Test script for Processing LWGEOM Provider issue, http://hub.qgis.org/issues/9105

liblwgeom_issue9105_test.py

#!/usr/bin/env python

import sys

from ctypes import *
from ctypes.util import find_library
import binascii


class GBOX(Structure):
    _fields_ = [
        ("flags", c_ubyte),
        ("xmin", c_double),
        ("xmax", c_double),
        ("ymin", c_double),
        ("ymax", c_double),
        ("zmin", c_double),
        ("zmax", c_double),
        ("mmin", c_double),
        ("mmax", c_double)
    ]


class LWGEOM(Structure):
    _fields_ = [
        ("type", c_ubyte),
        ("flags", c_ubyte),
        ("bbox", POINTER(GBOX)),
        ("srid", c_uint),
        ("data", c_void_p),
    ]


def combine_bytes(*args):
    """
    given the bytes of a multi byte number combine into one
    pass them in least to most significant
    """
    ans = 0
    for i, val in enumerate(args):
        ans += (val << i*32)
    return ans

lw = None
lw_path = find_library('lwgeom')
if lw_path:
    lw = CDLL(lw_path)
    print repr(lw)
else:
    print 'Could not find lwgeom library'
    sys.exit()

invalid_wkt = create_string_buffer(
    'POLYGON((-1.19961978542487024 0.83367217371454649,'
    '-1.29389587970096454 0.65017049021286311,'
    '-0.94877803458311938 0.8723927124350852,'
    '-0.87807096387604866 0.65353749357986657,'
    '-1.21645480225988711 0.63838597842835121,'
    '-1.19961978542487024 0.83367217371454649))'
)

invalid_wkb = create_string_buffer(binascii.a2b_hex(
    '01030000000100000006000000b88c2084a431f3bffe0d364471adea3facea7b2accb3f4b'
    'fae3b095832cee43f3053b6c0635ceebf74ad251fa4eaeb3f42462d472819ecbfae543476'
    'c7e9e43f364b8c4f9976f3bf3064726ea86de43fb88c2084a431f3bffe0d364471adea3f'
))
invalid_wkb_size = c_size_t(sizeof(invalid_wkb))
invalid_wkb_p = cast(addressof(invalid_wkb), POINTER(c_ubyte))
# print invalid_wkb_size
# print int(valid_wkb[0:1]) # == b'\x01'
# #
# sys.exit()

LW_PARSER_CHECK_NONE = c_char(chr(0))
WKT_ISO = c_uint8(1)
WKB_HEX = c_uint8(2)

# LWGEOM *lwgeom_from_wkt(const char *wkt,
#                         const char check)
lw.lwgeom_from_wkt.argtypes = [c_char_p, c_char]
lw.lwgeom_from_wkt.restype = POINTER(LWGEOM)

# LWGEOM* lwgeom_from_wkb(const uint8_t *wkb,
#                         const size_t wkb_size,
#                         const char check)
lw.lwgeom_from_wkb.argtypes = [POINTER(c_ubyte), c_size_t, c_char]
lw.lwgeom_from_wkb.restype = POINTER(LWGEOM)

# int lwgeom_ndims(const LWGEOM *geom)
lw.lwgeom_ndims.argtypes = [POINTER(LWGEOM)]
lw.lwgeom_ndims.restype = c_int

# LWGEOM* lwgeom_make_valid(LWGEOM* lwgeom_in)
lw.lwgeom_make_valid.argtypes = [POINTER(LWGEOM)]
lw.lwgeom_make_valid.restype = POINTER(LWGEOM)

# char* lwgeom_to_wkt(const LWGEOM *geom,
#                     uint8_t variant,
#                     int precision,
#                     size_t *size_out)
lw.lwgeom_to_wkt.argtypes = [POINTER(LWGEOM), c_ubyte, c_int, POINTER(c_size_t)]
lw.lwgeom_to_wkt.restype = c_char_p

# char* lwgeom_to_hexwkb(const LWGEOM *geom,
#                        uint8_t variant,
#                        size_t *size_out)
lw.lwgeom_to_hexwkb.argtypes = [POINTER(LWGEOM), c_ubyte, POINTER(c_size_t)]
lw.lwgeom_to_hexwkb.restype = c_char_p

# void lwgeom_free(LWGEOM *lwgeom)
lw.lwgeom_free.argtypes = [POINTER(LWGEOM)]

lwgi_wkt, lwgi_wkb, lwgv_wkt, lwgv_wkb = None, None, None, None

try:
    lwgi_wkt = lw.lwgeom_from_wkt(invalid_wkt, LW_PARSER_CHECK_NONE)
    print 'invalid_wkt: ' + repr(invalid_wkt)
    print 'lwgi_wkt: ' + repr(lwgi_wkt)
    print 'lwgi_wkt dimensions: {0}'.format(lw.lwgeom_ndims(lwgi_wkt))

    lwgi_wkb = lw.lwgeom_from_wkb(invalid_wkb_p, invalid_wkb_size,
                                  LW_PARSER_CHECK_NONE)
    print 'invalid_wkb_p: ' + repr(invalid_wkb_p)
    print 'lwgi_wkb: ' + repr(lwgi_wkb)
    print 'lwgi_wkb dimensions: {0}'.format(lw.lwgeom_ndims(lwgi_wkb))

    lwgv_wkt = lw.lwgeom_make_valid(lwgi_wkt)
    print 'lwgv_wkt: ' + repr(lwgv_wkt)

    lwgv_wkb = lw.lwgeom_make_valid(lwgi_wkb)
    print 'lwgv_wkb: ' + repr(lwgv_wkb)

    lwgv_wkt_size_out = c_size_t()
    lwgv_wkt_out = lw.lwgeom_to_wkt(lwgv_wkt, WKT_ISO, c_int(17),
                                    byref(lwgv_wkt_size_out))
    print 'lwgv_wkt_out: ' + lwgv_wkt_out

    lwgv_wkb_size_out = c_size_t()
    lwgv_wkb_out = lw.lwgeom_to_hexwkb(lwgi_wkb, WKB_HEX,
                                       byref(lwgv_wkb_size_out))
    print 'lwgv_wkb_out: ' + lwgv_wkb_out

finally:
    for lwgeom_obj in [lwgi_wkt, lwgi_wkb, lwgv_wkt, lwgv_wkb]:
        if lwgeom_obj is not None:
            lw.lwgeom_free(lwgeom_obj)
            del lwgeom_obj