/**************************************************************************
 *
 *  XVID MPEG-4 VIDEO CODEC
 *  -  Motion sad header  -
 *
 *  This program is an implementation of a part of one or more MPEG-4
 *  Video tools as specified in ISO/IEC 14496-2 standard.  Those intending
 *  to use this software module in hardware or software products are
 *  advised that its use may infringe existing patents or copyrights, and
 *  any such use would be at such party's own risk.  The original
 *  developer of this software module and his/her company, and subsequent
 *  editors and their companies, will have no liability for use of this
 *  software or modifications or derivatives thereof.
 *
 *  This program 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.
 *
 *  This program 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 this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 *  $Id: motion.h,v 1.5 2002/06/14 13:26:47 Isibaar Exp $
 *
 ***************************************************************************/

#ifndef _MOTION_SAD_H_
#define _MOTION_SAD_H_

#include "../portab.h"
#include "../global.h"

extern int first_P_seq;
extern int first_P_gop;
/*
 * Calculate the min/max range (in halfpixels)
 * relative to the _MACROBLOCK_ position
 */

static void __inline
get_range(int32_t * const min_dx,
		  int32_t * const max_dx,
		  int32_t * const min_dy,
		  int32_t * const max_dy,
		  const uint32_t x,
		  const uint32_t y,
		  const uint32_t block_sz,	/* block dimension, 8 or 16 */

		  const uint32_t width,
		  const uint32_t height,
		  const uint32_t fcode)
{
/* fyh comment */
	/*const int search_range = 32 << (fcode - 1);*/
	const int search_range = 32;/* half pixel search range */

	const int high = search_range - 1;
	const int low = -search_range;

	/* convert full-pixel measurements to half pixel */
	const int hp_width = 2 * width;
	const int hp_height = 2 * height;
	const int hp_edge = 2 * block_sz;

	/* we need _right end_ of block, not x-coordinate */
	const int hp_x = 2 * (x) * block_sz;

	/* same for _bottom end_ */
	const int hp_y = 2 * (y) * block_sz;

	*max_dx = min(high, hp_width - hp_x);
	*max_dy = min(high, hp_height - hp_y);
	*min_dx = max(low, -(hp_edge + hp_x));
	*min_dy = max(low, -(hp_edge + hp_y));

}


/*
 * getref: calculate reference image pointer 
 * the decision to use interpolation h/v/hv or the normal image is
 * based on dx & dy.
 */

static __inline const uint8_t *
get_ref(const uint8_t * const refn,
		const uint8_t * const refh,
		const uint8_t * const refv,
		const uint8_t * const refhv,
		const uint32_t x,
		const uint32_t y,
		const uint32_t block,	/* block dimension, 8 or 16 */

		const int32_t dx,
		const int32_t dy,
		const uint32_t stride)
{


	switch (((dx & 1) << 1) + (dy & 1)) {	/* ((dx%2)?2:0)+((dy%2)?1:0) */
	case 0:
		return refn + (int) ((x * block + dx / 2) + (y * block + dy / 2) * stride);
	case 1:
		return refv + (int) ((x * block + dx / 2) + (y * block +
											  (dy - 1) / 2) * stride);
	case 2:
		return refh + (int) ((x * block + (dx - 1) / 2) + (y * block +
													dy / 2) * stride);
	default:
	case 3:
		return refhv + (int) ((x * block + (dx - 1) / 2) + (y * block +
													 (dy - 1) / 2) * stride);
	}

}

#endif							/* _MOTION_SAD_H_ */