LWGEOM_asGML()

Datum LWGEOM_asGML

(

PG_FUNCTION_ARGS

)

Definition at line 209 of file lwgeom_export.c.

{
        GSERIALIZED *geom;
        LWGEOM *lwgeom;
        char *gml = NULL;
        text *result;
        int version;
        char *srs;
        int32_t srid;
        int option = 0;
        int lwopts = LW_GML_IS_DIMS;
        int precision = DBL_DIG;
        static const char* default_prefix = "gml:"; /* default prefix */
        const char* prefix = default_prefix;
        const char* gml_id = NULL;
        size_t len;
        char *gml_id_buf, *prefix_buf;
        text *prefix_text, *gml_id_text;
 
 
        /* Get the version */
        version = PG_GETARG_INT32(0);
        if ( version != 2 && version != 3 )
        {
                elog(ERROR, "Only GML 2 and GML 3 are supported");
                PG_RETURN_NULL();
        }
 
        /* Get the geometry */
        if ( PG_ARGISNULL(1) ) PG_RETURN_NULL();
        geom = PG_GETARG_GSERIALIZED_P(1);
 
        /* Retrieve precision if any (default is max) */
        if (PG_NARGS() > 2 && !PG_ARGISNULL(2))
        {
                precision = PG_GETARG_INT32(2);
                /* TODO: leave this to liblwgeom ? */
                if (precision > DBL_DIG)
                        precision = DBL_DIG;
                else if (precision < 0)
                        precision = 0;
        }
 
        /* retrieve option */
        if (PG_NARGS() > 3 && !PG_ARGISNULL(3)) option = PG_GETARG_INT32(3);
 
        /* retrieve prefix */
        if (PG_NARGS() >4 && !PG_ARGISNULL(4))
        {
                prefix_text = PG_GETARG_TEXT_P(4);
                if ( VARSIZE(prefix_text) == VARHDRSZ )
                {
                        prefix = "";
                }
                else
                {
                        len = VARSIZE_ANY_EXHDR(prefix_text);
                        prefix_buf = palloc(len + 2); /* +2 is one for the ':' and one for term null */
                        memcpy(prefix_buf, VARDATA(prefix_text), len);
                        /* add colon and null terminate */
                        prefix_buf[len] = ':';
                        prefix_buf[len+1] = '\0';
                        prefix = prefix_buf;
                }
        }
 
        if (PG_NARGS() >5 && !PG_ARGISNULL(5))
        {
                gml_id_text = PG_GETARG_TEXT_P(5);
                if ( VARSIZE(gml_id_text) == VARHDRSZ )
                {
                        gml_id = "";
                }
                else
                {
                        len = VARSIZE_ANY_EXHDR(gml_id_text);
                        gml_id_buf = palloc(len+1);
                        memcpy(gml_id_buf, VARDATA(gml_id_text), len);
                        gml_id_buf[len] = '\0';
                        gml_id = gml_id_buf;
                }
        }
 
        srid = gserialized_get_srid(geom);
        if (srid == SRID_UNKNOWN)      srs = NULL;
        else if (option & 1)
                srs = getSRSbySRID(fcinfo, srid, false);
        else
                srs = getSRSbySRID(fcinfo, srid, true);
 
        if (option & 2) lwopts &= ~LW_GML_IS_DIMS;
        if (option & 4) lwopts |= LW_GML_SHORTLINE;
        if (option & 8)
        {
                elog(ERROR,
                     "Options %d passed to ST_AsGML(geography) sets "
                     "unsupported value 8",
                     option);
                PG_RETURN_NULL();
        }
        if (option & 16) lwopts |= LW_GML_IS_DEGREE;
        if (option & 32) lwopts |= LW_GML_EXTENT;
 
        lwgeom = lwgeom_from_gserialized(geom);
 
        if (version == 2)
        {
                if (lwopts & LW_GML_EXTENT)
                        gml = lwgeom_extent_to_gml2(
                            lwgeom, srs, precision, prefix);
                else
                        gml = lwgeom_to_gml2(lwgeom, srs, precision, prefix);
        }
        if (version == 3)
        {
                if (lwopts & LW_GML_EXTENT)
                        gml = lwgeom_extent_to_gml3(
                            lwgeom, srs, precision, lwopts, prefix);
                else
                        gml = lwgeom_to_gml3(
                            lwgeom, srs, precision, lwopts, prefix, gml_id);
        }
 
        lwgeom_free(lwgeom);
        PG_FREE_IF_COPY(geom, 1);
 
        /* Return null on null */
        if ( ! gml )
                PG_RETURN_NULL();
 
        result = cstring_to_text(gml);
        lwfree(gml);
        PG_RETURN_TEXT_P(result);
}

References getSRSbySRID(), gserialized_get_srid(), LW_GML_EXTENT, LW_GML_IS_DEGREE, LW_GML_IS_DIMS, LW_GML_SHORTLINE, lwfree(), lwgeom_extent_to_gml2(), lwgeom_extent_to_gml3(), lwgeom_free(), lwgeom_from_gserialized(), lwgeom_to_gml2(), lwgeom_to_gml3(), precision, and SRID_UNKNOWN.

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