diff -r 000000000000 -r 0d40e90630ef web/lib/django/contrib/gis/geos/libgeos.py --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/web/lib/django/contrib/gis/geos/libgeos.py Wed Jan 20 00:34:04 2010 +0100 @@ -0,0 +1,128 @@ +""" + This module houses the ctypes initialization procedures, as well + as the notice and error handler function callbacks (get called + when an error occurs in GEOS). + + This module also houses GEOS Pointer utilities, including + get_pointer_arr(), and GEOM_PTR. +""" +import atexit, os, re, sys +from ctypes import c_char_p, Structure, CDLL, CFUNCTYPE, POINTER +from ctypes.util import find_library +from django.contrib.gis.geos.error import GEOSException + +# Custom library path set? +try: + from django.conf import settings + lib_path = settings.GEOS_LIBRARY_PATH +except (AttributeError, EnvironmentError, ImportError): + lib_path = None + +# Setting the appropriate names for the GEOS-C library. +if lib_path: + lib_names = None +elif os.name == 'nt': + # Windows NT libraries + lib_names = ['libgeos_c-1'] +elif os.name == 'posix': + # *NIX libraries + lib_names = ['geos_c', 'GEOS'] +else: + raise ImportError('Unsupported OS "%s"' % os.name) + +# Using the ctypes `find_library` utility to find the path to the GEOS +# shared library. This is better than manually specifiying each library name +# and extension (e.g., libgeos_c.[so|so.1|dylib].). +if lib_names: + for lib_name in lib_names: + lib_path = find_library(lib_name) + if not lib_path is None: break + +# No GEOS library could be found. +if lib_path is None: + raise ImportError('Could not find the GEOS library (tried "%s"). ' + 'Try setting GEOS_LIBRARY_PATH in your settings.' % + '", "'.join(lib_names)) + +# Getting the GEOS C library. The C interface (CDLL) is used for +# both *NIX and Windows. +# See the GEOS C API source code for more details on the library function calls: +# http://geos.refractions.net/ro/doxygen_docs/html/geos__c_8h-source.html +lgeos = CDLL(lib_path) + +# The notice and error handler C function callback definitions. +# Supposed to mimic the GEOS message handler (C below): +# "typedef void (*GEOSMessageHandler)(const char *fmt, ...);" +NOTICEFUNC = CFUNCTYPE(None, c_char_p, c_char_p) +def notice_h(fmt, lst, output_h=sys.stdout): + try: + warn_msg = fmt % lst + except: + warn_msg = fmt + output_h.write('GEOS_NOTICE: %s\n' % warn_msg) +notice_h = NOTICEFUNC(notice_h) + +ERRORFUNC = CFUNCTYPE(None, c_char_p, c_char_p) +def error_h(fmt, lst, output_h=sys.stderr): + try: + err_msg = fmt % lst + except: + err_msg = fmt + output_h.write('GEOS_ERROR: %s\n' % err_msg) +error_h = ERRORFUNC(error_h) + +# The initGEOS routine should be called first, however, that routine takes +# the notice and error functions as parameters. Here is the C code that +# is wrapped: +# "extern void GEOS_DLL initGEOS(GEOSMessageHandler notice_function, GEOSMessageHandler error_function);" +lgeos.initGEOS(notice_h, error_h) + +#### GEOS Geometry C data structures, and utility functions. #### + +# Opaque GEOS geometry structures, used for GEOM_PTR and CS_PTR +class GEOSGeom_t(Structure): pass +class GEOSPrepGeom_t(Structure): pass +class GEOSCoordSeq_t(Structure): pass + +# Pointers to opaque GEOS geometry structures. +GEOM_PTR = POINTER(GEOSGeom_t) +PREPGEOM_PTR = POINTER(GEOSPrepGeom_t) +CS_PTR = POINTER(GEOSCoordSeq_t) + +# Used specifically by the GEOSGeom_createPolygon and GEOSGeom_createCollection +# GEOS routines +def get_pointer_arr(n): + "Gets a ctypes pointer array (of length `n`) for GEOSGeom_t opaque pointer." + GeomArr = GEOM_PTR * n + return GeomArr() + +# Returns the string version of the GEOS library. Have to set the restype +# explicitly to c_char_p to ensure compatibility accross 32 and 64-bit platforms. +geos_version = lgeos.GEOSversion +geos_version.argtypes = None +geos_version.restype = c_char_p + +# Regular expression should be able to parse version strings such as +# '3.0.0rc4-CAPI-1.3.3', or '3.0.0-CAPI-1.4.1' +version_regex = re.compile(r'^(?P(?P\d+)\.(?P\d+)\.\d+)(rc(?P\d+))?-CAPI-(?P\d+\.\d+\.\d+)$') +def geos_version_info(): + """ + Returns a dictionary containing the various version metadata parsed from + the GEOS version string, including the version number, whether the version + is a release candidate (and what number release candidate), and the C API + version. + """ + ver = geos_version() + m = version_regex.match(ver) + if not m: raise GEOSException('Could not parse version info string "%s"' % ver) + return dict((key, m.group(key)) for key in ('version', 'release_candidate', 'capi_version', 'major', 'minor')) + +# Version numbers and whether or not prepared geometry support is available. +_verinfo = geos_version_info() +GEOS_MAJOR_VERSION = int(_verinfo['major']) +GEOS_MINOR_VERSION = int(_verinfo['minor']) +del _verinfo +GEOS_PREPARE = GEOS_MAJOR_VERSION > 3 or GEOS_MAJOR_VERSION == 3 and GEOS_MINOR_VERSION >= 1 + +# Calling the finishGEOS() upon exit of the interpreter. +atexit.register(lgeos.finishGEOS)