import threading
from ctypes import byref,c_char_p,c_int,c_char,c_size_t,Structure,POINTER
from django.contrib.gis.geos.base import GEOSBase
from django.contrib.gis.geos.libgeos import GEOM_PTR
from django.contrib.gis.geos.prototypes.errcheck import check_geom,check_string,check_sized_string
from django.contrib.gis.geos.prototypes.geom import c_uchar_p,geos_char_p
from django.contrib.gis.geos.prototypes.threadsafe import GEOSFunc
### The WKB/WKT Reader/Writer structures and pointers ###
class WKTReader_st(Structure): pass
class WKTWriter_st(Structure): pass
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')
wkt_writer_destroy.argtypes = [WKT_WRITE_PTR]
wkt_writer_write = GEOSFunc('GEOSWKTWriter_write')
wkt_writer_write.argtypes = [WKT_WRITE_PTR, GEOM_PTR]
wkt_writer_write.restype = geos_char_p
wkt_writer_write.errcheck = check_string
### WKBReader routines ###
wkb_reader_create = GEOSFunc('GEOSWKBReader_create')
wkb_reader_create.restype = WKB_READ_PTR
wkb_reader_destroy = GEOSFunc('GEOSWKBReader_destroy')
wkb_reader_destroy.argtypes = [WKB_READ_PTR]
def wkb_read_func(func):
# Although the function definitions take `const unsigned char *`
# as their parameter, we use c_char_p here so the function may
# take Python strings directly as parameters. Inside Python there
# is not a difference between signed and unsigned characters, so
# it is not a problem.
func.argtypes = [WKB_READ_PTR, c_char_p, c_size_t]
func.restype = GEOM_PTR
func.errcheck = check_geom
return func
wkb_reader_read = wkb_read_func(GEOSFunc('GEOSWKBReader_read'))
wkb_reader_read_hex = wkb_read_func(GEOSFunc('GEOSWKBReader_readHEX'))
### WKBWriter routines ###
wkb_writer_create = GEOSFunc('GEOSWKBWriter_create')
wkb_writer_create.restype = WKB_WRITE_PTR
wkb_writer_destroy = GEOSFunc('GEOSWKBWriter_destroy')
wkb_writer_destroy.argtypes = [WKB_WRITE_PTR]
# WKB Writing prototypes.
def wkb_write_func(func):
func.argtypes = [WKB_WRITE_PTR, GEOM_PTR, POINTER(c_size_t)]
func.restype = c_uchar_p
func.errcheck = check_sized_string
return func
wkb_writer_write = wkb_write_func(GEOSFunc('GEOSWKBWriter_write'))
wkb_writer_write_hex = wkb_write_func(GEOSFunc('GEOSWKBWriter_writeHEX'))
# WKBWriter property getter/setter prototypes.
def wkb_writer_get(func, restype=c_int):
func.argtypes = [WKB_WRITE_PTR]
func.restype = restype
return func
def wkb_writer_set(func, argtype=c_int):
func.argtypes = [WKB_WRITE_PTR, argtype]
return func
wkb_writer_get_byteorder = wkb_writer_get(GEOSFunc('GEOSWKBWriter_getByteOrder'))
wkb_writer_set_byteorder = wkb_writer_set(GEOSFunc('GEOSWKBWriter_setByteOrder'))
wkb_writer_get_outdim = wkb_writer_get(GEOSFunc('GEOSWKBWriter_getOutputDimension'))
wkb_writer_set_outdim = wkb_writer_set(GEOSFunc('GEOSWKBWriter_setOutputDimension'))
wkb_writer_get_include_srid = wkb_writer_get(GEOSFunc('GEOSWKBWriter_getIncludeSRID'), restype=c_char)
wkb_writer_set_include_srid = wkb_writer_set(GEOSFunc('GEOSWKBWriter_setIncludeSRID'), argtype=c_char)
### Base I/O Class ###
class IOBase(GEOSBase):
"Base class for GEOS I/O objects."
def __init__(self):
# Getting the pointer with the constructor.
self.ptr = self._constructor()
def __del__(self):
# Cleaning up with the appropriate destructor.
if self._ptr: self._destructor(self._ptr)
### Base WKB/WKT Reading and Writing objects ###
# Non-public WKB/WKT reader classes for internal use because
# their `read` methods return _pointers_ instead of GEOSGeometry
# objects.
class _WKTReader(IOBase):
_constructor = wkt_reader_create
_destructor = wkt_reader_destroy
ptr_type = WKT_READ_PTR
def read(self, wkt):
if not isinstance(wkt, basestring): raise TypeError
return wkt_reader_read(self.ptr, wkt)
class _WKBReader(IOBase):
_constructor = wkb_reader_create
_destructor = wkb_reader_destroy
ptr_type = WKB_READ_PTR
def read(self, wkb):
"Returns a _pointer_ to C GEOS Geometry object from the given WKB."
if isinstance(wkb, buffer):
wkb_s = str(wkb)
return wkb_reader_read(self.ptr, wkb_s, len(wkb_s))
elif isinstance(wkb, basestring):
return wkb_reader_read_hex(self.ptr, wkb, len(wkb))
else:
raise TypeError
### WKB/WKT Writer Classes ###
class WKTWriter(IOBase):
_constructor = wkt_writer_create
_destructor = wkt_writer_destroy
ptr_type = WKT_WRITE_PTR
def write(self, geom):
"Returns the WKT representation of the given geometry."
return wkt_writer_write(self.ptr, geom.ptr)
class WKBWriter(IOBase):
_constructor = wkb_writer_create
_destructor = wkb_writer_destroy
ptr_type = WKB_WRITE_PTR
def write(self, geom):
"Returns the WKB representation of the given geometry."
return buffer(wkb_writer_write(self.ptr, geom.ptr, byref(c_size_t())))
def write_hex(self, geom):
"Returns the HEXEWKB representation of the given geometry."
return wkb_writer_write_hex(self.ptr, geom.ptr, byref(c_size_t()))
### WKBWriter Properties ###
# Property for getting/setting the byteorder.
def _get_byteorder(self):
return wkb_writer_get_byteorder(self.ptr)
def _set_byteorder(self, order):
if not order in (0, 1): raise ValueError('Byte order parameter must be 0 (Big Endian) or 1 (Little Endian).')
wkb_writer_set_byteorder(self.ptr, order)
byteorder = property(_get_byteorder, _set_byteorder)
# Property for getting/setting the output dimension.
def _get_outdim(self):
return wkb_writer_get_outdim(self.ptr)
def _set_outdim(self, new_dim):
if not new_dim in (2, 3): raise ValueError('WKB output dimension must be 2 or 3')
wkb_writer_set_outdim(self.ptr, new_dim)
outdim = property(_get_outdim, _set_outdim)
# Property for getting/setting the include srid flag.
def _get_include_srid(self):
return bool(ord(wkb_writer_get_include_srid(self.ptr)))
def _set_include_srid(self, include):
if bool(include): flag = chr(1)
else: flag = chr(0)
wkb_writer_set_include_srid(self.ptr, flag)
srid = property(_get_include_srid, _set_include_srid)
# `ThreadLocalIO` object holds instances of the WKT and WKB reader/writer
# objects that are local to the thread. The `GEOSGeometry` internals
# access these instances by calling the module-level functions, defined
# below.
class ThreadLocalIO(threading.local):
wkt_r = None
wkt_w = None
wkb_r = None
wkb_w = None
ewkb_w = None
ewkb_w3d = None
thread_context = ThreadLocalIO()
# These module-level routines return the I/O object that is local to the
# the thread. If the I/O object does not exist yet it will be initialized.
def wkt_r():
if not thread_context.wkt_r:
thread_context.wkt_r = _WKTReader()
return thread_context.wkt_r
def wkt_w():
if not thread_context.wkt_w:
thread_context.wkt_w = WKTWriter()
return thread_context.wkt_w
def wkb_r():
if not thread_context.wkb_r:
thread_context.wkb_r = _WKBReader()
return thread_context.wkb_r
def wkb_w():
if not thread_context.wkb_w:
thread_context.wkb_w = WKBWriter()
return thread_context.wkb_w
def ewkb_w():
if not thread_context.ewkb_w:
thread_context.ewkb_w = WKBWriter()
thread_context.ewkb_w.srid = True
return thread_context.ewkb_w
def ewkb_w3d():
if not thread_context.ewkb_w3d:
thread_context.ewkb_w3d = WKBWriter()
thread_context.ewkb_w3d.srid = True
thread_context.ewkb_w3d.outdim = 3
return thread_context.ewkb_w3d
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