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from ctypes import c_double, c_int, c_uint, POINTER
from django.contrib.gis.geos.libgeos import lgeos, GEOM_PTR, CS_PTR
from django.contrib.gis.geos.prototypes.errcheck import last_arg_byref, GEOSException
## Error-checking routines specific to coordinate sequences. ##
def check_cs_ptr(result, func, cargs):
"Error checking on routines that return Geometries."
if not result:
raise GEOSException('Error encountered checking Coordinate Sequence returned from GEOS C function "%s".' % func.__name__)
return result
def check_cs_op(result, func, cargs):
"Checks the status code of a coordinate sequence operation."
if result == 0:
raise GEOSException('Could not set value on coordinate sequence')
else:
return result
def check_cs_get(result, func, cargs):
"Checking the coordinate sequence retrieval."
check_cs_op(result, func, cargs)
# Object in by reference, return its value.
return last_arg_byref(cargs)
## Coordinate sequence prototype generation functions. ##
def cs_int(func):
"For coordinate sequence routines that return an integer."
func.argtypes = [CS_PTR, POINTER(c_uint)]
func.restype = c_int
func.errcheck = check_cs_get
return func
def cs_operation(func, ordinate=False, get=False):
"For coordinate sequence operations."
if get:
# Get routines get double parameter passed-in by reference.
func.errcheck = check_cs_get
dbl_param = POINTER(c_double)
else:
func.errcheck = check_cs_op
dbl_param = c_double
if ordinate:
# Get/Set ordinate routines have an extra uint parameter.
func.argtypes = [CS_PTR, c_uint, c_uint, dbl_param]
else:
func.argtypes = [CS_PTR, c_uint, dbl_param]
func.restype = c_int
return func
def cs_output(func, argtypes):
"For routines that return a coordinate sequence."
func.argtypes = argtypes
func.restype = CS_PTR
func.errcheck = check_cs_ptr
return func
## Coordinate Sequence ctypes prototypes ##
# Coordinate Sequence constructors & cloning.
cs_clone = cs_output(lgeos.GEOSCoordSeq_clone, [CS_PTR])
create_cs = cs_output(lgeos.GEOSCoordSeq_create, [c_uint, c_uint])
get_cs = cs_output(lgeos.GEOSGeom_getCoordSeq, [GEOM_PTR])
# Getting, setting ordinate
cs_getordinate = cs_operation(lgeos.GEOSCoordSeq_getOrdinate, ordinate=True, get=True)
cs_setordinate = cs_operation(lgeos.GEOSCoordSeq_setOrdinate, ordinate=True)
# For getting, x, y, z
cs_getx = cs_operation(lgeos.GEOSCoordSeq_getX, get=True)
cs_gety = cs_operation(lgeos.GEOSCoordSeq_getY, get=True)
cs_getz = cs_operation(lgeos.GEOSCoordSeq_getZ, get=True)
# For setting, x, y, z
cs_setx = cs_operation(lgeos.GEOSCoordSeq_setX)
cs_sety = cs_operation(lgeos.GEOSCoordSeq_setY)
cs_setz = cs_operation(lgeos.GEOSCoordSeq_setZ)
# These routines return size & dimensions.
cs_getsize = cs_int(lgeos.GEOSCoordSeq_getSize)
cs_getdims = cs_int(lgeos.GEOSCoordSeq_getDimensions)
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