Datum transform_geom(PG_FUNCTION_ARGS)
{
GSERIALIZED *geom;
GSERIALIZED *result=NULL;
LWGEOM *lwgeom;
projPJ input_pj, output_pj;
char *input_proj4, *output_proj4;
text *input_proj4_text;
text *output_proj4_text;
int32 result_srid ;
char *pj_errstr;
result_srid = PG_GETARG_INT32(3);
if (result_srid == SRID_UNKNOWN)
{
elog(ERROR,"tranform: destination SRID = %d",SRID_UNKNOWN);
PG_RETURN_NULL();
}
geom = (GSERIALIZED *)PG_DETOAST_DATUM_COPY(PG_GETARG_DATUM(0));
if (gserialized_get_srid(geom) == SRID_UNKNOWN)
{
pfree(geom);
elog(ERROR,"transform_geom: source SRID = %d",SRID_UNKNOWN);
PG_RETURN_NULL();
}
/* Set the search path if we haven't already */
SetPROJ4LibPath();
/* Read the arguments */
input_proj4_text = (PG_GETARG_TEXT_P(1));
output_proj4_text = (PG_GETARG_TEXT_P(2));
/* Convert from text to cstring for libproj */
input_proj4 = text2cstring(input_proj4_text);
output_proj4 = text2cstring(output_proj4_text);
/* make input and output projection objects */
input_pj = lwproj_from_string(input_proj4);
if ( input_pj == NULL )
{
pj_errstr = pj_strerrno(*pj_get_errno_ref());
if ( ! pj_errstr ) pj_errstr = "";
/* we need this for error reporting */
/* pfree(input_proj4); */
pfree(output_proj4);
pfree(geom);
elog(ERROR,
"transform_geom: could not parse proj4 string '%s' %s",
input_proj4, pj_errstr);
PG_RETURN_NULL();
}
pfree(input_proj4);
output_pj = lwproj_from_string(output_proj4);
if ( output_pj == NULL )
{
pj_errstr = pj_strerrno(*pj_get_errno_ref());
if ( ! pj_errstr ) pj_errstr = "";
/* we need this for error reporting */
/* pfree(output_proj4); */
pj_free(input_pj);
pfree(geom);
elog(ERROR,
"transform_geom: couldn't parse proj4 output string: '%s': %s",
output_proj4, pj_errstr);
PG_RETURN_NULL();
}
pfree(output_proj4);
/* now we have a geometry, and input/output PJ structs. */
lwgeom = lwgeom_from_gserialized(geom);
lwgeom_transform(lwgeom, input_pj, output_pj);
lwgeom->srid = result_srid;
/* clean up */
pj_free(input_pj);
pj_free(output_pj);
/* Re-compute bbox if input had one (COMPUTE_BBOX TAINTING) */
if ( lwgeom->bbox )
{
lwgeom_drop_bbox(lwgeom);
lwgeom_add_bbox(lwgeom);
}
result = geometry_serialize(lwgeom);
lwgeom_free(lwgeom);
PG_FREE_IF_COPY(geom, 0);
PG_RETURN_POINTER(result); /* new geometry */
}
/**
* Add an entry to the local PROJ4 SRS cache. If we need to wrap around then
* we must make sure the entry we choose to delete does not contain other_srid
* which is the definition for the other half of the transformation.
*/
static void
AddToPROJ4SRSCache(PROJ4PortalCache *PROJ4Cache, int srid, int other_srid)
{
MemoryContext PJMemoryContext;
projPJ projection = NULL;
char *proj_str;
int* pj_errno_ref;
/*
** Turn the SRID number into a proj4 string, by reading from spatial_ref_sys
** or instantiating a magical value from a negative srid.
*/
proj_str = GetProj4String(srid);
if ( ! proj_str )
{
elog(ERROR, "GetProj4String returned NULL for SRID (%d)", srid);
}
projection = lwproj_from_string(proj_str);
pj_errno_ref = pj_get_errno_ref();
if ( (projection == NULL) || (*pj_errno_ref))
{
/* we need this for error reporting */
/*pfree(projection); */
elog(ERROR, "AddToPROJ4SRSCache: couldn't parse proj4 string: '%s': %s", proj_str, pj_strerrno(*pj_errno_ref));
}
/*
* If the cache is already full then find the first entry
* that doesn't contain other_srid and use this as the
* subsequent value of PROJ4SRSCacheCount
*/
if (PROJ4Cache->PROJ4SRSCacheCount == PROJ4_CACHE_ITEMS)
{
bool found = false;
int i;
for (i = 0; i < PROJ4_CACHE_ITEMS; i++)
{
if (PROJ4Cache->PROJ4SRSCache[i].srid != other_srid && found == false)
{
POSTGIS_DEBUGF(3, "choosing to remove item from query cache with SRID %d and index %d", PROJ4Cache->PROJ4SRSCache[i].srid, i);
DeleteFromPROJ4SRSCache(PROJ4Cache, PROJ4Cache->PROJ4SRSCache[i].srid);
PROJ4Cache->PROJ4SRSCacheCount = i;
found = true;
}
}
}
/*
* Now create a memory context for this projection and
* store it in the backend hash
*/
POSTGIS_DEBUGF(3, "adding SRID %d with proj4text \"%s\" to query cache at index %d", srid, proj_str, PROJ4Cache->PROJ4SRSCacheCount);
PJMemoryContext = MemoryContextCreate(T_AllocSetContext, 8192,
&PROJ4SRSCacheContextMethods,
PROJ4Cache->PROJ4SRSCacheContext,
"PostGIS PROJ4 PJ Memory Context");
/* Create the backend hash if it doesn't already exist */
if (!PJHash)
PJHash = CreatePJHash();
/*
* Add the MemoryContext to the backend hash so we can
* clean up upon portal shutdown
*/
POSTGIS_DEBUGF(3, "adding projection object (%p) to hash table with MemoryContext key (%p)", projection, PJMemoryContext);
AddPJHashEntry(PJMemoryContext, projection);
PROJ4Cache->PROJ4SRSCache[PROJ4Cache->PROJ4SRSCacheCount].srid = srid;
PROJ4Cache->PROJ4SRSCache[PROJ4Cache->PROJ4SRSCacheCount].projection = projection;
PROJ4Cache->PROJ4SRSCache[PROJ4Cache->PROJ4SRSCacheCount].projection_mcxt = PJMemoryContext;
PROJ4Cache->PROJ4SRSCacheCount++;
/* Free the projection string */
pfree(proj_str);
}
