class WKBReader_st(Structure):
pass
class WKBWriter_st(Structure):
pass
WKT_READ_PTR = POINTER(WKTReader_st)
WKT_WRITE_PTR = POINTER(WKTWriter_st)
WKB_READ_PTR = POINTER(WKBReader_st)
WKB_WRITE_PTR = POINTER(WKBReader_st)
### WKTReader routines ###
wkt_reader_create = GEOSFunc("GEOSWKTReader_create")
wkt_reader_create.restype = WKT_READ_PTR
wkt_reader_destroy = GEOSFunc("GEOSWKTReader_destroy")
wkt_reader_destroy.argtypes = [WKT_READ_PTR]
wkt_reader_read = GEOSFunc("GEOSWKTReader_read")
wkt_reader_read.argtypes = [WKT_READ_PTR, c_char_p]
wkt_reader_read.restype = GEOM_PTR
wkt_reader_read.errcheck = check_geom
### WKTWriter routines ###
wkt_writer_create = GEOSFunc("GEOSWKTWriter_create")
wkt_writer_create.restype = WKT_WRITE_PTR
wkt_writer_destroy = GEOSFunc("GEOSWKTWriter_destroy")
from ctypes import c_char
from djangocg.contrib.gis.geos.libgeos import GEOM_PTR, PREPGEOM_PTR
from djangocg.contrib.gis.geos.prototypes.errcheck import check_predicate
from djangocg.contrib.gis.geos.prototypes.threadsafe import GEOSFunc
# Prepared geometry constructor and destructors.
geos_prepare = GEOSFunc('GEOSPrepare')
geos_prepare.argtypes = [GEOM_PTR]
geos_prepare.restype = PREPGEOM_PTR
prepared_destroy = GEOSFunc('GEOSPreparedGeom_destroy')
prepared_destroy.argtpes = [PREPGEOM_PTR]
prepared_destroy.restype = None
# Prepared geometry binary predicate support.
def prepared_predicate(func):
func.argtypes= [PREPGEOM_PTR, GEOM_PTR]
func.restype = c_char
func.errcheck = check_predicate
return func
prepared_contains = prepared_predicate(GEOSFunc('GEOSPreparedContains'))
prepared_contains_properly = prepared_predicate(GEOSFunc('GEOSPreparedContainsProperly'))
prepared_covers = prepared_predicate(GEOSFunc('GEOSPreparedCovers'))
prepared_intersects = prepared_predicate(GEOSFunc('GEOSPreparedIntersects'))
func.errcheck = check_geom
return func
### Topology Routines ###
geos_boundary = topology(GEOSFunc('GEOSBoundary'))
geos_buffer = topology(GEOSFunc('GEOSBuffer'), c_double, c_int)
geos_centroid = topology(GEOSFunc('GEOSGetCentroid'))
geos_convexhull = topology(GEOSFunc('GEOSConvexHull'))
geos_difference = topology(GEOSFunc('GEOSDifference'), GEOM_PTR)
geos_envelope = topology(GEOSFunc('GEOSEnvelope'))
geos_intersection = topology(GEOSFunc('GEOSIntersection'), GEOM_PTR)
geos_linemerge = topology(GEOSFunc('GEOSLineMerge'))
geos_pointonsurface = topology(GEOSFunc('GEOSPointOnSurface'))
geos_preservesimplify = topology(GEOSFunc('GEOSTopologyPreserveSimplify'), c_double)
geos_simplify = topology(GEOSFunc('GEOSSimplify'), c_double)
geos_symdifference = topology(GEOSFunc('GEOSSymDifference'), GEOM_PTR)
geos_union = topology(GEOSFunc('GEOSUnion'), GEOM_PTR)
# GEOSRelate returns a string, not a geometry.
geos_relate = GEOSFunc('GEOSRelate')
geos_relate.argtypes = [GEOM_PTR, GEOM_PTR]
geos_relate.restype = geos_char_p
geos_relate.errcheck = check_string
# Routines only in GEOS 3.1+
if GEOS_PREPARE:
geos_cascaded_union = GEOSFunc('GEOSUnionCascaded')
geos_cascaded_union.argtypes = [GEOM_PTR]
geos_cascaded_union.restype = GEOM_PTR
__all__.append('geos_cascaded_union')
"""
Error checking functions for GEOS ctypes prototype functions.
"""
import os
from ctypes import c_void_p, string_at, CDLL
from djangocg.contrib.gis.geos.error import GEOSException
from djangocg.contrib.gis.geos.libgeos import GEOS_VERSION
from djangocg.contrib.gis.geos.prototypes.threadsafe import GEOSFunc
# Getting the `free` routine used to free the memory allocated for
# string pointers returned by GEOS.
if GEOS_VERSION >= (3, 1, 1):
# In versions 3.1.1 and above, `GEOSFree` was added to the C API
# because `free` isn't always available on all platforms.
free = GEOSFunc('GEOSFree')
free.argtypes = [c_void_p]
free.restype = None
else:
# Getting the `free` routine from the C library of the platform.
if os.name == 'nt':
# On NT, use the MS C library.
libc = CDLL('msvcrt')
else:
# On POSIX platforms C library is obtained by passing None into `CDLL`.
libc = CDLL(None)
free = libc.free
### ctypes error checking routines ###
def last_arg_byref(args):
"Returns the last C argument's value by reference."
return args[-1]._obj.value
# Polygon and collection creation routines are special and will not
# have their argument types defined.
create_polygon = geom_output(GEOSFunc('GEOSGeom_createPolygon'), None)
create_collection = geom_output(GEOSFunc('GEOSGeom_createCollection'), None)
# Ring routines
get_extring = geom_output(GEOSFunc('GEOSGetExteriorRing'), [GEOM_PTR])
get_intring = geom_index(GEOSFunc('GEOSGetInteriorRingN'))
get_nrings = int_from_geom(GEOSFunc('GEOSGetNumInteriorRings'))
# Collection Routines
get_geomn = geom_index(GEOSFunc('GEOSGetGeometryN'))
# Cloning
geom_clone = GEOSFunc('GEOSGeom_clone')
geom_clone.argtypes = [GEOM_PTR]
geom_clone.restype = GEOM_PTR
# Destruction routine.
destroy_geom = GEOSFunc('GEOSGeom_destroy')
destroy_geom.argtypes = [GEOM_PTR]
destroy_geom.restype = None
# SRID routines
geos_get_srid = GEOSFunc('GEOSGetSRID')
geos_get_srid.argtypes = [GEOM_PTR]
geos_get_srid.restype = c_int
geos_set_srid = GEOSFunc('GEOSSetSRID')
geos_set_srid.argtypes = [GEOM_PTR, c_int]
__all__ = ['geos_area', 'geos_distance', 'geos_length']
### ctypes generator function ###
def dbl_from_geom(func, num_geom=1):
"""
Argument is a Geometry, return type is double that is passed
in by reference as the last argument.
"""
argtypes = [GEOM_PTR for i in xrange(num_geom)]
argtypes += [POINTER(c_double)]
func.argtypes = argtypes
func.restype = c_int # Status code returned
func.errcheck = check_dbl
return func
### ctypes prototypes ###
# Area, distance, and length prototypes.
geos_area = dbl_from_geom(GEOSFunc('GEOSArea'))
geos_distance = dbl_from_geom(GEOSFunc('GEOSDistance'), num_geom=2)
geos_length = dbl_from_geom(GEOSFunc('GEOSLength'))
# Validity reason; only in GEOS 3.1+
if GEOS_PREPARE:
geos_isvalidreason = GEOSFunc('GEOSisValidReason')
geos_isvalidreason.argtypes = [GEOM_PTR]
geos_isvalidreason.restype = geos_char_p
geos_isvalidreason.errcheck = check_string
__all__.append('geos_isvalidreason')
