dct.h

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/*===========================================================================*
 * dct.h								     *
 *									     *
 *	DCT procedures							     *
 *									     *
 *===========================================================================*/

/*
 * Copyright (c) 1995 The Regents of the University of California.
 * All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose, without fee, and without written agreement is
 * hereby granted, provided that the above copyright notice and the following
 * two paragraphs appear in all copies of this software.
 *
 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
 * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
 * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 */


#ifndef DCT_INCLUDED
#define DCT_INCLUDED


#include "ansi.h"



#define DCTSIZE     8   /* you really don't want to change this */
#define DCTSIZE_SQ 64   /* you really don't want to change this */

#define DCTSIZE2    64
typedef short DCTELEM;
typedef DCTELEM DCTBLOCK[DCTSIZE2];
typedef DCTELEM DCTBLOCK_2D[DCTSIZE][DCTSIZE];


/*  
 *  from mfwddct.c:
 */
extern void mp_fwd_dct_block2 _ANSI_ARGS_((DCTBLOCK_2D src, DCTBLOCK_2D dest));

/* jrevdct.c */
extern void init_pre_idct _ANSI_ARGS_((void ));
extern void mpeg_jrevdct _ANSI_ARGS_((DCTBLOCK data ));


/* We assume that right shift corresponds to signed division by 2 with
 * rounding towards minus infinity.  This is correct for typical "arithmetic
 * shift" instructions that shift in copies of the sign bit.  But some
 * C compilers implement >> with an unsigned shift.  For these machines you
 * must define RIGHT_SHIFT_IS_UNSIGNED.
 * RIGHT_SHIFT provides a proper signed right shift of an int32 quantity.
 * It is only applied with constant shift counts.  SHIFT_TEMPS must be
 * included in the variables of any routine using RIGHT_SHIFT.
 */

#ifdef RIGHT_SHIFT_IS_UNSIGNED
#define SHIFT_TEMPS     int32 shift_temp;
#define RIGHT_SHIFT(x,shft)  \
        ((shift_temp = (x)) < 0 ? \
         (shift_temp >> (shft)) | ((~((int32) 0)) << (32-(shft))) : \
         (shift_temp >> (shft)))
#else
#define SHIFT_TEMPS
#define RIGHT_SHIFT(x,shft)     ((x) >> (shft))
#endif


#endif /* DCT_INCLUDED */