm_wday, tm_yday and tm_isdst fields of the passed value. No timezone shift will be applied. This function returns 0 for the 1/1/1970 00:00:00

  Parameters

    brokendowntime – broken-downtime UTC time.

  Returns

    a number of seconds since the Epoch encoded as a value of type GIntBig, or -1 if the time cannot be represented.

int CPLParseRFC822DateTime(const char *pszRFC822DateTime, int *pnYear, int *pnMonth, int *pnDay, int *pnHour, int *pnMinute, int *pnSecond, int *pnTZFlag, int *pnWeekDay)

  Parse a RFC822 formatted date-time string.

  Such as [Fri,] 28 Dec 2007 05:24[:17] GMT

  Since

    GDAL 2.3

  Parameters

    - pszRFC822DateTime – formatted string.

    - pnYear – pointer to int receiving year (like 1980, 2000, etc…), or NULL

    - pnMonth – pointer to int receiving month (between 1 and 12), or NULL

    - pnDay – pointer to int receiving day of month (between 1 and 31), or NULL

    - pnHour – pointer to int receiving hour of day (between 0 and 23), or NULL

    - pnMinute – pointer to int receiving minute (between 0 and 59), or NULL

    - pnSecond – pointer to int receiving second (between 0 and 60, or -1 if unknown), or NULL

    - pnTZFlag – pointer to int receiving time zone flag (0=unknown, 100=GMT, 101=GMT+15minute, 99=GMT-15minute), or NULL

    - pnWeekDay – pointer to int receiving day of week (between 1 and 7, or 0 if invalid/unset), or NULL

  Returns

    TRUE if parsing is successful

## cpl_virtualmem.h

Virtual memory management.

This file provides mechanism to define virtual memory mappings, whose content is allocated transparently and filled on-the-fly. Those virtual memory mappings can be much larger than the available RAM, but only parts of the virtual memory mapping, in the limit of the allowed the cache size, will actually be physically allocated.

This exploits low-level mechanisms of the operating system (virtual memory allocation, page protection and handler of virtual memory exceptions).

It is also possible to create a virtual memory mapping from a file or part of a file.

The current implementation is Linux only.

Typedefs

typedef struct CPLVirtualMem CPLVirtualMem

  Opaque type that represents a virtual memory mapping.

typedef void (*CPLVirtualMemCachePageCbk)(CPLVirtualMem *ctxt, size_t nOffset, void *pPageToFill, size_t nToFill, void *pUserData)

  Callback triggered when a still unmapped page of virtual memory is accessed.

  The callback has the responsibility of filling the page with relevant values

  Parameters

    - ctxt – virtual memory handle.

    - nOffset – offset of the page in the memory mapping.

    - pPageToFill – address of the page to fill. Note that the address might be a temporary location, and not at CPLVirtualMemGetAddr() + nOffset.

    - nToFill – number of bytes of the page.

    - pUserData – user data that was passed to CPLVirtualMemNew().

typedef void (*CPLVirtualMemUnCachePageCbk)(CPLVirtualMem *ctxt, size_t nOffset, const void *pPageToBeEvicted, size_t nToBeEvicted, void *pUserData)

  Callback triggered when a dirty mapped page is going to be freed.

  (saturation of cache, or termination of the virtual memory mapping).

  Parameters

    - ctxt – virtual memory handle.

    - nOffset – offset of the page in the memory mapping.

    - pPageToBeEvicted – address of the page that will be flushed. Note that the address might be a temporary location, and not at CPLVirtualMemGetAddr() + nOffset.

    - nToBeEvicted – number of bytes of the page.

    - pUserData – user data that was passed to CPLVirtualMemNew().

typedef void (*CPLVirtualMemFreeUserData)(void *pUserData)

  Callback triggered when a virtual memory mapping is destroyed.

  Parameters

    pUserData – user data that was passed to CPLVirtualMemNew().

Enums

enum CPLVirtualMemAccessMode

  Access mode of a virtual memory mapping.

  Values:

  enumerator VIRTUALMEM_READONLY

    The mapping is meant at being read-only, but writes will not be prevented. Note that any content written will be lost.

  enumerator VIRTUALMEM_READONLY_ENFORCED

    The mapping is meant at being read-only, and this will be enforced through the operating system page protection mechanism.

  enumerator VIRTUALMEM_READWRITE

    The mapping is meant at being read-write, and modified pages can be saved thanks to the pfnUnCachePage callback

Functions

size_t CPLGetPageSize(void)

  Return the size of a page of virtual memory.

  Since

    GDAL 1.11

  Returns

    the page size.

CPLVirtualMem *CPLVirtualMemNew(size_t nSize, size_t nCacheSize, size_t nPageSizeHint, int bSingleThreadUsage, CPLVirtualMemAccessMode eAccessMode, CPLVirtualMemCachePageCbk pfnCachePage, CPLVirtualMemUnCachePageCbk pfnUnCachePage, CPLVirtualMemFreeUserData pfnFreeUserData, void *pCbkUserData)

  Create a new virtual memory mapping.

  This will reserve an area of virtual memory of size nSize, whose size might be potentially much larger than the physical memory available. Initially, no physical memory will be allocated. As soon as memory pages will be accessed, they will be allocated transparently and filled with the pfnCachePage callback. When the allowed cache size is reached, the least recently used pages will be unallocated.

  On Linux AMD64 platforms, the maximum value for nSize is 128 TB. On Linux x86 platforms, the maximum value for nSize is 2 GB.

  Only supported on Linux for now.

  Note that on Linux, this function will install a SIGSEGV handler. The original handler will be restored by CPLVirtualMemManagerTerminate().

  Since

    GDAL 1.11

  Parameters

    - nSize – size in bytes of the virtual memory mapping.

    - nCacheSize – size in bytes of the maximum memory that will be really allocated (must ideally fit into RAM).

    - nPageSizeHint – hint for the page size. Must be a multiple of the system page size, returned by CPLGetPageSize(). Minimum value is generally 4096. Might be set to 0 to let the function determine a default page size.

    - bSingleThreadUsage – set to TRUE if there will be no concurrent threads that will access the virtual memory mapping. This can optimize performance a bit.

    - eAccessMode – permission to use for the virtual memory mapping.

    - pfnCachePage – callback triggered when a still unmapped page of virtual memory is accessed. The callback has the responsibility of filling the page with relevant values.

    - pfnUnCachePage – callback triggered when a dirty mapped page is going to be freed (saturation of cache, or termination of the virtual memory mapping). Might be NULL.

    - pfnFreeUserData – callback that can be used to free pCbkUserData. Might be NULL

    - pCbkUserData – user data passed to pfnCachePage and pfnUnCachePage.

  Returns

    a virtual memory object that must be freed by CPLVirtualMemFree(), or NULL in case of failure.

int CPLIsVirtualMemFileMapAvailable(void)

  Return if virtual memory mapping of a file is available.

  Since

    GDAL 1.11

  Returns

    TRUE if virtual memory mapping of a file is available.

CPLVirtualMem *CPLVirtualMemFileMapNew(VSILFILE *fp, vsi_l_offset nOffset, vsi_l_offset nLength, CPLVirtualMemAccessMode eAccessMode, CPLVirtualMemFreeUserData pfnFreeUserData, void *pCbkUserData)

  Create a new virtual memory mapping from a file.

  The file must be a “real” file recognized by the operating system, and not a VSI extended virtual file.

  In VIRTUALMEM_READWRITE mode, updates to the memory mapping will be written in the file.

  On Linux AMD64 platforms, the maximum value for nLength is 128 TB. On Linux x86 platforms, the maximum value for nLength is 2 GB.

  Supported on Linux only in GDAL <= 2.0, and all POSIX systems supporting mmap() in GDAL >= 2.1

  Since

    GDAL 1.11

  Parameters

    - fp – Virtual file handle.

    - nOffset – Offset in the file to start the mapping from.

    - nLength – Length of the portion of the file to map into memory.

    - eAccessMode – Permission to use for the virtual memory mapping. This must be consistent with how the file has been opened.

    - pfnFreeUserData – callback that is called when the object is destroyed.

    - pCbkUserData – user data passed to pfnFreeUserData.

  Returns

    a virtual memory object that must be freed by CPLVirtualMemFree(), or NULL in case of failure.

CPLVirtualMem *CPLVirtualMemDerivedNew(CPLVirtualMem *pVMemBase, vsi_l_offset nOffset, vsi_l_offset nSize, CPLVirtualMemFreeUserData pfnFreeUserData, void *pCbkUserData)

  Create a new virtual memory mapping derived from an other virtual memory mapping.

  This may be useful in case of creating mapping for pixel interleaved data.

  The new mapping takes a reference on the base mapping.

  Since

    GDAL 1.11

  Parameters

    - pVMemBase – Base virtual memory mapping

    - nOffset – Offset in the base virtual memory mapping from which to start the new mapping.

    - nSize – Size of the base virtual memory mapping to expose in the the new mapping.

    - pfnFreeUserData – callback that is called when the object is destroyed.

    - pCbkUserData – user data passed to pfnFreeUserData.

  Returns

    a virtual memory object that must be freed by CPLVirtualMemFree(), or NULL in case of failure.

void CPLVirtualMemFree(CPLVirtualMem *ctxt)

  Free a virtual memory mapping.

  The pointer returned by CPLVirtualMemGetAddr() will no longer be valid. If the virtual memory mapping was created with read/write permissions and that they are dirty (i.e. modified) pages, they will be flushed through the pfnUnCachePage callback before being freed.

  Since

    GDAL 1.11

  Parameters

    ctxt – context returned by CPLVirtualMemNew().

void *CPLVirtualMemGetAddr(CPLVirtualMem *ctxt)

  Return the pointer to the start of a virtual memory mapping.

  The bytes in the range [p:p+CPLVirtualMemGetSize()-1] where p is the pointer returned by this function will be valid, until CPLVirtualMemFree() is called.

  Note that if a range of bytes used as an argument of a system call (such as read() or write()) contains pages that have not been “realized”, the system call will fail with EFAULT. CPLVirtualMemPin() can be used to work around this issue.

  Since

    GDAL 1.11

  Parameters

    ctxt – context returned by CPLVirtualMemNew().

  Returns

    the pointer to the start of a virtual memory mapping.

size_t CPLVirtualMemGetSize(CPLVirtualMem *ctxt)

  Return the size of the virtual memory mapping.

  Since

    GDAL 1.11

  Parameters

    ctxt – context returned by CPLVirtualMemNew().

  Returns

    the size of the virtual memory mapping.

int CPLVirtualMemIsFileMapping(CPLVirtualMem *ctxt)

  Return if the virtual memory mapping is a direct file mapping.

  Since

    GDAL 1.11

  Parameters

    ctxt – context returned by CPLVirtualMemNew().

  Returns

    TRUE if the virtual memory mapping is a direct file mapping.

CPLVirtualMemAccessMode CPLVirtualMemGetAccessMode(CPLVirtualMem *ctxt)

  Return the access mode of the virtual memory mapping.

  Since

    GDAL 1.11

  Parameters

    ctxt – context returned by CPLVirtualMemNew().

  Returns

    the access mode of the virtual memory mapping.

size_t CPLVirtualMemGetPageSize(CPLVirtualMem *ctxt)

  Return the page size associated to a virtual memory mapping.

  The value returned will be at least CPLGetPageSize(), but potentially larger.

  Since

    GDAL 1.11

  Parameters

    ctxt – context returned by CPLVirtualMemNew().

  Returns

    the page size

int CPLVirtualMemIsAccessThreadSafe(CPLVirtualMem *ctxt)

  Return TRUE if this memory mapping can be accessed safely from concurrent threads.

  The situation that can cause problems is when several threads try to access a page of the mapping that is not yet mapped.

  The return value of this function depends on whether bSingleThreadUsage has been set of not in CPLVirtualMemNew() and/or the implementation.

  On Linux, this will always return TRUE if bSingleThreadUsage = FALSE.

  Since

    GDAL 1.11

  Parameters

    ctxt – context returned by CPLVirtualMemNew().

  Returns

    TRUE if this memory mapping can be accessed safely from concurrent threads.

void CPLVirtualMemDeclareThread(CPLVirtualMem *ctxt)

  Declare that a thread will access a virtual memory mapping.

  This function must be called by a thread that wants to access the content of a virtual memory mapping, except if the virtual memory mapping has been created with bSingleThreadUsage = TRUE.

  This function must be paired with CPLVirtualMemUnDeclareThread().

  Since

    GDAL 1.11

  Parameters

    ctxt – context returned by CPLVirtualMemNew().

void CPLVirtualMemUnDeclareThread(CPLVirtualMem *ctxt)

  Declare that a thread will stop accessing a virtual memory mapping.

  This function must be called by a thread that will no longer access the content of a virtual memory mapping, except if the virtual memory mapping has been created with bSingleThreadUsage = TRUE.

  This function must be paired with CPLVirtualMemDeclareThread().

  Since

    GDAL 1.11

  Parameters

    ctxt – context returned by CPLVirtualMemNew().

void CPLVirtualMemPin(CPLVirtualMem *ctxt, void *pAddr, size_t nSize, int bWriteOp)

  Make sure that a region of virtual memory will be realized.

  Calling this function is not required, but might be useful when debugging a process with tools like gdb or valgrind that do not naturally like segmentation fault signals.

  It is also needed when wanting to provide part of virtual memory mapping to a system call such as read() or write(). If read() or write() is called on a memory region not yet realized, the call will fail with EFAULT.

  Since

    GDAL 1.11

  Parameters

    - ctxt – context returned by CPLVirtualMemNew().

    - pAddr – the memory region to pin.

    - nSize – the size of the memory region.

    - bWriteOp – set to TRUE if the memory are will be accessed in write mode.

void CPLVirtualMemManagerTerminate(void)

  Cleanup any resource and handlers related to virtual memory.

  This function must be called after the last CPLVirtualMem object has been freed.

  Since

    GDAL 2.0

## cpl_vsi_error.h

Defines

VSIE_None

VSIE_FileError

VSIE_HttpError

VSIE_AWSError

VSIE_AWSAccessDenied

VSIE_AWSBucketNotFound

VSIE_AWSObjectNotFound

VSIE_AWSInvalidCredentials

VSIE_AWSSignatureDoesNotMatch

Typedefs

typedef int VSIErrorNum

Functions

void VSIError(VSIErrorNum err_no, const char *fmt, ...)

  Report an VSI filesystem error.

  This function records an error in the filesystem that may or may not be used in the future, for example converted into a CPLError. This allows filesystem errors to be available to error handling functionality, but reported only when necessary.

  Parameters

    - err_no – the error number (VSIE_*) from cpl_vsi_error.h.

    - fmt – a printf() style format string. Any additional arguments will be treated as arguments to fill in this format in a manner similar to printf().

void VSIErrorReset(void)

  Erase any traces of previous errors.

  This is used to clear out the latest file system error when it is either translated into a CPLError call or when it is determined to be ignorable.

VSIErrorNum VSIGetLastErrorNo(void)

  Fetch the last error number.

  Fetches the last error number posted with VSIError(), that hasn’t been cleared by VSIErrorReset(). This is the error number, not the error class.

  Returns

    the error number of the last error to occur, or VSIE_None (0) if there are no posted errors.

const char *VSIGetLastErrorMsg(void)

  Get the last error message.

  Fetches the last error message posted with VSIError(), that hasn’t been cleared by VSIErrorReset(). The returned pointer is to an internal string that should not be altered or freed.

  Returns

    the last error message, or NULL if there is no posted error message.

int VSIToCPLError(CPLErr eErrClass, CPLErrorNum eDefaultErrorNo)

  Translate the VSI error into a CPLError call.

  If there is a VSIError that is set, translate it to a CPLError call with the given CPLErr error class, and either an appropriate CPLErrorNum given the VSIErrorNum, or the given default CPLErrorNum.

  Returns

    TRUE if a CPLError was issued, or FALSE if not.

## cpl_vsi.h

Standard C Covers

The VSI functions are intended to be hookable aliases for Standard C I/O, memory allocation and other system functions. They are intended to allow virtualization of disk I/O so that non file data sources can be made to appear as files, and so that additional error trapping and reporting can be interested. The memory access API is aliased so that special application memory management services can be used.

It is intended that each of these functions retains exactly the same calling pattern as the original Standard C functions they relate to. This means we don’t have to provide custom documentation, and also means that the default implementation is very simple.

Defines

VSI_ISLNK(x)

  Test if the file is a symbolic link.

VSI_ISREG(x)

  Test if the file is a regular file.

VSI_ISDIR(x)

  Test if the file is a directory.

VSI_L_OFFSET_MAX

  Maximum value for a file offset.

VSIStatBufL

  Type for VSIStatL()

VSI_STAT_EXISTS_FLAG

  Flag provided to VSIStatExL() to test if the file exists.

VSI_STAT_NATURE_FLAG

  Flag provided to VSIStatExL() to query the nature (file/dir) of the file.

VSI_STAT_SIZE_FLAG

  Flag provided to VSIStatExL() to query the file size.

VSI_STAT_SET_ERROR_FLAG

  Flag provided to VSIStatExL() to issue a VSIError in case of failure.

VSI_STAT_CACHE_ONLY

  Flag provided to VSIStatExL() to only use already cached results.

  Since

    GDAL 3.4

VSI_MALLOC_ALIGNED_AUTO_VERBOSE(size)

  VSIMallocAlignedAutoVerbose() with FILE and LINE reporting.

VSI_MALLOC_VERBOSE(size)

  VSI_MALLOC_VERBOSE.

VSI_MALLOC2_VERBOSE(nSize1, nSize2)

  VSI_MALLOC2_VERBOSE.

VSI_MALLOC3_VERBOSE(nSize1, nSize2, nSize3)

  VSI_MALLOC3_VERBOSE.

VSI_CALLOC_VERBOSE(nCount, nSize)

  VSI_CALLOC_VERBOSE.

VSI_REALLOC_VERBOSE(pOldPtr, nNewSize)

  VSI_REALLOC_VERBOSE.

VSI_STRDUP_VERBOSE(pszStr)

  VSI_STRDUP_VERBOSE.

CPLReadDir

  Alias of VSIReadDir()

Typedefs

typedef GUIntBig vsi_l_offset

  Type for a file offset.

typedef FILE VSILFILE

  Opaque type for a FILE that implements the VSIVirtualHandle API.

typedef struct VSIDIR VSIDIR

  Opaque type for a directory iterator.

typedef size_t (*VSIWriteFunction)(const void *ptr, size_t size, size_t nmemb, FILE *stream)

  Callback used by VSIStdoutSetRedirection()

typedef int (*VSIFilesystemPluginStatCallback)(void *pUserData, const char *pszFilename, VSIStatBufL *pStatBuf, int nFlags)

  Return information about a handle.

  Optional (driver dependent)

  Since

    GDAL 3.0

typedef int (*VSIFilesystemPluginUnlinkCallback)(void *pUserData, const char *pszFilename)

  Remove handle by name.

  Optional

  Since

    GDAL 3.0

typedef int (*VSIFilesystemPluginRenameCallback)(void *pUserData, const char *oldpath, const char *newpath)

  Rename handle.

  Optional

  Since

    GDAL 3.0

typedef int (*VSIFilesystemPluginMkdirCallback)(void *pUserData, const char *pszDirname, long nMode)

  Create Directory.

  Optional

  Since

    GDAL 3.0

typedef int (*VSIFilesystemPluginRmdirCallback)(void *pUserData, const char *pszDirname)

  Delete Directory.

  Optional

  Since

    GDAL 3.0

typedef char **(*VSIFilesystemPluginReadDirCallback)(void *pUserData, const char *pszDirname, int nMaxFiles)

  List directory content.

  Optional

  Since

    GDAL 3.0

typedef char **(*VSIFilesystemPluginSiblingFilesCallback)(void *pUserData, const char *pszDirname)

  List related files.

  Must return NULL if unknown, or a list of relative filenames that can be opened along the main file. If no other file than pszFilename needs to be opened, return static_cast<char**> (CPLCalloc(1,sizeof(char*)));

  Optional

  Since

    GDAL 3.2

typedef void *(*VSIFilesystemPluginOpenCallback)(void *pUserData, const char *pszFilename, const char *pszAccess)

  Open a handle.

  Mandatory. Returns an opaque pointer that will be used in subsequent file I/O calls. Should return null and/or set errno if the handle does not exist or the access mode is incorrect.

  Since

    GDAL 3.0

typedef vsi_l_offset (*VSIFilesystemPluginTellCallback)(void *pFile)

  Return current position in handle.

  Mandatory

  Since

    GDAL 3.0

typedef int (*VSIFilesystemPluginSeekCallback)(void *pFile, vsi_l_offset nOffset, int nWhence)

  Seek to position in handle.

  Mandatory except for write only handles

  Since

    GDAL 3.0

typedef size_t (*VSIFilesystemPluginReadCallback)(void *pFile, void *pBuffer, size_t nSize, size_t nCount)

  Read data from current position, returns the number of blocks correctly read.

  Mandatory except for write only handles

  Since

    GDAL 3.0

typedef int (*VSIFilesystemPluginReadMultiRangeCallback)(void *pFile, int nRanges, void **ppData, const vsi_l_offset *panOffsets, const size_t *panSizes)

  Read from multiple offsets.

  Optional, will be replaced by multiple calls to Read() if not provided

  Since

    GDAL 3.0

typedef VSIRangeStatus (*VSIFilesystemPluginGetRangeStatusCallback)(void *pFile, vsi_l_offset nOffset, vsi_l_offset nLength)

  Get empty ranges.

  Optional

  Since

    GDAL 3.0

typedef int (*VSIFilesystemPluginEofCallback)(void *pFile)

  Has end of file been reached.

  Mandatory? for read handles.

  Since

    GDAL 3.0

typedef size_t (*VSIFilesystemPluginWriteCallback)(void *pFile, const void *pBuffer, size_t nSize, size_t nCount)

  Write bytes at current offset.

  Mandatory for writable handles

  Since

    GDAL 3.0

typedef int (*VSIFilesystemPluginFlushCallback)(void *pFile)

  Sync written bytes.

  Optional

  Since

    GDAL 3.0

typedef int (*VSIFilesystemPluginTruncateCallback)(void *pFile, vsi_l_offset nNewSize)

  Truncate handle.

  Mandatory (driver dependent?) for write handles

typedef int (*VSIFilesystemPluginCloseCallback)(void *pFile)

  Close file handle.

  Optional

  Since

    GDAL 3.0

Enums

enum VSIRangeStatus

  Range status.

  Values:

  enumerator VSI_RANGE_STATUS_UNKNOWN

    Unknown.

  enumerator VSI_RANGE_STATUS_DATA

    Data present.

  enumerator VSI_RANGE_STATUS_HOLE

    Hole.

Functions

VSILFILE *VSIFOpenL(const char*, const char*)

  Open file.

  This function opens a file with the desired access. Large files (larger than 2GB) should be supported. Binary access is always implied and the “b” does not need to be included in the pszAccess string.

  Note that the “VSILFILE *” returned since GDAL 1.8.0 by this function is NOT a standard C library FILE *, and cannot be used with any functions other than the “VSI*L” family of functions. They aren’t “real” FILE objects.

  On windows it is possible to define the configuration option GDAL_FILE_IS_UTF8 to have pszFilename treated as being in the local encoding instead of UTF-8, restoring the pre-1.8.0 behavior of VSIFOpenL().

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory.

  Analog of the POSIX fopen() function.

  Parameters

    - pszFilename – the file to open. UTF-8 encoded.

    - pszAccess – access requested (i.e. “r”, “r+”, “w”)

  Returns

    NULL on failure, or the file handle.

VSILFILE *VSIFOpenExL(const char*, const char*, int)

  Open file.

  This function opens a file with the desired access. Large files (larger than 2GB) should be supported. Binary access is always implied and the “b” does not need to be included in the pszAccess string.

  Note that the “VSILFILE *” returned by this function is NOT a standard C library FILE *, and cannot be used with any functions other than the “VSI*L” family of functions. They aren’t “real” FILE objects.

  On windows it is possible to define the configuration option GDAL_FILE_IS_UTF8 to have pszFilename treated as being in the local encoding instead of UTF-8, restoring the pre-1.8.0 behavior of VSIFOpenL().

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory.

  Analog of the POSIX fopen() function.

  Since

    GDAL 2.1

  Parameters

    - pszFilename – the file to open. UTF-8 encoded.

    - pszAccess – access requested (i.e. “r”, “r+”, “w”)

    - bSetError – flag determining whether or not this open call should set VSIErrors on failure.

  Returns

    NULL on failure, or the file handle.

VSILFILE *VSIFOpenEx2L(const char*, const char*, int, CSLConstList)

  Open file.

  This function opens a file with the desired access. Large files (larger than 2GB) should be supported. Binary access is always implied and the “b” does not need to be included in the pszAccess string.

  Note that the “VSILFILE *” returned by this function is NOT a standard C library FILE *, and cannot be used with any functions other than the “VSI*L” family of functions. They aren’t “real” FILE objects.

  On windows it is possible to define the configuration option GDAL_FILE_IS_UTF8 to have pszFilename treated as being in the local encoding instead of UTF-8, restoring the pre-1.8.0 behavior of VSIFOpenL().

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory.

  Analog of the POSIX fopen() function.

  Since

    GDAL 3.3

  Parameters

    - pszFilename – the file to open. UTF-8 encoded.

    - pszAccess – access requested (i.e. “r”, “r+”, “w”)

    - bSetError – flag determining whether or not this open call should set VSIErrors on failure.

    - papszOptions – NULL or NULL-terminated list of strings. The content is highly file system dependent. Currently only MIME headers such as Content-Type and Content-Encoding are supported for the /vsis3/, /vsigs/, /vsiaz/, /vsiadls/ file systems.

  Returns

    NULL on failure, or the file handle.

int VSIFCloseL(VSILFILE*)

  Close file.

  This function closes the indicated file.

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory.

  Analog of the POSIX fclose() function.

  Parameters

    fp – file handle opened with VSIFOpenL(). Passing a nullptr produces undefined behavior.

  Returns

    0 on success or -1 on failure.

int VSIFSeekL(VSILFILE*, vsi_l_offset, int)

  Seek to requested offset.

  Seek to the desired offset (nOffset) in the indicated file.

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory.

  Analog of the POSIX fseek() call.

  Caution: vsi_l_offset is a unsigned type, so SEEK_CUR can only be used for positive seek. If negative seek is needed, use VSIFSeekL( fp, VSIFTellL(fp) + negative_offset, SEEK_SET ).

  Parameters

    - fp – file handle opened with VSIFOpenL().

    - nOffset – offset in bytes.

    - nWhence – one of SEEK_SET, SEEK_CUR or SEEK_END.

  Returns

    0 on success or -1 one failure.

vsi_l_offset VSIFTellL(VSILFILE*)

  Tell current file offset.

  Returns the current file read/write offset in bytes from the beginning of the file.

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory.

  Analog of the POSIX ftell() call.

  Parameters

    fp – file handle opened with VSIFOpenL().

  Returns

    file offset in bytes.

void VSIRewindL(VSILFILE*)

  Rewind the file pointer to the beginning of the file.

  This is equivalent to VSIFSeekL( fp, 0, SEEK_SET )

  Analog of the POSIX rewind() call.

  Parameters

    fp – file handle opened with VSIFOpenL().

size_t VSIFReadL(void*, size_t, size_t, VSILFILE*)

  Read bytes from file.

  Reads nCount objects of nSize bytes from the indicated file at the current offset into the indicated buffer.

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory.

  Analog of the POSIX fread() call.

  Parameters

    - pBuffer – the buffer into which the data should be read (at least nCount * nSize bytes in size.

    - nSize – size of objects to read in bytes.

    - nCount – number of objects to read.

    - fp – file handle opened with VSIFOpenL().

  Returns

    number of objects successfully read.

int VSIFReadMultiRangeL(int nRanges, void **ppData, const vsi_l_offset *panOffsets, const size_t *panSizes, VSILFILE*)

  Read several ranges of bytes from file.

  Reads nRanges objects of panSizes[i] bytes from the indicated file at the offset panOffsets[i] into the buffer ppData[i].

  Ranges must be sorted in ascending start offset, and must not overlap each other.

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory or /vsicurl/.

  Since

    GDAL 1.9.0

  Parameters

    - nRanges – number of ranges to read.

    - ppData – array of nRanges buffer into which the data should be read (ppData[i] must be at list panSizes[i] bytes).

    - panOffsets – array of nRanges offsets at which the data should be read.

    - panSizes – array of nRanges sizes of objects to read (in bytes).

    - fp – file handle opened with VSIFOpenL().

  Returns

    0 in case of success, -1 otherwise.

size_t VSIFWriteL(const void*, size_t, size_t, VSILFILE*)

  Write bytes to file.

  Writess nCount objects of nSize bytes to the indicated file at the current offset into the indicated buffer.

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory.

  Analog of the POSIX fwrite() call.

  Parameters

    - pBuffer – the buffer from which the data should be written (at least nCount * nSize bytes in size.

    - nSize – size of objects to read in bytes.

    - nCount – number of objects to read.

    - fp – file handle opened with VSIFOpenL().

  Returns

    number of objects successfully written.

int VSIFEofL(VSILFILE*)

  Test for end of file.

  Returns TRUE (non-zero) if an end-of-file condition occurred during the previous read operation. The end-of-file flag is cleared by a successful VSIFSeekL() call.

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory.

  Analog of the POSIX feof() call.

  Parameters

    fp – file handle opened with VSIFOpenL().

  Returns

    TRUE if at EOF else FALSE.

int VSIFTruncateL(VSILFILE*, vsi_l_offset)

  Truncate/expand the file to the specified size.

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory.

  Analog of the POSIX ftruncate() call.

  Since

    GDAL 1.9.0

  Parameters

    - fp – file handle opened with VSIFOpenL().

    - nNewSize – new size in bytes.

  Returns

    0 on success

int VSIFFlushL(VSILFILE*)

  Flush pending writes to disk.

  For files in write or update mode and on filesystem types where it is applicable, all pending output on the file is flushed to the physical disk.

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory.

  Analog of the POSIX fflush() call.

  Parameters

    fp – file handle opened with VSIFOpenL().

  Returns

    0 on success or -1 on error.

int VSIFPrintfL(VSILFILE*, const char*, ...)

  Formatted write to file.

  Provides fprintf() style formatted output to a VSI*L file. This formats an internal buffer which is written using VSIFWriteL().

  Analog of the POSIX fprintf() call.

  Parameters

    - fp – file handle opened with VSIFOpenL().

    - pszFormat – the printf() style format string.

  Returns

    the number of bytes written or -1 on an error.

int VSIFPutcL(int, VSILFILE*)

  Write a single byte to the file.

  Writes the character nChar, cast to an unsigned char, to file.

  Almost an analog of the POSIX fputc() call, except that it returns the number of character written (1 or 0), and not the (cast) character itself or EOF.

  Parameters

    - nChar – character to write.

    - fp – file handle opened with VSIFOpenL().

  Returns

    1 in case of success, 0 on error.

VSIRangeStatus VSIFGetRangeStatusL(VSILFILE *fp, vsi_l_offset nStart, vsi_l_offset nLength)

  Return if a given file range contains data or holes filled with zeroes.

  This uses the filesystem capabilities of querying which regions of a sparse file are allocated or not. This is currently only implemented for Linux (and no other Unix derivatives) and Windows.

  Note: A return of VSI_RANGE_STATUS_DATA doesn’t exclude that the extent is filled with zeroes! It must be interpreted as “may

  contain non-zero data”.

  Since

    GDAL 2.2

  Parameters

    - fp – file handle opened with VSIFOpenL().

    - nOffset – offset of the start of the extent.

    - nLength – extent length.

  Returns

    extent status: VSI_RANGE_STATUS_UNKNOWN, VSI_RANGE_STATUS_DATA or VSI_RANGE_STATUS_HOLE

int VSIIngestFile(VSILFILE *fp, const char *pszFilename, GByte **ppabyRet, vsi_l_offset *pnSize, GIntBig nMaxSize)

  Ingest a file into memory.

  Read the whole content of a file into a memory buffer.

  Either fp or pszFilename can be NULL, but not both at the same time.

  If fp is passed non-NULL, it is the responsibility of the caller to close it.

  If non-NULL, the returned buffer is guaranteed to be NUL-terminated.

  Since

    GDAL 1.11

  Parameters

    - fp – file handle opened with VSIFOpenL().

    - pszFilename – filename.

    - ppabyRet – pointer to the target buffer. *ppabyRet must be freed with VSIFree()

    - pnSize – pointer to variable to store the file size. May be NULL.

    - nMaxSize – maximum size of file allowed. If no limit, set to a negative value.

  Returns

    TRUE in case of success.

int VSIOverwriteFile(VSILFILE *fpTarget, const char *pszSourceFilename)

  Overwrite an existing file with content from another one.

  Since

    GDAL 3.1

  Parameters

    - fpTarget – file handle opened with VSIFOpenL() with “rb+” flag.

    - pszSourceFilename – source filename

  Returns

    TRUE in case of success.

int VSIStatL(const char*, VSIStatBufL*)

  Get filesystem object info.

  Fetches status information about a filesystem object (file, directory, etc). The returned information is placed in the VSIStatBufL structure. For portability, only use the st_size (size in bytes) and st_mode (file type). This method is similar to VSIStat(), but will work on large files on systems where this requires special calls.

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory.

  Analog of the POSIX stat() function.

  Parameters

    - pszFilename – the path of the filesystem object to be queried. UTF-8 encoded.

    - psStatBuf – the structure to load with information.

  Returns

    0 on success or -1 on an error.

int VSIStatExL(const char *pszFilename, VSIStatBufL *psStatBuf, int nFlags)

  Get filesystem object info.

  Fetches status information about a filesystem object (file, directory, etc). The returned information is placed in the VSIStatBufL structure. For portability, only use the st_size (size in bytes) and st_mode (file type). This method is similar to VSIStat(), but will work on large files on systems where this requires special calls.

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory.

  Analog of the POSIX stat() function, with an extra parameter to specify which information is needed, which offers a potential for speed optimizations on specialized and potentially slow virtual filesystem objects (/vsigzip/, /vsicurl/)

  Since

    GDAL 1.8.0

  Parameters

    - pszFilename – the path of the filesystem object to be queried. UTF-8 encoded.

    - psStatBuf – the structure to load with information.

    - nFlags – 0 to get all information, or VSI_STAT_EXISTS_FLAG, VSI_STAT_NATURE_FLAG, VSI_STAT_SIZE_FLAG, VSI_STAT_SET_ERROR_FLAG, VSI_STAT_CACHE_ONLY or a combination of those to get partial info.

  Returns

    0 on success or -1 on an error.

int VSIIsCaseSensitiveFS(const char *pszFilename)

  Returns if the filenames of the filesystem are case sensitive.

  This method retrieves to which filesystem belongs the passed filename and return TRUE if the filenames of that filesystem are case sensitive.

  Currently, this will return FALSE only for Windows real filenames. Other VSI virtual filesystems are case sensitive.

  This methods avoid ugly #ifndef WIN32 / #endif code, that is wrong when dealing with virtual filenames.

  Since

    GDAL 1.8.0

  Parameters

    pszFilename – the path of the filesystem object to be tested. UTF-8 encoded.

  Returns

    TRUE if the filenames of the filesystem are case sensitive.

int VSISupportsSparseFiles(const char *pszPath)

  Returns if the filesystem supports sparse files.

  Only supported on Linux (and no other Unix derivatives) and Windows. On Linux, the answer depends on a few hardcoded signatures for common filesystems. Other filesystems will be considered as not supporting sparse files.

  Since

    GDAL 2.2

  Parameters

    pszPath – the path of the filesystem object to be tested. UTF-8 encoded.

  Returns

    TRUE if the file system is known to support sparse files. FALSE may be returned both in cases where it is known to not support them, or when it is unknown.

int VSIHasOptimizedReadMultiRange(const char *pszPath)

  Returns if the filesystem supports efficient multi-range reading.

  Currently only returns TRUE for /vsicurl/ and derived file systems.

  Since

    GDAL 2.3

  Parameters

    pszPath – the path of the filesystem object to be tested. UTF-8 encoded.

  Returns

    TRUE if the file system is known to have an efficient multi-range reading.

const char *VSIGetActualURL(const char *pszFilename)

  Returns the actual URL of a supplied filename.

  Currently only returns a non-NULL value for network-based virtual file systems. For example “/vsis3/bucket/filename” will be expanded as “https://bucket.s3.amazon.com/filename”

  Note that the lifetime of the returned string, is short, and may be invalidated by any following GDAL functions.

  Since

    GDAL 2.3

  Parameters

    pszFilename – the path of the filesystem object. UTF-8 encoded.

  Returns

    the actual URL corresponding to the supplied filename, or NULL. Should not be freed.

char *VSIGetSignedURL(const char *pszFilename, CSLConstList papszOptions)

  Returns a signed URL of a supplied filename.

  Currently only returns a non-NULL value for /vsis3/, /vsigs/, /vsiaz/ and /vsioss/ For example “/vsis3/bucket/filename” will be expanded as “https://bucket.s3.amazon.com/filename?X-Amz-Algorithm=AWS4-HMAC-SHA256…” Configuration options that apply for file opening (typically to provide credentials), and are returned by VSIGetFileSystemOptions(), are also valid in that context.

  /vsiaz/ supports additional options:

  - SIGNEDIDENTIFIER=value: to relate the given shared access signature to a corresponding stored access policy.

  - SIGNEDPERMISSIONS=r|w: permissions associated with the shared access signature. Normally deduced from VERB.

  Since

    GDAL 2.3

  Parameters

    - pszFilename – the path of the filesystem object. UTF-8 encoded.

    - papszOptions – list of options, or NULL. Depend on file system handler. For /vsis3/, /vsigs/, /vsiaz/ and /vsioss/, the following options are supported:

      - START_DATE=YYMMDDTHHMMSSZ: date and time in UTC following ISO 8601 standard, corresponding to the start of validity of the URL. If not specified, current date time.

      - EXPIRATION_DELAY=number_of_seconds: number between 1 and 604800 (seven days) for the validity of the signed URL. Defaults to 3600 (one hour)

      - VERB=GET/HEAD/DELETE/PUT/POST: HTTP VERB for which the request will be used. Default to GET.

  Returns

    a signed URL, or NULL. Should be freed with CPLFree().

const char *VSIGetFileSystemOptions(const char *pszFilename)

  Return the list of options associated with a virtual file system handler as a serialized XML string.

  Those options may be set as configuration options with CPLSetConfigOption().

  Since

    GDAL 2.3

  Parameters

    pszFilename – a filename, or prefix of a virtual file system handler.

  Returns

    a string, which must not be freed, or NULL if no options is declared.

char **VSIGetFileSystemsPrefixes(void)

  Return the list of prefixes for virtual file system handlers currently registered.

  Typically: “”, “/vsimem/”, “/vsicurl/”, etc

  Since

    GDAL 2.3

  Returns

    a NULL terminated list of prefixes. Must be freed with CSLDestroy()

void *VSIFGetNativeFileDescriptorL(VSILFILE*)

  Returns the “native” file descriptor for the virtual handle.

  This will only return a non-NULL value for “real” files handled by the operating system (to be opposed to GDAL virtual file systems).

  On POSIX systems, this will be a integer value (“fd”) cast as a void*. On Windows systems, this will be the HANDLE.

  Parameters

    fp – file handle opened with VSIFOpenL().

  Returns

    the native file descriptor, or NULL.

char **VSIGetFileMetadata(const char *pszFilename, const char *pszDomain, CSLConstList papszOptions)

  Get metadata on files.

  Implemented currently only for network-like filesystems.

  Since

    GDAL 3.1.0

  Parameters

    - pszFilename – the path of the filesystem object to be queried. UTF-8 encoded.

    - pszDomain – Metadata domain to query. Depends on the file system. The following are supported:

      - HEADERS: to get HTTP headers for network-like filesystems (/vsicurl/, /vsis3/, /vsgis/, etc)

      - TAGS:

        - /vsis3/: to get S3 Object tagging information

        - /vsiaz/: to get blob tags. Refer to https://docs.microsoft.com/en-us/rest/api/storageservices/get-blob-tags

      - STATUS: specific to /vsiadls/: returns all system defined properties for a path (seems in practice to be a subset of HEADERS)

      - ACL: specific to /vsiadls/ and /vsigs/: returns the access control list for a path. For /vsigs/, a single XML=xml_content string is returned. Refer to https://cloud.google.com/storage/docs/xml-api/get-object-acls

      - METADATA: specific to /vsiaz/: to set blob metadata. Refer to https://docs.microsoft.com/en-us/rest/api/storageservices/get-blob-metadata. Note: this will be a subset of what pszDomain=HEADERS returns

    - papszOptions – Unused. Should be set to NULL.

  Returns

    a NULL-terminated list of key=value strings, to be freed with CSLDestroy() or NULL in case of error / empty list.

int VSISetFileMetadata(const char *pszFilename, CSLConstList papszMetadata, const char *pszDomain, CSLConstList papszOptions)

  Set metadata on files.

  Implemented currently only for /vsis3/, /vsigs/, /vsiaz/ and /vsiadls/

  Since

    GDAL 3.1.0

  Parameters

    - pszFilename – the path of the filesystem object to be set. UTF-8 encoded.

    - papszMetadata – NULL-terminated list of key=value strings.

    - pszDomain – Metadata domain to set. Depends on the file system. The following are supported:

      - HEADERS: specific to /vsis3/ and /vsigs/: to set HTTP headers, such as “Content-Type”, or other file system specific header. For /vsigs/, this also includes: x-goog-meta-{key}={value}. Note that you should specify all metadata to be set, as existing metadata will be overridden.

      - TAGS: Content of papszMetadata should be KEY=VALUE pairs.

        - /vsis3/: to set S3 Object tagging information

        - /vsiaz/: to set blob tags. Refer to https://docs.microsoft.com/en-us/rest/api/storageservices/set-blob-tags. Note: storageV2 must be enabled on the account

      - PROPERTIES:

        - to /vsiaz/: to set properties. Refer to https://docs.microsoft.com/en-us/rest/api/storageservices/set-blob-properties.

        - to /vsiadls/: to set properties. Refer to https://docs.microsoft.com/en-us/rest/api/storageservices/datalakestoragegen2/path/update for headers valid for action=setProperties.

      - ACL: specific to /vsiadls/ and /vsigs/: to set access control list. For /vsiadls/, refer to https://docs.microsoft.com/en-us/rest/api/storageservices/datalakestoragegen2/path/update for headers valid for action=setAccessControl or setAccessControlRecursive. In setAccessControlRecursive, x-ms-acl must be specified in papszMetadata. For /vsigs/, refer to https://cloud.google.com/storage/docs/xml-api/put-object-acls. A single XML=xml_content string should be specified as in papszMetadata.

      - METADATA: specific to /vsiaz/: to set blob metadata. Refer to https://docs.microsoft.com/en-us/rest/api/storageservices/set-blob-metadata. Content of papszMetadata should be strings in the form x-ms-meta-name=value

    - papszOptions – NULL or NULL terminated list of options. For /vsiadls/ and pszDomain=ACL, “RECURSIVE=TRUE” can be set to set the access control list recursively. When RECURSIVE=TRUE is set, MODE should also be set to one of “set”, “modify” or “remove”.

  Returns

    TRUE in case of success.

void VSISetCredential(const char *pszPathPrefix, const char *pszKey, const char *pszValue)

  Set a credential (or more generally an option related to a virtual file system) for a given path prefix.

  That option may also be set as a configuration option with CPLSetConfigOption(), but this function allows to specify them with a granularity at the level of a file path, which makes it easier if using the same virtual file system but with different credentials (e.g. different credentials for bucket “/vsis3/foo” and “/vsis3/bar”)

  This is supported for the following virtual file systems: /vsis3/, /vsigs/, /vsiaz/, /vsioss/, /vsiwebhdfs, /vsiswift. Note: setting them for a path starting with /vsiXXX/ will also apply for /vsiXXX_streaming/ requests.

  Note that no particular care is taken to store them in RAM in a secure way. So they might accidentally hit persistent storage if swapping occurs, or someone with access to the memory allocated by the process may be able to read them.

  Since

    GDAL 3.5

  Parameters

    - pszPathPrefix – a path prefix of a virtual file system handler. Typically of the form “/vsiXXX/bucket”. Must NOT be NULL.

    - pszKey – Option name. Must NOT be NULL.

    - pszValue – Option value. May be NULL to erase it.

void VSIClearCredentials(const char *pszPathPrefix)

  Clear credentials set with VSISetCredential()

  Note that no particular care is taken to remove them from RAM in a secure way.

  Since

    GDAL 3.5

  Parameters

    pszPathPrefix – If set to NULL, all credentials are cleared. If set to not-NULL, only those set with VSISetCredential(pszPathPrefix, …) will be cleared.

const char *VSIGetCredential(const char *pszPath, const char *pszKey, const char *pszDefault)

  Get a credential option for a given path.

  If no match occurs, CPLGetConfigOption(pszKey, pszDefault) is returned.

  Mostly to be use by virtual file system implementations.

  See also

  VSISetCredential()

  Since

    GDAL 3.5

void *VSICalloc(size_t, size_t)

  Analog of calloc().

  Use VSIFree() to free

void *VSIMalloc(size_t)

  Analog of malloc().

  Use VSIFree() to free

void VSIFree(void*)

  Analog of free() for data allocated with VSIMalloc(), VSICalloc(), VSIRealloc()

void *VSIRealloc(void*, size_t)

  Analog of realloc().

  Use VSIFree() to free

char *VSIStrdup(const char*)

  Analog of strdup().

  Use VSIFree() to free

void *VSIMallocAligned(size_t nAlignment, size_t nSize)

  Allocates a buffer with an alignment constraint.

  The return value must be freed with VSIFreeAligned().

  Since

    GDAL 2.2

  Parameters

    - nAlignment – Must be a power of 2, multiple of sizeof(void*), and lesser than 256.

    - nSize – Size of the buffer to allocate.

  Returns

    a buffer aligned on nAlignment and of size nSize, or NULL

void *VSIMallocAlignedAuto(size_t nSize)

  Allocates a buffer with an alignment constraint such that it can be used by the most demanding vector instruction set on that platform.

  The return value must be freed with VSIFreeAligned().

  Since

    GDAL 2.2

  Parameters

    nSize – Size of the buffer to allocate.

  Returns

    an aligned buffer of size nSize, or NULL

void VSIFreeAligned(void *ptr)

  Free a buffer allocated with VSIMallocAligned().

  Since

    GDAL 2.2

  Parameters

    ptr – Buffer to free.

void *VSIMallocAlignedAutoVerbose(size_t nSize, const char *pszFile, int nLine)

  See VSIMallocAlignedAuto()

void *VSIMalloc2(size_t nSize1, size_t nSize2)

  VSIMalloc2 allocates (nSize1 * nSize2) bytes.

  In case of overflow of the multiplication, or if memory allocation fails, a NULL pointer is returned and a CE_Failure error is raised with CPLError(). If nSize1 == 0 || nSize2 == 0, a NULL pointer will also be returned. CPLFree() or VSIFree() can be used to free memory allocated by this function.

void *VSIMalloc3(size_t nSize1, size_t nSize2, size_t nSize3)

  VSIMalloc3 allocates (nSize1 * nSize2 * nSize3) bytes.

  In case of overflow of the multiplication, or if memory allocation fails, a NULL pointer is returned and a CE_Failure error is raised with CPLError(). If nSize1 == 0 || nSize2 == 0 || nSize3 == 0, a NULL pointer will also be returned. CPLFree() or VSIFree() can be used to free memory allocated by this function.

void *VSIMallocVerbose(size_t nSize, const char *pszFile, int nLine)

  VSIMallocVerbose.

void *VSIMalloc2Verbose(size_t nSize1, size_t nSize2, const char *pszFile, int nLine)

  VSIMalloc2Verbose.

void *VSIMalloc3Verbose(size_t nSize1, size_t nSize2, size_t nSize3, const char *pszFile, int nLine)

  VSIMalloc3Verbose.

void *VSICallocVerbose(size_t nCount, size_t nSize, const char *pszFile, int nLine)

  VSICallocVerbose.

void *VSIReallocVerbose(void *pOldPtr, size_t nNewSize, const char *pszFile, int nLine)

  VSIReallocVerbose.

char *VSIStrdupVerbose(const char *pszStr, const char *pszFile, int nLine)

  VSIStrdupVerbose.

GIntBig CPLGetPhysicalRAM(void)

  Return the total physical RAM in bytes.

  In the context of a container using cgroups (typically Docker), this will take into account that limitation (starting with GDAL 2.4.0)

  You should generally use CPLGetUsablePhysicalRAM() instead.

  Since

    GDAL 2.0

  Returns

    the total physical RAM in bytes (or 0 in case of failure).

GIntBig CPLGetUsablePhysicalRAM(void)

  Return the total physical RAM, usable by a process, in bytes.

  This is the same as CPLGetPhysicalRAM() except it will limit to 2 GB for 32 bit processes.

  Starting with GDAL 2.4.0, it will also take account resource limits on Posix systems.

  Note: This memory may already be partly used by other processes.

  Since

    GDAL 2.0

  Returns

    the total physical RAM, usable by a process, in bytes (or 0 in case of failure).

char **VSIReadDir(const char*)

  Read names in a directory.

  This function abstracts access to directory contains. It returns a list of strings containing the names of files, and directories in this directory. The resulting string list becomes the responsibility of the application and should be freed with CSLDestroy() when no longer needed.

  Note that no error is issued via CPLError() if the directory path is invalid, though NULL is returned.

  This function used to be known as CPLReadDir(), but the old name is now deprecated.

  Parameters

    pszPath – the relative, or absolute path of a directory to read. UTF-8 encoded.

  Returns

    The list of entries in the directory, or NULL if the directory doesn’t exist. Filenames are returned in UTF-8 encoding.

char **VSIReadDirRecursive(const char *pszPath)

  Read names in a directory recursively.

  This function abstracts access to directory contents and subdirectories. It returns a list of strings containing the names of files and directories in this directory and all subdirectories. The resulting string list becomes the responsibility of the application and should be freed with CSLDestroy() when no longer needed.

  Note that no error is issued via CPLError() if the directory path is invalid, though NULL is returned.

  Since

    GDAL 1.10.0

  Parameters

    pszPathIn – the relative, or absolute path of a directory to read. UTF-8 encoded.

  Returns

    The list of entries in the directory and subdirectories or NULL if the directory doesn’t exist. Filenames are returned in UTF-8 encoding.

char **VSIReadDirEx(const char *pszPath, int nMaxFiles)

  Read names in a directory.

  This function abstracts access to directory contains. It returns a list of strings containing the names of files, and directories in this directory. The resulting string list becomes the responsibility of the application and should be freed with CSLDestroy() when no longer needed.

  Note that no error is issued via CPLError() if the directory path is invalid, though NULL is returned.

  If nMaxFiles is set to a positive number, directory listing will stop after that limit has been reached. Note that to indicate truncate, at least one element more than the nMaxFiles limit will be returned. If CSLCount() on the result is lesser or equal to nMaxFiles, then no truncation occurred.

  Since

    GDAL 2.1

  Parameters

    - pszPath – the relative, or absolute path of a directory to read. UTF-8 encoded.

    - nMaxFiles – maximum number of files after which to stop, or 0 for no limit.

  Returns

    The list of entries in the directory, or NULL if the directory doesn’t exist. Filenames are returned in UTF-8 encoding.

char **VSISiblingFiles(const char *pszPath)

  Return related filenames.

  This function is essentially meant at being used by GDAL internals.

  Since

    GDAL 3.2

  Parameters

    pszFilename – the path of a filename to inspect UTF-8 encoded.

  Returns

    The list of entries, relative to the directory, of all sidecar files available or NULL if the list is not known. Filenames are returned in UTF-8 encoding. Most implementations will return NULL, and a subsequent ReadDir will list all files available in the file’s directory. This function will be overridden by VSI FilesystemHandlers that wish to force e.g. an empty list to avoid opening non-existent files on slow filesystems. The return value shall be destroyed with CSLDestroy()

VSIDIR *VSIOpenDir(const char *pszPath, int nRecurseDepth, const char *const *papszOptions)

  Open a directory to read its entries.

  This function is close to the POSIX opendir() function.

  For /vsis3/, /vsigs/, /vsioss/, /vsiaz/ and /vsiadls/, this function has an efficient implementation, minimizing the number of network requests, when invoked with nRecurseDepth <= 0.

  Entries are read by calling VSIGetNextDirEntry() on the handled returned by that function, until it returns NULL. VSICloseDir() must be called once done with the returned directory handle.

  Since

    GDAL 2.4

  Parameters

    - pszPath – the relative, or absolute path of a directory to read. UTF-8 encoded.

    - nRecurseDepth – 0 means do not recurse in subdirectories, 1 means recurse only in the first level of subdirectories, etc. -1 means unlimited recursion level

    - papszOptions – NULL terminated list of options, or NULL. The following options are implemented:

      - PREFIX=string: (GDAL >= 3.4) Filter to select filenames only starting with the specified prefix. Implemented efficiently for /vsis3/, /vsigs/, and /vsiaz/ (but not /vsiadls/)

      - NAME_AND_TYPE_ONLY=YES/NO: (GDAL >= 3.4) Defaults to NO. If set to YES, only the pszName and nMode members of VSIDIR are guaranteed to be set. This is implemented efficiently for the Unix virtual file system.

  Returns

    a handle, or NULL in case of error

const VSIDIREntry *VSIGetNextDirEntry(VSIDIR *dir)

  Return the next entry of the directory.

  This function is close to the POSIX readdir() function. It actually returns more information (file size, last modification time), which on ‘real’ file systems involve one ‘stat’ call per file.

  For filesystems that can have both a regular file and a directory name of the same name (typically /vsis3/), when this situation of duplicate happens, the directory name will be suffixed by a slash character. Otherwise directory names are not suffixed by slash.

  The returned entry remains valid until the next call to VSINextDirEntry() or VSICloseDir() with the same handle.

  Since

    GDAL 2.4

  Parameters

    dir – Directory handled returned by VSIOpenDir(). Must not be NULL.

  Returns

    a entry, or NULL if there is no more entry in the directory. This return value must not be freed.

void VSICloseDir(VSIDIR *dir)

  Close a directory.

  This function is close to the POSIX closedir() function.

  Since

    GDAL 2.4

  Parameters

    dir – Directory handled returned by VSIOpenDir().

int VSIMkdir(const char *pszPathname, long mode)

  Create a directory.

  Create a new directory with the indicated mode. For POSIX-style systems, the mode is modified by the file creation mask (umask). However, some file systems and platforms may not use umask, or they may ignore the mode completely. So a reasonable cross-platform default mode value is 0755.

  Analog of the POSIX mkdir() function.

  Parameters

    - pszPathname – the path to the directory to create. UTF-8 encoded.

    - mode – the permissions mode.

  Returns

    0 on success or -1 on an error.

int VSIMkdirRecursive(const char *pszPathname, long mode)

  Create a directory and all its ancestors.

  Since

    GDAL 2.3

  Parameters

    - pszPathname – the path to the directory to create. UTF-8 encoded.

    - mode – the permissions mode.

  Returns

    0 on success or -1 on an error.

int VSIRmdir(const char *pszDirname)

  Delete a directory.

  Deletes a directory object from the file system. On some systems the directory must be empty before it can be deleted.

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory.

  Analog of the POSIX rmdir() function.

  Parameters

    pszDirname – the path of the directory to be deleted. UTF-8 encoded.

  Returns

    0 on success or -1 on an error.

int VSIRmdirRecursive(const char *pszDirname)

  Delete a directory recursively.

  Deletes a directory object and its content from the file system.

  Starting with GDAL 3.1, /vsis3/ has an efficient implementation of this function. Starting with GDAL 3.4, /vsigs/ has an efficient implementation of this function, provided that OAuth2 authentication is used.

  Since

    GDAL 2.3

  Returns

    0 on success or -1 on an error.

int VSIUnlink(const char *pszFilename)

  Delete a file.

  Deletes a file object from the file system.

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory.

  Analog of the POSIX unlink() function.

  Parameters

    pszFilename – the path of the file to be deleted. UTF-8 encoded.

  Returns

    0 on success or -1 on an error.

int *VSIUnlinkBatch(CSLConstList papszFiles)

  Delete several files, possibly in a batch.

  All files should belong to the same file system handler.

  This is implemented efficiently for /vsis3/ and /vsigs/ (provided for /vsigs/ that OAuth2 authentication is used).

  Since

    GDAL 3.1

  Parameters

    papszFiles – NULL terminated list of files. UTF-8 encoded.

  Returns

    an array of size CSLCount(papszFiles), whose values are TRUE or FALSE depending on the success of deletion of the corresponding file. The array should be freed with VSIFree(). NULL might be return in case of a more general error (for example, files belonging to different file system handlers)

int VSIRename(const char *oldpath, const char *newpath)

  Rename a file.

  Renames a file object in the file system. It should be possible to rename a file onto a new filesystem, but it is safest if this function is only used to rename files that remain in the same directory.

  This method goes through the VSIFileHandler virtualization and may work on unusual filesystems such as in memory.

  Analog of the POSIX rename() function.

  Parameters

    - oldpath – the name of the file to be renamed. UTF-8 encoded.

    - newpath – the name the file should be given. UTF-8 encoded.

  Returns

    0 on success or -1 on an error.

int VSISync(const char *pszSource, const char *pszTarget, const char *const *papszOptions, GDALProgressFunc pProgressFunc, void *pProgressData, char ***ppapszOutputs)

  Synchronize a source file/directory with a target file/directory.

  This is a analog of the ‘rsync’ utility. In the current implementation, rsync would be more efficient for local file copying, but VSISync() main interest is when the source or target is a remote file system like /vsis3/ or /vsigs/, in which case it can take into account the timestamps of the files (or optionally the ETag/MD5Sum) to avoid unneeded copy operations.

  This is only implemented efficiently for:

  - local filesystem <–> remote filesystem.

  - remote filesystem <–> remote filesystem (starting with GDAL 3.1). Where the source and target remote filesystems are the same and one of /vsis3/, /vsigs/ or /vsiaz/

  Similarly to rsync behavior, if the source filename ends with a slash, it means that the content of the directory must be copied, but not the directory name. For example, assuming “/home/even/foo” contains a file “bar”, VSISync(“/home/even/foo/”, “/mnt/media”, …) will create a “/mnt/media/bar” file. Whereas VSISync(“/home/even/foo”, “/mnt/media”, …) will create a “/mnt/media/foo” directory which contains a bar file.

  Since

    GDAL 2.4

  Parameters

    - pszSource – Source file or directory. UTF-8 encoded.

    - pszTarget – Target file or directory. UTF-8 encoded.

    - papszOptions – Null terminated list of options, or NULL. Currently accepted options are:

      - RECURSIVE=NO (the default is YES)

      - SYNC_STRATEGY=TIMESTAMP/ETAG/OVERWRITE. Determines which criterion is used to determine if a target file must be replaced when it already exists and has the same file size as the source. Only applies for a source or target being a network filesystem.

        The default is TIMESTAMP (similarly to how ‘aws s3 sync’ works), that is to say that for an upload operation, a remote file is replaced if it has a different size or if it is older than the source. For a download operation, a local file is replaced if it has a different size or if it is newer than the remote file.

        The ETAG strategy assumes that the ETag metadata of the remote file is the MD5Sum of the file content, which is only true in the case of /vsis3/ for files not using KMS server side encryption and uploaded in a single PUT operation (so smaller than 50 MB given the default used by GDAL). Only to be used for /vsis3/, /vsigs/ or other filesystems using a MD5Sum as ETAG.

        The OVERWRITE strategy (GDAL >= 3.2) will always overwrite the target file with the source one.

      - NUM_THREADS=integer. (GDAL >= 3.1) Number of threads to use for parallel file copying. Only use for when /vsis3/, /vsigs/, /vsiaz/ or /vsiadls/ is in source or target. The default is 10 since GDAL 3.3

      - CHUNK_SIZE=integer. (GDAL >= 3.1) Maximum size of chunk (in bytes) to use to split large objects when downloading them from /vsis3/, /vsigs/, /vsiaz/ or /vsiadls/ to local file system, or for upload to /vsis3/, /vsiaz/ or /vsiadls/ from local file system. Only used if NUM_THREADS > 1. For upload to /vsis3/, this chunk size must be set at least to 5 MB. The default is 8 MB since GDAL 3.3

      - x-amz-KEY=value. (GDAL >= 3.5) MIME header to pass during creation of a /vsis3/ object.

      - x-goog-KEY=value. (GDAL >= 3.5) MIME header to pass during creation of a /vsigs/ object.

      - x-ms-KEY=value. (GDAL >= 3.5) MIME header to pass during creation of a /vsiaz/ or /vsiadls/ object.

    - pProgressFunc – Progress callback, or NULL.

    - pProgressData – User data of progress callback, or NULL.

    - ppapszOutputs – Unused. Should be set to NULL for now.

  Returns

    TRUE on success or FALSE on an error.

int VSIAbortPendingUploads(const char *pszFilename)

  Abort ongoing multi-part uploads.

  Abort ongoing multi-part uploads on AWS S3 and Google Cloud Storage. This can be used in case a process doing such uploads was killed in a unclean way.

  Without effect on other virtual file systems.

  Since

    GDAL 3.4

  Parameters

    pszFilename – filename or prefix of a directory into which multipart uploads must be aborted. This can be the root directory of a bucket. UTF-8 encoded.

  Returns

    TRUE on success or FALSE on an error.

char *VSIStrerror(int)

  Return the error string corresponding to the error number.

  Do not free it

GIntBig VSIGetDiskFreeSpace(const char *pszDirname)

  Return free disk space available on the filesystem.

  This function returns the free disk space available on the filesystem.

  Since

    GDAL 2.1

  Parameters

    pszDirname – a directory of the filesystem to query.

  Returns

    The free space in bytes. Or -1 in case of error.

void VSINetworkStatsReset(void)

  Clear network related statistics.

  The effect of the CPL_VSIL_NETWORK_STATS_ENABLED configuration option will also be reset. That is, that the next network access will check its value again.

  Since

    GDAL 3.2.0

char *VSINetworkStatsGetAsSerializedJSON(char **papszOptions)

  Return network related statistics, as a JSON serialized object.

  Statistics collecting should be enabled with the CPL_VSIL_NETWORK_STATS_ENABLED configuration option set to YES before any network activity starts (for efficiency, reading it is cached on first access, until VSINetworkStatsReset() is called)

  Statistics can also be emitted on standard output at process termination if the CPL_VSIL_SHOW_NETWORK_STATS configuration option is set to YES.

  Example of output:

  Since

    GDAL 3.2.0

  Parameters

    papszOptions – Unused.

  Returns

    a JSON serialized string to free with VSIFree(), or nullptr

void VSIInstallMemFileHandler(void)

  Install “memory” file system handler.

  A special file handler is installed that allows block of memory to be treated as files. All portions of the file system underneath the base path “/vsimem/” will be handled by this driver.

  Normal VSI*L functions can be used freely to create and destroy memory arrays treating them as if they were real file system objects. Some additional methods exist to efficient create memory file system objects without duplicating original copies of the data or to “steal” the block of memory associated with a memory file.

  Directory related functions are supported.

  This code example demonstrates using GDAL to translate from one memory buffer to another.

      GByte *ConvertBufferFormat( GByte *pabyInData, vsi_l_offset nInDataLength,
                                  vsi_l_offset *pnOutDataLength )
      {
          // create memory file system object from buffer.
          VSIFCloseL( VSIFileFromMemBuffer( "/vsimem/work.dat", pabyInData,
                                            nInDataLength, FALSE ) );

          // Open memory buffer for read.
          GDALDatasetH hDS = GDALOpen( "/vsimem/work.dat", GA_ReadOnly );

          // Get output format driver.
          GDALDriverH hDriver = GDALGetDriverByName( "GTiff" );
          GDALDatasetH hOutDS;

          hOutDS = GDALCreateCopy( hDriver, "/vsimem/out.tif", hDS, TRUE, NULL,
                                   NULL, NULL );

          // close source file, and "unlink" it.
          GDALClose( hDS );
          VSIUnlink( "/vsimem/work.dat" );

          // seize the buffer associated with the output file.

          return VSIGetMemFileBuffer( "/vsimem/out.tif", pnOutDataLength, TRUE );
      }

void VSIInstallSubFileHandler(void)

  Install /vsisubfile/ virtual file handler.

  See /vsisubfile/ documentation

void VSIInstallCurlFileHandler(void)

  Install /vsicurl/ HTTP/FTP file system handler (requires libcurl)

  See /vsicurl/ documentation

  Since

    GDAL 1.8.0

void VSICurlClearCache(void)

  Clean local cache associated with /vsicurl/ (and related file systems)

  /vsicurl (and related file systems like /vsis3/, /vsigs/, /vsiaz/, /vsioss/, /vsiswift/) cache a number of metadata and data for faster execution in read-only scenarios. But when the content on the server-side may change during the same process, those mechanisms can prevent opening new files, or give an outdated version of them.

  Since

    GDAL 2.2.1

void VSICurlPartialClearCache(const char *pszFilenamePrefix)

  Clean local cache associated with /vsicurl/ (and related file systems) for a given filename (and its subfiles and subdirectories if it is a directory)

  /vsicurl (and related file systems like /vsis3/, /vsigs/, /vsiaz/, /vsioss/, /vsiswift/) cache a number of metadata and data for faster execution in read-only scenarios. But when the content on the server-side may change during the same process, those mechanisms can prevent opening new files, or give an outdated version of them.

  Since

    GDAL 2.4.0

  Parameters

    pszFilenamePrefix – Filename prefix

void VSIInstallCurlStreamingFileHandler(void)

  Install /vsicurl_streaming/ HTTP/FTP file system handler (requires libcurl).

  See /vsicurl_streaming/ documentation

  Since

    GDAL 1.10

void VSIInstallS3FileHandler(void)

  Install /vsis3/ Amazon S3 file system handler (requires libcurl)

  See /vsis3/ documentation

  Since

    GDAL 2.1

void VSIInstallS3StreamingFileHandler(void)

  Install /vsis3_streaming/ Amazon S3 file system handler (requires libcurl).

  See /vsis3_streaming/ documentation

  Since

    GDAL 2.1

void VSIInstallGSFileHandler(void)

  Install /vsigs/ Google Cloud Storage file system handler (requires libcurl)

  See /vsigs/ documentation

  Since

    GDAL 2.2

void VSIInstallGSStreamingFileHandler(void)

  Install /vsigs_streaming/ Google Cloud Storage file system handler (requires libcurl)

  See /vsigs_streaming/ documentation

  Since

    GDAL 2.2

void VSIInstallAzureFileHandler(void)

  Install /vsiaz/ Microsoft Azure Blob file system handler (requires libcurl)

  See /vsiaz/ documentation

  Since

    GDAL 2.3

void VSIInstallAzureStreamingFileHandler(void)

  Install /vsiaz_streaming/ Microsoft Azure Blob file system handler (requires libcurl)

  See /vsiaz_streaming/ documentation

  Since

    GDAL 2.3

void VSIInstallADLSFileHandler(void)

  Install /vsiaz/ Microsoft Azure Data Lake Storage Gen2 file system handler (requires libcurl)

  See /vsiadls/ documentation

  Since

    GDAL 3.3

void VSIInstallOSSFileHandler(void)

  Install /vsioss/ Alibaba Cloud Object Storage Service (OSS) file system handler (requires libcurl)

  See /vsioss/ documentation

  Since

    GDAL 2.3

void VSIInstallOSSStreamingFileHandler(void)

  Install /vsiaz_streaming/ Alibaba Cloud Object Storage Service (OSS) (requires libcurl)

  See /vsioss_streaming/ documentation

  Since

    GDAL 2.3

void VSIInstallSwiftFileHandler(void)

  Install /vsiswift/ OpenStack Swif Object Storage (Swift) file system handler (requires libcurl)

  See /vsiswift/ documentation

  Since

    GDAL 2.3

void VSIInstallSwiftStreamingFileHandler(void)

  Install /vsiswift_streaming/ OpenStack Swif Object Storage (Swift) file system handler (requires libcurl)

  See /vsiswift_streaming/ documentation

  Since

    GDAL 2.3

void VSIInstallGZipFileHandler(void)

  Install GZip file system handler.

  A special file handler is installed that allows reading on-the-fly and writing in GZip (.gz) files.

  All portions of the file system underneath the base path “/vsigzip/” will be handled by this driver.

  See /vsigzip/ documentation

  Since

    GDAL 1.6.0

void VSIInstallZipFileHandler(void)

  Install ZIP file system handler.

  A special file handler is installed that allows reading on-the-fly in ZIP (.zip) archives.

  All portions of the file system underneath the base path “/vsizip/” will be handled by this driver.

  See /vsizip/ documentation

  Since

    GDAL 1.6.0

void VSIInstallStdinHandler(void)

  Install /vsistdin/ file system handler.

  A special file handler is installed that allows reading from the standard input stream.

  The file operations available are of course limited to Read() and forward Seek() (full seek in the first MB of a file).

  See /vsistdin/ documentation

  Since

    GDAL 1.8.0

void VSIInstallHdfsHandler(void)

  Install /vsihdfs/ file system handler (requires JVM and HDFS support)

  Since

    GDAL 2.4.0

void VSIInstallWebHdfsHandler(void)

  Install /vsiwebhdfs/ WebHDFS (Hadoop File System) REST API file system handler (requires libcurl)

  See /vsiwebhdfs/ documentation

  Since

    GDAL 2.4

void VSIInstallStdoutHandler(void)

  Install /vsistdout/ file system handler.

  A special file handler is installed that allows writing to the standard output stream.

  The file operations available are of course limited to Write().

  A variation of this file system exists as the /vsistdout_redirect/ file system handler, where the output function can be defined with VSIStdoutSetRedirection().

  See /vsistdout/ documentation

  Since

    GDAL 1.8.0

void VSIInstallSparseFileHandler(void)

  Install /vsisparse/ virtual file handler.

  See /vsisparse/ documentation

void VSIInstallTarFileHandler(void)

  Install /vsitar/ file system handler.

  A special file handler is installed that allows reading on-the-fly in TAR (regular .tar, or compressed .tar.gz/.tgz) archives.

  All portions of the file system underneath the base path “/vsitar/” will be handled by this driver.

  See /vsitar/ documentation

  Since

    GDAL 1.8.0

void VSIInstallCryptFileHandler(void)

  Install /vsicrypt/ encrypted file system handler (requires libcrypto++)

  A special file handler is installed that allows reading/creating/update encrypted files on the fly, with random access capabilities.

  The cryptographic algorithms used are block ciphers, with symmetric key.

  In their simplest form, recognized filenames are of the form /vsicrypt//absolute_path/to/file, /vsicrypt/c:/absolute_path/to/file or /vsicrypt/relative/path/to/file.

  Options can also be used with the following format : /vsicrypt/option1=val1,option2=val2,…,file=/path/to/file

  They can also be passed as configuration option/environment variable, because in some use cases, the syntax with option in the filename might not properly work with some drivers.

  In all modes, the encryption key must be provided. There are several ways of doing so :

  - By adding a key= parameter to the filename, like /vsicrypt/key=my_secret_key,file=/path/to/file. Note that this restricts the key to be in text format, whereas at its full power, it can be binary content.

  - By adding a key_b64= parameter to the filename, to specify a binary key expressed in Base64 encoding, like /vsicrypt/key_b64=th1sl00kslikebase64=,file=/path/to/file.

  - By setting the VSICRYPT_KEY configuration option. The key should be in text format.

  - By setting the VSICRYPT_KEY_B64 configuration option. The key should be encoded in Base64.

  - By using the VSISetCryptKey() C function.

  When creating a file, if key=GENERATE_IT or VSICRYPT_KEY=GENERATE_IT is passed, the encryption key will be generated from the pseudo-random number generator of the operating system. The key will be displayed on the standard error stream in a Base64 form (unless the VSICRYPT_DISPLAY_GENERATED_KEY configuration option is set to OFF), and the VSICRYPT_KEY_B64 configuration option will also be set with the Base64 form of the key (so that CPLGetConfigOption(“VSICRYPT_KEY_B64”, NULL) can be used to get it back).

  The available options are :

  - alg=AES/Blowfish/Camellia/CAST256/DES_EDE2/DES_EDE3/MARS/IDEA/RC5/RC6/Serpent/SHACAL2/SKIPJACK/Twofish/XTEA: to specify the block cipher algorithm. The default is AES. Only used on creation. Ignored otherwise. Note: depending on how GDAL is build, if linked against the DLL version of libcrypto++, only a subset of those algorithms will be available, namely AES, DES_EDE2, DES_EDE3 and SKIPJACK. Also available as VSICRYPT_ALG configuration option.

  - mode=CBC/CFB/OFB/CTR/CBC_CTS: to specify the block cipher mode of operation. The default is CBC. Only used on creation. Ignored otherwise. Also available as VSICRYPT_MODE configuration option.

  - key=text_key: see above.

  - key_b64=base64_encoded_key: see above.

  - freetext=some_text: to specify a text content that will be written unencrypted in the file header, for informational purposes. Default to empty. Only used on creation. Ignored otherwise. Also available as VSICRYPT_FREETEXT configuration option.

  - sector_size=int_value: to specify the size of the “sector”, which is the unit chunk of information that is encrypted/decrypted. Default to 512 bytes. The valid values depend on the algorithm and block cipher mode of operation. Only used on creation. Ignored otherwise. Also available as VSICRYPT_SECTOR_SIZE configuration option.

  - iv=initial_vector_as_text: to specify the Initial Vector. This is an advanced option that should generally NOT be used. It is only useful to get completely deterministic output given the plaintext, key and other parameters, which in general NOT what you want to do. By default, a random initial vector of the appropriate size will be generated for each new file created. Only used on creation. Ignored otherwise. Also available as VSICRYPT_IV configuration option.

  - add_key_check=YES/NO: whether a special value should be encrypted in the header, so as to be quickly able to determine if the decryption key is correct. Defaults to NO. Only used on creation. Ignored otherwise. Also available as VSICRYPT_ADD_KEY_CHECK configuration option.

  - file=filename. To specify the filename. This must be the last option put in the option list (so as to make it possible to use filenames with comma in them. )

  This special file handler can be combined with other virtual filesystems handlers, such as /vsizip. For example, /vsicrypt//vsicurl/path/to/remote/encrypted/file.tif

  Implementation details:

  The structure of encrypted files is the following: a header, immediately followed by the encrypted payload (by sectors, i.e. chunks of sector_size bytes).

  The header structure is the following :

  1. 8 bytes. Signature. Fixed value: VSICRYPT.

  2. UINT16_LE. Header size (including previous signature bytes).

  3. UINT8. Format major version. Current value: 1.

  4. UINT8. Format minor version. Current value: 0.

  5. UINT16. Sector size.

  6. UINT8. Cipher algorithm. Valid values are: 0 = AES (Rijndael), 1 = Blowfish, 2 = Camellia, 3 = CAST256, 4 = DES_EDE2, 5 = DES_EDE3, 6 = MARS, 7 = IDEA, 8 = RC5, 9 = RC6, 10 = Serpent, 11 = SHACAL2, 12 = SKIPJACK, 13 = Twofish, 14 = XTEA.

  7. UINT8. Block cipher mode of operation. Valid values are: 0 = CBC, 1 = CFB, 2 = OFB, 3 = CTR, 4 = CBC_CTS.

  8. UINT8. Size in bytes of the Initial Vector.

  9. N bytes with the content of the Initial Vector, where N is the value of the previous field.

  10. UINT16_LE. Size in bytes of the free text.

  11. N bytes with the content of the free text, where N is the value of the previous field.

  12. UINT8. Size in bytes of encrypted content (key check), or 0 if key check is absent.

  13. N bytes with encrypted content (key check), where N is the value of the previous field.

  14. UINT64_LE. Size of the unencrypted file, in bytes.

  15. UINT16_LE. Size in bytes of extra content (of unspecified semantics). For v1.0, fixed value of 0

  16. N bytes with extra content (of unspecified semantics), where N is the value of the previous field.

  This design does not provide any means of authentication or integrity check.

  Each sector is encrypted/decrypted independently of other sectors. For that, the Initial Vector contained in the header is XOR’ed with the file offset (relative to plain text file) of the start of the sector being processed, as a 8-byte integer. More precisely, the first byte of the main IV is XOR’ed with the 8 least-significant bits of the sector offset, the second byte of the main IV is XOR’ed with the following 8 bits of the sector offset, etc… until the 8th byte.

  This design could potentially be prone to chosen-plaintext attack, for example if the attacker managed to get (part of) an existing encrypted file to be encrypted from plaintext he might have selected.

  Note: if “hostile” code can explore process content, or attach to it with a debugger, it might be relatively easy to retrieve the encryption key. A GDAL plugin could for example get the content of configuration options, or list opened datasets and see the key/key_b64 values, so disabling plugin loading might be a first step, as well as linking statically GDAL to application code. If plugin loading is enabled or GDAL dynamically linked, using VSISetCryptKey() to set the key might make it a bit more complicated to spy the key. But, as said initially, this is in no way a perfect protection.

  Since

    GDAL 2.1.0

void VSISetCryptKey(const GByte *pabyKey, int nKeySize)

  Installs the encryption/decryption key.

  By passing a NULL key, the previously installed key will be cleared. Note, however, that it is not guaranteed that there won’t be trace of it in other places in memory or in on-disk temporary file.

  See also

  VSIInstallCryptFileHandler() for documentation on /vsicrypt/

  Parameters

    - pabyKey – key. Might be NULL to clear previously set key.

    - nKeySize – length of the key in bytes. Might be 0 to clear previously set key.

VSILFILE *VSIFileFromMemBuffer(const char *pszFilename, GByte *pabyData, vsi_l_offset nDataLength, int bTakeOwnership)

  Create memory “file” from a buffer.

  A virtual memory file is created from the passed buffer with the indicated filename. Under normal conditions the filename would need to be absolute and within the /vsimem/ portion of the filesystem.

  If bTakeOwnership is TRUE, then the memory file system handler will take ownership of the buffer, freeing it when the file is deleted. Otherwise it remains the responsibility of the caller, but should not be freed as long as it might be accessed as a file. In no circumstances does this function take a copy of the pabyData contents.

  Parameters

    - pszFilename – the filename to be created.

    - pabyData – the data buffer for the file.

    - nDataLength – the length of buffer in bytes.

    - bTakeOwnership – TRUE to transfer “ownership” of buffer or FALSE.

  Returns

    open file handle on created file (see VSIFOpenL()).

GByte *VSIGetMemFileBuffer(const char *pszFilename, vsi_l_offset *pnDataLength, int bUnlinkAndSeize)

  Fetch buffer underlying memory file.

  This function returns a pointer to the memory buffer underlying a virtual “in memory” file. If bUnlinkAndSeize is TRUE the filesystem object will be deleted, and ownership of the buffer will pass to the caller otherwise the underlying file will remain in existence.

  Parameters

    - pszFilename – the name of the file to grab the buffer of.

    - pnDataLength – (file) length returned in this variable.

    - bUnlinkAndSeize – TRUE to remove the file, or FALSE to leave unaltered.

  Returns

    pointer to memory buffer or NULL on failure.

void VSIStdoutSetRedirection(VSIWriteFunction pFct, FILE *stream)

  Set an alternative write function and output file handle instead of fwrite() / stdout.

  Since

    GDAL 2.0

  Parameters

    - pFct – Function with same signature as fwrite()

    - stream – File handle on which to output. Passed to pFct.

VSIFilesystemPluginCallbacksStruct *VSIAllocFilesystemPluginCallbacksStruct(void)

  return a VSIFilesystemPluginCallbacksStruct to be populated at runtime with handler callbacks

  Since

    GDAL 3.0

void VSIFreeFilesystemPluginCallbacksStruct(VSIFilesystemPluginCallbacksStruct *poCb)

  free resources allocated by VSIAllocFilesystemPluginCallbacksStruct

  Since

    GDAL 3.0

int VSIInstallPluginHandler(const char *pszPrefix, const VSIFilesystemPluginCallbacksStruct *poCb)

  register a handler on the given prefix.

  All IO on datasets opened with the filename /prefix/xxxxxx will go through these callbacks. pszPrefix must begin and end with a ‘/’

  Since

    GDAL 3.0

struct VSIDIREntry
  #include <cpl_vsi.h>

  Directory entry.

  Public Members

  char *pszName

    Filename.

  int nMode

    File mode.

    See VSI_ISREG() / VSI_ISDIR()

  vsi_l_offset nSize

    File size.

  GIntBig nMTime

    Last modification time (seconds since 1970/01/01)

  char bModeKnown

    Whether nMode is known: 0 = unknown, 1 = known.

  char bSizeKnown

    Whether nSize is known: 0 = unknown, 1 = known.

  char bMTimeKnown

    Whether nMTime is known: 0 = unknown, 1 = known.

  char **papszExtra

    NULL-terminated list of extra properties.

struct VSIFilesystemPluginCallbacksStruct
  #include <cpl_vsi.h>

  struct containing callbacks to used by the handler.

  (rw), (r), (w) or () at the end indicate whether the given callback is mandatory for reading and or writing handlers. A (?) indicates that the callback might be mandatory for certain drivers only.

  Since

    GDAL 3.0

  Public Members

  void *pUserData

    Optional opaque pointer passed back to filemanager callbacks (e.g.

    open, stat, rmdir)

  VSIFilesystemPluginStatCallback stat

    stat handle by name (rw)

  VSIFilesystemPluginUnlinkCallback unlink

    unlink handle by name ()

  VSIFilesystemPluginRenameCallback rename

    rename handle ()

  VSIFilesystemPluginMkdirCallback mkdir

    make directory ()

  VSIFilesystemPluginRmdirCallback rmdir

    remove directory ()

  VSIFilesystemPluginReadDirCallback read_dir

    list directory content (r?)

  VSIFilesystemPluginOpenCallback open

    open handle by name (rw)

  VSIFilesystemPluginTellCallback tell

    get current position of handle (rw)

  VSIFilesystemPluginSeekCallback seek

    set current position of handle (rw)

  VSIFilesystemPluginReadCallback read

    read from current position (r)

  VSIFilesystemPluginReadMultiRangeCallback read_multi_range

    read multiple blocks ()

  VSIFilesystemPluginGetRangeStatusCallback get_range_status

    get range status ()

  VSIFilesystemPluginEofCallback eof

    has end of file been reached (r?)

  VSIFilesystemPluginWriteCallback write

    write bytes to current position (w)

  VSIFilesystemPluginFlushCallback flush

    sync bytes (w)

  VSIFilesystemPluginTruncateCallback truncate

    truncate handle (w?)

  VSIFilesystemPluginCloseCallback close

    close handle (rw)

  size_t nBufferSize

    buffer small reads (makes handler read only)

  size_t nCacheSize

    max mem to use per file when buffering

  VSIFilesystemPluginSiblingFilesCallback sibling_files

    list related files

See also

Common Portability Library C++ API.