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/*****************************************************************************
* dct.c: h264 encoder library
*****************************************************************************
* Copyright (C) 2003 Laurent Aimar
* $Id: dct.c,v 1.1 2003/11/09 23:25:04 fenrir Exp $
*
* Authors: Laurent Aimar <fenrir@via.ecp.fr>
*
* 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, USA.
*****************************************************************************/

#include <stdlib.h>
#include <string.h>
#include <stdint.h>

#include "dct.h"
/*
* XXX For all dct input could be equal to output so ...
*/

static void dct2x2dc( int16_t dct[2][2], int16_t diff[2][2] )
{
int tmp[2][2];

tmp[0][0] = diff[0][0] + diff[0][1];
tmp[1][0] = diff[0][0] - diff[0][1];
tmp[0][1] = diff[1][0] + diff[1][1];
tmp[1][1] = diff[1][0] - diff[1][1];

dct[0][0] = tmp[0][0] + tmp[0][1];
dct[0][1] = tmp[1][0] + tmp[1][1];
dct[1][0] = tmp[0][0] - tmp[0][1];
dct[1][1] = tmp[1][0] - tmp[1][1];
}

static void idct2x2dc( int16_t diff[2][2], int16_t dct[2][2] )
{
dct2x2dc( dct, diff );
}

static void dct4x4dc( int16_t dct[4][4], int16_t diff[4][4] )
{
int16_t tmp[4][4];
int s01, s23;
int d01, d23;
int i;

for( i = 0; i < 4; i++ )
{
s01 = diff[i][0] + diff[i][1];
d01 = diff[i][0] - diff[i][1];
s23 = diff[i][2] + diff[i][3];
d23 = diff[i][2] - diff[i][3];

tmp[0][i] = s01 + s23;
tmp[1][i] = s01 - s23;
tmp[2][i] = d01 - d23;
tmp[3][i] = d01 + d23;
}

for( i = 0; i < 4; i++ )
{
s01 = tmp[i][0] + tmp[i][1];
d01 = tmp[i][0] - tmp[i][1];
s23 = tmp[i][2] + tmp[i][3];
d23 = tmp[i][2] - tmp[i][3];

dct[0][i] = ( s01 + s23 + 1 ) >> 1;
dct[1][i] = ( s01 - s23 + 1 ) >> 1;
dct[2][i] = ( d01 - d23 + 1 ) >> 1;
dct[3][i] = ( d01 + d23 + 1 ) >> 1;
}
}

static void idct4x4dc( int16_t diff[4][4], int16_t dct[4][4] )
{
int16_t tmp[4][4];
int s01, s23;
int d01, d23;
int i;

for( i = 0; i < 4; i++ )
{
s01 = dct[0][i] + dct[1][i];
d01 = dct[0][i] - dct[1][i];
s23 = dct[2][i] + dct[3][i];
d23 = dct[2][i] - dct[3][i];

tmp[0][i] = s01 + s23;
tmp[1][i] = s01 - s23;
tmp[2][i] = d01 - d23;
tmp[3][i] = d01 + d23;
}

for( i = 0; i < 4; i++ )
{
s01 = tmp[i][0] + tmp[i][1];
d01 = tmp[i][0] - tmp[i][1];
s23 = tmp[i][2] + tmp[i][3];
d23 = tmp[i][2] - tmp[i][3];

diff[i][0] = s01 + s23;
diff[i][1] = s01 - s23;
diff[i][2] = d01 - d23;
diff[i][3] = d01 + d23;
}
}


static void dct4x4( int16_t dct[4][4], int16_t diff[4][4] )
{
int16_t tmp[4][4];
int s03, s12;
int d03, d12;
int i;

for( i = 0; i < 4; i++ )
{
s03 = diff[i][0] + diff[i][3];
s12 = diff[i][1] + diff[i][2];
d03 = diff[i][0] - diff[i][3];
d12 = diff[i][1] - diff[i][2];

tmp[0][i] = s03 + s12;
tmp[1][i] = 2*d03 + d12;
tmp[2][i] = s03 - s12;
tmp[3][i] = d03 - 2*d12;
}

for( i = 0; i < 4; i++ )
{
s03 = tmp[i][0] + tmp[i][3];
s12 = tmp[i][1] + tmp[i][2];
d03 = tmp[i][0] - tmp[i][3];
d12 = tmp[i][1] - tmp[i][2];

dct[0][i] = s03 + s12;
dct[1][i] = 2*d03 + d12;
dct[2][i] = s03 - s12;
dct[3][i] = d03 - 2*d12;
}
}

static void idct4x4( int16_t diff[4][4], int16_t dct[4][4] )
{
int16_t tmp[4][4];
int s02, d02;
int s13, d13;
int i;

for( i = 0; i < 4; i++ )
{
s02 = dct[0][i] + dct[2][i];
d02 = dct[0][i] - dct[2][i];
s13 = dct[1][i] + (dct[3][i]>>1);
d13 = (dct[1][i]>>1) - dct[3][i];

tmp[0][i] = s02 + s13;
tmp[1][i] = d02 + d13;
tmp[2][i] = d02 - d13;
tmp[3][i] = s02 - s13;
}

for( i = 0; i < 4; i++ )
{
s02 = tmp[i][0] + tmp[i][2];
d02 = tmp[i][0] - tmp[i][2];
s13 = tmp[i][1] + (tmp[i][3]>>1);
d13 = (tmp[i][1]>>1) - tmp[i][3];

diff[i][0] = ( s02 + s13 + 32 ) >> 6;
diff[i][1] = ( d02 + d13 + 32 ) >> 6;
diff[i][2] = ( d02 - d13 + 32 ) >> 6;
diff[i][3] = ( s02 - s13 + 32 ) >> 6;
}
}
void x264_dct_init( int cpu, x264_dct_function_t *dctf )
{
dctf->dct4x4 = dct4x4;
dctf->dct4x4dc = dct4x4dc;
dctf->idct4x4 = idct4x4;
dctf->idct4x4dc = idct4x4dc;
dctf->dct2x2dc = dct2x2dc;
dctf->idct2x2dc = idct2x2dc;
}