Fixed #9747 -- now explicitly set response type on C functions that return WKB and WKT.

from ctypes import c_char_p, c_int, c_size_t, c_uint, POINTER

from ctypes import c_char_p, c_int, c_size_t, c_ubyte, c_uint, POINTER

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

from django.contrib.gis.geos.prototypes.errcheck import \

    check_geom, check_minus_one, check_sized_string, check_string, check_zero

# This is the return type used by binary output (WKB, HEX) routines.

c_uchar_p = POINTER(c_ubyte)

# We create a simple subclass of c_char_p here because when the response

# type is set to c_char_p, you get a _Python_ string and there's no way

# to access the string's address inside the error checking function.

# In other words, you can't free the memory allocated inside GEOS.  Previously,

# the return type would just be omitted and the integer address would be

# used -- but this allows us to be specific in the function definition and

# keeps the reference so it may be free'd.

class geos_char_p(c_char_p):

    pass

### ctypes generation functions ###

def bin_constructor(func):

    "Generates a prototype for binary construction (HEX, WKB) GEOS routines."

    "Generates a prototype for the routines that return a a sized string."

    func.argtypes = [GEOM_PTR, POINTER(c_size_t)]

    func.errcheck = check_sized_string

    func.restype = c_uchar_p

    return func

def geom_output(func, argtypes):

    # We do _not_ specify an argument type because we want just an

    # address returned from the function.

    func.argtypes = [GEOM_PTR]

    func.restype = geos_char_p

    func.errcheck = check_string

    return func