LWGEOM_asGML()

Datum LWGEOM_asGML

(

PG_FUNCTION_ARGS

)

Definition at line 56 of file lwgeom_export.c.

{
        GSERIALIZED *geom;
        LWGEOM *lwgeom;
        lwvarlena_t *v = NULL;
        int version;
        const char *srs;
        int32_t srid;
        int option = 0;
        int lwopts = LW_GML_IS_DIMS;
        int precision = OUT_DEFAULT_DECIMAL_DIGITS;
        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;
 
        /*
         * Two potential callers, one starts with GML version,
         * one starts with geometry, and we check for initial
         * argument type and then dynamically change what args
         * we read based on presence/absence
         */
        Oid first_type = get_fn_expr_argtype(fcinfo->flinfo, 0);
        int argnum = 0;
        if (first_type != INT4OID)
        {
                version = 2;
        }
        else
        {
                /* Get the version */
                version = PG_GETARG_INT32(argnum++);
                if (version != 2 && version != 3)
                {
                        elog(ERROR, "Only GML 2 and GML 3 are supported");
                        PG_RETURN_NULL();
                }
        }
 
        /* Get the geometry */
        if (PG_ARGISNULL(argnum))
                PG_RETURN_NULL();
        geom = PG_GETARG_GSERIALIZED_P(argnum++);
 
        /* Retrieve precision if any (default is max) */
        if (PG_NARGS() > argnum && !PG_ARGISNULL(argnum))
        {
                precision = PG_GETARG_INT32(argnum);
        }
        argnum++;
 
        /* retrieve option */
        if (PG_NARGS() > argnum && !PG_ARGISNULL(argnum))
                option = PG_GETARG_INT32(argnum);
        argnum++;
 
        /* retrieve prefix */
        if (PG_NARGS() > argnum && !PG_ARGISNULL(argnum))
        {
                prefix_text = PG_GETARG_TEXT_P(argnum);
                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;
                }
        }
        argnum++;
 
        if (PG_NARGS() > argnum && !PG_ARGISNULL(argnum))
        {
                gml_id_text = PG_GETARG_TEXT_P(argnum);
                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;
                }
        }
        argnum++;
 
        srid = gserialized_get_srid(geom);
        if (srid == SRID_UNKNOWN)      srs = NULL;
        else if (option & 1)
                srs = GetSRSCacheBySRID(fcinfo, srid, false);
        else
                srs = GetSRSCacheBySRID(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(geometry) 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)
                        v = lwgeom_extent_to_gml2(lwgeom, srs, precision, prefix);
                else
                        v = lwgeom_to_gml2(lwgeom, srs, precision, prefix);
        }
        if (version == 3)
        {
                if (lwopts & LW_GML_EXTENT)
                        v = lwgeom_extent_to_gml3(lwgeom, srs, precision, lwopts, prefix);
                else
                        v = lwgeom_to_gml3(lwgeom, srs, precision, lwopts, prefix, gml_id);
        }
 
        if (!v)
                PG_RETURN_NULL();
        PG_RETURN_TEXT_P(v);
}

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

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