PostGIS 3.7.0dev-r@@SVN_REVISION@@
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◆ gserialized2_from_lwgeom()

GSERIALIZED * gserialized2_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 1147 of file gserialized2.c.

1148{
1149 size_t expected_size = 0;
1150 size_t return_size = 0;
1151 uint8_t *ptr = NULL;
1152 GSERIALIZED *g = NULL;
1153 assert(geom);
1154
1155 /*
1156 ** See if we need a bounding box, add one if we don't have one.
1157 */
1158 if ((!geom->bbox) && lwgeom_needs_bbox(geom) && (!lwgeom_is_empty(geom)))
1159 {
1160 lwgeom_add_bbox(geom);
1161 }
1162
1163 /*
1164 ** Harmonize the flags to the state of the lwgeom
1165 */
1166 FLAGS_SET_BBOX(geom->flags, (geom->bbox ? 1 : 0));
1167
1168 /* Set up the uint8_t buffer into which we are going to write the serialized geometry. */
1169 expected_size = gserialized2_from_lwgeom_size(geom);
1170 ptr = lwalloc(expected_size);
1171 g = (GSERIALIZED*)(ptr);
1172
1173 /* Set the SRID! */
1174 gserialized2_set_srid(g, geom->srid);
1175 /*
1176 ** We are aping PgSQL code here, PostGIS code should use
1177 ** VARSIZE to set this for real.
1178 */
1179 LWSIZE_SET(g->size, expected_size);
1180 g->gflags = lwflags_get_g2flags(geom->flags);
1181
1182 /* Move write head past size, srid and flags. */
1183 ptr += 8;
1184
1185 /* Write in the extended flags if necessary */
1186 ptr += gserialized2_from_extended_flags(geom->flags, ptr);
1187
1188 /* Write in the serialized form of the gbox, if necessary. */
1189 if (geom->bbox)
1190 ptr += gserialized2_from_gbox(geom->bbox, ptr);
1191
1192 /* Write in the serialized form of the geometry. */
1193 ptr += gserialized2_from_lwgeom_any(geom, ptr);
1194
1195 /* Calculate size as returned by data processing functions. */
1196 return_size = ptr - (uint8_t*)g;
1197
1198 assert(expected_size == return_size);
1199 if (size) /* Return the output size to the caller if necessary. */
1200 *size = return_size;
1201
1202 return g;
1203}
void gserialized2_set_srid(GSERIALIZED *g, int32_t srid)
Write the SRID into the serialized form (it is packed into three bytes so this is a handy function).
static size_t gserialized2_from_gbox(const GBOX *gbox, uint8_t *buf)
uint8_t lwflags_get_g2flags(lwflags_t lwflags)
static size_t gserialized2_from_lwgeom_any(const LWGEOM *geom, uint8_t *buf)
size_t gserialized2_from_lwgeom_size(const LWGEOM *geom)
Return the memory size a GSERIALIZED will occupy for a given LWGEOM.
static size_t gserialized2_from_extended_flags(lwflags_t lwflags, uint8_t *buf)
#define FLAGS_SET_BBOX(flags, value)
Definition liblwgeom.h:174
int lwgeom_needs_bbox(const LWGEOM *geom)
Check whether or not a lwgeom is big enough to warrant a bounding box.
Definition lwgeom.c:1299
void * lwalloc(size_t size)
Definition lwutil.c:227
#define LWSIZE_SET(varsize, len)
Definition liblwgeom.h:325
void lwgeom_add_bbox(LWGEOM *lwgeom)
Compute a bbox if not already computed.
Definition lwgeom.c:723
static int lwgeom_is_empty(const LWGEOM *geom)
Return true or false depending on whether a geometry is an "empty" geometry (no vertices members)
Definition lwinline.h:199
uint32_t size
Definition liblwgeom.h:444
uint8_t gflags
Definition liblwgeom.h:446
GBOX * bbox
Definition liblwgeom.h:458
int32_t srid
Definition liblwgeom.h:460
lwflags_t flags
Definition liblwgeom.h:461

References LWGEOM::bbox, LWGEOM::flags, FLAGS_SET_BBOX, GSERIALIZED::gflags, gserialized2_from_extended_flags(), gserialized2_from_gbox(), gserialized2_from_lwgeom_any(), gserialized2_from_lwgeom_size(), gserialized2_set_srid(), lwalloc(), lwflags_get_g2flags(), lwgeom_add_bbox(), lwgeom_is_empty(), lwgeom_needs_bbox(), LWSIZE_SET, GSERIALIZED::size, and LWGEOM::srid.

Referenced by gserialized_from_lwgeom(), peek2_point_helper(), test_gserialized2_extended_flags(), test_gserialized2_is_empty(), test_gserialized2_peek_gbox_p_gets_correct_box(), test_gserialized2_peek_gbox_p_no_box_when_empty(), test_lwgeom_from_gserialized2(), and test_on_gser2_lwgeom_count_vertices().

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