geography_as_gml()

Datum geography_as_gml

(

PG_FUNCTION_ARGS

)

Definition at line 204 of file geography_inout.c.

{
        LWGEOM *lwgeom = NULL;
        GSERIALIZED *g = NULL;
        lwvarlena_t *v;
        int version;
        const char *srs;
        int32_t srid = SRID_DEFAULT;
        int precision = -1;
        int option = 0;
        int lwopts = LW_GML_IS_DIMS;
        static const char *default_prefix = "gml:";
        const char *prefix = default_prefix;
        char *prefix_buf = "";
        text *prefix_text, *id_text = NULL;
        const char *id = NULL;
        char *id_buf;
 
        /*
        * Two potential callers, one starts with GML version,
        * one starts with geography, 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 parameters, both callers have same order */
        g = PG_GETARG_GSERIALIZED_P(argnum++);
        precision = PG_GETARG_INT32(argnum++);
        option = PG_GETARG_INT32(argnum++);
        prefix_text = PG_GETARG_TEXT_P(argnum++);
        id_text = PG_GETARG_TEXT_P(argnum++);
 
        /* Convert to lwgeom so we can run the old functions */
        lwgeom = lwgeom_from_gserialized(g);
 
        /* Condition the prefix argument */
        if (VARSIZE_ANY_EXHDR(prefix_text) > 0)
        {
                /* +2 is one for the ':' and one for term null */
                prefix_buf = palloc(VARSIZE_ANY_EXHDR(prefix_text)+2);
                memcpy(prefix_buf, VARDATA_ANY(prefix_text),
                       VARSIZE_ANY_EXHDR(prefix_text));
                /* add colon and null terminate */
                prefix_buf[VARSIZE_ANY_EXHDR(prefix_text)] = ':';
                prefix_buf[VARSIZE_ANY_EXHDR(prefix_text)+1] = '\0';
                prefix = prefix_buf;
        }
        else
        {
                prefix = "";
        }
 
        if (VARSIZE_ANY_EXHDR(id_text) > 0)
        {
                id_buf = palloc(VARSIZE_ANY_EXHDR(id_text)+2);
                memcpy(id_buf, VARDATA(id_text), VARSIZE_ANY_EXHDR(id_text));
                id_buf[VARSIZE_ANY_EXHDR(id_text)+1] = '\0';
                id = id_buf;
        }
 
        if (option & 1)
                srs = GetSRSCacheBySRID(fcinfo, srid, false);
        else
                srs = GetSRSCacheBySRID(fcinfo, srid, true);
        if (!srs)
        {
                elog(ERROR, "SRID %d unknown in spatial_ref_sys table", SRID_DEFAULT);
                PG_RETURN_NULL();
        }
 
        /* Revert lat/lon only with long SRS */
        if (option & 1) lwopts |= LW_GML_IS_DEGREE;
        if (option & 2) lwopts &= ~LW_GML_IS_DIMS;
        if (option & 8)
        {
                elog(ERROR,
                     "Options %d passed to ST_AsGML(geography) sets "
                     "unsupported value 8",
                     option);
                PG_RETURN_NULL();
        }
        if ((option & 4) || (option & 16) || (option & 32))
        {
                elog(ERROR,
                     "Options %d passed to ST_AsGML(geography) but are only "
                     "applicable to ST_AsGML(geometry)",
                     option);
                PG_RETURN_NULL();
        }
 
        if (version == 2)
                v = lwgeom_to_gml2(lwgeom, srs, precision, prefix);
        else
                v = lwgeom_to_gml3(lwgeom, srs, precision, lwopts, prefix, id);
 
        if (!v)
                PG_RETURN_NULL();
        else
                PG_RETURN_TEXT_P(v);
}

References LW_GML_IS_DEGREE, LW_GML_IS_DIMS, lwgeom_from_gserialized(), lwgeom_to_gml2(), lwgeom_to_gml3(), precision, and SRID_DEFAULT.

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