/******************************************************************************
 *
 * Project:  ZMap driver
 * Purpose:  GDALDataset driver for ZMap dataset.
 * Author:   Even Rouault, <even dot rouault at spatialys.com>
 *
 ******************************************************************************
 * Copyright (c) 2011-2012, Even Rouault <even dot rouault at spatialys.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 ****************************************************************************/

#include "cpl_string.h"
#include "cpl_vsi_virtual.h"
#include "gdal_frmts.h"
#include "gdal_pam.h"

#include <cmath>

/************************************************************************/
/* ==================================================================== */
/*                              ZMapDataset                             */
/* ==================================================================== */
/************************************************************************/

class ZMapRasterBand;

class ZMapDataset final : public GDALPamDataset
{
    friend class ZMapRasterBand;

    VSILFILE *fp;
    int nValuesPerLine;
    int nFieldSize;
    int nDecimalCount;
    int nColNum;
    double dfNoDataValue;
    vsi_l_offset nDataStartOff;
    double adfGeoTransform[6];

  public:
    ZMapDataset();
    virtual ~ZMapDataset();

    virtual CPLErr GetGeoTransform(double *) override;

    static GDALDataset *Open(GDALOpenInfo *);
    static int Identify(GDALOpenInfo *);
    static GDALDataset *CreateCopy(const char *pszFilename,
                                   GDALDataset *poSrcDS, int bStrict,
                                   char **papszOptions,
                                   GDALProgressFunc pfnProgress,
                                   void *pProgressData);
};

/************************************************************************/
/* ==================================================================== */
/*                            ZMapRasterBand                            */
/* ==================================================================== */
/************************************************************************/

class ZMapRasterBand final : public GDALPamRasterBand
{
    friend class ZMapDataset;

  public:
    explicit ZMapRasterBand(ZMapDataset *);

    virtual CPLErr IReadBlock(int, int, void *) override;
    virtual double GetNoDataValue(int *pbSuccess = nullptr) override;
};

/************************************************************************/
/*                           ZMapRasterBand()                           */
/************************************************************************/

ZMapRasterBand::ZMapRasterBand(ZMapDataset *poDSIn)

{
    poDS = poDSIn;
    nBand = 1;

    eDataType = GDT_Float64;

    nBlockXSize = 1;
    nBlockYSize = poDSIn->GetRasterYSize();
}

/************************************************************************/
/*                             IReadBlock()                             */
/************************************************************************/

CPLErr ZMapRasterBand::IReadBlock(int nBlockXOff, CPL_UNUSED int nBlockYOff,
                                  void *pImage)
{
    ZMapDataset *poGDS = reinterpret_cast<ZMapDataset *>(poDS);

    if (poGDS->fp == nullptr)
        return CE_Failure;

    if (nBlockXOff < poGDS->nColNum + 1)
    {
        VSIFSeekL(poGDS->fp, poGDS->nDataStartOff, SEEK_SET);
        poGDS->nColNum = -1;
    }

    if (nBlockXOff > poGDS->nColNum + 1)
    {
        for (int i = poGDS->nColNum + 1; i < nBlockXOff; i++)
        {
            if (IReadBlock(i, 0, pImage) != CE_None)
                return CE_Failure;
        }
    }

    int i = 0;
    const double dfExp = std::pow(10.0, poGDS->nDecimalCount);
    while (i < nRasterYSize)
    {
        char *pszLine = const_cast<char *>(CPLReadLineL(poGDS->fp));
        if (pszLine == nullptr)
            return CE_Failure;
        int nExpected = nRasterYSize - i;
        if (nExpected > poGDS->nValuesPerLine)
            nExpected = poGDS->nValuesPerLine;
        if (static_cast<int>(strlen(pszLine)) != nExpected * poGDS->nFieldSize)
            return CE_Failure;

        for (int j = 0; j < nExpected; j++)
        {
            char *pszValue = pszLine + j * poGDS->nFieldSize;
            const char chSaved = pszValue[poGDS->nFieldSize];
            pszValue[poGDS->nFieldSize] = 0;
            if (strchr(pszValue, '.') != nullptr)
                reinterpret_cast<double *>(pImage)[i + j] = CPLAtofM(pszValue);
            else
                reinterpret_cast<double *>(pImage)[i + j] =
                    atoi(pszValue) * dfExp;
            pszValue[poGDS->nFieldSize] = chSaved;
        }

        i += nExpected;
    }

    poGDS->nColNum++;

    return CE_None;
}

/************************************************************************/
/*                          GetNoDataValue()                            */
/************************************************************************/

double ZMapRasterBand::GetNoDataValue(int *pbSuccess)
{
    ZMapDataset *poGDS = reinterpret_cast<ZMapDataset *>(poDS);

    if (pbSuccess)
        *pbSuccess = TRUE;

    return poGDS->dfNoDataValue;
}

/************************************************************************/
/*                            ~ZMapDataset()                            */
/************************************************************************/

ZMapDataset::ZMapDataset()
    : fp(nullptr), nValuesPerLine(0), nFieldSize(0), nDecimalCount(0),
      nColNum(-1), dfNoDataValue(0.0), nDataStartOff(0)
{
    adfGeoTransform[0] = 0;
    adfGeoTransform[1] = 1;
    adfGeoTransform[2] = 0;
    adfGeoTransform[3] = 0;
    adfGeoTransform[4] = 0;
    adfGeoTransform[5] = 1;
}

/************************************************************************/
/*                            ~ZMapDataset()                            */
/************************************************************************/

ZMapDataset::~ZMapDataset()

{
    FlushCache(true);
    if (fp)
        VSIFCloseL(fp);
}

/************************************************************************/
/*                             Identify()                               */
/************************************************************************/

int ZMapDataset::Identify(GDALOpenInfo *poOpenInfo)
{
    if (poOpenInfo->nHeaderBytes == 0)
        return FALSE;

    /* -------------------------------------------------------------------- */
    /*      Check that it looks roughly as a ZMap dataset                   */
    /* -------------------------------------------------------------------- */
    const char *pszData =
        reinterpret_cast<const char *>(poOpenInfo->pabyHeader);

    /* Skip comments line at the beginning */
    int i = 0;
    if (pszData[i] == '!')
    {
        i++;
        for (; i < poOpenInfo->nHeaderBytes; i++)
        {
            char ch = pszData[i];
            if (ch == 13 || ch == 10)
            {
                i++;
                if (ch == 13 && pszData[i] == 10)
                    i++;
                if (pszData[i] != '!')
                    break;
            }
        }
    }

    if (pszData[i] != '@')
        return FALSE;
    i++;

    char **papszTokens = CSLTokenizeString2(pszData + i, ",", 0);
    if (CSLCount(papszTokens) < 3)
    {
        CSLDestroy(papszTokens);
        return FALSE;
    }

    const char *pszToken = papszTokens[1];
    while (*pszToken == ' ')
        pszToken++;

    if (!STARTS_WITH(pszToken, "GRID"))
    {
        CSLDestroy(papszTokens);
        return FALSE;
    }

    CSLDestroy(papszTokens);
    return TRUE;
}

/************************************************************************/
/*                                Open()                                */
/************************************************************************/

GDALDataset *ZMapDataset::Open(GDALOpenInfo *poOpenInfo)

{
    if (!Identify(poOpenInfo) || poOpenInfo->fpL == nullptr)
        return nullptr;

    /* -------------------------------------------------------------------- */
    /*      Confirm the requested access is supported.                      */
    /* -------------------------------------------------------------------- */
    if (poOpenInfo->eAccess == GA_Update)
    {
        CPLError(CE_Failure, CPLE_NotSupported,
                 "The ZMAP driver does not support update access to existing"
                 " datasets.");
        return nullptr;
    }
    /* -------------------------------------------------------------------- */
    /*      Find dataset characteristics                                    */
    /* -------------------------------------------------------------------- */

    const char *pszLine;

    while ((pszLine = CPLReadLine2L(poOpenInfo->fpL, 100, nullptr)) != nullptr)
    {
        if (*pszLine == '!')
        {
            continue;
        }
        else
            break;
    }
    // cppcheck-suppress knownConditionTrueFalse
    if (pszLine == nullptr)
    {
        VSIFCloseL(poOpenInfo->fpL);
        poOpenInfo->fpL = nullptr;
        return nullptr;
    }

    /* Parse first header line */
    char **papszTokens = CSLTokenizeString2(pszLine, ",", 0);
    if (CSLCount(papszTokens) != 3)
    {
        CSLDestroy(papszTokens);
        VSIFCloseL(poOpenInfo->fpL);
        poOpenInfo->fpL = nullptr;
        return nullptr;
    }

    const int nValuesPerLine = atoi(papszTokens[2]);
    if (nValuesPerLine <= 0)
    {
        CSLDestroy(papszTokens);
        VSIFCloseL(poOpenInfo->fpL);
        poOpenInfo->fpL = nullptr;
        return nullptr;
    }

    CSLDestroy(papszTokens);
    papszTokens = nullptr;

    /* Parse second header line */
    pszLine = CPLReadLine2L(poOpenInfo->fpL, 100, nullptr);
    if (pszLine == nullptr)
    {
        VSIFCloseL(poOpenInfo->fpL);
        poOpenInfo->fpL = nullptr;
        return nullptr;
    }
    papszTokens = CSLTokenizeString2(pszLine, ",", 0);
    if (CSLCount(papszTokens) != 5)
    {
        CSLDestroy(papszTokens);
        VSIFCloseL(poOpenInfo->fpL);
        poOpenInfo->fpL = nullptr;
        return nullptr;
    }

    const int nFieldSize = atoi(papszTokens[0]);
    const double dfNoDataValue = CPLAtofM(papszTokens[1]);
    const int nDecimalCount = atoi(papszTokens[3]);
    const int nColumnNumber = atoi(papszTokens[4]);

    CSLDestroy(papszTokens);
    papszTokens = nullptr;

    if (nFieldSize <= 0 || nFieldSize >= 40 || nDecimalCount <= 0 ||
        nDecimalCount >= nFieldSize || nColumnNumber != 1)
    {
        CPLDebug("ZMap", "nFieldSize=%d, nDecimalCount=%d, nColumnNumber=%d",
                 nFieldSize, nDecimalCount, nColumnNumber);
        VSIFCloseL(poOpenInfo->fpL);
        poOpenInfo->fpL = nullptr;
        return nullptr;
    }

    /* Parse third header line */
    pszLine = CPLReadLine2L(poOpenInfo->fpL, 100, nullptr);
    if (pszLine == nullptr)
    {
        VSIFCloseL(poOpenInfo->fpL);
        poOpenInfo->fpL = nullptr;
        return nullptr;
    }
    papszTokens = CSLTokenizeString2(pszLine, ",", 0);
    if (CSLCount(papszTokens) != 6)
    {
        CSLDestroy(papszTokens);
        VSIFCloseL(poOpenInfo->fpL);
        poOpenInfo->fpL = nullptr;
        return nullptr;
    }

    const int nRows = atoi(papszTokens[0]);
    const int nCols = atoi(papszTokens[1]);
    const double dfMinX = CPLAtofM(papszTokens[2]);
    const double dfMaxX = CPLAtofM(papszTokens[3]);
    const double dfMinY = CPLAtofM(papszTokens[4]);
    const double dfMaxY = CPLAtofM(papszTokens[5]);

    CSLDestroy(papszTokens);
    papszTokens = nullptr;

    if (!GDALCheckDatasetDimensions(nCols, nRows) || nCols == 1 || nRows == 1)
    {
        VSIFCloseL(poOpenInfo->fpL);
        poOpenInfo->fpL = nullptr;
        return nullptr;
    }

    /* Ignore fourth header line */
    pszLine = CPLReadLine2L(poOpenInfo->fpL, 100, nullptr);
    if (pszLine == nullptr)
    {
        VSIFCloseL(poOpenInfo->fpL);
        poOpenInfo->fpL = nullptr;
        return nullptr;
    }

    /* Check fifth header line */
    pszLine = CPLReadLine2L(poOpenInfo->fpL, 100, nullptr);
    if (pszLine == nullptr || pszLine[0] != '@')
    {
        VSIFCloseL(poOpenInfo->fpL);
        poOpenInfo->fpL = nullptr;
        return nullptr;
    }

    /* -------------------------------------------------------------------- */
    /*      Create a corresponding GDALDataset.                             */
    /* -------------------------------------------------------------------- */
    ZMapDataset *poDS = new ZMapDataset();
    poDS->fp = poOpenInfo->fpL;
    poOpenInfo->fpL = nullptr;
    poDS->nDataStartOff = VSIFTellL(poDS->fp);
    poDS->nValuesPerLine = nValuesPerLine;
    poDS->nFieldSize = nFieldSize;
    poDS->nDecimalCount = nDecimalCount;
    poDS->nRasterXSize = nCols;
    poDS->nRasterYSize = nRows;
    poDS->dfNoDataValue = dfNoDataValue;

    if (CPLTestBool(CPLGetConfigOption("ZMAP_PIXEL_IS_POINT", "FALSE")))
    {
        const double dfStepX = (dfMaxX - dfMinX) / (nCols - 1);
        const double dfStepY = (dfMaxY - dfMinY) / (nRows - 1);

        poDS->adfGeoTransform[0] = dfMinX - dfStepX / 2;
        poDS->adfGeoTransform[1] = dfStepX;
        poDS->adfGeoTransform[3] = dfMaxY + dfStepY / 2;
        poDS->adfGeoTransform[5] = -dfStepY;
    }
    else
    {
        const double dfStepX = (dfMaxX - dfMinX) / nCols;
        const double dfStepY = (dfMaxY - dfMinY) / nRows;

        poDS->adfGeoTransform[0] = dfMinX;
        poDS->adfGeoTransform[1] = dfStepX;
        poDS->adfGeoTransform[3] = dfMaxY;
        poDS->adfGeoTransform[5] = -dfStepY;
    }

    /* -------------------------------------------------------------------- */
    /*      Create band information objects.                                */
    /* -------------------------------------------------------------------- */
    poDS->nBands = 1;
    poDS->SetBand(1, new ZMapRasterBand(poDS));

    /* -------------------------------------------------------------------- */
    /*      Initialize any PAM information.                                 */
    /* -------------------------------------------------------------------- */
    poDS->SetDescription(poOpenInfo->pszFilename);
    poDS->TryLoadXML();

    /* -------------------------------------------------------------------- */
    /*      Support overviews.                                              */
    /* -------------------------------------------------------------------- */
    poDS->oOvManager.Initialize(poDS, poOpenInfo->pszFilename);
    return poDS;
}

/************************************************************************/
/*                       WriteRightJustified()                          */
/************************************************************************/

static void WriteRightJustified(VSILFILE *fp, const char *pszValue, int nWidth)
{
    int nLen = (int)strlen(pszValue);
    CPLAssert(nLen <= nWidth);
    for (int i = 0; i < nWidth - nLen; i++)
        VSIFWriteL(" ", 1, 1, fp);
    VSIFWriteL(pszValue, 1, nLen, fp);
}

static void WriteRightJustified(VSILFILE *fp, int nValue, int nWidth)
{
    CPLString osValue(CPLSPrintf("%d", nValue));
    WriteRightJustified(fp, osValue.c_str(), nWidth);
}

static void WriteRightJustified(VSILFILE *fp, double dfValue, int nWidth,
                                int nDecimals = -1)
{
    char szFormat[32];
    if (nDecimals >= 0)
        snprintf(szFormat, sizeof(szFormat), "%%.%df", nDecimals);
    else
        snprintf(szFormat, sizeof(szFormat), "%%g");
    char *pszValue = const_cast<char *>(CPLSPrintf(szFormat, dfValue));
    char *pszE = strchr(pszValue, 'e');
    if (pszE)
        *pszE = 'E';

    if (static_cast<int>(strlen(pszValue)) > nWidth)
    {
        CPLAssert(nDecimals >= 0);
        snprintf(szFormat, sizeof(szFormat), "%%.%dg", nDecimals);
        pszValue = const_cast<char *>(CPLSPrintf(szFormat, dfValue));
        pszE = strchr(pszValue, 'e');
        if (pszE)
            *pszE = 'E';
    }

    CPLString osValue(pszValue);
    WriteRightJustified(fp, osValue.c_str(), nWidth);
}

/************************************************************************/
/*                             CreateCopy()                             */
/************************************************************************/

GDALDataset *ZMapDataset::CreateCopy(const char *pszFilename,
                                     GDALDataset *poSrcDS, int bStrict,
                                     CPL_UNUSED char **papszOptions,
                                     GDALProgressFunc pfnProgress,
                                     void *pProgressData)
{
    /* -------------------------------------------------------------------- */
    /*      Some some rudimentary checks                                    */
    /* -------------------------------------------------------------------- */
    int nBands = poSrcDS->GetRasterCount();
    if (nBands == 0)
    {
        CPLError(
            CE_Failure, CPLE_NotSupported,
            "ZMap driver does not support source dataset with zero band.\n");
        return nullptr;
    }

    if (nBands != 1)
    {
        CPLError((bStrict) ? CE_Failure : CE_Warning, CPLE_NotSupported,
                 "ZMap driver only uses the first band of the dataset.\n");
        if (bStrict)
            return nullptr;
    }

    if (pfnProgress && !pfnProgress(0.0, nullptr, pProgressData))
        return nullptr;

    /* -------------------------------------------------------------------- */
    /*      Get source dataset info                                         */
    /* -------------------------------------------------------------------- */

    const int nXSize = poSrcDS->GetRasterXSize();
    const int nYSize = poSrcDS->GetRasterYSize();
    if (nXSize == 1 || nYSize == 1)
    {
        return nullptr;
    }

    double adfGeoTransform[6];
    poSrcDS->GetGeoTransform(adfGeoTransform);
    if (adfGeoTransform[2] != 0 || adfGeoTransform[4] != 0)
    {
        CPLError(CE_Failure, CPLE_NotSupported,
                 "ZMap driver does not support CreateCopy() from skewed or "
                 "rotated dataset.\n");
        return nullptr;
    }

    /* -------------------------------------------------------------------- */
    /*      Create target file                                              */
    /* -------------------------------------------------------------------- */

    VSILFILE *fp = VSIFOpenL(pszFilename, "wb");
    if (fp == nullptr)
    {
        CPLError(CE_Failure, CPLE_AppDefined, "Cannot create %s", pszFilename);
        return nullptr;
    }

    const int nFieldSize = 20;
    const int nValuesPerLine = 4;
    const int nDecimalCount = 7;

    int bHasNoDataValue = FALSE;
    double dfNoDataValue =
        poSrcDS->GetRasterBand(1)->GetNoDataValue(&bHasNoDataValue);
    if (!bHasNoDataValue)
        dfNoDataValue = 1.e30;

    VSIFPrintfL(fp, "!\n");
    VSIFPrintfL(fp, "! Created by GDAL.\n");
    VSIFPrintfL(fp, "!\n");
    VSIFPrintfL(fp, "@GRID FILE, GRID, %d\n", nValuesPerLine);

    WriteRightJustified(fp, nFieldSize, 10);
    VSIFPrintfL(fp, ",");
    WriteRightJustified(fp, dfNoDataValue, nFieldSize, nDecimalCount);
    VSIFPrintfL(fp, ",");
    WriteRightJustified(fp, "", 10);
    VSIFPrintfL(fp, ",");
    WriteRightJustified(fp, nDecimalCount, 10);
    VSIFPrintfL(fp, ",");
    WriteRightJustified(fp, 1, 10);
    VSIFPrintfL(fp, "\n");

    WriteRightJustified(fp, nYSize, 10);
    VSIFPrintfL(fp, ",");
    WriteRightJustified(fp, nXSize, 10);
    VSIFPrintfL(fp, ",");

    if (CPLTestBool(CPLGetConfigOption("ZMAP_PIXEL_IS_POINT", "FALSE")))
    {
        WriteRightJustified(fp, adfGeoTransform[0] + adfGeoTransform[1] / 2, 14,
                            7);
        VSIFPrintfL(fp, ",");
        WriteRightJustified(fp,
                            adfGeoTransform[0] + adfGeoTransform[1] * nXSize -
                                adfGeoTransform[1] / 2,
                            14, 7);
        VSIFPrintfL(fp, ",");
        WriteRightJustified(fp,
                            adfGeoTransform[3] + adfGeoTransform[5] * nYSize -
                                adfGeoTransform[5] / 2,
                            14, 7);
        VSIFPrintfL(fp, ",");
        WriteRightJustified(fp, adfGeoTransform[3] + adfGeoTransform[5] / 2, 14,
                            7);
    }
    else
    {
        WriteRightJustified(fp, adfGeoTransform[0], 14, 7);
        VSIFPrintfL(fp, ",");
        WriteRightJustified(
            fp, adfGeoTransform[0] + adfGeoTransform[1] * nXSize, 14, 7);
        VSIFPrintfL(fp, ",");
        WriteRightJustified(
            fp, adfGeoTransform[3] + adfGeoTransform[5] * nYSize, 14, 7);
        VSIFPrintfL(fp, ",");
        WriteRightJustified(fp, adfGeoTransform[3], 14, 7);
    }

    VSIFPrintfL(fp, "\n");

    VSIFPrintfL(fp, "0.0, 0.0, 0.0\n");
    VSIFPrintfL(fp, "@\n");

    /* -------------------------------------------------------------------- */
    /*      Copy imagery                                                    */
    /* -------------------------------------------------------------------- */
    double *padfLineBuffer =
        reinterpret_cast<double *>(CPLMalloc(nYSize * sizeof(double)));

    CPLErr eErr = CE_None;
    for (int i = 0; i < nXSize && eErr == CE_None; i++)
    {
        eErr = poSrcDS->GetRasterBand(1)->RasterIO(GF_Read, i, 0, 1, nYSize,
                                                   padfLineBuffer, 1, nYSize,
                                                   GDT_Float64, 0, 0, nullptr);
        if (eErr != CE_None)
            break;
        bool bEOLPrinted = false;
        int j = 0;
        for (; j < nYSize; j++)
        {
            WriteRightJustified(fp, padfLineBuffer[j], nFieldSize,
                                nDecimalCount);
            if (((j + 1) % nValuesPerLine) == 0)
            {
                bEOLPrinted = true;
                VSIFPrintfL(fp, "\n");
            }
            else
                bEOLPrinted = false;
        }
        if (!bEOLPrinted)
            VSIFPrintfL(fp, "\n");

        if (pfnProgress != nullptr &&
            !pfnProgress((j + 1) * 1.0 / nYSize, nullptr, pProgressData))
        {
            eErr = CE_Failure;
            break;
        }
    }
    CPLFree(padfLineBuffer);
    VSIFCloseL(fp);

    if (eErr != CE_None)
        return nullptr;

    return reinterpret_cast<GDALDataset *>(GDALOpen(pszFilename, GA_ReadOnly));
}

/************************************************************************/
/*                          GetGeoTransform()                           */
/************************************************************************/

CPLErr ZMapDataset::GetGeoTransform(double *padfTransform)

{
    memcpy(padfTransform, adfGeoTransform, 6 * sizeof(double));

    return CE_None;
}

/************************************************************************/
/*                         GDALRegister_ZMap()                          */
/************************************************************************/

void GDALRegister_ZMap()

{
    if (GDALGetDriverByName("ZMap") != nullptr)
        return;

    GDALDriver *poDriver = new GDALDriver();

    poDriver->SetDescription("ZMap");
    poDriver->SetMetadataItem(GDAL_DCAP_RASTER, "YES");
    poDriver->SetMetadataItem(GDAL_DMD_LONGNAME, "ZMap Plus Grid");
    poDriver->SetMetadataItem(GDAL_DMD_HELPTOPIC, "drivers/raster/zmap.html");
    poDriver->SetMetadataItem(GDAL_DMD_EXTENSION, "dat");
    poDriver->SetMetadataItem(GDAL_DCAP_VIRTUALIO, "YES");

    poDriver->pfnOpen = ZMapDataset::Open;
    poDriver->pfnIdentify = ZMapDataset::Identify;
    poDriver->pfnCreateCopy = ZMapDataset::CreateCopy;

    GetGDALDriverManager()->RegisterDriver(poDriver);
}
