PostGIS  2.5.2dev-r@@SVN_REVISION@@

◆ gserialized_from_lwgeom()

GSERIALIZED* gserialized_from_lwgeom ( LWGEOM geom,
size_t *  size 
)

Allocate a new GSERIALIZED from an LWGEOM.

For all non-point types, a bounding box will be calculated and embedded in the serialization. The geodetic flag is used to control the box calculation (cartesian or geocentric). If set, the size pointer will contain the size of the final output, which is useful for setting the PgSQL VARSIZE information.

Definition at line 1175 of file g_serialized.c.

References LWGEOM::bbox, GSERIALIZED::flags, LWGEOM::flags, FLAGS_SET_BBOX, genraster::g_size, gserialized_from_gbox(), gserialized_from_lwgeom_any(), gserialized_from_lwgeom_size(), gserialized_set_srid(), lwalloc(), lwerror(), lwgeom_add_bbox(), lwgeom_from_gserialized_buffer(), lwgeom_is_empty(), lwgeom_needs_bbox(), GSERIALIZED::size, and LWGEOM::srid.

Referenced by cluster_within_distance_garray(), geography_centroid(), geography_point_outside(), LWGEOM_dumppoints(), lwgeom_over_gserialized(), polyhedralsurface_parse(), RASTER_convex_hull(), RASTER_dumpAsPolygons(), RASTER_envelope(), RASTER_getPixelPolygons(), ST_GeneratePoints(), ST_OffsetCurve(), test_gbox_same_2d(), test_gserialized_from_lwgeom(), test_gserialized_is_empty(), test_gserialized_peek_gbox_p_gets_correct_box(), test_gserialized_peek_gbox_p_no_box_when_empty(), test_lwgeom_from_gserialized(), test_on_gser_lwgeom_count_vertices(), tin_parse(), and triangle_parse().

1176 {
1177  size_t expected_size = 0;
1178  size_t return_size = 0;
1179  uint8_t *serialized = NULL;
1180  uint8_t *ptr = NULL;
1181  GSERIALIZED *g = NULL;
1182  assert(geom);
1183 
1184  /*
1185  ** See if we need a bounding box, add one if we don't have one.
1186  */
1187  if ( (! geom->bbox) && lwgeom_needs_bbox(geom) && (!lwgeom_is_empty(geom)) )
1188  {
1189  lwgeom_add_bbox(geom);
1190  }
1191 
1192  /*
1193  ** Harmonize the flags to the state of the lwgeom
1194  */
1195  if ( geom->bbox )
1196  FLAGS_SET_BBOX(geom->flags, 1);
1197  else
1198  FLAGS_SET_BBOX(geom->flags, 0);
1199 
1200  /* Set up the uint8_t buffer into which we are going to write the serialized geometry. */
1201  expected_size = gserialized_from_lwgeom_size(geom);
1202  serialized = lwalloc(expected_size);
1203  ptr = serialized;
1204 
1205  /* Move past size, srid and flags. */
1206  ptr += 8;
1207 
1208  /* Write in the serialized form of the gbox, if necessary. */
1209  if ( geom->bbox )
1210  ptr += gserialized_from_gbox(geom->bbox, ptr);
1211 
1212  /* Write in the serialized form of the geometry. */
1213  ptr += gserialized_from_lwgeom_any(geom, ptr);
1214 
1215  /* Calculate size as returned by data processing functions. */
1216  return_size = ptr - serialized;
1217 
1218  if ( expected_size != return_size ) /* Uh oh! */
1219  {
1220  lwerror("Return size (%d) not equal to expected size (%d)!", return_size, expected_size);
1221  return NULL;
1222  }
1223 
1224  if ( size ) /* Return the output size to the caller if necessary. */
1225  *size = return_size;
1226 
1227  g = (GSERIALIZED*)serialized;
1228 
1229  /*
1230  ** We are aping PgSQL code here, PostGIS code should use
1231  ** VARSIZE to set this for real.
1232  */
1233  g->size = return_size << 2;
1234 
1235  /* Set the SRID! */
1236  gserialized_set_srid(g, geom->srid);
1237 
1238  g->flags = geom->flags;
1239 
1240  return g;
1241 }
GBOX * bbox
Definition: liblwgeom.h:401
uint8_t flags
Definition: liblwgeom.h:400
static size_t gserialized_from_gbox(const GBOX *gbox, uint8_t *buf)
void gserialized_set_srid(GSERIALIZED *s, int32_t srid)
Write the SRID into the serialized form (it is packed into three bytes so this is a handy function)...
Definition: g_serialized.c:117
int32_t srid
Definition: liblwgeom.h:402
#define FLAGS_SET_BBOX(flags, value)
Definition: liblwgeom.h:148
size_t gserialized_from_lwgeom_size(const LWGEOM *geom)
Calculate required memory segment to contain a serialized form of the LWGEOM.
Definition: g_serialized.c:808
uint32_t size
Definition: liblwgeom.h:384
void lwgeom_add_bbox(LWGEOM *lwgeom)
Compute a bbox if not already computed.
Definition: lwgeom.c:686
static size_t gserialized_from_lwgeom_any(const LWGEOM *geom, uint8_t *buf)
void * lwalloc(size_t size)
Definition: lwutil.c:229
int lwgeom_is_empty(const LWGEOM *geom)
Return true or false depending on whether a geometry is an "empty" geometry (no vertices members) ...
Definition: lwgeom.c:1393
unsigned char uint8_t
Definition: uthash.h:79
int lwgeom_needs_bbox(const LWGEOM *geom)
Check whether or not a lwgeom is big enough to warrant a bounding box.
Definition: lwgeom.c:1197
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:190
uint8_t flags
Definition: liblwgeom.h:386
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