1 import os, re, sys

     2 from ctypes import c_char_p, CDLL

     3 from ctypes.util import find_library

     4 from django.contrib.gis.gdal.error import OGRException

     5 

     6 # Custom library path set?

     7 try:

     8     from django.conf import settings

     9     lib_path = settings.GDAL_LIBRARY_PATH

    10 except (AttributeError, EnvironmentError, ImportError):

    11     lib_path = None

    12 

    13 if lib_path:

    14     lib_names = None

    15 elif os.name == 'nt':

    16     # Windows NT shared library

    17     lib_names = ['gdal16', 'gdal15']

    18 elif os.name == 'posix':

    19     # *NIX library names.

    20     lib_names = ['gdal', 'GDAL', 'gdal1.6.0', 'gdal1.5.0', 'gdal1.4.0']

    21 else:

    22     raise OGRException('Unsupported OS "%s"' % os.name)

    23 

    24 # Using the ctypes `find_library` utility  to find the 

    25 # path to the GDAL library from the list of library names.

    26 if lib_names:

    27     for lib_name in lib_names:

    28         lib_path = find_library(lib_name)

    29         if not lib_path is None: break

    30         

    31 if lib_path is None:

    32     raise OGRException('Could not find the GDAL library (tried "%s"). '

    33                        'Try setting GDAL_LIBRARY_PATH in your settings.' % 

    34                        '", "'.join(lib_names))

    35 

    36 # This loads the GDAL/OGR C library

    37 lgdal = CDLL(lib_path)

    38 

    39 # On Windows, the GDAL binaries have some OSR routines exported with 

    40 # STDCALL, while others are not.  Thus, the library will also need to 

    41 # be loaded up as WinDLL for said OSR functions that require the 

    42 # different calling convention.

    43 if os.name == 'nt':

    44     from ctypes import WinDLL

    45     lwingdal = WinDLL(lib_path)

    46 

    47 def std_call(func):

    48     """

    49     Returns the correct STDCALL function for certain OSR routines on Win32

    50     platforms.

    51     """

    52     if os.name == 'nt':

    53         return lwingdal[func]

    54     else:

    55         return lgdal[func]

    56 

    57 #### Version-information functions. ####

    58 

    59 # Returns GDAL library version information with the given key.

    60 _version_info = std_call('GDALVersionInfo')

    61 _version_info.argtypes = [c_char_p]

    62 _version_info.restype = c_char_p

    63 

    64 def gdal_version():

    65     "Returns only the GDAL version number information."

    66     return _version_info('RELEASE_NAME')

    67 

    68 def gdal_full_version(): 

    69     "Returns the full GDAL version information."

    70     return _version_info('')

    71 

    72 def gdal_release_date(date=False): 

    73     """

    74     Returns the release date in a string format, e.g, "2007/06/27".

    75     If the date keyword argument is set to True, a Python datetime object

    76     will be returned instead.

    77     """

    78     from datetime import date as date_type

    79     rel = _version_info('RELEASE_DATE')

    80     yy, mm, dd = map(int, (rel[0:4], rel[4:6], rel[6:8]))

    81     d = date_type(yy, mm, dd)

    82     if date: return d

    83     else: return d.strftime('%Y/%m/%d')

    84 

    85 version_regex = re.compile(r'^(?P<major>\d+)\.(?P<minor>\d+)(\.(?P<subminor>\d+))?')

    86 def gdal_version_info():

    87     ver = gdal_version()

    88     m = version_regex.match(ver)

    89     if not m: raise OGRException('Could not parse GDAL version string "%s"' % ver)

    90     return dict([(key, m.group(key)) for key in ('major', 'minor', 'subminor')])

    91 

    92 _verinfo = gdal_version_info()

    93 GDAL_MAJOR_VERSION = int(_verinfo['major'])

    94 GDAL_MINOR_VERSION = int(_verinfo['minor'])

    95 GDAL_SUBMINOR_VERSION = _verinfo['subminor'] and int(_verinfo['subminor'])

    96 GDAL_VERSION = (GDAL_MAJOR_VERSION, GDAL_MINOR_VERSION, GDAL_SUBMINOR_VERSION)

    97 del _verinfo

    98 

    99 # GeoJSON support is available only in GDAL 1.5+.

   100 if GDAL_VERSION >= (1, 5):

   101     GEOJSON = True

   102 else:

   103     GEOJSON = False

   104