PostGIS  2.5.0dev-r@@SVN_REVISION@@
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 1174 of file g_serialized.c.

References LWGEOM::bbox, GSERIALIZED::flags, LWGEOM::flags, FLAGS_SET_BBOX, gserialized_from_gbox(), gserialized_from_lwgeom_any(), gserialized_from_lwgeom_size(), gserialized_set_srid(), lwalloc(), lwerror(), lwgeom_add_bbox(), 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().

1175 {
1176  size_t expected_size = 0;
1177  size_t return_size = 0;
1178  uint8_t *serialized = NULL;
1179  uint8_t *ptr = NULL;
1180  GSERIALIZED *g = NULL;
1181  assert(geom);
1182 
1183  /*
1184  ** See if we need a bounding box, add one if we don't have one.
1185  */
1186  if ( (! geom->bbox) && lwgeom_needs_bbox(geom) && (!lwgeom_is_empty(geom)) )
1187  {
1188  lwgeom_add_bbox(geom);
1189  }
1190 
1191  /*
1192  ** Harmonize the flags to the state of the lwgeom
1193  */
1194  if ( geom->bbox )
1195  FLAGS_SET_BBOX(geom->flags, 1);
1196 
1197  /* Set up the uint8_t buffer into which we are going to write the serialized geometry. */
1198  expected_size = gserialized_from_lwgeom_size(geom);
1199  serialized = lwalloc(expected_size);
1200  ptr = serialized;
1201 
1202  /* Move past size, srid and flags. */
1203  ptr += 8;
1204 
1205  /* Write in the serialized form of the gbox, if necessary. */
1206  if ( geom->bbox )
1207  ptr += gserialized_from_gbox(geom->bbox, ptr);
1208 
1209  /* Write in the serialized form of the geometry. */
1210  ptr += gserialized_from_lwgeom_any(geom, ptr);
1211 
1212  /* Calculate size as returned by data processing functions. */
1213  return_size = ptr - serialized;
1214 
1215  if ( expected_size != return_size ) /* Uh oh! */
1216  {
1217  lwerror("Return size (%d) not equal to expected size (%d)!", return_size, expected_size);
1218  return NULL;
1219  }
1220 
1221  if ( size ) /* Return the output size to the caller if necessary. */
1222  *size = return_size;
1223 
1224  g = (GSERIALIZED*)serialized;
1225 
1226  /*
1227  ** We are aping PgSQL code here, PostGIS code should use
1228  ** VARSIZE to set this for real.
1229  */
1230  g->size = return_size << 2;
1231 
1232  /* Set the SRID! */
1233  gserialized_set_srid(g, geom->srid);
1234 
1235  g->flags = geom->flags;
1236 
1237  return g;
1238 }
GBOX * bbox
Definition: liblwgeom.h:397
uint8_t flags
Definition: liblwgeom.h:396
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:116
int32_t srid
Definition: liblwgeom.h:398
#define FLAGS_SET_BBOX(flags, value)
Definition: liblwgeom.h:147
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:807
uint32_t size
Definition: liblwgeom.h:380
void lwgeom_add_bbox(LWGEOM *lwgeom)
Compute a bbox if not already computed.
Definition: lwgeom.c:679
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:1386
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:1190
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:190
uint8_t flags
Definition: liblwgeom.h:382

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