#!/usr/bin/env python
###############################################################################
# $Id: netcdf_cfchecks.py d7e898f6034a9c6c0f83cfbff921434dfc2082be 2018-04-18 23:07:52 +1000 Ben Elliston $
#
# Project:  GDAL/OGR Test Suite
# Purpose:  Test NetCDF driver CF compliance.
# Author:   Etienne Tourigny <etourigny.dev at gmail dot com>
#
###############################################################################
# No copyright in original script...  apparently under BSD licence
# original can be found at http://pypi.python.org/pypi/cfchecker
#
# Slightly modified to please pyflakes and being imported by Python3 (but
# actually untested with python3)
###############################################################################
# Adapted for numpy/ma/cdms2 by convertcdms.py
# -------------------------------------------------------------
# Name: cfchecks.py
#
# Author: Rosalyn Hatcher - Met Office, UK
#
# Maintainer: Rosalyn Hatcher - NCAS-CMS, Univ. of Reading, UK
#
#
# File Revision:
#
# CF Checker Version: 2.0.9-gdal
#
# -------------------------------------------------------------
''' cfchecker [-a|--area_types area_types.xml] [-s|--cf_standard_names standard_names.xml] [-u|--udunits udunits.dat] [-v|--version CFVersion] file1 [file2...]

Description:
 The cfchecker checks NetCDF files for compliance to the CF standard.

Options:
 -a or --area_types:
       the location of the CF area types table (xml)

 -s or --cf_standard_names:
       the location of the CF standard name table (xml)

 -u or --udunits:
       the location of the udunits.dat file

 -h or --help: Prints this help text.

 -v or --version: CF version to check against, use auto to auto-detect the file version.

'''

import cdms2 as cdms
import re
import string
import numpy
import sys

from cdms2.axis import FileAxis
from cdms2.auxcoord import FileAuxAxis1D

# Use ctypes to interface to the UDUNITS-2 shared library
# The udunits2 library needs to be in a standard path o/w export LD_LIBRARY_PATH
import ctypes
udunits = ctypes.CDLL("libudunits2.so")

STANDARDNAME = 'http://cfconventions.org/Data/cf-standard-names/current/src/cf-standard-name-table.xml'
AREATYPES = 'http://cfconventions.org/Data/area-type-table/current/src/area-type-table.xml'

# -----------------------------------------------------------
from xml.sax import ContentHandler
from xml.sax import make_parser
from xml.sax.handler import feature_namespaces


def normalize_whitespace(text):
    "Remove redundant whitespace from a string."
    return ' '.join(text.split())


def my_cmp(a, b):
    return (a > b) - (a < b)


class CFVersion(object):
    """A CF version number, stored as a tuple, that can be instantiated with
    a tuple or a string, written out as a string, and compared with another version"""

    def __init__(self, value=()):
        "Instantiate CFVersion with a string or with a tuple of ints"
        if isinstance(value, str):
            if value.startswith("CF-"):
                value = value[3:]
            self.tuple = map(int, value.split("."))
        else:
            self.tuple = value

    def __nonzero__(self):
        if self.tuple:
            return True
        else:
            return False

    def __str__(self):
        return "CF-%s" % string.join(map(str, self.tuple), ".")

    def __cmp__(self, other):
        # maybe overkill but allow for different lengths in future e.g. 3.2 and 3.2.1
        pos = 0
        while True:
            in_s = (pos < len(self.tuple))
            in_o = (pos < len(other.tuple))
            if in_s:
                if in_o:
                    c = my_cmp(self.tuple[pos], other.tuple[pos])
                    if c != 0:
                        return c  # e.g. 1.x <=> 1.y
                else:  # in_s and not in_o
                    return 1  # e.g. 3.2.1 > 3.2
            else:
                if in_o:  # and not in_s
                    return -1  # e.g. 3.2 < 3.2.1
                else:  # not in_s and not in_o
                    return 0  # e.g. 3.2 == 3.2
            pos += 1


vn1_0 = CFVersion((1, 0))
vn1_1 = CFVersion((1, 1))
vn1_2 = CFVersion((1, 2))
vn1_3 = CFVersion((1, 3))
vn1_4 = CFVersion((1, 4))
vn1_5 = CFVersion((1, 5))
vn1_6 = CFVersion((1, 6))
cfVersions = [vn1_0, vn1_1, vn1_2, vn1_3, vn1_4, vn1_5, vn1_6]
newest_version = max(cfVersions)


class ConstructDict(ContentHandler):
    """Parse the xml standard_name table, reading all entries
       into a dictionary; storing standard_name and units.
    """

    def __init__(self):
        self.inUnitsContent = 0
        self.inEntryIdContent = 0
        self.inVersionNoContent = 0
        self.inLastModifiedContent = 0
        self.dict = {}

    def startElement(self, name, attrs):
        # If it's an entry element, save the id
        if name == 'entry':
            id = normalize_whitespace(attrs.get('id', ""))
            self.this_id = id

        # If it's the start of a canonical_units element
        elif name == 'canonical_units':
            self.inUnitsContent = 1
            self.units = ""

        elif name == 'alias':
            id = normalize_whitespace(attrs.get('id', ""))
            self.this_id = id

        elif name == 'entry_id':
            self.inEntryIdContent = 1
            self.entry_id = ""

        elif name == 'version_number':
            self.inVersionNoContent = 1
            self.version_number = ""

        elif name == 'last_modified':
            self.inLastModifiedContent = 1
            self.last_modified = ""

    def characters(self, ch):
        if self.inUnitsContent:
            self.units = self.units + ch

        elif self.inEntryIdContent:
            self.entry_id = self.entry_id + ch

        elif self.inVersionNoContent:
            self.version_number = self.version_number + ch

        elif self.inLastModifiedContent:
            self.last_modified = self.last_modified + ch

    def endElement(self, name):
        # If it's the end of the canonical_units element, save the units
        if name == 'canonical_units':
            self.inUnitsContent = 0
            self.units = normalize_whitespace(self.units)
            self.dict[self.this_id] = self.units

        # If it's the end of the entry_id element, find the units for the self.alias
        elif name == 'entry_id':
            self.inEntryIdContent = 0
            self.entry_id = normalize_whitespace(self.entry_id)
            try:
                self.dict[self.this_id] = self.dict[self.entry_id]
            except KeyError:
                print("")
                print("**WARNING** Error in standard_name table:  entry_id '" + self.entry_id + "' not found")
                print("Please contact Rosalyn Hatcher (r.s.hatcher@reading.ac.uk)")
                print("")

        # If it's the end of the version_number element, save it
        elif name == 'version_number':
            self.inVersionNoContent = 0
            self.version_number = normalize_whitespace(self.version_number)

        # If it's the end of the last_modified element, save the last modified date
        elif name == 'last_modified':
            self.inLastModifiedContent = 0
            self.last_modified = normalize_whitespace(self.last_modified)


class ConstructList(ContentHandler):
    """Parse the xml area_type table, reading all area_types
       into a list.
    """

    def __init__(self):
        self.inVersionNoContent = 0
        self.inLastModifiedContent = 0
        self.list = []

    def startElement(self, name, attrs):
        # If it's an entry element, save the id
        if name == 'entry':
            id = normalize_whitespace(attrs.get('id', ""))
            self.list.append(id)

        elif name == 'version_number':
            self.inVersionNoContent = 1
            self.version_number = ""

        elif name == 'date':
            self.inLastModifiedContent = 1
            self.last_modified = ""

    def characters(self, ch):
        if self.inVersionNoContent:
            self.version_number = self.version_number + ch

        elif self.inLastModifiedContent:
            self.last_modified = self.last_modified + ch

    def endElement(self, name):
        # If it's the end of the version_number element, save it
        if name == 'version_number':
            self.inVersionNoContent = 0
            self.version_number = normalize_whitespace(self.version_number)

        # If it's the end of the date element, save the last modified date
        elif name == 'date':
            self.inLastModifiedContent = 0
            self.last_modified = normalize_whitespace(self.last_modified)


def chkDerivedName(name):
    """Checks whether name is a derived standard name and adheres
       to the transformation rules. See CF standard names document
       for more information.
    """
    if re.search("^(direction|magnitude|square|divergence)_of_[a-zA-Z][a-zA-Z0-9_]*$", name):
        return 0

    if re.search("^rate_of_change_of_[a-zA-Z][a-zA-Z0-9_]*$", name):
        return 0

    if re.search("^(grid_)?(northward|southward|eastward|westward)_derivative_of_[a-zA-Z][a-zA-Z0-9_]*$", name):
        return 0

    if re.search("^product_of_[a-zA-Z][a-zA-Z0-9_]*_and_[a-zA-Z][a-zA-Z0-9_]*$", name):
        return 0

    if re.search("^ratio_of_[a-zA-Z][a-zA-Z0-9_]*_to_[a-zA-Z][a-zA-Z0-9_]*$", name):
        return 0

    if re.search("^derivative_of_[a-zA-Z][a-zA-Z0-9_]*_wrt_[a-zA-Z][a-zA-Z0-9_]*$", name):
        return 0

    if re.search("^(correlation|covariance)_over_[a-zA-Z][a-zA-Z0-9_]*_of_[a-zA-Z][a-zA-Z0-9_]*_and_[a-zA-Z][a-zA-Z0-9_]*$", name):
        return 0

    if re.search("^histogram_over_[a-zA-Z][a-zA-Z0-9_]*_of_[a-zA-Z][a-zA-Z0-9_]*$", name):
        return 0

    if re.search("^probability_distribution_over_[a-zA-Z][a-zA-Z0-9_]*_of_[a-zA-Z][a-zA-Z0-9_]*$", name):
        return 0

    if re.search("^probability_density_function_over_[a-zA-Z][a-zA-Z0-9_]*_of_[a-zA-Z][a-zA-Z0-9_]*$", name):
        return 0

    # Not a valid derived name
    return 1


# ======================
# Checking class
# ======================
class CFChecker:

    def __init__(self, uploader=None, useFileName="yes", badc=None, coards=None, cfStandardNamesXML=None, cfAreaTypesXML=None, udunitsDat=None, version=newest_version):
        self.uploader = uploader
        self.useFileName = useFileName
        self.badc = badc
        self.coards = coards
        self.standardNames = cfStandardNamesXML
        self.areaTypes = cfAreaTypesXML
        self.udunits = udunitsDat
        self.version = version
        self.err = 0
        self.warn = 0
        self.info = 0
        self.cf_roleCount = 0          # Number of occurrences of the cf_role attribute in the file
        self.raggedArrayFlag = 0       # Flag to indicate if file contains any ragged array representations

    def checker(self, file):

        fileSuffix = re.compile('^\S+\.nc$')

        print("")
        if self.uploader:
            realfile = string.split(file, ".nc")[0] + ".nc"
            print("CHECKING NetCDF FILE:", realfile)
        elif self.useFileName == "no":
            print("CHECKING NetCDF FILE")
        else:
            print("CHECKING NetCDF FILE:", file)
        print("=====================")

        # Check for valid filename
        if not fileSuffix.match(file):
            print("ERROR (2.1): Filename must have .nc suffix")
            exit(1)

        # Initialize udunits-2 package
        # (Temporarily ignore messages to std error stream to prevent "Definition override" warnings
        # being displayed see Trac #50)
        # Use ctypes callback functions to declare ut_error_message_handler (uemh)
        # Don't fully understand why this works!  Solution supplied by ctypes-mailing-list. 19.01.10
        uemh = ctypes.CFUNCTYPE(ctypes.c_int, ctypes.c_char_p)
        ut_set_error_message_handler = ctypes.CFUNCTYPE(uemh, uemh)(("ut_set_error_message_handler", udunits))
        ut_write_to_stderr = uemh(("ut_write_to_stderr", udunits))
        ut_ignore = uemh(("ut_ignore", udunits))

        # old_handler =
        ut_set_error_message_handler(ut_ignore)

        # if self.udunits=None this will load the UDUNITS2 xml file from the default place
        self.unitSystem = udunits.ut_read_xml(self.udunits)
        if not self.unitSystem:
            exit("Could not read the UDUNITS2 xml database from: %s" % self.udunits)

        # old_handler =
        ut_set_error_message_handler(ut_write_to_stderr)

        # Read in netCDF file
        try:
            self.f = cdms.open(file, "r")

        except AttributeError:
            print("NetCDF Attribute Error:")
            raise
        except:
            print("\nCould not open file, please check that NetCDF is formatted correctly.\n".upper())
            print("ERRORS detected:", 1)
            raise
            exit(1)

        # if 'auto' version, check the CF version in the file
        # if none found, use the default
        if not self.version:
            self.version = self.getFileCFVersion()
            if not self.version:
                print("WARNING: Cannot determine CF version from the Conventions attribute; checking against latest CF version:", newest_version)
                self.warn = self.warn + 1
                self.version = newest_version

        # Set up dictionary of all valid attributes, their type and use
        self.setUpAttributeList()

        # Set up dictionary of standard_names and their assoc. units
        parser = make_parser()
        parser.setFeature(feature_namespaces, 0)
        self.std_name_dh = ConstructDict()
        parser.setContentHandler(self.std_name_dh)
        parser.parse(self.standardNames)

        if self.version >= vn1_4:
            # Set up list of valid area_types
            self.area_type_lh = ConstructList()
            parser.setContentHandler(self.area_type_lh)
            parser.parse(self.areaTypes)

        print("Using CF Checker Version 2.0.9-gdal")

        if not self.version:
            print("Checking against CF Version (auto)")
        else:
            print("Checking against CF Version %s" % self.version)

        print("Using Standard Name Table Version " + self.std_name_dh.version_number + " (" + self.std_name_dh.last_modified + ")")

        if self.version >= vn1_4:
            print("Using Area Type Table Version " + self.area_type_lh.version_number + " (" + self.area_type_lh.last_modified + ")")
        print("")

        # Read in netCDF file
        try:
            self.f = cdms.open(file, "r")

        except AttributeError:
            print("NetCDF Attribute Error:")
            raise
        except:
            print("\nCould not open file, please check that NetCDF is formatted correctly.\n".upper())
            print("ERRORS detected:", 1)
            raise

        try:
            return self._checker()
        finally:
            self.f.close()

    def _checker(self):
        """
        Main implementation of checker assuming self.f exists.
        """
        lowerVars = []
        rc = 1

        # Check global attributes
        if not self.chkGlobalAttributes():
            rc = 0

        (coordVars, auxCoordVars, boundsVars, climatologyVars, gridMappingVars) = self.getCoordinateDataVars()
        self.coordVars = coordVars
        self.auxCoordVars = auxCoordVars
        self.boundsVars = boundsVars
        self.climatologyVars = climatologyVars
        self.gridMappingVars = gridMappingVars

        # print "Auxiliary Coordinate Vars:",auxCoordVars
        # print "Coordinate Vars: ",coordVars

        allCoordVars = coordVars[:]
        allCoordVars[len(allCoordVars):] = auxCoordVars[:]

        self.setUpFormulas()

        axes = self.f.axes.keys()

        # Check each variable
        for var in self.f._file_.variables.keys():
            print("")
            print("------------------")
            print("Checking variable:", var)
            print("------------------")

            if not self.validName(var):
                print("ERROR (2.3): Invalid variable name -", var)
                self.err = self.err + 1
                rc = 0

            # Check to see if a variable with this name already exists (case-insensitive)
            lowerVar = var.lower()
            if lowerVar in lowerVars:
                print("WARNING (2.3): variable clash:-", var)
                self.warn = self.warn + 1
            else:
                lowerVars.append(lowerVar)

            if var not in axes:
                # Non-coordinate variable
                if not self.chkDimensions(var, allCoordVars):
                    rc = 0

            if not self.chkDescription(var):
                rc = 0

            for attribute in self.f[var].attributes.keys():
                if not self.chkAttribute(attribute, var, allCoordVars):
                    rc = 0

            if not self.chkUnits(var, allCoordVars):
                rc = 0

            if not self.chkValidMinMaxRange(var):
                rc = 0

            if not self.chk_FillValue(var):
                rc = 0

            if not self.chkAxisAttribute(var):
                rc = 0

            if not self.chkPositiveAttribute(var):
                rc = 0

            if not self.chkCellMethods(var):
                rc = 0

            if not self.chkCellMeasures(var):
                rc = 0

            if not self.chkFormulaTerms(var, allCoordVars):
                rc = 0

            if not self.chkCompressAttr(var):
                rc = 0

            if not self.chkPackedData(var):
                rc = 0

            if self.version >= vn1_3:
                # Additional conformance checks from CF-1.3 onwards
                if not self.chkFlags(var):
                    rc = 0

            if self.version >= vn1_6:
                # Additional conformance checks from CF-1.6 onwards
                if not self.chkCFRole(var):
                    rc = 0
                if not self.chkRaggedArray(var):
                    rc = 0

            if var in coordVars:
                if not self.chkMultiDimCoord(var, axes):
                    rc = 0
                if not self.chkValuesMonotonic(var):
                    rc = 0

            if var in gridMappingVars:
                if not self.chkGridMappingVar(var):
                    rc = 0

            # print "Axes:",axes
            if var in axes:
                # Check var is a FileAxis.  If not then there may be a problem with its declaration.
                # I.e. Multi-dimensional coordinate var with a dimension of the same name
                # or an axis that hasn't been identified through the coordinates attribute
                # CRM035 (17.04.07)
                if not (isinstance(self.f[var], FileAxis) or isinstance(self.f[var], FileAuxAxis1D)):
                    print("WARNING (5): Possible incorrect declaration of a coordinate variable.")
                    self.warn = self.warn + 1
                else:
                    if self.f[var].isTime():
                        if not self.chkTimeVariableAttributes(var):
                            rc = 0

        if rc:
            pass

        # print self.cf_roleCount,"variable(s) have the cf_role attribute set"
        if self.version >= vn1_6:
            print(" ")

            if self.raggedArrayFlag != 0 and 'featureType' not in self.f.attributes:
                print("ERROR (9.4): The global attribute 'featureType' must be present (A ragged array representation has been used)")
                self.err = self.err + 1

            if 'featureType' in self.f.attributes:
                featureType = self.f.attributes['featureType']

                if self.cf_roleCount == 0 and featureType != "point":
                    print("WARNING (9.5): A variable with the attribute cf_role should be included in a Discrete Geometry CF File")
                    self.warn = self.warn + 1

                if re.match('^(timeSeries|trajectory|profile)$', featureType, re.I) and self.cf_roleCount != 1:
                    # Should only be a single occurrence of a cf_role attribute
                    print("WARNING (9.5): CF Files containing", featureType, "featureType should only include a single occurrence of a cf_role attribute")
                    self.warn = self.warn + 1

                elif re.match('^(timeSeriesProfile|trajectoryProfile)$', featureType, re.I) and self.cf_roleCount > 2:
                    # May contain up to 2 occurrences of cf_roles attribute
                    print("ERROR (9.5): CF Files containing", featureType, "featureType may contain 2 occurrences of a cf_role attribute")
                    self.err = self.err + 1

        print("")
        print("ERRORS detected:", self.err)
        print("WARNINGS given:", self.warn)
        print("INFORMATION messages:", self.info)

        if self.err:
            # Return number of errors found
            return self.err
        elif self.warn:
            # No errors, but some warnings found
            return -(self.warn)
        else:
            # No errors or warnings - return success!
            return 0

        # -----------------------------
    def setUpAttributeList(self):
        # -----------------------------
        """Set up Dictionary of valid attributes, their corresponding
        Type; S(tring), N(umeric) D(ata variable type) and Use C(oordinate),
        D(ata non-coordinate) or G(lobal) variable."""

        self.AttrList = {}
        self.AttrList['add_offset'] = ['N', 'D']
        self.AttrList['ancillary_variables'] = ['S', 'D']
        self.AttrList['axis'] = ['S', 'C']
        self.AttrList['bounds'] = ['S', 'C']
        self.AttrList['calendar'] = ['S', 'C']
        self.AttrList['cell_measures'] = ['S', 'D']
        self.AttrList['cell_methods'] = ['S', 'D']
        self.AttrList['climatology'] = ['S', 'C']
        self.AttrList['comment'] = ['S', ('G', 'D')]
        self.AttrList['compress'] = ['S', 'C']
        self.AttrList['Conventions'] = ['S', 'G']
        self.AttrList['coordinates'] = ['S', 'D']
        self.AttrList['_FillValue'] = ['D', 'D']
        self.AttrList['flag_meanings'] = ['S', 'D']
        self.AttrList['flag_values'] = ['D', 'D']
        self.AttrList['formula_terms'] = ['S', 'C']
        self.AttrList['grid_mapping'] = ['S', 'D']
        self.AttrList['history'] = ['S', 'G']
        self.AttrList['institution'] = ['S', ('G', 'D')]
        self.AttrList['leap_month'] = ['N', 'C']
        self.AttrList['leap_year'] = ['N', 'C']
        self.AttrList['long_name'] = ['S', ('C', 'D')]
        self.AttrList['missing_value'] = ['D', 'D']
        self.AttrList['month_lengths'] = ['N', 'C']
        self.AttrList['positive'] = ['S', 'C']
        self.AttrList['references'] = ['S', ('G', 'D')]
        self.AttrList['scale_factor'] = ['N', 'D']
        self.AttrList['source'] = ['S', ('G', 'D')]
        self.AttrList['standard_error_multiplier'] = ['N', 'D']
        self.AttrList['standard_name'] = ['S', ('C', 'D')]
        self.AttrList['title'] = ['S', 'G']
        self.AttrList['units'] = ['S', ('C', 'D')]
        self.AttrList['valid_max'] = ['N', ('C', 'D')]
        self.AttrList['valid_min'] = ['N', ('C', 'D')]
        self.AttrList['valid_range'] = ['N', ('C', 'D')]

        if self.version >= vn1_3:
            self.AttrList['flag_masks'] = ['D', 'D']

        if self.version >= vn1_6:
            self.AttrList['cf_role'] = ['S', 'C']
            self.AttrList['featureType'] = ['S', 'G']
            self.AttrList['instance_dimension'] = ['S', 'D']
            self.AttrList['sample_dimension'] = ['S', 'D']

        return

        # ---------------------------
    def uniqueList(self, list):
        # ---------------------------
        """Determine if list has any repeated elements."""
        # Rewrite to allow list to be either a list or a Numeric array
        seen = []

        for x in list:
            if x in seen:
                return 0
            else:
                seen.append(x)
        return 1

        # -------------------------
    def isNumeric(self, var):
        # -------------------------
        """Determine if variable is of Numeric data type."""
        types = ['i', 'f', 'd']
        rc = 1
        if self.getTypeCode(self.f[var]) not in types:
            rc = 0
        return rc

        # -------------------------
    def getStdNameOld(self, var):
        # -------------------------
        """Get standard_name of variable (i.e. just first part of standard_name attribute, without modifier)"""
        attName = 'standard_name'
        attDict = var.attributes
        if attName not in attDict.keys():
            return None
        bits = string.split(attDict[attName])
        if bits:
            return bits[0]
        else:
            return ""

        # -------------------------
    def getStdName(self, var):
        # -------------------------
        """Get standard_name of variable.  Return it as 2 parts - the standard name and the modifier, if present."""
        attName = 'standard_name'
        attDict = var.attributes

        if attName not in attDict.keys():
            return None

        bits = string.split(attDict[attName])

        if len(bits) == 1:
            # Only standard_name part present
            return (bits[0], "")
        elif len(bits) == 0:
            # Standard Name is blank
            return ("", "")
        else:
            # At least 2 elements so return the first 2.
            # If there are more than 2, which is invalid syntax, this will have been picked up by chkDescription()
            return (bits[0], bits[1])

        # --------------------------------------------------
    def getInterpretation(self, units, positive=None):
        # --------------------------------------------------
        """Determine the interpretation (time - T, height or depth - Z,
        latitude - Y or longitude - X) of a dimension."""

        if units in ['level', 'layer', 'sigma_level']:
            # Dimensionless vertical coordinate
            return "Z"

        # Parse the string representation of units into its binary representation for use by udunits
        binaryUnit = udunits.ut_parse(self.unitSystem, units, "UT_ASCII")
        if not binaryUnit:
            # Don't print this message out o/w it is repeated for every variable
            # that has this dimension.  CRM033 return "None" instead
            # print "ERROR: Invalid units:",units
            # self.err = self.err+1
            return None

#    print "here"

        # Time Coordinate
        # 19.08.10 - Workaround since udunits2 deems a unit without reference time not convertible to a
        # unit with reference time and vice versa
        if udunits.ut_are_convertible(binaryUnit, udunits.ut_parse(self.unitSystem, "second", "UT_ASCII")):
            return "T"
        elif udunits.ut_are_convertible(binaryUnit, udunits.ut_parse(self.unitSystem, "seconds since 1-1-1 0:0:0", "UT_ASCII")):
            return "T"

        # Vertical Coordinate
        if positive and re.match('(up|down)', positive, re.I):
            return "Z"

        # Variable is a vertical coordinate if the units are dimensionally
        # equivalent to Pressure
        if udunits.ut_are_convertible(binaryUnit, udunits.ut_parse(self.unitSystem, "Pa", "UT_ASCII")):
            return "Z"

        # Latitude Coordinate
        if re.match('(degrees_north|degree_north|degrees_N|degree_N|degreesN|degreeN)', units):
            return "Y"

        # Longitude Coordinate
        if re.match('(degrees_east|degree_east|degrees_E|degree_E|degreesE|degreeE)', units):
            return "X"

        # Not possible to deduce interpretation
        return None

        # --------------------------------
    def getCoordinateDataVars(self):
        # --------------------------------
        """Obtain list of coordinate data variables, boundary
        variables, climatology variables and grid_mapping variables."""

        variables = self.f.variables.keys()     # List of variables, but doesn't include coord vars
        allVariables = self.f._file_.variables.keys()   # List of all vars, including coord vars
        axes = self.f.axes.keys()

        coordVars = []
        boundaryVars = []
        climatologyVars = []
        gridMappingVars = []
        auxCoordVars = []

        for var in allVariables:
            if var not in variables:
                # Coordinate variable - 1D & dimension is the same name as the variable
                coordVars.append(var)

# Commented out 21.02.06 - Duplicate code also in method chkDimensions
# Probably can be completely removed.
# if var not in coordVars:
# Non-coordinate variable so check if it has any repeated dimensions
# dimensions=self.f[var].getAxisIds()
# dimensions.sort()
# if not self.uniqueList(dimensions):
# print "ERROR: variable has repeated dimensions"
#                 self.err = self.err+1

            # ------------------------
            # Auxiliary Coord Checks
            # ------------------------
            if 'coordinates' in self.f[var].attributes:
                # Check syntax of 'coordinates' attribute
                if not self.parseBlankSeparatedList(self.f[var].attributes['coordinates']):
                    print("ERROR (5): Invalid syntax for 'coordinates' attribute in", var)
                    self.err = self.err + 1
                else:
                    coordinates = string.split(self.f[var].attributes['coordinates'])
                    for dataVar in coordinates:
                        if dataVar in variables:

                            # Has Auxiliary Coordinate already been identified and checked?
                            if dataVar not in auxCoordVars:
                                auxCoordVars.append(dataVar)

                                # Is the auxiliary coordinate var actually a label?
                                if self.getTypeCode(self.f[dataVar]) == 'c':
                                    # Label variable
                                    num_dimensions = len(self.f[dataVar].getAxisIds())
                                    if self.version < vn1_4:
                                        if not num_dimensions == 2:
                                            print("ERROR (6.1): Label variable", dataVar, "must have 2 dimensions only")
                                            self.err = self.err + 1

                                    if self.version >= vn1_4:
                                        if num_dimensions != 1 and num_dimensions != 2:
                                            print("ERROR (6.1): Label variable", dataVar, "must have 1 or 2 dimensions, but has", num_dimensions)
                                            self.err = self.err + 1

                                    if num_dimensions == 2:
                                        if self.f[dataVar].getAxisIds()[0] not in self.f[var].getAxisIds():
                                            if self.version >= vn1_6 and 'featureType' in self.f.attributes:
                                                # This file contains Discrete Sampling Geometries
                                                print("INFO (6.1): File contains a Discrete Sampling Geometry. Skipping check on dimensions of", dataVar)
                                                self.info = self.info + 1
                                            else:
                                                print("ERROR (6.1): Leading dimension of", dataVar, "must match one of those for", var)
                                                self.err = self.err + 1
                                else:
                                    # Not a label variable

                                    # 31.05.13 The other exception is a ragged array (chapter 9 - Discrete sampling geometries
                                    # Todo - implement exception
                                    # A ragged array is identified by the presence of either the attribute sample_dimension
                                    # or instance_dimension. Need to check that the sample dimension is the dimension of
                                    # the variable to which the aux coord var is attached.

                                    # print dataVar,"- Not a label variable. Dimensions are:",self.f[dataVar].getAxisIds()
                                    # print var,"dimensions are:",self.f[var].getAxisIds()

                                    for dim in self.f[dataVar].getAxisIds():
                                        if dim not in self.f[var].getAxisIds():
                                            if self.version >= vn1_6 and 'featureType' in self.f.attributes:
                                                # This file contains Discrete Sampling Geometries
                                                print("INFO (5): File contains a Discrete Sampling Geometry. Skipping check on dimensions of", dataVar)
                                                self.info = self.info + 1
                                            else:
                                                print("ERROR (5): Dimensions of", dataVar, "must be a subset of dimensions of", var)
                                                self.err = self.err + 1

                                            break

                        elif dataVar not in allVariables:
                            print("ERROR (5): coordinates attribute referencing non-existent variable:", dataVar)
                            self.err = self.err + 1

            # -------------------------
            # Boundary Variable Checks
            # -------------------------
            if 'bounds' in self.f[var].attributes:
                bounds = self.f[var].attributes['bounds']
                # Check syntax of 'bounds' attribute
                if not re.search("^[a-zA-Z0-9_]*$", bounds):
                    print("ERROR (7.1): Invalid syntax for 'bounds' attribute")
                    self.err = self.err + 1
                else:
                    if bounds in variables:
                        boundaryVars.append(bounds)

                        if not self.isNumeric(bounds):
                            print("ERROR (7.1): boundary variable with non-numeric data type")
                            self.err = self.err + 1
                        if len(self.f[var].shape) + 1 == len(self.f[bounds].shape):
                            if var in axes:
                                varDimensions = [var]
                            else:
                                varDimensions = self.f[var].getAxisIds()

                            for dim in varDimensions:
                                if dim not in self.f[bounds].getAxisIds():
                                    print("ERROR (7.1): Incorrect dimensions for boundary variable:", bounds)
                                    self.err = self.err + 1
                        else:
                            print("ERROR (7.1): Incorrect number of dimensions for boundary variable:", bounds)
                            self.err = self.err + 1

                        if 'units' in self.f[bounds].attributes:
                            if self.f[bounds].attributes['units'] != self.f[var].attributes['units']:
                                print("ERROR (7.1): Boundary var", bounds, "has inconsistent units to", var)
                                self.err = self.err + 1
                        if 'standard_name' in self.f[bounds].attributes and 'standard_name' in self.f[var].attributes:
                            if self.f[bounds].attributes['standard_name'] != self.f[var].attributes['standard_name']:
                                print("ERROR (7.1): Boundary var", bounds, "has inconsistent std_name to", var)
                                self.err = self.err + 1
                    else:
                        print("ERROR (7.1): bounds attribute referencing non-existent variable:", bounds)
                        self.err = self.err + 1

                # Check that points specified by a coordinate or auxiliary coordinate
                # variable should lie within, or on the boundary, of the cells specified by
                # the associated boundary variable.
                if bounds in variables:
                    # Is boundary variable 2 dimensional?  If so can check that points
                    # lie within, or on the boundary.
                    if len(self.f[bounds].getAxisIds()) <= 2:
                        varData = self.f[var].getValue()
                        boundsData = self.f[bounds].getValue()

                        try:
                            length = len(varData)
                        except TypeError:
                            length = 1  # scalar (no len); treat as length 1

                        if length == 0:
                            print("WARNING: Problem with variable: '" + var + "' - Skipping check that data lies within cell boundaries.")
                            self.warn = self.warn + 1

                        elif length == 1:
                            # Gone for belts and braces approach here!!
                            # Variable contains only one value
                            # Bounds array will be 1 dimensional
                            if not ((varData <= boundsData[0] and varData >= boundsData[1]) or
                                    (varData >= boundsData[0] and varData <= boundsData[1])):
                                print("WARNING (7.1): Data for variable", var, "lies outside cell boundaries")
                                self.warn = self.warn + 1
                        else:
                            i = 0
                            for value in varData:
                                if not ((value <= boundsData[i][0] and value >= boundsData[i][1]) or
                                        (value >= boundsData[i][0] and value <= boundsData[i][1])):
                                    print("WARNING (7.1): Data for variable", var, "lies outside cell boundaries")
                                    self.warn = self.warn + 1
                                    break
                                i = i + 1

            # ----------------------------
            # Climatology Variable Checks
            # ----------------------------
            if 'climatology' in self.f[var].attributes:
                climatology = self.f[var].attributes['climatology']
                # Check syntax of 'climatology' attribute
                if not re.search("^[a-zA-Z0-9_]*$", climatology):
                    print("ERROR (7.4): Invalid syntax for 'climatology' attribute")
                    self.err = self.err + 1
                else:
                    if climatology in variables:
                        climatologyVars.append(climatology)
                        if not self.isNumeric(climatology):
                            print("ERROR (7.4): climatology variable with non-numeric data type")
                            self.err = self.err + 1
                        if 'units' in self.f[climatology].attributes:
                            if self.f[climatology].attributes['units'] != self.f[var].attributes['units']:
                                print("ERROR (7.4): Climatology var", climatology, "has inconsistent units to", var)
                                self.err = self.err + 1
                        if 'standard_name' in self.f[climatology].attributes:
                            if self.f[climatology].attributes['standard_name'] != self.f[var].attributes['standard_name']:
                                print("ERROR (7.4): Climatology var", climatology, "has inconsistent std_name to", var)
                                self.err = self.err + 1
                        if 'calendar' in self.f[climatology].attributes:
                            if self.f[climatology].attributes['calendar'] != self.f[var].attributes['calendar']:
                                print("ERROR (7.4): Climatology var", climatology, "has inconsistent calendar to", var)
                                self.err = self.err + 1
                    else:
                        print("ERROR (7.4): climatology attribute referencing non-existent variable")
                        self.err = self.err + 1

            # ------------------------------------------
            # Is there a grid_mapping variable?
            # ------------------------------------------
            if 'grid_mapping' in self.f[var].attributes:
                grid_mapping = self.f[var].attributes['grid_mapping']
                # Check syntax of grid_mapping attribute: a string whose value is a single variable name.
                if not re.search("^[a-zA-Z0-9_]*$", grid_mapping):
                    print("ERROR (5.6):", var, "- Invalid syntax for 'grid_mapping' attribute")
                    self.err = self.err + 1
                else:
                    if grid_mapping in variables:
                        gridMappingVars.append(grid_mapping)
                    else:
                        print("ERROR (5.6): grid_mapping attribute referencing non-existent variable", grid_mapping)
                        self.err = self.err + 1

        return (coordVars, auxCoordVars, boundaryVars, climatologyVars, gridMappingVars)

        # -------------------------------------
    def chkGridMappingVar(self, varName):
        # -------------------------------------
        """Section 5.6: Grid Mapping Variable Checks"""
        rc = 1
        var = self.f[varName]

        if 'grid_mapping_name' in var.attributes:
            # Check grid_mapping_name is valid
            validNames = ['albers_conical_equal_area', 'azimuthal_equidistant', 'lambert_azimuthal_equal_area',
                          'lambert_conformal_conic', 'polar_stereographic', 'rotated_latitude_longitude',
                          'stereographic', 'transverse_mercator']
            validNames += ['geostationary']  # GDAL addition

            if self.version >= vn1_2:
                # Extra grid_mapping_names at vn1.2
                validNames[len(validNames):] = ['latitude_longitude', 'vertical_perspective']

            if self.version >= vn1_4:
                # Extra grid_mapping_names at vn1.4
                validNames[len(validNames):] = ['lambert_cylindrical_equal_area', 'mercator', 'orthographic']

            if var.grid_mapping_name not in validNames:
                print("ERROR (5.6): Invalid grid_mapping_name:", var.grid_mapping_name)
                self.err = self.err + 1
                rc = 0
        else:
            print("ERROR (5.6): No grid_mapping_name attribute set")
            self.err = self.err + 1
            rc = 0

        if len(var.getAxisIds()) != 0:
            print("WARNING (5.6): A grid mapping variable should have 0 dimensions")
            self.warn = self.warn + 1

        return rc

        # ------------------------
    def setUpFormulas(self):
        # ------------------------
        """Set up dictionary of all valid formulas"""
        self.formulas = {}
        self.alias = {}
        self.alias['atmosphere_ln_pressure_coordinate'] = 'atmosphere_ln_pressure_coordinate'
        self.alias['atmosphere_sigma_coordinate'] = 'sigma'
        self.alias['sigma'] = 'sigma'
        self.alias['atmosphere_hybrid_sigma_pressure_coordinate'] = 'hybrid_sigma_pressure'
        self.alias['hybrid_sigma_pressure'] = 'hybrid_sigma_pressure'
        self.alias['atmosphere_hybrid_height_coordinate'] = 'atmosphere_hybrid_height_coordinate'
        self.alias['ocean_sigma_coordinate'] = 'ocean_sigma_coordinate'
        self.alias['ocean_s_coordinate'] = 'ocean_s_coordinate'
        self.alias['ocean_sigma_z_coordinate'] = 'ocean_sigma_z_coordinate'
        self.alias['ocean_double_sigma_coordinate'] = 'ocean_double_sigma_coordinate'

        self.formulas['atmosphere_ln_pressure_coordinate'] = ['p(k)=p0*exp(-lev(k))']
        self.formulas['sigma'] = ['p(n,k,j,i)=ptop+sigma(k)*(ps(n,j,i)-ptop)']

        self.formulas['hybrid_sigma_pressure'] = ['p(n,k,j,i)=a(k)*p0+b(k)*ps(n,j,i)', 'p(n,k,j,i)=ap(k)+b(k)*ps(n,j,i)']

        self.formulas['atmosphere_hybrid_height_coordinate'] = ['z(n,k,j,i)=a(k)+b(k)*orog(n,j,i)']

        self.formulas['ocean_sigma_coordinate'] = ['z(n,k,j,i)=eta(n,j,i)+sigma(k)*(depth(j,i)+eta(n,j,i))']

        self.formulas['ocean_s_coordinate'] = ['z(n,k,j,i)=eta(n,j,i)*(1+s(k))+depth_c*s(k)+(depth(j,i)-depth_c)*C(k)', 'C(k)=(1-b)*sinh(a*s(k))/sinh(a)+b*[tanh(a*(s(k)+0.5))/(2*tanh(0.5*a))-0.5]']

        self.formulas['ocean_sigma_z_coordinate'] = ['z(n,k,j,i)=eta(n,j,i)+sigma(k)*(min(depth_c,depth(j,i))+eta(n,j,i))', 'z(n,k,j,i)=zlev(k)']

        self.formulas['ocean_double_sigma_coordinate'] = ['z(k,j,i)=sigma(k)*f(j,i)', 'z(k,j,i)=f(j,i)+(sigma(k)-1)*(depth(j,i)-f(j,i))', 'f(j,i)=0.5*(z1+z2)+0.5*(z1-z2)*tanh(2*a/(z1-z2)*(depth(j,i)-href))']

        # ----------------------------------------
    def parseBlankSeparatedList(self, list):
        # ----------------------------------------
        """Parse blank separated list"""
        if re.match("^[a-zA-Z0-9_ ]*$", list):
            return 1
        else:
            return 0

        # -------------------------------------------
    def extendedBlankSeparatedList(self, list):
        # -------------------------------------------
        """Check list is a blank separated list of words containing alphanumeric characters
        plus underscore '_', period '.', plus '+', hyphen '-', or "at" sign '@'."""
        if re.match("^[a-zA-Z0-9_ @\-\+\.]*$", list):
            return 1
        else:
            return 0

        # -------------------------------------------
    def commaOrBlankSeparatedList(self, list):
        # -------------------------------------------
        """Check list is a blank or comma separated list of words containing alphanumeric
        characters plus underscore '_', period '.', plus '+', hyphen '-', or "at" sign '@'."""
        if re.match("^[a-zA-Z0-9_ @\-\+\.,]*$", list):
            return 1
        else:
            return 0

        # ------------------------------
    def chkGlobalAttributes(self):
        # ------------------------------
        """Check validity of global attributes."""
        rc = 1
        if 'Conventions' in self.f.attributes:
            conventions = self.f.attributes['Conventions']

            # Conventions attribute can be a blank separated (or comma separated) list of conforming conventions
            if not self.commaOrBlankSeparatedList(conventions):
                print("ERROR(2.6.1): Conventions attribute must be a blank (or comma) separated list of convention names")
                self.err = self.err + 1
                rc = 0
            else:
                # Split string up into component parts
                # If a comma is present we assume a comma separated list as names cannot contain commas
                if re.match("^.*,.*$", conventions):
                    conventionList = string.split(conventions, ",")
                else:
                    conventionList = string.split(conventions)

                found = 0
                for convention in conventionList:
                    if convention.strip() in map(str, cfVersions):
                        found = 1
                        break

                if found != 1:
                    print("ERROR (2.6.1): This netCDF file does not appear to contain CF Convention data.")
                    self.err = self.err + 1
                    rc = 0
                else:
                    if convention.strip() != str(self.version):
                        print("WARNING: Inconsistency - This netCDF file appears to contain " + convention + " data, but you've requested a validity check against %s" % self.version)
                        self.warn = self.warn + 1

        else:
            print("WARNING (2.6.1): No 'Conventions' attribute present")
            self.warn = self.warn + 1
            rc = 1

        # Discrete geometries
        if self.version >= vn1_6 and 'featureType' in self.f.attributes:
            featureType = self.f.attributes['featureType']

            if not re.match('^(point|timeSeries|trajectory|profile|timeSeriesProfile|trajectoryProfile)$', featureType, re.I):
                print("ERROR (9.4): Global attribute 'featureType' contains invalid value")

            # self.chkFeatureType()

        for attribute in ['title', 'history', 'institution', 'source', 'reference', 'comment']:
            if attribute in self.f.attributes:
                if not isinstance(self.f.attributes[attribute], str):
                    print("ERROR (2.6.2): Global attribute", attribute, "must be of type 'String'")
                    self.err = self.err + 1
        return rc

        # ------------------------------
    def getFileCFVersion(self):
        # ------------------------------
        """Return CF version of file, used for auto version option. If Conventions is COARDS return CF-1.0,
        else a valid version based on Conventions else an empty version (for auto version)"""
        rc = CFVersion()
        if 'Conventions' in self.f.attributes:
            conventions = self.f.attributes['Conventions']

            # Split string up into component parts
            # If a comma is present we assume a comma separated list as names cannot contain commas
            if re.match("^.*,.*$", conventions):
                conventionList = string.split(conventions, ",")
            else:
                conventionList = string.split(conventions)

            found = 0
            coards = 0
            for convention in conventionList:
                if convention.strip() in map(str, cfVersions):
                    found = 1
                    rc = CFVersion(convention.strip())
                    break
                elif convention.strip() == 'COARDS':
                    coards = 1

            if not found and coards:
                print("WARNING: The conventions attribute specifies COARDS, assuming CF-1.0")
                rc = CFVersion((1, 0))

        return rc

        # --------------------------
    def validName(self, name):
        # --------------------------
        """ Check for valid name.  They must begin with a
        letter and be composed of letters, digits and underscores."""

        nameSyntax = re.compile('^[a-zA-Z][a-zA-Z0-9_]*$')
        if not nameSyntax.match(name):
            return 0

        return 1

        # ---------------------------------------------
    def chkDimensions(self, varName, allcoordVars):
        # ---------------------------------------------
        """Check variable has non-repeated dimensions, that
           space/time dimensions are listed in the order T,Z,Y,X
           and that any non space/time dimensions are added to
           the left of the space/time dimensions, unless it
           is a boundary variable or climatology variable, where
           1 trailing dimension is allowed."""

        var = self.f[varName]
        dimensions = var.getAxisIds()
        trailingVars = []

        if len(dimensions) > 1:
            order = ['T', 'Z', 'Y', 'X']
            axesFound = [0, 0, 0, 0]  # Holding array to record whether a dimension with an axis value has been found.
            i = -1
            lastPos = -1
            # trailing=0   # Flag to indicate trailing dimension

            # Flags to hold positions of first space/time dimension and
            # last Non-space/time dimension in variable declaration.
            firstST = -1
            lastNonST = -1
            nonSpaceDimensions = []

            for dim in dimensions:
                i = i + 1
                try:
                    if hasattr(self.f[dim], 'axis'):
                        pos = order.index(self.f[dim].axis)

                        # Is there already a dimension with this axis attribute specified.
                        if axesFound[pos] == 1:
                            print("ERROR (4): Variable has more than 1 coordinate variable with same axis value")
                            self.err = self.err + 1
                        else:
                            axesFound[pos] = 1
                    elif hasattr(self.f[dim], 'units') and self.f[dim].units != "":
                        # Determine interpretation of variable by units attribute
                        if hasattr(self.f[dim], 'positive'):
                            interp = self.getInterpretation(self.f[dim].units, self.f[dim].positive)
                        else:
                            interp = self.getInterpretation(self.f[dim].units)

                        if not interp:
                            raise ValueError
                        pos = order.index(interp)
                    else:
                        # No axis or units attribute so can't determine interpretation of variable
                        raise ValueError

                    if firstST == -1:
                        firstST = pos
                except AttributeError:
                    print("ERROR: Problem accessing variable:", dim, "(May not exist in file).")
                    self.err = self.err + 1
                    exit(self.err)
                except ValueError:
                    # Dimension is not T,Z,Y or X axis
                    nonSpaceDimensions.append(dim)
                    trailingVars.append(dim)
                    lastNonST = i
                else:
                    # Is the dimensional position of this dimension further to the right than the previous dim?
                    if pos >= lastPos:
                        lastPos = pos
                        trailingVars = []
                    else:
                        print("WARNING (2.4): space/time dimensions appear in incorrect order")
                        self.warn = self.warn + 1

            # As per CRM #022
            # This check should only be applied for COARDS conformance.
            if self.coards:
                validTrailing = self.boundsVars[:]
                validTrailing[len(validTrailing):] = self.climatologyVars[:]
                if lastNonST > firstST and firstST != -1:
                    if len(trailingVars) == 1:
                        if var.id not in validTrailing:
                            print("WARNING (2.4): dimensions", nonSpaceDimensions, "should appear to left of space/time dimensions")
                            self.warn = self.warn + 1
                    else:
                        print("WARNING (2.4): dimensions", nonSpaceDimensions, "should appear to left of space/time dimensions")
                        self.warn = self.warn + 1

            dimensions.sort()
            if not self.uniqueList(dimensions):
                print("ERROR (2.4): variable has repeated dimensions")
                self.err = self.err + 1

# Removed this check as per emails 11 June 2004 (See CRM #020)
# Check all dimensions of data variables have associated coordinate variables
# for dim in dimensions:
# if dim not in f._file_.variables.keys() or dim not in allcoordVars:
# if dim not in trailingVars:
# dim is not a valid trailing dimension. (valid trailing dimensions e.g. for bounds
# vars; do not need to have an associated coordinate variable CF doc 7.1)
# print "WARNING: Dimension:",dim,"does not have an associated coordinate variable"
#                 self.warn = self.warn+1

        # -------------------------------------------------------
    def getTypeCode(self, obj):
        # -------------------------------------------------------
        """
        Get the type, as a 1-character code, of an object that may be a
        CDMS FileAxis, a CDMS FileVariable, or a numpy.ndarray
        """
        # A previous comment in the code claimed:
        #
        # # 26.02.10 - CDAT-5.2 - An inconsistency means that determining the type of
        # # a FileAxis or FileVariable is different.  C.Doutriaux will hopefully
        # # make this more uniform (Raised on the cdat mailing list) CF Trac #
        #
        # in fact it seems that both cdms.axis.FileAxis and cdms.fvariable.FileVariable
        # support obj.typecode() (although the FileVariable also supports obj.dtype.char,
        # so obj.typecode() will work for both of these.  However, numpy.ndarray only
        # supports obj.dtype.char

        if isinstance(obj, numpy.ndarray):
            return obj.dtype.char
        return obj.typecode()

        # -------------------------------------------------------
    def chkAttribute(self, attribute, varName, allCoordVars):
        # -------------------------------------------------------
        """Check the syntax of the attribute name, that the attribute
        is of the correct type and that it is attached to the right
        kind of variable."""
        rc = 1
        var = self.f[varName]

        if not self.validName(attribute) and attribute != "_FillValue":
            print("ERROR: Invalid attribute name -", attribute)
            self.err = self.err + 1
            return 0

        value = var.attributes[attribute]

        # ------------------------------------------------------------
        # Attribute of wrong 'type' in the sense numeric/non-numeric
        # ------------------------------------------------------------
        if attribute in self.AttrList:
            # Standard Attribute, therefore check type

            attrType = type(value)

            if isinstance(value, str):
                attrType = 'S'
            elif isinstance(value, int) or isinstance(value, float):
                attrType = 'N'
            elif isinstance(value, numpy.ndarray):
                attrType = 'N'
            elif isinstance(value, type(None)):
                # attrType=self.AttrList[attribute][0]
                attrType = 'NoneType'
            else:
                print("Unknown Type for attribute:", attribute, attrType)

            # If attrType = 'NoneType' then it has been automatically created e.g. missing_value
            typeError = 0
            if attrType != 'NoneType':
                if self.AttrList[attribute][0] == 'D':
                    # Special case for 'D' as these attributes will always be caught
                    # by one of the above cases.
                    # Attributes of type 'D' should be the same type as the data variable
                    # they are attached to.
                    if attrType == 'S':
                        # Note: A string is an array of chars
                        if self.getTypeCode(var) != 'c':
                            typeError = 1
                    else:
                        if self.getTypeCode(var) != self.getTypeCode(var.attributes[attribute]):
                            typeError = 1

                elif self.AttrList[attribute][0] != attrType:
                    typeError = 1

                if typeError:
                    print("ERROR: Attribute", attribute, "of incorrect type")
                    self.err = self.err + 1
                    rc = 0

            # Attribute attached to the wrong kind of variable
            uses = self.AttrList[attribute][1]
            usesLen = len(uses)
            i = 1
            for use in uses:
                if use == "C" and var.id in allCoordVars:
                    # Valid association
                    break
                elif use == "D" and var.id not in allCoordVars:
                    # Valid association
                    break
                elif i == usesLen:
                    if attribute == "missing_value":
                        # Special case since missing_value attribute is present for all
                        # variables whether set explicitly or not. Is this a cdms thing?
                        # Using var.missing_value is null then missing_value not set in the file
                        if var.missing_value:
                            print("WARNING: attribute", attribute, "attached to wrong kind of variable")
                            self.warn = self.warn + 1
                    else:
                        print("INFO: attribute '" + attribute + "' is being used in a non-standard way")
                        self.info = self.info + 1
                else:
                    i = i + 1

            # Check no time variable attributes. E.g. calendar, month_lengths etc.
            TimeAttributes = ['calendar', 'month_lengths', 'leap_year', 'leap_month', 'climatology']
            if attribute in TimeAttributes:

                if 'units' in var.attributes:
                    varUnits = udunits.ut_parse(self.unitSystem, var.attributes['units'], "UT_ASCII")
                    secsSinceEpoch = udunits.ut_parse(self.unitSystem, "seconds since 1970-01-01", "UT_ASCII")
                    if not udunits.ut_are_convertible(varUnits, secsSinceEpoch):
                        print("ERROR (4.4.1): Attribute", attribute, "may only be attached to time coordinate variable")
                        self.err = self.err + 1
                        rc = 0

                    # Free up resources associated with varUnits
                    udunits.ut_free(varUnits)
                    udunits.ut_free(secsSinceEpoch)

                else:
                    print("ERROR (4.4.1): Attribute", attribute, "may only be attached to time coordinate variable")
                    self.err = self.err + 1
                    rc = 0

        return rc

        # ----------------------------------
    def chkCellMethods(self, varName):
        # ----------------------------------
        """Checks on cell_methods attribute
        1) Correct syntax
        2) Valid methods
        3) Valid names
        4) No duplicate entries for dimension other than 'time'"""
        # dim1: [dim2: [dim3: ...]] method [ (comment) ]
        # where comment is of the form:  ([interval: value unit [interval: ...] comment:] remainder)
        rc = 1
        error = 0  # Flag to indicate validity of cell_methods string syntax
        varDimensions = {}
        var = self.f[varName]

        if 'cell_methods' in var.attributes:
            cellMethods = var.attributes['cell_methods']
            getComments = re.compile(r'\([^)]+\)')

            # Remove comments from the cell_methods string and split at these points
            noComments = getComments.sub('%5A', cellMethods)
            substrings = re.split('%5A', noComments)
            pr = re.compile(r'^\s*(\S+\s*:\s*(\S+\s*:\s*)*(point|sum|maximum|median|mid_range|minimum|mean|mode|standard_deviation|variance)(\s+(over|within)\s+(days|years))?\s*)+$')
            # Validate each substring
            for s in substrings:
                if s:
                    if not pr.match(s):
                        strError = s
                        error = 1
                        break

                    # Validate dim and check that it only appears once unless it is 'time'
                    allDims = re.findall(r'\S+\s*:', s)
                    for part in allDims:
                        dims = re.split(':', part)
                        for d in dims:
                            if d:
                                if var.getAxisIndex(d) == -1 and d not in self.std_name_dh.dict.keys():
                                    print("ERROR (7.3): Invalid 'name' in cell_methods attribute:", d)
                                    self.err = self.err + 1
                                    rc = 0
                                elif d in varDimensions and d != "time":
                                    print("ERROR (7.3): Multiple cell_methods entries for dimension:", d)
                                    self.err = self.err + 1
                                else:
                                    varDimensions[d] = 1

            # Validate the comment if it is standardized
            # RSH TO DO:  Still need to implement validation of unit in the standardized comment.
            if not error:
                comments = getComments.findall(cellMethods)
                cpr = re.compile(r'^\((interval:\s+\d+\s+(years|months|days|hours|minutes|seconds)\s*)*(comment: .+)?\)')
                for c in comments:
                    if re.search(r'^\(\s*interval', c):
                        # Only need to check standardized comments i.e. those beginning (interval ...)
                        if not cpr.match(c):
                            strError = c
                            error = 1
                            break

            if error:
                print("ERROR (7.3): Invalid cell_methods syntax: '" + strError + "'")
                self.err = self.err + 1
                rc = 0

        return rc

        # ----------------------------
    def chkCFRole(self, varName):
        # ----------------------------
        # Validate cf_role attribute
        rc = 1
        var = self.f[varName]

        if 'cf_role' in var.attributes:
            cf_role = var.attributes['cf_role']

            # Keep a tally of how many variables have the cf_role attribute set
            # print "ROS: Attribute cf_role found!!"
            self.cf_roleCount = self.cf_roleCount + 1

            if cf_role not in ['timeseries_id', 'profile_id', 'trajectory_id']:
                print("ERROR (9.5): Invalid value for cf_role attribute")
                self.err = self.err + 1

                rc = 0
        return rc

        # ---------------------------------
    def chkRaggedArray(self, varName):
        # ---------------------------------
        # Validate count/index variable
        # rc=1
        var = self.f[varName]

        if 'sample_dimension' in var.attributes:

            # print varName," is a count variable (Discrete Geometries)"
            self.raggedArrayFlag = 1

            if self.getTypeCode(var) != 'i':
                print("ERROR (9.3): count variable '" + varName + "' must be of type integer")
                self.err = self.err + 1

        if 'instance_dimension' in var.attributes:

            # print varName," is an index variable (Discrete Geometries)"
            self.raggedArrayFlag = 1

            if self.getTypeCode(var) != 'i':
                print("ERROR (9.3): index variable '" + varName + "' must be of type integer")
                self.err = self.err + 1

        # ----------------------------------
    def isValidUdunitsUnit(self, unit):
        # ----------------------------------
        # units must be recognizable by udunits package
        udunitsUnit = udunits.ut_parse(self.unitSystem, unit, "UT_ASCII")
        if udunitsUnit:
            # Valid unit
            rc = 1
        else:
            # Invalid unit
            rc = 0

        # Free up resources associated with udunitsUnit
        udunits.ut_free(udunitsUnit)

        return rc

        # ---------------------------------------------------
    def isValidCellMethodTypeValue(self, type, value):
        # ---------------------------------------------------
        """ Is <type1> or <type2> in the cell_methods attribute a valid value"""
        rc = 1
        # Is it a string-valued aux coord var with standard_name of area_type?
        if value in self.auxCoordVars:
            if self.getTypeCode(self.f[value]) != 'c':
                rc = 0
            elif type == "type2":
                # <type2> has the additional requirement that it is not allowed a leading dimension of more than one
                leadingDim = self.f[value].getAxisIds()[0]
                # Must not be a value of more than one
                if self.f.dimensions[leadingDim] > 1:
                    print("ERROR (7.3):", value, "is not allowed a leading dimension of more than one.")
                    self.err = self.err + 1

            if 'standard_name' in self.f[value].attributes:
                if self.f[value].attributes['standard_name'] != 'area_type':
                    rc = 0

        # Is type a valid area_type according to the area_type table
        elif value not in self.area_type_lh.list:
            rc = 0

        return rc

        # ----------------------------------
    def chkCellMethods_redefined(self, varName):
        # ----------------------------------
        """Checks on cell_methods attribute
           dim1: [dim2: [dim3: ...]] method [where type1 [over type2]] [ (comment) ]
           where comment is of the form:  ([interval: value unit [interval: ...] comment:] remainder)
        """

        rc = 1
        # error = 0  # Flag to indicate validity of cell_methods string syntax
        varDimensions = {}
        var = self.f[varName]

        if 'cell_methods' in var.attributes:
            cellMethods = var.attributes['cell_methods']

#        cellMethods="lat: area: maximum (interval: 1 hours interval: 3 hours comment: fred)"

            pr1 = re.compile(r'^'
                             r'(\s*\S+\s*:\s*(\S+\s*:\s*)*'
                             r'([a-z_]+)'
                             r'(\s+where\s+\S+(\s+over\s+\S+)?)?'
                             r'(\s+(over|within)\s+(days|years))?\s*'
                             r'(\((interval:\s+\d+\s+\S+\s*)*(comment: .+)?.*\))?)'
                             r'+$')

            # Validate the entire string
            m = pr1.match(cellMethods)
            if not m:
                print("ERROR (7.3) Invalid syntax for cell_methods attribute")
                self.err = self.err + 1
                rc = 0

            # Grab each word-list - dim1: [dim2: [dim3: ...]] method [where type1 [over type2]] [within|over days|years] [(comment)]
            pr2 = re.compile(r'(?P<dimensions>\s*\S+\s*:\s*(\S+\s*:\s*)*'
                             r'(?P<method>[a-z_]+)'
                             r'(?:\s+where\s+(?P<type1>\S+)(?:\s+over\s+(?P<type2>\S+))?)?'
                             r'(?:\s+(?:over|within)\s+(?:days|years))?\s*)'
                             r'(?P<comment>\([^)]+\))?')

            substr_iter = pr2.finditer(cellMethods)

            # Validate each substring
            for s in substr_iter:
                if not re.match(r'point|sum|maximum|median|mid_range|minimum|mean|mode|standard_deviation|variance', s.group('method')):
                    print("ERROR (7.3): Invalid cell_method:", s.group('method'))
                    self.err = self.err + 1
                    rc = 0

                if self.version >= vn1_4:
                    if s.group('type1'):
                        if not self.isValidCellMethodTypeValue('type1', s.group('type1')):
                            print("ERROR (7.3): Invalid type1: '" + s.group('type1') + "' - must be a variable name or valid area_type")
                            self.err = self.err + 1

                    if s.group('type2'):
                        if not self.isValidCellMethodTypeValue('type2', s.group('type2')):
                            print("ERROR (7.3): Invalid type2: '" + s.group('type2') + "' - must be a variable name or valid area_type")
                            self.err = self.err + 1

                # Validate dim and check that it only appears once unless it is 'time'
                allDims = re.findall(r'\S+\s*:', s.group('dimensions'))
                dc = 0          # Number of dims

                for part in allDims:
                    dims = re.split(':', part)

                    for d in dims:
                        if d:
                            dc = dc + 1
                            if var.getAxisIndex(d) == -1 and d not in self.std_name_dh.dict.keys():
                                if self.version >= vn1_4:
                                    # Extra constraints at CF-1.4 and above
                                    if d != "area":
                                        print("ERROR (7.3): Invalid 'name' in cell_methods attribute:", d)
                                        self.err = self.err + 1
                                        rc = 0
                                else:
                                    print("ERROR (7.3): Invalid 'name' in cell_methods attribute:", d)
                                    self.err = self.err + 1
                                    rc = 0

                            else:
                                # dim is a variable dimension
                                if d in varDimensions and d != "time":
                                    print("ERROR (7.3): Multiple cell_methods entries for dimension:", d)
                                    self.err = self.err + 1
                                    rc = 0
                                else:
                                    varDimensions[d] = 1

                                if self.version >= vn1_4:
                                    # If dim is a coordinate variable and cell_method is not 'point' check
                                    # if the coordinate variable has either bounds or climatology attributes
                                    if d in self.coordVars and s.group('method') != 'point':
                                        if 'bounds' not in self.f[d].attributes and 'climatology' not in self.f[d].attributes:
                                            print("WARNING (7.3): Coordinate variable", d, "should have bounds or climatology attribute")
                                            self.warn = self.warn + 1

                # Validate the comment associated with this method, if present
                comment = s.group('comment')
                if comment:
                    getIntervals = re.compile(r'(?P<interval>interval:\s+\d+\s+(?P<unit>\S+)\s*)')
                    allIntervals = getIntervals.finditer(comment)

                    # There must be zero, one or exactly as many interval clauses as there are dims
                    i = 0   # Number of intervals present
                    for m in allIntervals:
                        i = i + 1
                        unit = m.group('unit')
                        if not self.isValidUdunitsUnit(unit):
                            print("ERROR (7.3): Invalid unit", unit, "in cell_methods comment")
                            self.err = self.err + 1
                            rc = 0

                    if i > 1 and i != dc:
                        print("ERROR (7.3): Incorrect number or interval clauses in cell_methods attribute")
                        self.err = self.err + 1
                        rc = 0

        return rc

        # ----------------------------------
    def chkCellMeasures(self, varName):
        # ----------------------------------
        """Checks on cell_measures attribute:
        1) Correct syntax
        2) Reference valid variable
        3) Valid measure"""
        rc = 1
        var = self.f[varName]

        if 'cell_measures' in var.attributes:
            cellMeasures = var.attributes['cell_measures']
            if not re.search("^([a-zA-Z0-9]+: +([a-zA-Z0-9_ ]+:?)*( +[a-zA-Z0-9_]+)?)$", cellMeasures):
                print("ERROR (7.2): Invalid cell_measures syntax")
                self.err = self.err + 1
                rc = 0
            else:
                # Need to validate the measure + name
                split = string.split(cellMeasures)
                splitIter = iter(split)
                try:
                    while 1:
                        measure = splitIter.next()
                        variable = splitIter.next()

                        if variable not in self.f.variables.keys():
                            print("WARNING (7.2): cell_measures referring to variable '" + variable + "' that doesn't exist in this netCDF file.")
                            print("INFO (7.2): This is strictly an error if the cell_measures variable is not included in the dataset.")
                            self.warn = self.warn + 1
                            rc = 0

                        else:
                            # Valid variable name in cell_measures so carry on with tests.
                            if len(self.f[variable].getAxisIds()) > len(var.getAxisIds()):
                                print("ERROR (7.2): Dimensions of", variable, "must be same or a subset of", var.getAxisIds())
                                self.err = self.err + 1
                                rc = 0
                            else:
                                # If cell_measures variable has more dims than var then this check automatically will fail
                                # Put in else so as not to duplicate ERROR messages.
                                for dim in self.f[variable].getAxisIds():
                                    if dim not in var.getAxisIds():
                                        print("ERROR (7.2): Dimensions of", variable, "must be same or a subset of", var.getAxisIds())
                                        self.err = self.err + 1
                                        rc = 0

                            measure = re.sub(':', '', measure)
                            if not re.match("^(area|volume)$", measure):
                                print("ERROR (7.2): Invalid measure in attribute cell_measures")
                                self.err = self.err + 1
                                rc = 0

                            if measure == "area" and self.f[variable].units != "m2":
                                print("ERROR (7.2): Must have square meters for area measure")
                                self.err = self.err + 1
                                rc = 0

                            if measure == "volume" and self.f[variable].units != "m3":
                                print("ERROR (7.2): Must have cubic meters for volume measure")
                                self.err = self.err + 1
                                rc = 0

                except StopIteration:
                    pass

        return rc

        # ----------------------------------
    def chkFormulaTerms(self, varName, allCoordVars):
        # ----------------------------------
        """Checks on formula_terms attribute (CF Section 4.3.2):
        formula_terms = var: term var: term ...
        1) No standard_name present
        2) No formula defined for std_name
        3) Invalid formula_terms syntax
        4) Var referenced, not declared"""
        rc = 1
        var = self.f[varName]

        if 'formula_terms' in var.attributes:

            if varName not in allCoordVars:
                print("ERROR (4.3.2): formula_terms attribute only allowed on coordinate variables")
                self.err = self.err + 1

            # Get standard_name to determine which formula is to be used
            if 'standard_name' not in var.attributes:
                print("ERROR (4.3.2): Cannot get formula definition as no standard_name")
                self.err = self.err + 1
                # No sense in carrying on as can't validate formula_terms without valid standard name
                return 0

            (stdName, modifier) = self.getStdName(var)

            if stdName not in self.alias:
                print("ERROR (4.3.2): No formula defined for standard name:", stdName)
                self.err = self.err + 1
                # No formula available so can't validate formula_terms
                return 0

            index = self.alias[stdName]

            formulaTerms = var.attributes['formula_terms']
            if not re.search("^([a-zA-Z0-9_]+: +[a-zA-Z0-9_]+( +)?)*$", formulaTerms):
                print("ERROR (4.3.2): Invalid formula_terms syntax")
                self.err = self.err + 1
                rc = 0
            else:
                # Need to validate the term & var
                split = string.split(formulaTerms)
                for x in split[:]:
                    if not re.search("^[a-zA-Z0-9_]+:$", x):
                        # Variable - should be declared in netCDF file
                        if x not in self.f._file_.variables.keys():
                            print("ERROR (4.3.2):", x, "is not declared as a variable")
                            self.err = self.err + 1
                            rc = 0
                    else:
                        # Term - Should be present in formula
                        x = re.sub(':', '', x)
                        found = 'false'
                        for formula in self.formulas[index]:
                            if re.search(x, formula):
                                found = 'true'
                                break

                        if found == 'false':
                            print("ERROR (4.3.2): term", x, "not present in formula")
                            self.err = self.err + 1
                            rc = 0

        return rc

        # ----------------------------------------
    def chkUnits(self, varName, allCoordVars):
        # ----------------------------------------
        """Check units attribute"""
        rc = 1
        var = self.f[varName]

        if self.badc:
            rc = self.chkBADCUnits(var)
            # If unit is a BADC unit then no need to check via udunits
            if rc:
                return rc

        # Test for blank since coordinate variables have 'units' defined even if not specifically defined in the file
        if 'units' in var.attributes and var.attributes['units'] != '':
            # Type of units is a string
            units = var.attributes['units']
            if not isinstance(units, str):
                print("ERROR (3.1): units attribute must be of type 'String'")
                self.err = self.err + 1
                # units not a string so no point carrying out further tests
                return 0

            # units - level, layer and sigma_level are deprecated
            if units in ['level', 'layer', 'sigma_level']:
                print("WARNING (3.1): units", units, "is deprecated")
                self.warn = self.warn + 1
            elif units == 'month':
                print("WARNING (4.4): The unit 'month', defined by udunits to be exactly year/12, should")
                print("         be used with caution.")
                self.warn = self.warn + 1
            elif units == 'year':
                print("WARNING (4.4): The unit 'year', defined by udunits to be exactly 365.242198781 days,")
                print("         should be used with caution. It is not a calendar year.")
            else:

                # units must be recognizable by udunits package
                varUnit = udunits.ut_parse(self.unitSystem, units, "UT_ASCII")
                if not varUnit:
                    print("ERROR (3.1): Invalid units: ", units)
                    self.err = self.err + 1
                    # Invalid units so no point continuing with further unit checks
                    return 0

                # units of a variable that specifies a standard_name must
                # be consistent with units given in standard_name table
                if 'standard_name' in var.attributes:
                    (stdName, modifier) = self.getStdName(var)

                    # Is the Standard Name modifier number_of_observations being used.
                    if modifier == 'number_of_observations':
                        # Standard Name modifier is number_of_observations therefore units should be "1".  See Appendix C
                        if not units == "1":
                            print("ERROR (3.3): Standard Name modifier 'number_of_observations' present therefore units must be set to 1.")
                            self.err = self.err + 1

                    elif stdName in self.std_name_dh.dict.keys():
                        # Get canonical units from standard name table
                        stdNameUnits = self.std_name_dh.dict[stdName]

                        # stdNameUnits is unicode which udunits can't deal with.  Explicitly convert it to ASCII
                        stdNameUnits = stdNameUnits.encode('ascii')

                        canonicalUnit = udunits.ut_parse(self.unitSystem, stdNameUnits, "UT_ASCII")

                        # To compare units we need to remove the reference time from the variable units
                        if re.search("since", units):
                            # unit attribute contains a reference time - remove it
                            udunits.ut_free(varUnit)
                            varUnit = udunits.ut_parse(self.unitSystem, units.split()[0], "UT_ASCII")

                        # If variable has cell_methods=variance we need to square standard_name table units
                        if 'cell_methods' in var.attributes:
                            # Remove comments from the cell_methods string - no need to search these
                            getComments = re.compile(r'\([^)]+\)')
                            noComments = getComments.sub('%5A', var.attributes['cell_methods'])

                            if re.search(r'(\s+|:)variance', noComments):
                                # Variance method so standard_name units need to be squared.
                                unit1 = udunits.ut_parse(self.unitSystem, stdNameUnits, "UT_ASCII")
                                canonicalUnit = udunits.ut_multiply(unit1, unit1)
                                udunits.ut_free(unit1)

                        if not udunits.ut_are_convertible(varUnit, canonicalUnit):
                            # Conversion unsuccessful
                            print("ERROR (3.1): Units are not consistent with those given in the standard_name table.")
                            self.err = self.err + 1
                            rc = 0

                        # Free resources associated with canonicalUnit
                        udunits.ut_free(canonicalUnit)

                # Free resources associated with udunitsUnit
                udunits.ut_free(varUnit)

        else:

            # No units attribute - is this a coordinate variable or
            # dimensionless vertical coordinate var
            if var.id in allCoordVars:

                # Label variables do not require units attribute
                if self.f[var.id].typecode() != 'c':
                    if 'axis' in var.attributes:
                        if not var.axis == 'Z':
                            print("WARNING (3.1): units attribute should be present")
                            self.warn = self.warn + 1
                    elif not hasattr(var, 'positive') and not hasattr(var, 'formula_terms') and not hasattr(var, 'compress'):
                        print("WARNING (3.1): units attribute should be present")
                        self.warn = self.warn + 1

            elif var.id not in self.boundsVars and var.id not in self.climatologyVars and var.id not in self.gridMappingVars:
                # Variable is not a boundary or climatology variable

                dimensions = self.f[var.id].getAxisIds()

                if not hasattr(var, 'flag_values') and len(dimensions) != 0 and self.f[var.id].typecode() != 'c':
                    # Variable is not a flag variable or a scalar or a label

                    print("INFO (3.1): No units attribute set.  Please consider adding a units attribute for completeness.")
                    self.info = self.info + 1

        return rc

        # ----------------------------
    def chkBADCUnits(self, var):
        # ----------------------------
        """Check units allowed by BADC"""
        units_lines = open("/usr/local/cf-checker/lib/badc_units.txt").readlines()

        # badc_units test case
        # units_lines=open("/home/ros/SRCE_projects/CF_Checker_W/main/Test_Files/badc_units.txt").readlines()

        # units must be recognizable by the BADC units file
        for line in units_lines:
            if hasattr(var, 'units') and var.attributes['units'] in string.split(line):
                print("Valid units in BADC list:", var.attributes['units'])
                rc = 1
                break
            else:
                rc = 0

        return rc

        # ---------------------------------------
    def chkValidMinMaxRange(self, varName):
        # ---------------------------------------
        """Check that valid_range and valid_min/valid_max are not both specified"""
        var = self.f[varName]

        if 'valid_range' in var.attributes:
            if 'valid_min' in var.attributes or \
               'valid_max' in var.attributes:

                print("ERROR (2.5.1): Illegal use of valid_range and valid_min/valid_max")
                self.err = self.err + 1
                return 0

        return 1

        # ---------------------------------
    def chk_FillValue(self, varName):
        # ---------------------------------
        """Check 1) type of _FillValue
        2) _FillValue lies outside of valid_range
        3) type of missing_value
        4) flag use of missing_value as deprecated"""
        rc = 1
        var = self.f[varName]

#       varType = self.getTypeCode(var)

        if '_FillValue' in var.__dict__:
            fillValue = var.__dict__['_FillValue']

# 05.02.08 No longer needed as this is now detected by chkAttribute as _FillValue
# has an attribute type of 'D'. See Trac #022
# if varType == 'c' or varType == types.StringType:
# if type(fillValue) != types.StringType:
# print "ERROR (2.5.1): _FillValue of different type to variable"
#                 self.err = self.err+1
# rc=0
# elif varType != self.getTypeCode(fillValue):
# print "ERROR (2.5.1): _FillValue of different type to variable"
#             self.err = self.err+1
# rc=0

            if 'valid_range' in var.attributes:
                # Check _FillValue is outside valid_range
                validRange = var.attributes['valid_range']
                if fillValue > validRange[0] and fillValue < validRange[1]:
                    print("WARNING (2.5.1): _FillValue should be outside valid_range")
                    self.warn = self.warn + 1

            if var.id in self.boundsVars:
                print("WARNING (7.1): Boundary Variable", var.id, "should not have _FillValue attribute")
                self.warn = self.warn + 1
            elif var.id in self.climatologyVars:
                print("ERROR (7.4): Climatology Variable", var.id, "must not have _FillValue attribute")
                self.err = self.err + 1
                rc = 0

        if 'missing_value' in var.attributes:
            missingValue = var.attributes['missing_value']

#        print type(missingValue)
#        print type(Numeric.array([]))

            try:
                if missingValue:
                    if '_FillValue' in var.__dict__:
                        if fillValue != missingValue:
                            # Special case: NaN == NaN is not detected as NaN does not compare equal to anything else
                            if not (numpy.isnan(fillValue) and numpy.isnan(missingValue)):
                                print("WARNING (2.5.1): missing_value and _FillValue set to differing values")

                                self.warn = self.warn + 1

# 08.12.10 missing_value is no longer deprecated by the NUG
# else:
# _FillValue not present
# print "WARNING (2.5.1): Use of 'missing_value' attribute is deprecated"
#                self.warn = self.warn+1

# 05.02.08 No longer needed as this is now detected by chkAttribute as missing_value
# has an attribute type of 'D'. See Trac #022
#             typeError = 0
# if varType == 'c':
# if type(missingValue) != types.StringType:
#                     typeError = 1
# elif varType != self.getTypeCode(missingValue):
#                 typeError = 1
#
# if typeError:
# print "ERROR (2.5.1): missing_value of different type to variable"
#                 self.err = self.err+1
# rc=0

                    if var.id in self.boundsVars:
                        print("WARNING (7.1): Boundary Variable", var.id, "should not have missing_value attribute")
                        self.warn = self.warn + 1
                    elif var.id in self.climatologyVars:
                        print("ERROR (7.4): Climatology Variable", var.id, "must not have missing_value attribute")
                        self.err = self.err + 1
                        rc = 0

            except ValueError:
                #            if type(missingValue) == type(Numeric.array([])):
                #                print "ERROR (2.5.1): missing_value should be a scalar value"
                #                self.err = self.err+1
                #                rc=0
                #            else:
                print("ValueError:", sys.exc_info()[1])
                print("INFO: Could not complete tests on missing_value attribute")
                raise
                rc = 0

        return rc

        # ------------------------------------
    def chkAxisAttribute(self, varName):
        # ------------------------------------
        """Check validity of axis attribute"""
        var = self.f[varName]

        if 'axis' in var.attributes:
            if not re.match('^(X|Y|Z|T)$', var.attributes['axis'], re.I):
                print("ERROR (4): Invalid value for axis attribute")
                self.err = self.err + 1
                return 0

            # axis attribute is allowed on an aux coord var as of CF-1.6
            if self.version >= vn1_1 and self.version < vn1_6 and varName in self.auxCoordVars:
                print("ERROR (4): Axis attribute is not allowed for auxiliary coordinate variables.")
                self.err = self.err + 1
                return 0

            # Check that axis attribute is consistent with the coordinate type
            # deduced from units and positive.
            if hasattr(var, 'units'):
                if hasattr(var, 'positive'):
                    interp = self.getInterpretation(var.units, var.positive)
                else:
                    interp = self.getInterpretation(var.units)
            else:
                # Variable does not have a units attribute so a consistency check cannot be made
                interp = None

#          print "interp:",interp
#          print "axis:",var.axis

            if interp is not None:
                # It was possible to deduce axis interpretation from units/positive
                if interp != var.axis:
                    print("ERROR (4): axis attribute inconsistent with coordinate type as deduced from units and/or positive")
                    self.err = self.err + 1
                    return 0

        return 1

        # ----------------------------------------
    def chkPositiveAttribute(self, varName):
        # ----------------------------------------
        var = self.f[varName]
        if 'positive' in var.attributes:
            if not re.match('^(down|up)$', var.attributes['positive'], re.I):
                print("ERROR (4.3): Invalid value for positive attribute")
                self.err = self.err + 1
                return 0

        return 1

        # -----------------------------------------
    def chkTimeVariableAttributes(self, varName):
        # -----------------------------------------
        rc = 1
        var = self.f[varName]

        if 'calendar' in var.attributes:
            if not re.match('(gregorian|standard|proleptic_gregorian|noleap|365_day|all_leap|366_day|360_day|julian|none)',
                            var.attributes['calendar'], re.I):
                # Non-standardized calendar so month_lengths should be present
                if 'month_lengths' not in var.attributes:
                    print("ERROR (4.4.1): Non-standard calendar, so month_lengths attribute must be present")
                    self.err = self.err + 1
                    rc = 0
            else:
                if 'month_lengths' in var.attributes or \
                   'leap_year' in var.attributes or \
                   'leap_month' in var.attributes:
                    print("ERROR (4.4.1): The attributes 'month_lengths', 'leap_year' and 'leap_month' must not appear when 'calendar' is present.")
                    self.err = self.err + 1
                    rc = 0

        if 'calendar' not in var.attributes and 'month_lengths' not in var.attributes:
            print("WARNING (4.4.1): Use of the calendar and/or month_lengths attributes is recommended for time coordinate variables")
            self.warn = self.warn + 1
            rc = 0

        if 'month_lengths' in var.attributes:
            if len(var.attributes['month_lengths']) != 12 and \
               self.getTypeCode(var.attributes['month_lengths']) != 'i':
                print("ERROR (4.4.1): Attribute 'month_lengths' should be an integer array of size 12")
                self.err = self.err + 1
                rc = 0

        if 'leap_year' in var.attributes:
            if self.getTypeCode(var.attributes['leap_year']) != 'i' and \
               len(var.attributes['leap_year']) != 1:
                print("ERROR (4.4.1): leap_year should be a scalar value")
                self.err = self.err + 1
                rc = 0

        if 'leap_month' in var.attributes:
            if not re.match("^(1|2|3|4|5|6|7|8|9|10|11|12)$",
                            str(var.attributes['leap_month'][0])):
                print("ERROR (4.4.1): leap_month should be between 1 and 12")
                self.err = self.err + 1
                rc = 0

            if 'leap_year' not in var.attributes:
                print("WARNING (4.4.1): leap_month is ignored as leap_year NOT specified")
                self.warn = self.warn + 1

        # Time units must contain a reference time
        # To do this; test if the "unit" in question is convertible with a known timestamp "unit".
        varUnits = udunits.ut_parse(self.unitSystem, var.units, "UT_ASCII")
        secsSinceEpoch = udunits.ut_parse(self.unitSystem, "seconds since 1970-01-01", "UT_ASCII")

        if not udunits.ut_are_convertible(secsSinceEpoch, varUnits):
            print("ERROR (4.4): Invalid units and/or reference time")
            self.err = self.err + 1

        # Free resources used by varUnits and secsSinceEpoch
        udunits.ut_free(varUnits)
        udunits.ut_free(secsSinceEpoch)

        return rc

        # ----------------------------------
    def chkDescription(self, varName):
        # ----------------------------------
        """Check 1) standard_name & long_name attributes are present
                 2) for a valid standard_name as listed in the standard name table."""
        rc = 1
        var = self.f[varName]

        if 'standard_name' not in var.attributes and \
           'long_name' not in var.attributes:

            exceptions = self.boundsVars + self.climatologyVars + self.gridMappingVars
            if var.id not in exceptions:
                print("WARNING (3): No standard_name or long_name attribute specified")
                self.warn = self.warn + 1

        if 'standard_name' in var.attributes:
            # Check if valid by the standard_name table and allowed modifiers
            std_name = var.attributes['standard_name']

            # standard_name attribute can comprise a standard_name only or a standard_name
            # followed by a modifier (E.g. atmosphere_cloud_liquid_water_content status_flag)
            std_name_el = string.split(std_name)
            if not std_name_el:
                print("ERROR (3.3): Empty string for 'standard_name' attribute")
                self.err = self.err + 1
                rc = 0

            elif not self.parseBlankSeparatedList(std_name) or len(std_name_el) > 2:
                print("ERROR (3.3): Invalid syntax for 'standard_name' attribute: '" + std_name + "'")
                self.err = self.err + 1
                rc = 0

            else:
                # Validate standard_name
                name = std_name_el[0]
                if name not in self.std_name_dh.dict.keys():
                    if chkDerivedName(name):
                        print("ERROR (3.3): Invalid standard_name:", name)
                        self.err = self.err + 1
                        rc = 0

                if len(std_name_el) == 2:
                    # Validate modifier
                    modifier = std_name_el[1]
                    if modifier not in ['detection_minimum', 'number_of_observations', 'standard_error', 'status_flag']:
                        print("ERROR (3.3): Invalid standard_name modifier: " + modifier)
                        rc = 0

        return rc

        # -----------------------------------
    def chkCompressAttr(self, varName):
        # -----------------------------------
        rc = 1
        var = self.f[varName]
        if 'compress' in var.attributes:
            compress = var.attributes['compress']

            if var.typecode() != 'i':
                print("ERROR (8.2):", var.id, "- compress attribute can only be attached to variable of type int.")
                self.err = self.err + 1
                return 0
            if not re.search("^[a-zA-Z0-9_ ]*$", compress):
                print("ERROR (8.2): Invalid syntax for 'compress' attribute")
                self.err = self.err + 1
                rc = 0
            else:
                dimensions = string.split(compress)
                dimProduct = 1
                for x in dimensions:
                    found = 'false'
                    if x in self.f.axes.keys():
                        # Get product of compressed dimension sizes for use later
                        # dimProduct=dimProduct*self.f.dimensions[x]
                        dimProduct = dimProduct * len(self.f.dimensionarray(x))
                        found = 'true'

                    if found != 'true':
                        print("ERROR (8.2): compress attribute naming non-existent dimension: ", x)
                        self.err = self.err + 1
                        rc = 0

                values = var.getValue()
                outOfRange = 0
                for val in values[:]:
                    if val < 0 or val > dimProduct - 1:
                        outOfRange = 1
                        break

                if outOfRange:
                    print("ERROR (8.2): values of", var.id, "must be in the range 0 to", dimProduct - 1)
                    self.err = self.err + 1
        return rc

        # ---------------------------------
    def chkPackedData(self, varName):
        # ---------------------------------
        rc = 1
        var = self.f[varName]
        if 'scale_factor' in var.attributes and 'add_offset' in var.attributes:
            if self.getTypeCode(var.attributes['scale_factor']) != self.getTypeCode(var.attributes['add_offset']):
                print("ERROR (8.1): scale_factor and add_offset must be the same numeric data type")
                self.err = self.err + 1
                # No point running rest of packed data tests
                return 0

        if 'scale_factor' in var.attributes:
            type = var.attributes['scale_factor'].dtype.char
        elif 'add_offset' in var.attributes:
            type = var.attributes['add_offset'].dtype.char
        else:
            # No packed Data attributes present
            return 1

        varType = self.getTypeCode(var)

        # One or other attributes present; run remaining checks
        if varType != type:
            if type != 'f' and type != 'd':
                print("ERROR (8.1): scale_factor and add_offset must be of type float or double")
                self.err = self.err + 1
                rc = 0

            if varType != 'b' and varType != 'h' and varType != 'i':
                print("ERROR (8.1):", var.id, "must be of type byte, short or int")
                self.err = self.err + 1
                rc = 0

            if type == 'f' and varType == 'i':
                print("WARNING (8.1): scale_factor/add_offset are type float, therefore", var.id, "should not be of type int")
                self.warn = self.warn + 1

        return rc

        # ----------------------------
    def chkFlags(self, varName):
        # ----------------------------
        var = self.f[varName]
        rc = 1

        if 'flag_meanings' in var.attributes:
            # Flag to indicate whether one of flag_values or flag_masks present
            values_or_masks = 0
            meanings = var.attributes['flag_meanings']

#          if not self.parseBlankSeparatedList(meanings):
            if not self.extendedBlankSeparatedList(meanings):
                print("ERROR (3.5): Invalid syntax for 'flag_meanings' attribute")
                self.err = self.err + 1
                rc = 0

            if 'flag_values' in var.attributes:
                values_or_masks = 1
                values = var.attributes['flag_values']

                # If values is a string of chars, split it up into a list of chars
#              print "Ros: flag_values:",values
#              print "Ros: flag_values type:",type(values)

#              if type(values) == str:
#                  print "Ros - flag_values is a string"
#                  values = values.split()

#              print "Ros: after split:",values
#              print "Ros: after split:",type(values)

                retcode = self.equalNumOfValues(values, meanings)
                if retcode == -1:
                    print("ERROR (3.5): Problem in subroutine equalNumOfValues")
                    rc = 0
                elif not retcode:
                    print("ERROR (3.5): Number of flag_values values must equal the number or words/phrases in flag_meanings")
                    self.err = self.err + 1
                    rc = 0

                # flag_values values must be mutually exclusive
                if type(values) == str:
                    values = values.split()

                if not self.uniqueList(values):
                    print("ERROR (3.5): flag_values attribute must contain a list of unique values")
                    self.err = self.err + 1
                    rc = 0

            if 'flag_masks' in var.attributes:
                values_or_masks = 1
                masks = var.attributes['flag_masks']

                retcode = self.equalNumOfValues(masks, meanings)
                if retcode == -1:
                    print("ERROR (3.5): Problem in subroutine equalNumOfValues")
                    rc = 0
                elif not retcode:
                    print("ERROR (3.5): Number of flag_masks values must equal the number or words/phrases in flag_meanings")
                    self.err = self.err + 1
                    rc = 0

                # flag_values values must be non-zero
                for v in masks:
                    if v == 0:
                        print("ERROR (3.5): flag_masks values must be non-zero")
                        self.err = self.err + 1
                        rc = 0

            # Doesn't make sense to do bitwise comparison for char variable
            if self.getTypeCode(var) != 'c':
                if 'flag_values' in var.attributes and 'flag_masks' in var.attributes:
                    # Both flag_values and flag_masks present
                    # Do a bitwise AND of each flag_value and its corresponding flag_mask value,
                    # the result must be equal to the flag_values entry
                    i = 0
                    for v in values:
                        bitwise_AND = v & masks[i]

                        if bitwise_AND != v:
                            print("WARNING (3.5): Bitwise AND of flag_value", v, "and corresponding flag_mask", masks[i], "doesn't match flag_value.")
                            self.warn = self.warn + 1
                        i = i + 1

            if values_or_masks == 0:
                # flag_meanings attribute present, but no flag_values or flag_masks
                print("ERROR (3.5): flag_meanings present, but no flag_values or flag_masks specified")
                self.err = self.err + 1
                rc = 0

            if 'flag_values' in var.attributes and 'flag_meanings' not in var.attributes:
                print("ERROR (3.5): flag_meanings attribute is missing")
                self.err = self.err + 1
                rc = 0

        return rc

        # -----------------------
    def getType(self, arg):
        # -----------------------
        if isinstance(arg, numpy.ndarray):
            return "array"

        elif type(arg) == str:
            return "str"

        elif type(arg) == list:
            return "list"

        else:
            print("<cfchecker> ERROR: Unknown Type in getType(" + arg + ")")
            return 0

        # ----------------------------------------
    def equalNumOfValues(self, arg1, arg2):
        # ----------------------------------------
        """ Check that arg1 and arg2 contain the same number of blank-separated elements."""

        # Determine the type of both arguments.  strings and arrays need to be handled differently
        type_arg1 = self.getType(arg1)
        type_arg2 = self.getType(arg2)

        if not type_arg1 or not type_arg2:
            return -1

        if type_arg1 == "str":
            len_arg1 = len(arg1.split())
        else:
            len_arg1 = len(arg1)

        if type_arg2 == "str":
            len_arg2 = len(arg2.split())
        else:
            len_arg2 = len(arg2)

        if len_arg1 != len_arg2:
            return 0

        return 1

        # ------------------------------------------
    def chkMultiDimCoord(self, varName, axes):
        # ------------------------------------------
        """If a coordinate variable is multi-dimensional, then it is recommended
        that the variable name should not match the name of any of its dimensions."""
        var = self.f[varName]

        # This is a temporary work around to obtain the dimensions of the coord
        # var.  In CDMS vn4.0 only 1D coord vars will be axis variables; There
        # will be no need to use _obj_. See CRM #011
        if var.id in axes and len(var._obj_.dimensions) > 1:
            # Multi-dimensional coordinate var
            if var.id in var._obj_.dimensions:
                print("WARNING (5): The name of a multi-dimensional coordinate variable")
                print("             should not match the name of any of its dimensions.")
                self.warn = self.warn + 1

        # --------------------------------------
    def chkValuesMonotonic(self, varName):
        # --------------------------------------
        """A coordinate variable must have values that are strictly monotonic
        (increasing or decreasing)."""
        # rc=1
        var = self.f[varName]
        values = var.getValue()
        i = 0
        for val in values[:]:
            if i == 0:
                # First value - no comparison to do
                i = i + 1
                lastVal = val
                continue
            elif i == 1:
                i = i + 1
                if val < lastVal:
                    # Decreasing sequence
                    type = 'decr'
                elif val > lastVal:
                    # Increasing sequence
                    type = 'incr'
                else:
                    # Same value - ERROR
                    print("ERROR (5): co-ordinate variable '" + var.id + "' not monotonic")
                    self.err = self.err + 1
                    return 1

                lastVal = val
            else:
                i = i + 1
                if val < lastVal and type != 'decr':
                    # ERROR - should be increasing value
                    print("ERROR (5): co-ordinate variable '" + var.id + "' not monotonic")
                    self.err = self.err + 1
                    return 1
                elif val > lastVal and type != 'incr':
                    # ERROR - should be decreasing value
                    print("ERROR (5): co-ordinate variable '" + var.id + "' not monotonic")
                    self.err = self.err + 1
                    return 1

                lastVal = val


def getargs(arglist):
    '''getargs(arglist): parse command line options and environment variables'''

    from getopt import getopt, GetoptError
    from os import environ
    from sys import stderr, exit

    udunitskey = 'UDUNITS'
    standardnamekey = 'CF_STANDARD_NAMES'
    areatypeskey = 'CF_AREA_TYPES'
    # set defaults
    udunits = None
    standardname = STANDARDNAME
    areatypes = AREATYPES
    uploader = None
    useFileName = "yes"
    badc = None
    coards = None
    version = newest_version

    # set to environment variables
    if udunitskey in environ:
        udunits = environ[udunitskey]
    if standardnamekey in environ:
        standardname = environ[standardnamekey]
    if areatypeskey in environ:
        areatypes = environ[areatypeskey]

    try:
        (opts, args) = getopt(arglist[1:], 'a:bchlnu:s:v:', ['area_types=', 'badc', 'coards', 'help', 'uploader', 'noname', 'udunits=', 'cf_standard_names=', 'version='])
    except GetoptError:
        stderr.write('%s\n' % __doc__)
        exit(1)

    for a, v in opts:
        if a in ('-a', '--area_types'):
            areatypes = v.strip()
            continue
        if a in ('-b', '--badc'):
            badc = "yes"
            continue
        if a in ('-c', '--coards'):
            coards = "yes"
            continue
        if a in ('-h', '--help'):
            print(__doc__)
            exit(0)
        if a in ('-l', '--uploader'):
            uploader = "yes"
            continue
        if a in ('-n', '--noname'):
            useFileName = "no"
            continue
        if a in ('-u', '--udunits'):
            udunits = v.strip()
            continue
        if a in ('-s', '--cf_standard_names'):
            standardname = v.strip()
            continue
        if a in ('-v', '--version'):
            if v == 'auto':
                version = CFVersion()
            else:
                try:
                    version = CFVersion(v)
                except ValueError:
                    print("WARNING: '%s' cannot be parsed as a version number." % v)
                    print("Performing check against newest version", newest_version)
                if version not in cfVersions:
                    print("WARNING: %s is not a valid CF version." % version)
                    print("Performing check against newest version", newest_version)
                    version = newest_version
            continue

    if len(args) == 0:
        stderr.write('ERROR in command line\n\nusage:\n%s\n' % __doc__)
        exit(1)

    return (badc, coards, uploader, useFileName, standardname, areatypes, udunits, version, args)


# --------------------------
# Main Program
# --------------------------

if __name__ == '__main__':

    from sys import argv, exit

    (badc, coards, uploader, useFileName, standardName, areaTypes, udunitsDat, version, files) = getargs(argv)

    inst = CFChecker(uploader=uploader, useFileName=useFileName, badc=badc, coards=coards, cfStandardNamesXML=standardName, cfAreaTypesXML=areaTypes, udunitsDat=udunitsDat, version=version)
    for file in files:
        rc = inst.checker(file)
        exit(rc)
