lwout_wkt.c

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/**********************************************************************
 *
 * PostGIS - Spatial Types for PostgreSQL
 * http://postgis.net
 *
 * PostGIS is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * PostGIS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with PostGIS.  If not, see <http://www.gnu.org/licenses/>.
 *
 **********************************************************************
 *
 * Copyright (C) 2009 Paul Ramsey <pramsey@cleverelephant.ca>
 *
 **********************************************************************/
 
 
#include "liblwgeom_internal.h"
#include "lwgeom_log.h"
#include "stringbuffer.h"
 
static void lwgeom_to_wkt_sb(const LWGEOM *geom, stringbuffer_t *sb, int precision, uint8_t variant);
 
 
/*
* ISO format uses both Z and M qualifiers.
* Extended format only uses an M qualifier for 3DM variants, where it is not
* clear what the third dimension represents.
* SFSQL format never has more than two dimensions, so no qualifiers.
*/
static void dimension_qualifiers_to_wkt_sb(const LWGEOM *geom, stringbuffer_t *sb, uint8_t variant)
{
 
        /* Extended WKT: POINTM(0 0 0) */
#if 0
        if ( (variant & WKT_EXTENDED) && ! (variant & WKT_IS_CHILD) && FLAGS_GET_M(geom->flags) && (!FLAGS_GET_Z(geom->flags)) )
#else
        if ( (variant & WKT_EXTENDED) && FLAGS_GET_M(geom->flags) && (!FLAGS_GET_Z(geom->flags)) )
#endif
        {
                stringbuffer_append(sb, "M"); /* "M" */
                return;
        }
 
        /* ISO WKT: POINT ZM (0 0 0 0) */
        if ( (variant & WKT_ISO) && (FLAGS_NDIMS(geom->flags) > 2) )
        {
                stringbuffer_append(sb, " ");
                if ( FLAGS_GET_Z(geom->flags) )
                        stringbuffer_append(sb, "Z");
                if ( FLAGS_GET_M(geom->flags) )
                        stringbuffer_append(sb, "M");
                stringbuffer_append(sb, " ");
        }
}
 
/*
* Write an empty token out, padding with a space if
* necessary.
*/
static void empty_to_wkt_sb(stringbuffer_t *sb)
{
        if ( ! strchr(" ,(", stringbuffer_lastchar(sb)) ) /* "EMPTY" */
        {
                stringbuffer_append(sb, " ");
        }
        stringbuffer_append(sb, "EMPTY");
}
 
/*
* Point array is a list of coordinates. Depending on output mode,
* we may suppress some dimensions. ISO and Extended formats include
* all dimensions. Standard OGC output only includes X/Y coordinates.
*/
static void ptarray_to_wkt_sb(const POINTARRAY *ptarray, stringbuffer_t *sb, int precision, uint8_t variant)
{
        /* OGC only includes X/Y */
        uint32_t dimensions = 2;
        uint32_t i, j;
        static size_t buffer_size = 128;
        char coord[buffer_size];
 
        /* ISO and extended formats include all dimensions */
        if ( variant & ( WKT_ISO | WKT_EXTENDED ) )
                dimensions = FLAGS_NDIMS(ptarray->flags);
 
        /* Opening paren? */
        if ( ! (variant & WKT_NO_PARENS) )
                stringbuffer_append(sb, "(");
 
        /* Digits and commas */
        for (i = 0; i < ptarray->npoints; i++)
        {
                double *dbl_ptr = (double*)getPoint_internal(ptarray, i);
 
                /* Commas before ever coord but the first */
                if ( i > 0 )
                        stringbuffer_append(sb, ",");
 
                for (j = 0; j < dimensions; j++)
                {
                        /* Spaces before every ordinate but the first */
                        if ( j > 0 )
                                stringbuffer_append(sb, " ");
                        lwprint_double(dbl_ptr[j],
                                       precision,
                                       coord,
                                       buffer_size);
                        stringbuffer_append(sb, coord);
                }
        }
 
        /* Closing paren? */
        if ( ! (variant & WKT_NO_PARENS) )
                stringbuffer_append(sb, ")");
}
 
/*
* A four-dimensional point will have different outputs depending on variant.
*   ISO: POINT ZM (0 0 0 0)
*   Extended: POINT(0 0 0 0)
*   OGC: POINT(0 0)
* A three-dimensional m-point will have different outputs too.
*   ISO: POINT M (0 0 0)
*   Extended: POINTM(0 0 0)
*   OGC: POINT(0 0)
*/
static void lwpoint_to_wkt_sb(const LWPOINT *pt, stringbuffer_t *sb, int precision, uint8_t variant)
{
        if ( ! (variant & WKT_NO_TYPE) )
        {
                stringbuffer_append(sb, "POINT"); /* "POINT" */
                dimension_qualifiers_to_wkt_sb((LWGEOM*)pt, sb, variant);
        }
 
        if ( lwpoint_is_empty(pt) )
        {
                empty_to_wkt_sb(sb);
                return;
        }
 
        ptarray_to_wkt_sb(pt->point, sb, precision, variant);
}
 
/*
* LINESTRING(0 0 0, 1 1 1)
*/
static void lwline_to_wkt_sb(const LWLINE *line, stringbuffer_t *sb, int precision, uint8_t variant)
{
        if ( ! (variant & WKT_NO_TYPE) )
        {
                stringbuffer_append(sb, "LINESTRING"); /* "LINESTRING" */
                dimension_qualifiers_to_wkt_sb((LWGEOM*)line, sb, variant);
        }
        if ( lwline_is_empty(line) )
        {
                empty_to_wkt_sb(sb);
                return;
        }
 
    ptarray_to_wkt_sb(line->points, sb, precision, variant);
}
 
/*
* POLYGON(0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)
*/
static void lwpoly_to_wkt_sb(const LWPOLY *poly, stringbuffer_t *sb, int precision, uint8_t variant)
{
        uint32_t i = 0;
        if ( ! (variant & WKT_NO_TYPE) )
        {
                stringbuffer_append(sb, "POLYGON"); /* "POLYGON" */
                dimension_qualifiers_to_wkt_sb((LWGEOM*)poly, sb, variant);
        }
        if ( lwpoly_is_empty(poly) )
        {
                empty_to_wkt_sb(sb);
                return;
        }
 
        stringbuffer_append(sb, "(");
        for ( i = 0; i < poly->nrings; i++ )
        {
                if ( i > 0 )
                        stringbuffer_append(sb, ",");
                ptarray_to_wkt_sb(poly->rings[i], sb, precision, variant);
        }
        stringbuffer_append(sb, ")");
}
 
/*
* CIRCULARSTRING
*/
static void lwcircstring_to_wkt_sb(const LWCIRCSTRING *circ, stringbuffer_t *sb, int precision, uint8_t variant)
{
        if ( ! (variant & WKT_NO_TYPE) )
        {
                stringbuffer_append(sb, "CIRCULARSTRING"); /* "CIRCULARSTRING" */
                dimension_qualifiers_to_wkt_sb((LWGEOM*)circ, sb, variant);
        }
        if ( lwcircstring_is_empty(circ) )
        {
                empty_to_wkt_sb(sb);
                return;
        }
        ptarray_to_wkt_sb(circ->points, sb, precision, variant);
}
 
 
/*
* Multi-points do not wrap their sub-members in parens, unlike other multi-geometries.
*   MULTPOINT(0 0, 1 1) instead of MULTIPOINT((0 0),(1 1))
*/
static void lwmpoint_to_wkt_sb(const LWMPOINT *mpoint, stringbuffer_t *sb, int precision, uint8_t variant)
{
        uint32_t i = 0;
        if ( ! (variant & WKT_NO_TYPE) )
        {
                stringbuffer_append(sb, "MULTIPOINT"); /* "MULTIPOINT" */
                dimension_qualifiers_to_wkt_sb((LWGEOM*)mpoint, sb, variant);
        }
        if ( mpoint->ngeoms < 1 )
        {
                empty_to_wkt_sb(sb);
                return;
        }
        stringbuffer_append(sb, "(");
        variant = variant | WKT_IS_CHILD; /* Inform the sub-geometries they are childre */
        for ( i = 0; i < mpoint->ngeoms; i++ )
        {
                if ( i > 0 )
                        stringbuffer_append(sb, ",");
                /* We don't want type strings or parens on our subgeoms */
                lwpoint_to_wkt_sb(mpoint->geoms[i], sb, precision, variant | WKT_NO_PARENS | WKT_NO_TYPE );
        }
        stringbuffer_append(sb, ")");
}
 
/*
* MULTILINESTRING
*/
static void lwmline_to_wkt_sb(const LWMLINE *mline, stringbuffer_t *sb, int precision, uint8_t variant)
{
        uint32_t i = 0;
 
        if ( ! (variant & WKT_NO_TYPE) )
        {
                stringbuffer_append(sb, "MULTILINESTRING"); /* "MULTILINESTRING" */
                dimension_qualifiers_to_wkt_sb((LWGEOM*)mline, sb, variant);
        }
        if ( mline->ngeoms < 1 )
        {
                empty_to_wkt_sb(sb);
                return;
        }
 
        stringbuffer_append(sb, "(");
        variant = variant | WKT_IS_CHILD; /* Inform the sub-geometries they are childre */
        for ( i = 0; i < mline->ngeoms; i++ )
        {
                if ( i > 0 )
                        stringbuffer_append(sb, ",");
                /* We don't want type strings on our subgeoms */
                lwline_to_wkt_sb(mline->geoms[i], sb, precision, variant | WKT_NO_TYPE );
        }
        stringbuffer_append(sb, ")");
}
 
/*
* MULTIPOLYGON
*/
static void lwmpoly_to_wkt_sb(const LWMPOLY *mpoly, stringbuffer_t *sb, int precision, uint8_t variant)
{
        uint32_t i = 0;
 
        if ( ! (variant & WKT_NO_TYPE) )
        {
                stringbuffer_append(sb, "MULTIPOLYGON"); /* "MULTIPOLYGON" */
                dimension_qualifiers_to_wkt_sb((LWGEOM*)mpoly, sb, variant);
        }
        if ( mpoly->ngeoms < 1 )
        {
                empty_to_wkt_sb(sb);
                return;
        }
 
        stringbuffer_append(sb, "(");
        variant = variant | WKT_IS_CHILD; /* Inform the sub-geometries they are childre */
        for ( i = 0; i < mpoly->ngeoms; i++ )
        {
                if ( i > 0 )
                        stringbuffer_append(sb, ",");
                /* We don't want type strings on our subgeoms */
                lwpoly_to_wkt_sb(mpoly->geoms[i], sb, precision, variant | WKT_NO_TYPE );
        }
        stringbuffer_append(sb, ")");
}
 
/*
* Compound curves provide type information for their curved sub-geometries
* but not their linestring sub-geometries.
*   COMPOUNDCURVE((0 0, 1 1), CURVESTRING(1 1, 2 2, 3 3))
*/
static void lwcompound_to_wkt_sb(const LWCOMPOUND *comp, stringbuffer_t *sb, int precision, uint8_t variant)
{
        uint32_t i = 0;
 
        if ( ! (variant & WKT_NO_TYPE) )
        {
                stringbuffer_append(sb, "COMPOUNDCURVE"); /* "COMPOUNDCURVE" */
                dimension_qualifiers_to_wkt_sb((LWGEOM*)comp, sb, variant);
        }
        if ( comp->ngeoms < 1 )
        {
                empty_to_wkt_sb(sb);
                return;
        }
 
        stringbuffer_append(sb, "(");
        variant = variant | WKT_IS_CHILD; /* Inform the sub-geometries they are childre */
        for ( i = 0; i < comp->ngeoms; i++ )
        {
                int type = comp->geoms[i]->type;
                if ( i > 0 )
                        stringbuffer_append(sb, ",");
                /* Linestring subgeoms don't get type identifiers */
                if ( type == LINETYPE )
                {
                        lwline_to_wkt_sb((LWLINE*)comp->geoms[i], sb, precision, variant | WKT_NO_TYPE );
                }
                /* But circstring subgeoms *do* get type identifiers */
                else if ( type == CIRCSTRINGTYPE )
                {
                        lwcircstring_to_wkt_sb((LWCIRCSTRING*)comp->geoms[i], sb, precision, variant );
                }
                else
                {
                        lwerror("lwcompound_to_wkt_sb: Unknown type received %d - %s", type, lwtype_name(type));
                }
        }
        stringbuffer_append(sb, ")");
}
 
/*
* Curve polygons provide type information for their curved rings
* but not their linestring rings.
*   CURVEPOLYGON((0 0, 1 1, 0 1, 0 0), CURVESTRING(0 0, 1 1, 0 1, 0.5 1, 0 0))
*/
static void lwcurvepoly_to_wkt_sb(const LWCURVEPOLY *cpoly, stringbuffer_t *sb, int precision, uint8_t variant)
{
        uint32_t i = 0;
 
        if ( ! (variant & WKT_NO_TYPE) )
        {
                stringbuffer_append(sb, "CURVEPOLYGON"); /* "CURVEPOLYGON" */
                dimension_qualifiers_to_wkt_sb((LWGEOM*)cpoly, sb, variant);
        }
        if ( cpoly->nrings < 1 )
        {
                empty_to_wkt_sb(sb);
                return;
        }
        stringbuffer_append(sb, "(");
        variant = variant | WKT_IS_CHILD; /* Inform the sub-geometries they are childre */
        for ( i = 0; i < cpoly->nrings; i++ )
        {
                int type = cpoly->rings[i]->type;
                if ( i > 0 )
                        stringbuffer_append(sb, ",");
                switch (type)
                {
                case LINETYPE:
                        /* Linestring subgeoms don't get type identifiers */
                        lwline_to_wkt_sb((LWLINE*)cpoly->rings[i], sb, precision, variant | WKT_NO_TYPE );
                        break;
                case CIRCSTRINGTYPE:
                        /* But circstring subgeoms *do* get type identifiers */
                        lwcircstring_to_wkt_sb((LWCIRCSTRING*)cpoly->rings[i], sb, precision, variant );
                        break;
                case COMPOUNDTYPE:
                        /* And compoundcurve subgeoms *do* get type identifiers */
                        lwcompound_to_wkt_sb((LWCOMPOUND*)cpoly->rings[i], sb, precision, variant );
                        break;
                default:
                        lwerror("lwcurvepoly_to_wkt_sb: Unknown type received %d - %s", type, lwtype_name(type));
                }
        }
        stringbuffer_append(sb, ")");
}
 
 
/*
* Multi-curves provide type information for their curved sub-geometries
* but not their linear sub-geometries.
*   MULTICURVE((0 0, 1 1), CURVESTRING(0 0, 1 1, 2 2))
*/
static void lwmcurve_to_wkt_sb(const LWMCURVE *mcurv, stringbuffer_t *sb, int precision, uint8_t variant)
{
        uint32_t i = 0;
 
        if ( ! (variant & WKT_NO_TYPE) )
        {
                stringbuffer_append(sb, "MULTICURVE"); /* "MULTICURVE" */
                dimension_qualifiers_to_wkt_sb((LWGEOM*)mcurv, sb, variant);
        }
        if ( mcurv->ngeoms < 1 )
        {
                empty_to_wkt_sb(sb);
                return;
        }
        stringbuffer_append(sb, "(");
        variant = variant | WKT_IS_CHILD; /* Inform the sub-geometries they are childre */
        for ( i = 0; i < mcurv->ngeoms; i++ )
        {
                int type = mcurv->geoms[i]->type;
                if ( i > 0 )
                        stringbuffer_append(sb, ",");
                switch (type)
                {
                case LINETYPE:
                        /* Linestring subgeoms don't get type identifiers */
                        lwline_to_wkt_sb((LWLINE*)mcurv->geoms[i], sb, precision, variant | WKT_NO_TYPE );
                        break;
                case CIRCSTRINGTYPE:
                        /* But circstring subgeoms *do* get type identifiers */
                        lwcircstring_to_wkt_sb((LWCIRCSTRING*)mcurv->geoms[i], sb, precision, variant );
                        break;
                case COMPOUNDTYPE:
                        /* And compoundcurve subgeoms *do* get type identifiers */
                        lwcompound_to_wkt_sb((LWCOMPOUND*)mcurv->geoms[i], sb, precision, variant );
                        break;
                default:
                        lwerror("lwmcurve_to_wkt_sb: Unknown type received %d - %s", type, lwtype_name(type));
                }
        }
        stringbuffer_append(sb, ")");
}
 
 
/*
* Multi-surfaces provide type information for their curved sub-geometries
* but not their linear sub-geometries.
*   MULTISURFACE(((0 0, 1 1, 1 0, 0 0)), CURVEPOLYGON(CURVESTRING(0 0, 1 1, 2 2, 0 1, 0 0)))
*/
static void lwmsurface_to_wkt_sb(const LWMSURFACE *msurf, stringbuffer_t *sb, int precision, uint8_t variant)
{
        uint32_t i = 0;
 
        if ( ! (variant & WKT_NO_TYPE) )
        {
                stringbuffer_append(sb, "MULTISURFACE"); /* "MULTISURFACE" */
                dimension_qualifiers_to_wkt_sb((LWGEOM*)msurf, sb, variant);
        }
        if ( msurf->ngeoms < 1 )
        {
                empty_to_wkt_sb(sb);
                return;
        }
        stringbuffer_append(sb, "(");
        variant = variant | WKT_IS_CHILD; /* Inform the sub-geometries they are childre */
        for ( i = 0; i < msurf->ngeoms; i++ )
        {
                int type = msurf->geoms[i]->type;
                if ( i > 0 )
                        stringbuffer_append(sb, ",");
                switch (type)
                {
                case POLYGONTYPE:
                        /* Linestring subgeoms don't get type identifiers */
                        lwpoly_to_wkt_sb((LWPOLY*)msurf->geoms[i], sb, precision, variant | WKT_NO_TYPE );
                        break;
                case CURVEPOLYTYPE:
                        /* But circstring subgeoms *do* get type identifiers */
                        lwcurvepoly_to_wkt_sb((LWCURVEPOLY*)msurf->geoms[i], sb, precision, variant);
                        break;
                default:
                        lwerror("lwmsurface_to_wkt_sb: Unknown type received %d - %s", type, lwtype_name(type));
                }
        }
        stringbuffer_append(sb, ")");
}
 
/*
* Geometry collections provide type information for all their curved sub-geometries
* but not their linear sub-geometries.
*   GEOMETRYCOLLECTION(POLYGON((0 0, 1 1, 1 0, 0 0)), CURVEPOLYGON(CURVESTRING(0 0, 1 1, 2 2, 0 1, 0 0)))
*/
static void lwcollection_to_wkt_sb(const LWCOLLECTION *collection, stringbuffer_t *sb, int precision, uint8_t variant)
{
        uint32_t i = 0;
 
        if ( ! (variant & WKT_NO_TYPE) )
        {
                stringbuffer_append(sb, "GEOMETRYCOLLECTION"); /* "GEOMETRYCOLLECTION" */
                dimension_qualifiers_to_wkt_sb((LWGEOM*)collection, sb, variant);
        }
        if ( collection->ngeoms < 1 )
        {
                empty_to_wkt_sb(sb);
                return;
        }
        stringbuffer_append(sb, "(");
        variant = variant | WKT_IS_CHILD; /* Inform the sub-geometries they are children */
        for ( i = 0; i < collection->ngeoms; i++ )
        {
                if ( i > 0 )
                        stringbuffer_append(sb, ",");
                lwgeom_to_wkt_sb((LWGEOM*)collection->geoms[i], sb, precision, variant );
        }
        stringbuffer_append(sb, ")");
}
 
/*
* TRIANGLE
*/
static void lwtriangle_to_wkt_sb(const LWTRIANGLE *tri, stringbuffer_t *sb, int precision, uint8_t variant)
{
        if ( ! (variant & WKT_NO_TYPE) )
        {
                stringbuffer_append(sb, "TRIANGLE"); /* "TRIANGLE" */
                dimension_qualifiers_to_wkt_sb((LWGEOM*)tri, sb, variant);
        }
        if ( lwtriangle_is_empty(tri) )
        {
                empty_to_wkt_sb(sb);
                return;
        }
 
        stringbuffer_append(sb, "("); /* Triangles have extraneous brackets */
        ptarray_to_wkt_sb(tri->points, sb, precision, variant);
        stringbuffer_append(sb, ")");
}
 
/*
* TIN
*/
static void lwtin_to_wkt_sb(const LWTIN *tin, stringbuffer_t *sb, int precision, uint8_t variant)
{
        uint32_t i = 0;
 
        if ( ! (variant & WKT_NO_TYPE) )
        {
                stringbuffer_append(sb, "TIN"); /* "TIN" */
                dimension_qualifiers_to_wkt_sb((LWGEOM*)tin, sb, variant);
        }
        if ( tin->ngeoms < 1 )
        {
                empty_to_wkt_sb(sb);
                return;
        }
 
        stringbuffer_append(sb, "(");
        for ( i = 0; i < tin->ngeoms; i++ )
        {
                if ( i > 0 )
                        stringbuffer_append(sb, ",");
                /* We don't want type strings on our subgeoms */
                lwtriangle_to_wkt_sb(tin->geoms[i], sb, precision, variant | WKT_NO_TYPE );
        }
        stringbuffer_append(sb, ")");
}
 
/*
* POLYHEDRALSURFACE
*/
static void lwpsurface_to_wkt_sb(const LWPSURFACE *psurf, stringbuffer_t *sb, int precision, uint8_t variant)
{
        uint32_t i = 0;
 
        if ( ! (variant & WKT_NO_TYPE) )
        {
                stringbuffer_append(sb, "POLYHEDRALSURFACE"); /* "POLYHEDRALSURFACE" */
                dimension_qualifiers_to_wkt_sb((LWGEOM*)psurf, sb, variant);
        }
        if ( psurf->ngeoms < 1 )
        {
                empty_to_wkt_sb(sb);
                return;
        }
 
        variant = variant | WKT_IS_CHILD; /* Inform the sub-geometries they are childre */
 
        stringbuffer_append(sb, "(");
        for ( i = 0; i < psurf->ngeoms; i++ )
        {
                if ( i > 0 )
                        stringbuffer_append(sb, ",");
                /* We don't want type strings on our subgeoms */
                lwpoly_to_wkt_sb(psurf->geoms[i], sb, precision, variant | WKT_NO_TYPE );
        }
        stringbuffer_append(sb, ")");
}
 
 
/*
* Generic GEOMETRY
*/
static void lwgeom_to_wkt_sb(const LWGEOM *geom, stringbuffer_t *sb, int precision, uint8_t variant)
{
        LWDEBUGF(4, "lwgeom_to_wkt_sb: type %s, hasz %d, hasm %d",
                lwtype_name(geom->type), (geom->type),
                FLAGS_GET_Z(geom->flags)?1:0, FLAGS_GET_M(geom->flags)?1:0);
 
        switch (geom->type)
        {
        case POINTTYPE:
                lwpoint_to_wkt_sb((LWPOINT*)geom, sb, precision, variant);
                break;
        case LINETYPE:
                lwline_to_wkt_sb((LWLINE*)geom, sb, precision, variant);
                break;
        case POLYGONTYPE:
                lwpoly_to_wkt_sb((LWPOLY*)geom, sb, precision, variant);
                break;
        case MULTIPOINTTYPE:
                lwmpoint_to_wkt_sb((LWMPOINT*)geom, sb, precision, variant);
                break;
        case MULTILINETYPE:
                lwmline_to_wkt_sb((LWMLINE*)geom, sb, precision, variant);
                break;
        case MULTIPOLYGONTYPE:
                lwmpoly_to_wkt_sb((LWMPOLY*)geom, sb, precision, variant);
                break;
        case COLLECTIONTYPE:
                lwcollection_to_wkt_sb((LWCOLLECTION*)geom, sb, precision, variant);
                break;
        case CIRCSTRINGTYPE:
                lwcircstring_to_wkt_sb((LWCIRCSTRING*)geom, sb, precision, variant);
                break;
        case COMPOUNDTYPE:
                lwcompound_to_wkt_sb((LWCOMPOUND*)geom, sb, precision, variant);
                break;
        case CURVEPOLYTYPE:
                lwcurvepoly_to_wkt_sb((LWCURVEPOLY*)geom, sb, precision, variant);
                break;
        case MULTICURVETYPE:
                lwmcurve_to_wkt_sb((LWMCURVE*)geom, sb, precision, variant);
                break;
        case MULTISURFACETYPE:
                lwmsurface_to_wkt_sb((LWMSURFACE*)geom, sb, precision, variant);
                break;
        case TRIANGLETYPE:
                lwtriangle_to_wkt_sb((LWTRIANGLE*)geom, sb, precision, variant);
                break;
        case TINTYPE:
                lwtin_to_wkt_sb((LWTIN*)geom, sb, precision, variant);
                break;
        case POLYHEDRALSURFACETYPE:
                lwpsurface_to_wkt_sb((LWPSURFACE*)geom, sb, precision, variant);
                break;
        default:
                lwerror("lwgeom_to_wkt_sb: Type %d - %s unsupported.",
                        geom->type, lwtype_name(geom->type));
        }
}
 
char* lwgeom_to_wkt(const LWGEOM *geom, uint8_t variant, int precision, size_t *size_out)
{
        stringbuffer_t *sb;
        char *str = NULL;
        if ( geom == NULL )
                return NULL;
        sb = stringbuffer_create();
        /* Extended mode starts with an "SRID=" section for geoms that have one */
        if ( (variant & WKT_EXTENDED) && lwgeom_has_srid(geom) )
        {
                stringbuffer_aprintf(sb, "SRID=%d;", geom->srid);
        }
        lwgeom_to_wkt_sb(geom, sb, precision, variant);
        if ( stringbuffer_getstring(sb) == NULL )
        {
                lwerror("Uh oh");
                return NULL;
        }
        str = stringbuffer_getstringcopy(sb);
        if ( size_out )
                *size_out = stringbuffer_getlength(sb) + 1;
        stringbuffer_destroy(sb);
        return str;
}