"""
This module is for the miscellaneous GEOS routines, particularly the
ones that return the area, distance, and length.
"""
from ctypes import c_int,c_double,POINTER
from django.contrib.gis.geos.libgeos import GEOM_PTR
from django.contrib.gis.geos.prototypes.errcheck import check_dbl
from django.contrib.gis.geos.prototypes.threadsafe import GEOSFunc
### 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'))
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