text: from ctypes import POINTER, c_char_p, c_double, c_int, c_void_p
  
  from django.contrib.gis.gdal.envelope import OGREnvelope
  from django.contrib.gis.gdal.libgdal import lgdal
  from django.contrib.gis.gdal.prototypes.errcheck import check_envelope
  from django.contrib.gis.gdal.prototypes.generation import (
      const_string_output, double_output, geom_output, int_output, srs_output,
      string_output, void_output,
  )
  
  
  # ### Generation routines specific to this module ###
  def env_func(f, argtypes):
      "For getting OGREnvelopes."
      f.argtypes = argtypes
      f.restype = None
      f.errcheck = check_envelope
      return f
  
  
  def pnt_func(f):
      "For accessing point information."
      return double_output(f, [c_void_p, c_int])
  
  
  def topology_func(f):
      f.argtypes = [c_void_p, c_void_p]
      f.restype = c_int
      f.errcheck = lambda result, func, cargs: bool(result)
      return f
  
  # ### OGR_G ctypes function prototypes ###
  
  # GeoJSON routines.
  from_json = geom_output(lgdal.OGR_G_CreateGeometryFromJson, [c_char_p])
  to_json = string_output(lgdal.OGR_G_ExportToJson, [c_void_p], str_result=True, decoding='ascii')
  to_kml = string_output(lgdal.OGR_G_ExportToKML, [c_void_p, c_char_p], str_result=True, decoding='ascii')
  
  # GetX, GetY, GetZ all return doubles.
  getx = pnt_func(lgdal.OGR_G_GetX)
  gety = pnt_func(lgdal.OGR_G_GetY)
  getz = pnt_func(lgdal.OGR_G_GetZ)
  
  # Geometry creation routines.
  from_wkb = geom_output(lgdal.OGR_G_CreateFromWkb, [c_char_p, c_void_p, POINTER(c_void_p), c_int], offset=-2)
  from_wkt = geom_output(lgdal.OGR_G_CreateFromWkt, [POINTER(c_char_p), c_void_p, POINTER(c_void_p)], offset=-1)
  create_geom = geom_output(lgdal.OGR_G_CreateGeometry, [c_int])
  clone_geom = geom_output(lgdal.OGR_G_Clone, [c_void_p])
  get_geom_ref = geom_output(lgdal.OGR_G_GetGeometryRef, [c_void_p, c_int])
  get_boundary = geom_output(lgdal.OGR_G_GetBoundary, [c_void_p])
  geom_convex_hull = geom_output(lgdal.OGR_G_ConvexHull, [c_void_p])
  geom_diff = geom_output(lgdal.OGR_G_Difference, [c_void_p, c_void_p])
  geom_intersection = geom_output(lgdal.OGR_G_Intersection, [c_void_p, c_void_p])
  geom_sym_diff = geom_output(lgdal.OGR_G_SymmetricDifference, [c_void_p, c_void_p])
  geom_union = geom_output(lgdal.OGR_G_Union, [c_void_p, c_void_p])
  
  # Geometry modification routines.
  add_geom = void_output(lgdal.OGR_G_AddGeometry, [c_void_p, c_void_p])
  import_wkt = void_output(lgdal.OGR_G_ImportFromWkt, [c_void_p, POINTER(c_char_p)])
  
  # Destroys a geometry
  destroy_geom = void_output(lgdal.OGR_G_DestroyGeometry, [c_void_p], errcheck=False)
  
  # Geometry export routines.
  to_wkb = void_output(lgdal.OGR_G_ExportToWkb, None, errcheck=True)  # special handling for WKB.
  to_wkt = string_output(lgdal.OGR_G_ExportToWkt, [c_void_p, POINTER(c_char_p)], decoding='ascii')
  to_gml = string_output(lgdal.OGR_G_ExportToGML, [c_void_p], str_result=True, decoding='ascii')
  get_wkbsize = int_output(lgdal.OGR_G_WkbSize, [c_void_p])
  
  # Geometry spatial-reference related routines.
  assign_srs = void_output(lgdal.OGR_G_AssignSpatialReference, [c_void_p, c_void_p], errcheck=False)
  get_geom_srs = srs_output(lgdal.OGR_G_GetSpatialReference, [c_void_p])
  
  # Geometry properties
  get_area = double_output(lgdal.OGR_G_GetArea, [c_void_p])
  get_centroid = void_output(lgdal.OGR_G_Centroid, [c_void_p, c_void_p])
  get_dims = int_output(lgdal.OGR_G_GetDimension, [c_void_p])
  get_coord_dim = int_output(lgdal.OGR_G_GetCoordinateDimension, [c_void_p])
  set_coord_dim = void_output(lgdal.OGR_G_SetCoordinateDimension, [c_void_p, c_int], errcheck=False)
  
  get_geom_count = int_output(lgdal.OGR_G_GetGeometryCount, [c_void_p])
  get_geom_name = const_string_output(lgdal.OGR_G_GetGeometryName, [c_void_p], decoding='ascii')
  get_geom_type = int_output(lgdal.OGR_G_GetGeometryType, [c_void_p])
  get_point_count = int_output(lgdal.OGR_G_GetPointCount, [c_void_p])
  get_point = void_output(lgdal.OGR_G_GetPoint,
      [c_void_p, c_int, POINTER(c_double), POINTER(c_double), POINTER(c_double)], errcheck=False
  )
  geom_close_rings = void_output(lgdal.OGR_G_CloseRings, [c_void_p], errcheck=False)
  
  # Topology routines.
  ogr_contains = topology_func(lgdal.OGR_G_Contains)
  ogr_crosses = topology_func(lgdal.OGR_G_Crosses)
  ogr_disjoint = topology_func(lgdal.OGR_G_Disjoint)
  ogr_equals = topology_func(lgdal.OGR_G_Equals)
  ogr_intersects = topology_func(lgdal.OGR_G_Intersects)
  ogr_overlaps = topology_func(lgdal.OGR_G_Overlaps)
  ogr_touches = topology_func(lgdal.OGR_G_Touches)
  ogr_within = topology_func(lgdal.OGR_G_Within)
  
  # Transformation routines.
  geom_transform = void_output(lgdal.OGR_G_Transform, [c_void_p, c_void_p])
  geom_transform_to = void_output(lgdal.OGR_G_TransformTo, [c_void_p, c_void_p])
  
  # For retrieving the envelope of the geometry.
  get_envelope = env_func(lgdal.OGR_G_GetEnvelope, [c_void_p, POINTER(OGREnvelope)])
  