lwgeom_to_wkb()

uint8_t* lwgeom_to_wkb	(	const LWGEOM *	geom,
		uint8_t	variant,
		size_t *	size_out
	)

Convert LWGEOM to a char* in WKB format.

Parameters

lwgeom	geometry to convert to WKT
variant	output format to use (WKB_ISO, WKB_SFSQL, WKB_EXTENDED, WKB_NDR, WKB_XDR)

Caller is responsible for freeing the returned array.

Parameters

variant.	Unsigned bitmask value. Accepts one of: WKB_ISO, WKB_EXTENDED, WKB_SFSQL. Accepts any of: WKB_NDR, WKB_HEX. For example: Variant = ( WKB_ISO | WKB_NDR ) would return the little-endian ISO form of WKB. For Example: Variant = ( WKB_EXTENDED | WKB_HEX ) would return the big-endian extended form of WKB, as hex-encoded ASCII (the "canonical form").
size_out	If supplied, will return the size of the returned memory segment, including the null terminator in the case of ASCII.

Definition at line 764 of file lwout_wkb.c.

References getMachineEndian(), lwalloc(), LWDEBUG, LWDEBUGF, lwerror(), lwfree(), lwgeom_to_wkb_buf(), lwgeom_to_wkb_size(), NDR, WKB_HEX, WKB_NDR, and WKB_XDR.

Referenced by cu_wkb(), cu_wkb_from_hexwkb(), cu_wkb_in(), geography_send(), LWGEOM_asBinary(), lwgeom_to_hexwkb(), polyhedralsurface_parse(), RASTER_asRaster(), RASTER_clip(), RASTER_setPixelValuesGeomval(), rt_raster_gdal_polygonize(), and WKBFromLWGEOM().

{
        size_t buf_size;
        uint8_t *buf = NULL;
        uint8_t *wkb_out = NULL;

        /* Initialize output size */
        if ( size_out ) *size_out = 0;

        if ( geom == NULL )
        {
                LWDEBUG(4,"Cannot convert NULL into WKB.");
                lwerror("Cannot convert NULL into WKB.");
                return NULL;
        }

        /* Calculate the required size of the output buffer */
        buf_size = lwgeom_to_wkb_size(geom, variant);
        LWDEBUGF(4, "WKB output size: %d", buf_size);

        if ( buf_size == 0 )
        {
                LWDEBUG(4,"Error calculating output WKB buffer size.");
                lwerror("Error calculating output WKB buffer size.");
                return NULL;
        }

        /* Hex string takes twice as much space as binary + a null character */
        if ( variant & WKB_HEX )
        {
                buf_size = 2 * buf_size + 1;
                LWDEBUGF(4, "Hex WKB output size: %d", buf_size);
        }

        /* If neither or both variants are specified, choose the native order */
        if ( ! (variant & WKB_NDR || variant & WKB_XDR) ||
               (variant & WKB_NDR && variant & WKB_XDR) )
        {
                if ( getMachineEndian() == NDR )
                        variant = variant | WKB_NDR;
                else
                        variant = variant | WKB_XDR;
        }

        /* Allocate the buffer */
        buf = lwalloc(buf_size);

        if ( buf == NULL )
        {
                LWDEBUGF(4,"Unable to allocate %d bytes for WKB output buffer.", buf_size);
                lwerror("Unable to allocate %d bytes for WKB output buffer.", buf_size);
                return NULL;
        }

        /* Retain a pointer to the front of the buffer for later */
        wkb_out = buf;

        /* Write the WKB into the output buffer */
        buf = lwgeom_to_wkb_buf(geom, buf, variant);

        /* Null the last byte if this is a hex output */
        if ( variant & WKB_HEX )
        {
                *buf = '\0';
                buf++;
        }

        LWDEBUGF(4,"buf (%p) - wkb_out (%p) = %d", buf, wkb_out, buf - wkb_out);

        /* The buffer pointer should now land at the end of the allocated buffer space. Let's check. */
        if ( buf_size != (buf - wkb_out) )
        {
                LWDEBUG(4,"Output WKB is not the same size as the allocated buffer.");
                lwerror("Output WKB is not the same size as the allocated buffer.");
                lwfree(wkb_out);
                return NULL;
        }

        /* Report output size */
        if ( size_out ) *size_out = buf_size;

        return wkb_out;
}

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