"""

 This module houses the GEOS ctypes prototype functions for the 

 topological operations on geometries.

"""

from ctypes import c_char_p, c_double, c_int

from django.contrib.gis.geos.libgeos import lgeos, GEOM_PTR

from django.contrib.gis.geos.prototypes.errcheck import check_geom, check_string

def topology(func, *args):

    "For GEOS unary topology functions."

    argtypes = [GEOM_PTR]

    if args: argtypes += args

    func.argtypes = argtypes

    func.restype = GEOM_PTR

    func.errcheck = check_geom

    return func

### Topology Routines ###

geos_boundary = topology(lgeos.GEOSBoundary)

geos_buffer = topology(lgeos.GEOSBuffer, c_double, c_int)

geos_centroid = topology(lgeos.GEOSGetCentroid)

geos_convexhull = topology(lgeos.GEOSConvexHull)

geos_difference = topology(lgeos.GEOSDifference, GEOM_PTR)

geos_envelope = topology(lgeos.GEOSEnvelope)

geos_intersection = topology(lgeos.GEOSIntersection, GEOM_PTR)

geos_pointonsurface = topology(lgeos.GEOSPointOnSurface)

geos_preservesimplify = topology(lgeos.GEOSTopologyPreserveSimplify, c_double)

geos_simplify = topology(lgeos.GEOSSimplify, c_double)

geos_symdifference = topology(lgeos.GEOSSymDifference, GEOM_PTR)

geos_union = topology(lgeos.GEOSUnion, GEOM_PTR)

# GEOSRelate returns a string, not a geometry.

geos_relate = lgeos.GEOSRelate

geos_relate.argtypes = [GEOM_PTR, GEOM_PTR]

geos_relate.errcheck = check_string