text: /**********************************************************************
   *
   * 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 2009 Paul Ramsey <pramsey@cleverelephant.ca>
   * Copyright 2017 Darafei Praliaskouski <me@komzpa.net>
   *
   **********************************************************************/
  
  /*
  *  GSERIALIZED verison 2 includes an optional extended flags uint64_t
  *  before the optional bounding box. There may be other optional
  *  components before the data area, but they all must be double
  *  aligned to that the ordinates remain double aligned.
  *
  *  <size> size        Used by PgSQL VARSIZE   g->size
  *  <srid               3 bytes                g->srid
  *   gflags>            1 byte                 g->gflags
  *  [<extendedflags>   Optional extended flags (check flags for cue)
  *   <extendedflags>]
  *  [<bbox-xmin>       Optional bounding box (check flags for cue)
  *   <bbox-xmax>       Number of dimensions is variable
  *   <bbox-ymin>       and also indicated in the flags
  *   <bbox-ymax>]
  *  ...
  *  data area
  */
  
  #include "liblwgeom_internal.h"
  #include "lwgeom_log.h"
  #include "lwgeodetic.h"
  #include "gserialized2.h"
  
  #include <stddef.h>
  
  /***********************************************************************
  * GSERIALIZED metadata utility functions.
  */
  
  static int gserialized2_read_gbox_p(const GSERIALIZED *g, GBOX *gbox);
  
  
  lwflags_t gserialized2_get_lwflags(const GSERIALIZED *g)
  {
  	lwflags_t lwflags = 0;
  	uint8_t gflags = g->gflags;
  	FLAGS_SET_Z(lwflags, G2FLAGS_GET_Z(gflags));
  	FLAGS_SET_M(lwflags, G2FLAGS_GET_M(gflags));
  	FLAGS_SET_BBOX(lwflags, G2FLAGS_GET_BBOX(gflags));
  	FLAGS_SET_GEODETIC(lwflags, G2FLAGS_GET_GEODETIC(gflags));
  	if (G2FLAGS_GET_EXTENDED(gflags))
  	{
  		uint64_t xflags = 0;
  		memcpy(&xflags, g->data, sizeof(uint64_t));
  		FLAGS_SET_SOLID(lwflags, xflags & G2FLAG_X_SOLID);
  	}
  	return lwflags;
  }
  
  static int lwflags_uses_extended_flags(lwflags_t lwflags)
  {
  	lwflags_t core_lwflags = LWFLAG_Z | LWFLAG_M | LWFLAG_BBOX | LWFLAG_GEODETIC;
  	return (lwflags & (~core_lwflags)) != 0;
  }
  
  
  static inline size_t gserialized2_box_size(const GSERIALIZED *g)
  {
  	if (G2FLAGS_GET_GEODETIC(g->gflags))
  		return 6 * sizeof(float);
  	else
  		return 2 * G2FLAGS_NDIMS(g->gflags) * sizeof(float);
  }
  
  static inline size_t gserialized2_header_size(const GSERIALIZED *g)
  {
  	uint32_t sz = 8; /* varsize (4) + srid(3) + flags (1) */
  
  	if (gserialized2_has_extended(g))
  		sz += 8;
  
  	if (gserialized2_has_bbox(g))
  		sz += gserialized2_box_size(g);
  
  	return sz;
  }
  
  /* Returns a pointer to the start of the geometry data */
  static inline uint8_t *
  gserialized2_get_geometry_p(const GSERIALIZED *g)
  {
  	uint32_t extra_data_bytes = 0;
  	if (gserialized2_has_extended(g))
  		extra_data_bytes += sizeof(uint64_t);
  
  	if (gserialized2_has_bbox(g))
  		extra_data_bytes += gserialized2_box_size(g);
  
  	return ((uint8_t *)g->data) + extra_data_bytes;
  }
  
  uint8_t lwflags_get_g2flags(lwflags_t lwflags)
  {
  	uint8_t gflags = 0;
  	G2FLAGS_SET_Z(gflags, FLAGS_GET_Z(lwflags));
  	G2FLAGS_SET_M(gflags, FLAGS_GET_M(lwflags));
  	G2FLAGS_SET_BBOX(gflags, FLAGS_GET_BBOX(lwflags));
  	G2FLAGS_SET_GEODETIC(gflags, FLAGS_GET_GEODETIC(lwflags));
  	G2FLAGS_SET_EXTENDED(gflags, lwflags_uses_extended_flags(lwflags));
  	G2FLAGS_SET_VERSION(gflags, 1);
  	return gflags;
  }
  
  /* handle missaligned uint32_t data */
  static inline uint32_t gserialized2_get_uint32_t(const uint8_t *loc)
  {
  	return *((uint32_t*)loc);
  }
  
  uint8_t g2flags(int has_z, int has_m, int is_geodetic)
  {
  	uint8_t gflags = 0;
  	if (has_z)
  		G2FLAGS_SET_Z(gflags, 1);
  	if (has_m)
  		G2FLAGS_SET_M(gflags, 1);
  	if (is_geodetic)
  		G2FLAGS_SET_GEODETIC(gflags, 1);
  	return gflags;
  }
  
  int gserialized2_has_bbox(const GSERIALIZED *g)
  {
  	return G2FLAGS_GET_BBOX(g->gflags);
  }
  
  int gserialized2_has_extended(const GSERIALIZED *g)
  {
  	return G2FLAGS_GET_EXTENDED(g->gflags);
  }
  
  int gserialized2_has_z(const GSERIALIZED *g)
  {
  	return G2FLAGS_GET_Z(g->gflags);
  }
  
  int gserialized2_has_m(const GSERIALIZED *g)
  {
  	return G2FLAGS_GET_M(g->gflags);
  }
  
  int gserialized2_ndims(const GSERIALIZED *g)
  {
  	return G2FLAGS_NDIMS(g->gflags);
  }
  
  int gserialized2_is_geodetic(const GSERIALIZED *g)
  {
  	  return G2FLAGS_GET_GEODETIC(g->gflags);
  }
  
  uint32_t gserialized2_max_header_size(void)
  {
  	/* GSERIALIZED size + max bbox according gbox_serialized_size (XYZM*2) + extended flags + type */
  	return offsetof(GSERIALIZED, data) + 8 * sizeof(float) + sizeof(uint64_t) + sizeof(uint32_t);
  }
  
  
  uint32_t gserialized2_get_type(const GSERIALIZED *g)
  {
  	uint8_t *ptr = gserialized2_get_geometry_p(g);
  	return *((uint32_t*)(ptr));
  }
  
  int32_t gserialized2_get_srid(const GSERIALIZED *g)
  {
  	int32_t srid = 0;
  	srid = srid | (g->srid[0] << 16);
  	srid = srid | (g->srid[1] << 8);
  	srid = srid | (g->srid[2]);
  	/* Only the first 21 bits are set. Slide up and back to pull
  	   the negative bits down, if we need them. */
  	srid = (srid<<11)>>11;
  
  	/* 0 is our internal unknown value. We'll map back and forth here for now */
  	if (srid == 0)
  		return SRID_UNKNOWN;
  	else
  		return srid;
  }
  
  void gserialized2_set_srid(GSERIALIZED *g, int32_t srid)
  {
  	LWDEBUGF(3, "%s called with srid = %d", __func__, srid);
  
  	srid = clamp_srid(srid);
  
  	/* 0 is our internal unknown value.
  	 * We'll map back and forth here for now */
  	if (srid == SRID_UNKNOWN)
  		srid = 0;
  
  	g->srid[0] = (srid & 0x001F0000) >> 16;
  	g->srid[1] = (srid & 0x0000FF00) >> 8;
  	g->srid[2] = (srid & 0x000000FF);
  }
  
  static size_t gserialized2_is_empty_recurse(const uint8_t *p, int *isempty);
  static size_t gserialized2_is_empty_recurse(const uint8_t *p, int *isempty)
  {
  	int i;
  	int32_t type, num;
  
  	memcpy(&type, p, 4);
  	memcpy(&num, p+4, 4);
  
  	if (lwtype_is_collection(type))
  	{
  		size_t lz = 8;
  		for ( i = 0; i < num; i++ )
  		{
  			lz += gserialized2_is_empty_recurse(p+lz, isempty);
  			if (!*isempty)
  				return lz;
  		}
  		*isempty = LW_TRUE;
  		return lz;
  	}
  	else
  	{
  		*isempty = (num == 0 ? LW_TRUE : LW_FALSE);
  		return 8;
  	}
  }
  
  int gserialized2_is_empty(const GSERIALIZED *g)
  {
  	int isempty = 0;
  	uint8_t *p = gserialized2_get_geometry_p(g);
  	gserialized2_is_empty_recurse(p, &isempty);
  	return isempty;
  }
  
  
  /* Prototype for lookup3.c */
  /* key = the key to hash */
  /* length = length of the key */
  /* pc = IN: primary initval, OUT: primary hash */
  /* pb = IN: secondary initval, OUT: secondary hash */
  void hashlittle2(const void *key, size_t length, uint32_t *pc, uint32_t *pb);
  
  int32_t
  gserialized2_hash(const GSERIALIZED *g1)
  {
  	int32_t hval;
  	int32_t pb = 0, pc = 0;
  	/* Point to just the type/coordinate part of buffer */
  	size_t hsz1 = gserialized2_header_size(g1);
  	uint8_t *b1 = (uint8_t *)g1 + hsz1;
  	/* Calculate size of type/coordinate buffer */
  	size_t sz1 = LWSIZE_GET(g1->size);
  	size_t bsz1 = sz1 - hsz1;
  	/* Calculate size of srid/type/coordinate buffer */
  	int32_t srid = gserialized2_get_srid(g1);
  	size_t bsz2 = bsz1 + sizeof(int);
  	uint8_t *b2 = lwalloc(bsz2);
  	/* Copy srid into front of combined buffer */
  	memcpy(b2, &srid, sizeof(int));
  	/* Copy type/coordinates into rest of combined buffer */
  	memcpy(b2+sizeof(int), b1, bsz1);
  	/* Hash combined buffer */
  	hashlittle2(b2, bsz2, (uint32_t *)&pb, (uint32_t *)&pc);
  	lwfree(b2);
  	hval = pb ^ pc;
  	return hval;
  }
  
  
  const float * gserialized2_get_float_box_p(const GSERIALIZED *g, size_t *ndims)
  {
  	uint8_t *ptr = (uint8_t*)(g->data);
  	size_t bndims = G2FLAGS_NDIMS_BOX(g->gflags);
  
  	if (ndims)
  		*ndims = bndims;
  
  	/* Cannot do anything if there's no box */
  	if (!(g && gserialized_has_bbox(g)))
  		return NULL;
  
  	/* Advance past optional extended flags */
  	if (gserialized2_has_extended(g))
  		ptr += 8;
  
  	return (const float *)(ptr);
  }
  
  int gserialized2_read_gbox_p(const GSERIALIZED *g, GBOX *gbox)
  {
  	uint8_t gflags = g->gflags;
  	/* Null input! */
  	if (!(g && gbox)) return LW_FAILURE;
  
  	/* Initialize the flags on the box */
  	gbox->flags = gserialized2_get_lwflags(g);
  
  	/* Has pre-calculated box */
  	if (G2FLAGS_GET_BBOX(gflags))
  	{
  		int i = 0;
  		const float *fbox = gserialized2_get_float_box_p(g, NULL);
  		gbox->xmin = fbox[i++];
  		gbox->xmax = fbox[i++];
  		gbox->ymin = fbox[i++];
  		gbox->ymax = fbox[i++];
  
  		/* Geodetic? Read next dimension (geocentric Z) and return */
  		if (G2FLAGS_GET_GEODETIC(gflags))
  		{
  			gbox->zmin = fbox[i++];
  			gbox->zmax = fbox[i++];
  			return LW_SUCCESS;
  		}
  		/* Cartesian? Read extra dimensions (if there) and return */
  		if (G2FLAGS_GET_Z(gflags))
  		{
  			gbox->zmin = fbox[i++];
  			gbox->zmax = fbox[i++];
  		}
  		if (G2FLAGS_GET_M(gflags))
  		{
  			gbox->mmin = fbox[i++];
  			gbox->mmax = fbox[i++];
  		}
  		return LW_SUCCESS;
  	}
  	return LW_FAILURE;
  }
  
  /*
  * Populate a bounding box *without* allocating an LWGEOM. Useful
  * for some performance purposes.
  */
  int
  gserialized2_peek_gbox_p(const GSERIALIZED *g, GBOX *gbox)
  {
  	uint32_t type = gserialized2_get_type(g);
  	uint8_t *geometry_start = gserialized2_get_geometry_p(g);
  	double *dptr = (double *)(geometry_start);
  	int32_t *iptr = (int32_t *)(geometry_start);
  
  	/* Peeking doesn't help if you already have a box or are geodetic */
  	if (G2FLAGS_GET_GEODETIC(g->gflags) || G2FLAGS_GET_BBOX(g->gflags))
  	{
  		return LW_FAILURE;
  	}
  
  	/* Boxes of points are easy peasy */
  	if (type == POINTTYPE)
  	{
  		int i = 1; /* Start past <pointtype><padding> */
  
  		/* Read the npoints flag */
  		int isempty = (iptr[1] == 0);
  
  		/* EMPTY point has no box */
  		if (isempty) return LW_FAILURE;
  
  		gbox->xmin = gbox->xmax = dptr[i++];
  		gbox->ymin = gbox->ymax = dptr[i++];
  		gbox->flags = gserialized2_get_lwflags(g);
  		if (G2FLAGS_GET_Z(g->gflags))
  		{
  			gbox->zmin = gbox->zmax = dptr[i++];
  		}
  		if (G2FLAGS_GET_M(g->gflags))
  		{
  			gbox->mmin = gbox->mmax = dptr[i++];
  		}
  		gbox_float_round(gbox);
  		return LW_SUCCESS;
  	}
  	/* We can calculate the box of a two-point cartesian line trivially */
  	else if (type == LINETYPE)
  	{
  		int ndims = G2FLAGS_NDIMS(g->gflags);
  		int i = 0; /* Start at <linetype><npoints> */
  		int npoints = iptr[1]; /* Read the npoints */
  
  		/* This only works with 2-point lines */
  		if (npoints != 2)
  			return LW_FAILURE;
  
  		/* Advance to X */
  		/* Past <linetype><npoints> */
  		i++;
  		gbox->xmin = FP_MIN(dptr[i], dptr[i+ndims]);
  		gbox->xmax = FP_MAX(dptr[i], dptr[i+ndims]);
  
  		/* Advance to Y */
  		i++;
  		gbox->ymin = FP_MIN(dptr[i], dptr[i+ndims]);
  		gbox->ymax = FP_MAX(dptr[i], dptr[i+ndims]);
  
  		gbox->flags = gserialized2_get_lwflags(g);
  		if (G2FLAGS_GET_Z(g->gflags))
  		{
  			/* Advance to Z */
  			i++;
  			gbox->zmin = FP_MIN(dptr[i], dptr[i+ndims]);
  			gbox->zmax = FP_MAX(dptr[i], dptr[i+ndims]);
  		}
  		if (G2FLAGS_GET_M(g->gflags))
  		{
  			/* Advance to M */
  			i++;
  			gbox->mmin = FP_MIN(dptr[i], dptr[i+ndims]);
  			gbox->mmax = FP_MAX(dptr[i], dptr[i+ndims]);
  		}
  		gbox_float_round(gbox);
  		return LW_SUCCESS;
  	}
  	/* We can also do single-entry multi-points */
  	else if (type == MULTIPOINTTYPE)
  	{
  		int i = 0; /* Start at <multipointtype><ngeoms> */
  		int ngeoms = iptr[1]; /* Read the ngeoms */
  		int npoints;
  
  		/* This only works with single-entry multipoints */
  		if (ngeoms != 1)
  			return LW_FAILURE;
  
  		/* Npoints is at <multipointtype><ngeoms><pointtype><npoints> */
  		npoints = iptr[3];
  
  		/* The check below is necessary because we can have a MULTIPOINT
  		 * that contains a single, empty POINT (ngeoms = 1, npoints = 0) */
  		if (npoints != 1)
  			return LW_FAILURE;
  
  		/* Move forward two doubles (four ints) */
  		/* Past <multipointtype><ngeoms> */
  		/* Past <pointtype><npoints> */
  		i += 2;
  
  		/* Read the doubles from the one point */
  		gbox->xmin = gbox->xmax = dptr[i++];
  		gbox->ymin = gbox->ymax = dptr[i++];
  		gbox->flags = gserialized2_get_lwflags(g);
  		if (G2FLAGS_GET_Z(g->gflags))
  		{
  			gbox->zmin = gbox->zmax = dptr[i++];
  		}
  		if (G2FLAGS_GET_M(g->gflags))
  		{
  			gbox->mmin = gbox->mmax = dptr[i++];
  		}
  		gbox_float_round(gbox);
  		return LW_SUCCESS;
  	}
  	/* And we can do single-entry multi-lines with two vertices (!!!) */
  	else if (type == MULTILINETYPE)
  	{
  		int ndims = G2FLAGS_NDIMS(g->gflags);
  		int i = 0; /* Start at <multilinetype><ngeoms> */
  		int ngeoms = iptr[1]; /* Read the ngeoms */
  		int npoints;
  
  		/* This only works with 1-line multilines */
  		if (ngeoms != 1)
  			return LW_FAILURE;
  
  		/* Npoints is at <multilinetype><ngeoms><linetype><npoints> */
  		npoints = iptr[3];
  
  		if (npoints != 2)
  			return LW_FAILURE;
  
  		/* Advance to X */
  		/* Move forward two doubles (four ints) */
  		/* Past <multilinetype><ngeoms> */
  		/* Past <linetype><npoints> */
  		i += 2;
  		gbox->xmin = FP_MIN(dptr[i], dptr[i+ndims]);
  		gbox->xmax = FP_MAX(dptr[i], dptr[i+ndims]);
  
  		/* Advance to Y */
  		i++;
  		gbox->ymin = FP_MIN(dptr[i], dptr[i+ndims]);
  		gbox->ymax = FP_MAX(dptr[i], dptr[i+ndims]);
  
  		gbox->flags = gserialized2_get_lwflags(g);
  		if (G2FLAGS_GET_Z(g->gflags))
  		{
  			/* Advance to Z */
  			i++;
  			gbox->zmin = FP_MIN(dptr[i], dptr[i+ndims]);
  			gbox->zmax = FP_MAX(dptr[i], dptr[i+ndims]);
  		}
  		if (G2FLAGS_GET_M(g->gflags))
  		{
  			/* Advance to M */
  			i++;
  			gbox->mmin = FP_MIN(dptr[i], dptr[i+ndims]);
  			gbox->mmax = FP_MAX(dptr[i], dptr[i+ndims]);
  		}
  		gbox_float_round(gbox);
  		return LW_SUCCESS;
  	}
  
  	return LW_FAILURE;
  }
  
  static inline void
  gserialized2_copy_point(double *dptr, lwflags_t flags, POINT4D *out_point)
  {
  	uint8_t dim = 0;
  	out_point->x = dptr[dim++];
  	out_point->y = dptr[dim++];
  
  	if (G2FLAGS_GET_Z(flags))
  	{
  		out_point->z = dptr[dim++];
  	}
  	if (G2FLAGS_GET_M(flags))
  	{
  		out_point->m = dptr[dim];
  	}
  }
  
  int
  gserialized2_peek_first_point(const GSERIALIZED *g, POINT4D *out_point)
  {
  	uint8_t *geometry_start = gserialized2_get_geometry_p(g);
  
  	uint32_t isEmpty = (((uint32_t *)geometry_start)[1]) == 0;
  	if (isEmpty)
  	{
  		return LW_FAILURE;
  	}
  
  	uint32_t type = (((uint32_t *)geometry_start)[0]);
  	/* Setup double_array_start depending on the geometry type */
  	double *double_array_start = NULL;
  	switch (type)
  	{
  	case (POINTTYPE):
  		/* For points we only need to jump over the type and npoints 32b ints */
  		double_array_start = (double *)(geometry_start + 2 * sizeof(uint32_t));
  		break;
  
  	default:
  		lwerror("%s is currently not implemented for type %d", __func__, type);
  		return LW_FAILURE;
  	}
  
  	gserialized2_copy_point(double_array_start, g->gflags, out_point);
  	return LW_SUCCESS;
  }
  
  /**
  * Read the bounding box off a serialization and calculate one if
  * it is not already there.
  */
  int gserialized2_get_gbox_p(const GSERIALIZED *g, GBOX *box)
  {
  	/* Try to just read the serialized box. */
  	if (gserialized2_read_gbox_p(g, box) == LW_SUCCESS)
  	{
  		return LW_SUCCESS;
  	}
  	/* No box? Try to peek into simpler geometries and */
  	/* derive a box without creating an lwgeom */
  	else if (gserialized2_peek_gbox_p(g, box) == LW_SUCCESS)
  	{
  		return LW_SUCCESS;
  	}
  	/* Damn! Nothing for it but to create an lwgeom... */
  	/* See http://trac.osgeo.org/postgis/ticket/1023 */
  	else
  	{
  		LWGEOM *lwgeom = lwgeom_from_gserialized(g);
  		int ret = lwgeom_calculate_gbox(lwgeom, box);
  		gbox_float_round(box);
  		lwgeom_free(lwgeom);
  		return ret;
  	}
  }
  
  /**
  * Read the bounding box off a serialization and fail if
  * it is not already there.
  */
  int gserialized2_fast_gbox_p(const GSERIALIZED *g, GBOX *box)
  {
  	/* Try to just read the serialized box. */
  	if (gserialized2_read_gbox_p(g, box) == LW_SUCCESS)
  	{
  		return LW_SUCCESS;
  	}
  	/* No box? Try to peek into simpler geometries and */
  	/* derive a box without creating an lwgeom */
  	else if (gserialized2_peek_gbox_p(g, box) == LW_SUCCESS)
  	{
  		return LW_SUCCESS;
  	}
  	else
  	{
  		return LW_FAILURE;
  	}
  }
  
  
  
  
  /***********************************************************************
  * Calculate the GSERIALIZED size for an LWGEOM.
  */
  
  /* Private functions */
  
  static size_t gserialized2_from_any_size(const LWGEOM *geom); /* Local prototype */
  
  static size_t gserialized2_from_lwpoint_size(const LWPOINT *point)
  {
  	size_t size = 4; /* Type number. */
  
  	assert(point);
  
  	size += 4; /* Number of points (one or zero (empty)). */
  	size += point->point->npoints * FLAGS_NDIMS(point->flags) * sizeof(double);
  
  	LWDEBUGF(3, "point size = %d", size);
  
  	return size;
  }
  
  static size_t gserialized2_from_lwline_size(const LWLINE *line)
  {
  	size_t size = 4; /* Type number. */
  
  	assert(line);
  
  	size += 4; /* Number of points (zero => empty). */
  	size += line->points->npoints * FLAGS_NDIMS(line->flags) * sizeof(double);
  
  	LWDEBUGF(3, "linestring size = %d", size);
  
  	return size;
  }
  
  static size_t gserialized2_from_lwtriangle_size(const LWTRIANGLE *triangle)
  {
  	size_t size = 4; /* Type number. */
  
  	assert(triangle);
  
  	size += 4; /* Number of points (zero => empty). */
  	size += triangle->points->npoints * FLAGS_NDIMS(triangle->flags) * sizeof(double);
  
  	LWDEBUGF(3, "triangle size = %d", size);
  
  	return size;
  }
  
  static size_t gserialized2_from_lwpoly_size(const LWPOLY *poly)
  {
  	size_t size = 4; /* Type number. */
  	uint32_t i = 0;
  	const size_t point_size = FLAGS_NDIMS(poly->flags) * sizeof(double);
  
  	assert(poly);
  
  	size += 4; /* Number of rings (zero => empty). */
  	if (poly->nrings % 2)
  		size += 4; /* Padding to double alignment. */
  
  	for (i = 0; i < poly->nrings; i++)
  	{
  		size += 4; /* Number of points in ring. */
  		size += poly->rings[i]->npoints * point_size;
  	}
  
  	LWDEBUGF(3, "polygon size = %d", size);
  
  	return size;
  }
  
  static size_t gserialized2_from_lwcircstring_size(const LWCIRCSTRING *curve)
  {
  	size_t size = 4; /* Type number. */
  
  	assert(curve);
  
  	size += 4; /* Number of points (zero => empty). */
  	size += curve->points->npoints * FLAGS_NDIMS(curve->flags) * sizeof(double);
  
  	LWDEBUGF(3, "circstring size = %d", size);
  
  	return size;
  }
  
  static size_t gserialized2_from_lwcollection_size(const LWCOLLECTION *col)
  {
  	size_t size = 4; /* Type number. */
  	uint32_t i = 0;
  
  	assert(col);
  
  	size += 4; /* Number of sub-geometries (zero => empty). */
  
  	for (i = 0; i < col->ngeoms; i++)
  	{
  		size_t subsize = gserialized2_from_any_size(col->geoms[i]);
  		size += subsize;
  		LWDEBUGF(3, "lwcollection subgeom(%d) size = %d", i, subsize);
  	}
  
  	LWDEBUGF(3, "lwcollection size = %d", size);
  
  	return size;
  }
  
  static size_t gserialized2_from_any_size(const LWGEOM *geom)
  {
  	LWDEBUGF(2, "Input type: %s", lwtype_name(geom->type));
  
  	switch (geom->type)
  	{
  	case POINTTYPE:
  		return gserialized2_from_lwpoint_size((LWPOINT *)geom);
  	case LINETYPE:
  		return gserialized2_from_lwline_size((LWLINE *)geom);
  	case POLYGONTYPE:
  		return gserialized2_from_lwpoly_size((LWPOLY *)geom);
  	case TRIANGLETYPE:
  		return gserialized2_from_lwtriangle_size((LWTRIANGLE *)geom);
  	case CIRCSTRINGTYPE:
  		return gserialized2_from_lwcircstring_size((LWCIRCSTRING *)geom);
  	case CURVEPOLYTYPE:
  	case COMPOUNDTYPE:
  	case MULTIPOINTTYPE:
  	case MULTILINETYPE:
  	case MULTICURVETYPE:
  	case MULTIPOLYGONTYPE:
  	case MULTISURFACETYPE:
  	case POLYHEDRALSURFACETYPE:
  	case TINTYPE:
  	case COLLECTIONTYPE:
  		return gserialized2_from_lwcollection_size((LWCOLLECTION *)geom);
  	default:
  		lwerror("Unknown geometry type: %d - %s", geom->type, lwtype_name(geom->type));
  		return 0;
  	}
  }
  
  /* Public function */
  
  size_t gserialized2_from_lwgeom_size(const LWGEOM *geom)
  {
  	size_t size = 8; /* Header overhead (varsize+flags+srid) */
  	assert(geom);
  
  	/* Reserve space for extended flags */
  	if (lwflags_uses_extended_flags(geom->flags))
  		size += 8;
  
  	/* Reserve space for bounding box */
  	if (geom->bbox)
  		size += gbox_serialized_size(geom->flags);
  
  	size += gserialized2_from_any_size(geom);
  	LWDEBUGF(3, "%s size = %d", __func__, size);
  
  	return size;
  }
  
  /***********************************************************************
  * Serialize an LWGEOM into GSERIALIZED.
  */
  
  /* Private functions */
  
  static size_t gserialized2_from_lwgeom_any(const LWGEOM *geom, uint8_t *buf);
  
  static size_t gserialized2_from_lwpoint(const LWPOINT *point, uint8_t *buf)
  {
  	uint8_t *loc;
  	int ptsize = ptarray_point_size(point->point);
  	int type = POINTTYPE;
  
  	assert(point);
  	assert(buf);
  
  	if (FLAGS_GET_ZM(point->flags) != FLAGS_GET_ZM(point->point->flags))
  		lwerror("Dimensions mismatch in lwpoint");
  
  	LWDEBUGF(2, "%s (%p, %p) called", __func__, point, buf);
  
  	loc = buf;
  
  	/* Write in the type. */
  	memcpy(loc, &type, sizeof(uint32_t));
  	loc += sizeof(uint32_t);
  	/* Write in the number of points (0 => empty). */
  	memcpy(loc, &(point->point->npoints), sizeof(uint32_t));
  	loc += sizeof(uint32_t);
  
  	/* Copy in the ordinates. */
  	if (point->point->npoints > 0)
  	{
  		memcpy(loc, getPoint_internal(point->point, 0), ptsize);
  		loc += ptsize;
  	}
  
  	return (size_t)(loc - buf);
  }
  
  static size_t gserialized2_from_lwline(const LWLINE *line, uint8_t *buf)
  {
  	uint8_t *loc;
  	int ptsize;
  	size_t size;
  	int type = LINETYPE;
  
  	assert(line);
  	assert(buf);
  
  	LWDEBUGF(2, "%s (%p, %p) called", __func__, line, buf);
  
  	if (FLAGS_GET_Z(line->flags) != FLAGS_GET_Z(line->points->flags))
  		lwerror("Dimensions mismatch in lwline");
  
  	ptsize = ptarray_point_size(line->points);
  
  	loc = buf;
  
  	/* Write in the type. */
  	memcpy(loc, &type, sizeof(uint32_t));
  	loc += sizeof(uint32_t);
  
  	/* Write in the npoints. */
  	memcpy(loc, &(line->points->npoints), sizeof(uint32_t));
  	loc += sizeof(uint32_t);
  
  	LWDEBUGF(3, "%s added npoints (%d)", __func__, line->points->npoints);
  
  	/* Copy in the ordinates. */
  	if (line->points->npoints > 0)
  	{
  		size = line->points->npoints * ptsize;
  		memcpy(loc, getPoint_internal(line->points, 0), size);
  		loc += size;
  	}
  	LWDEBUGF(3, "%s copied serialized_pointlist (%d bytes)", __func__, ptsize * line->points->npoints);
  
  	return (size_t)(loc - buf);
  }
  
  static size_t gserialized2_from_lwpoly(const LWPOLY *poly, uint8_t *buf)
  {
  	uint32_t i;
  	uint8_t *loc;
  	int ptsize;
  	int type = POLYGONTYPE;
  
  	assert(poly);
  	assert(buf);
  
  	LWDEBUGF(2, "%s called", __func__);
  
  	ptsize = sizeof(double) * FLAGS_NDIMS(poly->flags);
  	loc = buf;
  
  	/* Write in the type. */
  	memcpy(loc, &type, sizeof(uint32_t));
  	loc += sizeof(uint32_t);
  
  	/* Write in the nrings. */
  	memcpy(loc, &(poly->nrings), sizeof(uint32_t));
  	loc += sizeof(uint32_t);
  
  	/* Write in the npoints per ring. */
  	for (i = 0; i < poly->nrings; i++)
  	{
  		memcpy(loc, &(poly->rings[i]->npoints), sizeof(uint32_t));
  		loc += sizeof(uint32_t);
  	}
  
  	/* Add in padding if necessary to remain double aligned. */
  	if (poly->nrings % 2)
  	{
  		memset(loc, 0, sizeof(uint32_t));
  		loc += sizeof(uint32_t);
  	}
  
  	/* Copy in the ordinates. */
  	for (i = 0; i < poly->nrings; i++)
  	{
  		POINTARRAY *pa = poly->rings[i];
  		size_t pasize;
  
  		if (FLAGS_GET_ZM(poly->flags) != FLAGS_GET_ZM(pa->flags))
  			lwerror("Dimensions mismatch in lwpoly");
  
  		pasize = pa->npoints * ptsize;
  		if ( pa->npoints > 0 )
  			memcpy(loc, getPoint_internal(pa, 0), pasize);
  		loc += pasize;
  	}
  	return (size_t)(loc - buf);
  }
  
  static size_t gserialized2_from_lwtriangle(const LWTRIANGLE *triangle, uint8_t *buf)
  {
  	uint8_t *loc;
  	int ptsize;
  	size_t size;
  	int type = TRIANGLETYPE;
  
  	assert(triangle);
  	assert(buf);
  
  	LWDEBUGF(2, "%s (%p, %p) called", __func__, triangle, buf);
  
  	if (FLAGS_GET_ZM(triangle->flags) != FLAGS_GET_ZM(triangle->points->flags))
  		lwerror("Dimensions mismatch in lwtriangle");
  
  	ptsize = ptarray_point_size(triangle->points);
  
  	loc = buf;
  
  	/* Write in the type. */
  	memcpy(loc, &type, sizeof(uint32_t));
  	loc += sizeof(uint32_t);
  
  	/* Write in the npoints. */
  	memcpy(loc, &(triangle->points->npoints), sizeof(uint32_t));
  	loc += sizeof(uint32_t);
  
  	LWDEBUGF(3, "%s added npoints (%d)", __func__, triangle->points->npoints);
  
  	/* Copy in the ordinates. */
  	if (triangle->points->npoints > 0)
  	{
  		size = triangle->points->npoints * ptsize;
  		memcpy(loc, getPoint_internal(triangle->points, 0), size);
  		loc += size;
  	}
  	LWDEBUGF(3, "%s copied serialized_pointlist (%d bytes)", __func__, ptsize * triangle->points->npoints);
  
  	return (size_t)(loc - buf);
  }
  
  static size_t gserialized2_from_lwcircstring(const LWCIRCSTRING *curve, uint8_t *buf)
  {
  	uint8_t *loc;
  	int ptsize;
  	size_t size;
  	int type = CIRCSTRINGTYPE;
  
  	assert(curve);
  	assert(buf);
  
  	if (FLAGS_GET_ZM(curve->flags) != FLAGS_GET_ZM(curve->points->flags))
  		lwerror("Dimensions mismatch in lwcircstring");
  
  
  	ptsize = ptarray_point_size(curve->points);
  	loc = buf;
  
  	/* Write in the type. */
  	memcpy(loc, &type, sizeof(uint32_t));
  	loc += sizeof(uint32_t);
  
  	/* Write in the npoints. */
  	memcpy(loc, &curve->points->npoints, sizeof(uint32_t));
  	loc += sizeof(uint32_t);
  
  	/* Copy in the ordinates. */
  	if (curve->points->npoints > 0)
  	{
  		size = curve->points->npoints * ptsize;
  		memcpy(loc, getPoint_internal(curve->points, 0), size);
  		loc += size;
  	}
  
  	return (size_t)(loc - buf);
  }
  
  static size_t gserialized2_from_lwcollection(const LWCOLLECTION *coll, uint8_t *buf)
  {
  	size_t subsize = 0;
  	uint8_t *loc;
  	uint32_t i;
  	int type;
  
  	assert(coll);
  	assert(buf);
  
  	type = coll->type;
  	loc = buf;
  
  	/* Write in the type. */
  	memcpy(loc, &type, sizeof(uint32_t));
  	loc += sizeof(uint32_t);
  
  	/* Write in the number of subgeoms. */
  	memcpy(loc, &coll->ngeoms, sizeof(uint32_t));
  	loc += sizeof(uint32_t);
  
  	/* Serialize subgeoms. */
  	for (i = 0; i < coll->ngeoms; i++)
  	{
  		if (FLAGS_GET_ZM(coll->flags) != FLAGS_GET_ZM(coll->geoms[i]->flags))
  			lwerror("Dimensions mismatch in lwcollection");
  		subsize = gserialized2_from_lwgeom_any(coll->geoms[i], loc);
  		loc += subsize;
  	}
  
  	return (size_t)(loc - buf);
  }
  
  static size_t gserialized2_from_lwgeom_any(const LWGEOM *geom, uint8_t *buf)
  {
  	assert(geom);
  	assert(buf);
  
  	LWDEBUGF(2, "Input type (%d) %s, hasz: %d hasm: %d",
  		geom->type, lwtype_name(geom->type),
  		FLAGS_GET_Z(geom->flags), FLAGS_GET_M(geom->flags));
  	LWDEBUGF(2, "LWGEOM(%p) uint8_t(%p)", geom, buf);
  
  	switch (geom->type)
  	{
  	case POINTTYPE:
  		return gserialized2_from_lwpoint((LWPOINT *)geom, buf);
  	case LINETYPE:
  		return gserialized2_from_lwline((LWLINE *)geom, buf);
  	case POLYGONTYPE:
  		return gserialized2_from_lwpoly((LWPOLY *)geom, buf);
  	case TRIANGLETYPE:
  		return gserialized2_from_lwtriangle((LWTRIANGLE *)geom, buf);
  	case CIRCSTRINGTYPE:
  		return gserialized2_from_lwcircstring((LWCIRCSTRING *)geom, buf);
  	case CURVEPOLYTYPE:
  	case COMPOUNDTYPE:
  	case MULTIPOINTTYPE:
  	case MULTILINETYPE:
  	case MULTICURVETYPE:
  	case MULTIPOLYGONTYPE:
  	case MULTISURFACETYPE:
  	case POLYHEDRALSURFACETYPE:
  	case TINTYPE:
  	case COLLECTIONTYPE:
  		return gserialized2_from_lwcollection((LWCOLLECTION *)geom, buf);
  	default:
  		lwerror("Unknown geometry type: %d - %s", geom->type, lwtype_name(geom->type));
  		return 0;
  	}
  	return 0;
  }
  
  static size_t gserialized2_from_extended_flags(lwflags_t lwflags, uint8_t *buf)
  {
  	if (lwflags_uses_extended_flags(lwflags))
  	{
  		uint64_t xflags = 0;
  		if (FLAGS_GET_SOLID(lwflags))
  			xflags |= G2FLAG_X_SOLID;
  
  		// G2FLAG_X_CHECKED_VALID
  		// G2FLAG_X_IS_VALID
  		// G2FLAG_X_HAS_HASH
  
  		memcpy(buf, &xflags, sizeof(uint64_t));
  		return sizeof(uint64_t);
  	}
  	return 0;
  }
  
  static size_t gserialized2_from_gbox(const GBOX *gbox, uint8_t *buf)
  {
  	uint8_t *loc = buf;
  	float *f;
  	uint8_t i = 0;
  	size_t return_size;
  
  	assert(buf);
  
  	f = (float *)buf;
  	f[i++] = next_float_down(gbox->xmin);
  	f[i++] = next_float_up(gbox->xmax);
  	f[i++] = next_float_down(gbox->ymin);
  	f[i++] = next_float_up(gbox->ymax);
  	loc += 4 * sizeof(float);
  
  	if (FLAGS_GET_GEODETIC(gbox->flags))
  	{
  		f[i++] = next_float_down(gbox->zmin);
  		f[i++] = next_float_up(gbox->zmax);
  		loc += 2 * sizeof(float);
  
  		return_size = (size_t)(loc - buf);
  		LWDEBUGF(4, "returning size %d", return_size);
  		return return_size;
  	}
  
  	if (FLAGS_GET_Z(gbox->flags))
  	{
  		f[i++] = next_float_down(gbox->zmin);
  		f[i++] = next_float_up(gbox->zmax);
  		loc += 2 * sizeof(float);
  	}
  
  	if (FLAGS_GET_M(gbox->flags))
  	{
  		f[i++] = next_float_down(gbox->mmin);
  		f[i++] = next_float_up(gbox->mmax);
  		loc += 2 * sizeof(float);
  	}
  	return_size = (size_t)(loc - buf);
  	LWDEBUGF(4, "returning size %d", return_size);
  	return return_size;
  }
  
  /* Public function */
  
  GSERIALIZED* gserialized2_from_lwgeom(LWGEOM *geom, size_t *size)
  {
  	size_t expected_size = 0;
  	size_t return_size = 0;
  	uint8_t *ptr = NULL;
  	GSERIALIZED *g = NULL;
  	assert(geom);
  
  	/*
  	** See if we need a bounding box, add one if we don't have one.
  	*/
  	if ((!geom->bbox) && lwgeom_needs_bbox(geom) && (!lwgeom_is_empty(geom)))
  	{
  		lwgeom_add_bbox(geom);
  	}
  
  	/*
  	** Harmonize the flags to the state of the lwgeom
  	*/
  	FLAGS_SET_BBOX(geom->flags, (geom->bbox ? 1 : 0));
  
  	/* Set up the uint8_t buffer into which we are going to write the serialized geometry. */
  	expected_size = gserialized2_from_lwgeom_size(geom);
  	ptr = lwalloc(expected_size);
  	g = (GSERIALIZED*)(ptr);
  
  	/* Set the SRID! */
  	gserialized2_set_srid(g, geom->srid);
  	/*
  	** We are aping PgSQL code here, PostGIS code should use
  	** VARSIZE to set this for real.
  	*/
  	LWSIZE_SET(g->size, expected_size);
  	g->gflags = lwflags_get_g2flags(geom->flags);
  
  	/* Move write head past size, srid and flags. */
  	ptr += 8;
  
  	/* Write in the extended flags if necessary */
  	ptr += gserialized2_from_extended_flags(geom->flags, ptr);
  
  	/* Write in the serialized form of the gbox, if necessary. */
  	if (geom->bbox)
  		ptr += gserialized2_from_gbox(geom->bbox, ptr);
  
  	/* Write in the serialized form of the geometry. */
  	ptr += gserialized2_from_lwgeom_any(geom, ptr);
  
  	/* Calculate size as returned by data processing functions. */
  	return_size = ptr - (uint8_t*)g;
  
  	assert(expected_size == return_size);
  	if (size) /* Return the output size to the caller if necessary. */
  		*size = return_size;
  
  	return g;
  }
  
  // xxxx continue reviewing extended flags content from here
  
  /***********************************************************************
  * De-serialize GSERIALIZED into an LWGEOM.
  */
  
  static LWGEOM *lwgeom_from_gserialized2_buffer(uint8_t *data_ptr, lwflags_t lwflags, size_t *size, int32_t srid);
  
  static LWPOINT *
  lwpoint_from_gserialized2_buffer(uint8_t *data_ptr, lwflags_t lwflags, size_t *size, int32_t srid)
  {
  	uint8_t *start_ptr = data_ptr;
  	LWPOINT *point;
  	uint32_t npoints = 0;
  
  	assert(data_ptr);
  
  	point = (LWPOINT*)lwalloc(sizeof(LWPOINT));
  	point->srid = srid;
  	point->bbox = NULL;
  	point->type = POINTTYPE;
  	point->flags = lwflags;
  
  	data_ptr += 4; /* Skip past the type. */
  	npoints = gserialized2_get_uint32_t(data_ptr); /* Zero => empty geometry */
  	data_ptr += 4; /* Skip past the npoints. */
  
  	if (npoints > 0)
  		point->point = ptarray_construct_reference_data(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), 1, data_ptr);
  	else
  		point->point = ptarray_construct(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), 0); /* Empty point */
  
  	data_ptr += npoints * FLAGS_NDIMS(lwflags) * sizeof(double);
  
  	if (size)
  		*size = data_ptr - start_ptr;
  
  	return point;
  }
  
  static LWLINE *
  lwline_from_gserialized2_buffer(uint8_t *data_ptr, lwflags_t lwflags, size_t *size, int32_t srid)
  {
  	uint8_t *start_ptr = data_ptr;
  	LWLINE *line;
  	uint32_t npoints = 0;
  
  	assert(data_ptr);
  
  	line = (LWLINE*)lwalloc(sizeof(LWLINE));
  	line->srid = srid;
  	line->bbox = NULL;
  	line->type = LINETYPE;
  	line->flags = lwflags;
  
  	data_ptr += 4; /* Skip past the type. */
  	npoints = gserialized2_get_uint32_t(data_ptr); /* Zero => empty geometry */
  	data_ptr += 4; /* Skip past the npoints. */
  
  	if (npoints > 0)
  		line->points = ptarray_construct_reference_data(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), npoints, data_ptr);
  
  	else
  		line->points = ptarray_construct(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), 0); /* Empty linestring */
  
  	data_ptr += FLAGS_NDIMS(lwflags) * npoints * sizeof(double);
  
  	if (size)
  		*size = data_ptr - start_ptr;
  
  	return line;
  }
  
  static LWPOLY *
  lwpoly_from_gserialized2_buffer(uint8_t *data_ptr, lwflags_t lwflags, size_t *size, int32_t srid)
  {
  	uint8_t *start_ptr = data_ptr;
  	LWPOLY *poly;
  	uint8_t *ordinate_ptr;
  	uint32_t nrings = 0;
  	uint32_t i = 0;
  
  	assert(data_ptr);
  
  	poly = (LWPOLY*)lwalloc(sizeof(LWPOLY));
  	poly->srid = srid;
  	poly->bbox = NULL;
  	poly->type = POLYGONTYPE;
  	poly->flags = lwflags;
  
  	data_ptr += 4; /* Skip past the polygontype. */
  	nrings = gserialized2_get_uint32_t(data_ptr); /* Zero => empty geometry */
  	poly->nrings = nrings;
  	LWDEBUGF(4, "nrings = %d", nrings);
  	data_ptr += 4; /* Skip past the nrings. */
  
  	ordinate_ptr = data_ptr; /* Start the ordinate pointer. */
  	if (nrings > 0)
  	{
  		poly->rings = (POINTARRAY**)lwalloc( sizeof(POINTARRAY*) * nrings );
  		poly->maxrings = nrings;
  		ordinate_ptr += nrings * 4; /* Move past all the npoints values. */
  		if (nrings % 2) /* If there is padding, move past that too. */
  			ordinate_ptr += 4;
  	}
  	else /* Empty polygon */
  	{
  		poly->rings = NULL;
  		poly->maxrings = 0;
  	}
  
  	for (i = 0; i < nrings; i++)
  	{
  		uint32_t npoints = 0;
  
  		/* Read in the number of points. */
  		npoints = gserialized2_get_uint32_t(data_ptr);
  		data_ptr += 4;
  
  		/* Make a point array for the ring, and move the ordinate pointer past the ring ordinates. */
  		poly->rings[i] = ptarray_construct_reference_data(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), npoints, ordinate_ptr);
  
  		ordinate_ptr += sizeof(double) * FLAGS_NDIMS(lwflags) * npoints;
  	}
  
  	if (size)
  		*size = ordinate_ptr - start_ptr;
  
  	return poly;
  }
  
  static LWTRIANGLE *
  lwtriangle_from_gserialized2_buffer(uint8_t *data_ptr, lwflags_t lwflags, size_t *size, int32_t srid)
  {
  	uint8_t *start_ptr = data_ptr;
  	LWTRIANGLE *triangle;
  	uint32_t npoints = 0;
  
  	assert(data_ptr);
  
  	triangle = (LWTRIANGLE*)lwalloc(sizeof(LWTRIANGLE));
  	triangle->srid = srid; /* Default */
  	triangle->bbox = NULL;
  	triangle->type = TRIANGLETYPE;
  	triangle->flags = lwflags;
  
  	data_ptr += 4; /* Skip past the type. */
  	npoints = gserialized2_get_uint32_t(data_ptr); /* Zero => empty geometry */
  	data_ptr += 4; /* Skip past the npoints. */
  
  	if (npoints > 0)
  		triangle->points = ptarray_construct_reference_data(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), npoints, data_ptr);
  	else
  		triangle->points = ptarray_construct(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), 0); /* Empty triangle */
  
  	data_ptr += FLAGS_NDIMS(lwflags) * npoints * sizeof(double);
  
  	if (size)
  		*size = data_ptr - start_ptr;
  
  	return triangle;
  }
  
  static LWCIRCSTRING *
  lwcircstring_from_gserialized2_buffer(uint8_t *data_ptr, lwflags_t lwflags, size_t *size, int32_t srid)
  {
  	uint8_t *start_ptr = data_ptr;
  	LWCIRCSTRING *circstring;
  	uint32_t npoints = 0;
  
  	assert(data_ptr);
  
  	circstring = (LWCIRCSTRING*)lwalloc(sizeof(LWCIRCSTRING));
  	circstring->srid = srid;
  	circstring->bbox = NULL;
  	circstring->type = CIRCSTRINGTYPE;
  	circstring->flags = lwflags;
  
  	data_ptr += 4; /* Skip past the circstringtype. */
  	npoints = gserialized2_get_uint32_t(data_ptr); /* Zero => empty geometry */
  	data_ptr += 4; /* Skip past the npoints. */
  
  	if (npoints > 0)
  		circstring->points = ptarray_construct_reference_data(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), npoints, data_ptr);
  	else
  		circstring->points = ptarray_construct(FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), 0); /* Empty circularstring */
  
  	data_ptr += FLAGS_NDIMS(lwflags) * npoints * sizeof(double);
  
  	if (size)
  		*size = data_ptr - start_ptr;
  
  	return circstring;
  }
  
  static LWCOLLECTION *
  lwcollection_from_gserialized2_buffer(uint8_t *data_ptr, lwflags_t lwflags, size_t *size, int32_t srid)
  {
  	uint32_t type;
  	uint8_t *start_ptr = data_ptr;
  	LWCOLLECTION *collection;
  	uint32_t ngeoms = 0;
  	uint32_t i = 0;
  
  	assert(data_ptr);
  
  	type = gserialized2_get_uint32_t(data_ptr);
  	data_ptr += 4; /* Skip past the type. */
  
  	collection = (LWCOLLECTION*)lwalloc(sizeof(LWCOLLECTION));
  	collection->srid = srid;
  	collection->bbox = NULL;
  	collection->type = type;
  	collection->flags = lwflags;
  
  	ngeoms = gserialized2_get_uint32_t(data_ptr);
  	collection->ngeoms = ngeoms; /* Zero => empty geometry */
  	data_ptr += 4; /* Skip past the ngeoms. */
  
  	if (ngeoms > 0)
  	{
  		collection->geoms = lwalloc(sizeof(LWGEOM*) * ngeoms);
  		collection->maxgeoms = ngeoms;
  	}
  	else
  	{
  		collection->geoms = NULL;
  		collection->maxgeoms = 0;
  	}
  
  	/* Sub-geometries are never de-serialized with boxes (#1254) */
  	FLAGS_SET_BBOX(lwflags, 0);
  
  	for (i = 0; i < ngeoms; i++)
  	{
  		uint32_t subtype = gserialized2_get_uint32_t(data_ptr);
  		size_t subsize = 0;
  
  		if (!lwcollection_allows_subtype(type, subtype))
  		{
  			lwerror("Invalid subtype (%s) for collection type (%s)", lwtype_name(subtype), lwtype_name(type));
  			lwfree(collection);
  			return NULL;
  		}
  		collection->geoms[i] = lwgeom_from_gserialized2_buffer(data_ptr, lwflags, &subsize, srid);
  		data_ptr += subsize;
  	}
  
  	if (size)
  		*size = data_ptr - start_ptr;
  
  	return collection;
  }
  
  LWGEOM *
  lwgeom_from_gserialized2_buffer(uint8_t *data_ptr, lwflags_t lwflags, size_t *g_size, int32_t srid)
  {
  	uint32_t type;
  
  	assert(data_ptr);
  
  	type = gserialized2_get_uint32_t(data_ptr);
  
  	LWDEBUGF(2, "Got type %d (%s), hasz=%d hasm=%d geodetic=%d hasbox=%d", type, lwtype_name(type),
  		FLAGS_GET_Z(lwflags), FLAGS_GET_M(lwflags), FLAGS_GET_GEODETIC(lwflags), FLAGS_GET_BBOX(lwflags));
  
  	switch (type)
  	{
  	case POINTTYPE:
  		return (LWGEOM *)lwpoint_from_gserialized2_buffer(data_ptr, lwflags, g_size, srid);
  	case LINETYPE:
  		return (LWGEOM *)lwline_from_gserialized2_buffer(data_ptr, lwflags, g_size, srid);
  	case CIRCSTRINGTYPE:
  		return (LWGEOM *)lwcircstring_from_gserialized2_buffer(data_ptr, lwflags, g_size, srid);
  	case POLYGONTYPE:
  		return (LWGEOM *)lwpoly_from_gserialized2_buffer(data_ptr, lwflags, g_size, srid);
  	case TRIANGLETYPE:
  		return (LWGEOM *)lwtriangle_from_gserialized2_buffer(data_ptr, lwflags, g_size, srid);
  	case MULTIPOINTTYPE:
  	case MULTILINETYPE:
  	case MULTIPOLYGONTYPE:
  	case COMPOUNDTYPE:
  	case CURVEPOLYTYPE:
  	case MULTICURVETYPE:
  	case MULTISURFACETYPE:
  	case POLYHEDRALSURFACETYPE:
  	case TINTYPE:
  	case COLLECTIONTYPE:
  		return (LWGEOM *)lwcollection_from_gserialized2_buffer(data_ptr, lwflags, g_size, srid);
  	default:
  		lwerror("Unknown geometry type: %d - %s", type, lwtype_name(type));
  		return NULL;
  	}
  }
  
  LWGEOM* lwgeom_from_gserialized2(const GSERIALIZED *g)
  {
  	lwflags_t lwflags = 0;
  	int32_t srid = 0;
  	uint32_t lwtype = 0;
  	uint8_t *data_ptr = NULL;
  	LWGEOM *lwgeom = NULL;
  	GBOX bbox;
  	size_t size = 0;
  
  	assert(g);
  
  	srid = gserialized2_get_srid(g);
  	lwtype = gserialized2_get_type(g);
  	lwflags = gserialized2_get_lwflags(g);
  
  	LWDEBUGF(4, "Got type %d (%s), srid=%d", lwtype, lwtype_name(lwtype), srid);
  
  	data_ptr = (uint8_t*)g->data;
  
  	/* Skip optional flags */
  	if (G2FLAGS_GET_EXTENDED(g->gflags))
  	{
  		data_ptr += sizeof(uint64_t);
  	}
  
  	/* Skip over optional bounding box */
  	if (FLAGS_GET_BBOX(lwflags))
  		data_ptr += gbox_serialized_size(lwflags);
  
  	lwgeom = lwgeom_from_gserialized2_buffer(data_ptr, lwflags, &size, srid);
  
  	if (!lwgeom)
  		lwerror("%s: unable create geometry", __func__); /* Ooops! */
  
  	lwgeom->type = lwtype;
  	lwgeom->flags = lwflags;
  
  	if (gserialized2_read_gbox_p(g, &bbox) == LW_SUCCESS)
  	{
  		lwgeom->bbox = gbox_copy(&bbox);
  	}
  	else if (lwgeom_needs_bbox(lwgeom) && (lwgeom_calculate_gbox(lwgeom, &bbox) == LW_SUCCESS))
  	{
  		lwgeom->bbox = gbox_copy(&bbox);
  	}
  	else
  	{
  		lwgeom->bbox = NULL;
  	}
  
  	return lwgeom;
  }
  
  /**
  * Update the bounding box of a #GSERIALIZED, allocating a fresh one
  * if there is not enough space to just write the new box in.
  * <em>WARNING</em> if a new object needs to be created, the
  * input pointer will have to be freed by the caller! Check
  * to see if input == output. Returns null if there's a problem
  * like mismatched dimensions.
  */
  GSERIALIZED* gserialized2_set_gbox(GSERIALIZED *g, GBOX *gbox)
  {
  
  	int g_ndims = G2FLAGS_NDIMS_BOX(g->gflags);
  	int box_ndims = FLAGS_NDIMS_BOX(gbox->flags);
  	GSERIALIZED *g_out = NULL;
  	size_t box_size = 2 * g_ndims * sizeof(float);
  	float *fbox;
  	int fbox_pos = 0;
  
  	/* The dimensionality of the inputs has to match or we are SOL. */
  	if (g_ndims != box_ndims)
  	{
  		return NULL;
  	}
  
  	/* Serialized already has room for a box. */
  	if (G2FLAGS_GET_BBOX(g->gflags))
  	{
  		g_out = g;
  	}
  	/* Serialized has no box. We need to allocate enough space for the old
  	   data plus the box, and leave a gap in the memory segment to write
  	   the new values into.
  	*/
  	else
  	{
  		size_t varsize_in = LWSIZE_GET(g->size);
  		size_t varsize_out = varsize_in + box_size;
  		uint8_t *ptr_out, *ptr_in, *ptr;
  		g_out = lwalloc(varsize_out);
  		ptr_out = (uint8_t*)g_out;
  		ptr = ptr_in = (uint8_t*)g;
  		/* Copy the head of g into place */
  		memcpy(ptr_out, ptr_in, 8); ptr_out += 8; ptr_in += 8;
  		/* Optionally copy extended bit into place */
  		if (G2FLAGS_GET_EXTENDED(g->gflags))
  		{
  			memcpy(ptr_out, ptr_in, 8); ptr_out += 8; ptr_in += 8;
  		}
  		/* Copy the body of g into place after leaving space for the box */
  		ptr_out += box_size;
  		memcpy(ptr_out, ptr_in, varsize_in - (ptr_in - ptr));
  		G2FLAGS_SET_BBOX(g_out->gflags, 1);
  		LWSIZE_SET(g_out->size, varsize_out);
  	}
  
  	/* Move bounds to nearest float values */
  	gbox_float_round(gbox);
  	/* Now write the float box values into the memory segement */
  	fbox = (float*)(g_out->data);
  	/* Copy in X/Y */
  	fbox[fbox_pos++] = gbox->xmin;
  	fbox[fbox_pos++] = gbox->xmax;
  	fbox[fbox_pos++] = gbox->ymin;
  	fbox[fbox_pos++] = gbox->ymax;
  	/* Optionally copy in higher dims */
  	if(gserialized2_has_z(g) || gserialized2_is_geodetic(g))
  	{
  		fbox[fbox_pos++] = gbox->zmin;
  		fbox[fbox_pos++] = gbox->zmax;
  	}
  	if(gserialized2_has_m(g) && ! gserialized2_is_geodetic(g))
  	{
  		fbox[fbox_pos++] = gbox->mmin;
  		fbox[fbox_pos++] = gbox->mmax;
  	}
  
  	return g_out;
  }
  
  
  /**
  * Remove the bounding box from a #GSERIALIZED. Returns a freshly
  * allocated #GSERIALIZED every time.
  */
  GSERIALIZED* gserialized2_drop_gbox(GSERIALIZED *g)
  {
  	int g_ndims = G2FLAGS_NDIMS_BOX(g->gflags);
  	size_t box_size = 2 * g_ndims * sizeof(float);
  	size_t g_out_size = LWSIZE_GET(g->size) - box_size;
  	GSERIALIZED *g_out = lwalloc(g_out_size);
  
  	/* Copy the contents while omitting the box */
  	if (G2FLAGS_GET_BBOX(g->gflags))
  	{
  		uint8_t *outptr = (uint8_t*)g_out;
  		uint8_t *inptr = (uint8_t*)g;
  		/* Copy the header (size+type) of g into place */
  		memcpy(outptr, inptr, 8); outptr += 8; inptr += 8;
  		/* Copy extended flags, if there are any */
  		if (G2FLAGS_GET_EXTENDED(g->gflags))
  		{
  			memcpy(outptr, inptr, 8); outptr += 8; inptr += 8;
  		}
  		/* Advance past box */
  		inptr += box_size;
  		/* Copy parts after the box into place */
  		memcpy(outptr, inptr, g_out_size - 8);
  		G2FLAGS_SET_BBOX(g_out->gflags, 0);
  		LWSIZE_SET(g_out->size, g_out_size);
  	}
  	/* No box? Nothing to do but copy and return. */
  	else
  	{
  		memcpy(g_out, g, g_out_size);
  	}
  
  	return g_out;
  }
  