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

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

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

     4     check_geom, check_minus_one, check_sized_string, check_string, check_zero

     5 

     6 ### ctypes generation functions ###

     7 def bin_constructor(func):

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

     9     func.argtypes = [c_char_p, c_size_t]

    10     func.restype = GEOM_PTR

    11     func.errcheck = check_geom

    12     return func

    13 

    14 # HEX & WKB output

    15 def bin_output(func):

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

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

    18     func.errcheck = check_sized_string

    19     return func

    20 

    21 def geom_output(func, argtypes):

    22     "For GEOS routines that return a geometry."

    23     if argtypes: func.argtypes = argtypes

    24     func.restype = GEOM_PTR

    25     func.errcheck = check_geom

    26     return func

    27 

    28 def geom_index(func):

    29     "For GEOS routines that return geometries from an index."

    30     return geom_output(func, [GEOM_PTR, c_int])

    31 

    32 def int_from_geom(func, zero=False):

    33     "Argument is a geometry, return type is an integer."

    34     func.argtypes = [GEOM_PTR]

    35     func.restype = c_int

    36     if zero: 

    37         func.errcheck = check_zero

    38     else:

    39         func.errcheck = check_minus_one

    40     return func

    41 

    42 def string_from_geom(func):

    43     "Argument is a Geometry, return type is a string."

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

    45     # address returned from the function.

    46     func.argtypes = [GEOM_PTR]

    47     func.errcheck = check_string

    48     return func

    49 

    50 ### ctypes prototypes ###

    51 

    52 # TODO: Tell all users to use GEOS 3.0.0, instead of the release 

    53 #  candidates, and use the new Reader and Writer APIs (e.g.,

    54 #  GEOSWKT[Reader|Writer], GEOSWKB[Reader|Writer]).  A good time

    55 #  to do this will be when Refractions releases a Windows PostGIS

    56 #  installer using GEOS 3.0.0.

    57 

    58 # Creation routines from WKB, HEX, WKT

    59 from_hex = bin_constructor(lgeos.GEOSGeomFromHEX_buf)

    60 from_wkb = bin_constructor(lgeos.GEOSGeomFromWKB_buf)

    61 from_wkt = geom_output(lgeos.GEOSGeomFromWKT, [c_char_p])

    62 

    63 # Output routines

    64 to_hex = bin_output(lgeos.GEOSGeomToHEX_buf)

    65 to_wkb = bin_output(lgeos.GEOSGeomToWKB_buf)

    66 to_wkt = string_from_geom(lgeos.GEOSGeomToWKT)

    67 

    68 # The GEOS geometry type, typeid, num_coordites and number of geometries

    69 geos_normalize = int_from_geom(lgeos.GEOSNormalize)

    70 geos_type = string_from_geom(lgeos.GEOSGeomType)

    71 geos_typeid = int_from_geom(lgeos.GEOSGeomTypeId)

    72 get_dims = int_from_geom(lgeos.GEOSGeom_getDimensions, zero=True)

    73 get_num_coords = int_from_geom(lgeos.GEOSGetNumCoordinates)

    74 get_num_geoms = int_from_geom(lgeos.GEOSGetNumGeometries)

    75 

    76 # Geometry creation factories

    77 create_point = geom_output(lgeos.GEOSGeom_createPoint, [CS_PTR])

    78 create_linestring = geom_output(lgeos.GEOSGeom_createLineString, [CS_PTR]) 

    79 create_linearring = geom_output(lgeos.GEOSGeom_createLinearRing, [CS_PTR])

    80 

    81 # Polygon and collection creation routines are special and will not

    82 # have their argument types defined.

    83 create_polygon = geom_output(lgeos.GEOSGeom_createPolygon, None)

    84 create_collection = geom_output(lgeos.GEOSGeom_createCollection, None)

    85 

    86 # Ring routines

    87 get_extring = geom_output(lgeos.GEOSGetExteriorRing, [GEOM_PTR])

    88 get_intring = geom_index(lgeos.GEOSGetInteriorRingN)

    89 get_nrings = int_from_geom(lgeos.GEOSGetNumInteriorRings)

    90 

    91 # Collection Routines

    92 get_geomn = geom_index(lgeos.GEOSGetGeometryN)

    93 

    94 # Cloning

    95 geom_clone = lgeos.GEOSGeom_clone

    96 geom_clone.argtypes = [GEOM_PTR]

    97 geom_clone.restype = GEOM_PTR

    98 

    99 # Destruction routine.

   100 destroy_geom = lgeos.GEOSGeom_destroy

   101 destroy_geom.argtypes = [GEOM_PTR]

   102 destroy_geom.restype = None

   103 

   104 # SRID routines

   105 geos_get_srid = lgeos.GEOSGetSRID

   106 geos_get_srid.argtypes = [GEOM_PTR]

   107 geos_get_srid.restype = c_int

   108 

   109 geos_set_srid = lgeos.GEOSSetSRID

   110 geos_set_srid.argtypes = [GEOM_PTR, c_int]

   111 geos_set_srid.restype = None