FFmpeg/libavcodec/huffyuvencdsp.c

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/*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "config.h"
#include "libavutil/attributes.h"
#include "huffyuvencdsp.h"
#include "mathops.h"
// 0x00010001 or 0x0001000100010001 or whatever, depending on the cpu's native arithmetic size
#define pw_1 (ULONG_MAX / UINT16_MAX)
static void diff_int16_c(uint16_t *dst, const uint16_t *src1, const uint16_t *src2, unsigned mask, int w){
long i;
#if !HAVE_FAST_UNALIGNED
if((long)src2 & (sizeof(long)-1)){
for(i=0; i+3<w; i+=4){
dst[i+0] = (src1[i+0]-src2[i+0]) & mask;
dst[i+1] = (src1[i+1]-src2[i+1]) & mask;
dst[i+2] = (src1[i+2]-src2[i+2]) & mask;
dst[i+3] = (src1[i+3]-src2[i+3]) & mask;
}
}else
#endif
{
unsigned long pw_lsb = (mask >> 1) * pw_1;
unsigned long pw_msb = pw_lsb + pw_1;
for (i = 0; i <= w - (int)sizeof(long)/2; i += sizeof(long)/2) {
long a = *(long*)(src1+i);
long b = *(long*)(src2+i);
*(long*)(dst+i) = ((a|pw_msb) - (b&pw_lsb)) ^ ((a^b^pw_msb)&pw_msb);
}
}
for (; i<w; i++)
dst[i] = (src1[i] - src2[i]) & mask;
}
static void sub_hfyu_median_pred_int16_c(uint16_t *dst, const uint16_t *src1, const uint16_t *src2, unsigned mask, int w, int *left, int *left_top){
int i;
uint16_t l, lt;
l = *left;
lt = *left_top;
for(i=0; i<w; i++){
const int pred = mid_pred(l, src1[i], (l + src1[i] - lt) & mask);
lt = src1[i];
l = src2[i];
dst[i] = (l - pred) & mask;
}
*left = l;
*left_top = lt;
}
av_cold void ff_huffyuvencdsp_init(HuffYUVEncDSPContext *c, AVCodecContext *avctx)
{
c->diff_int16 = diff_int16_c;
c->sub_hfyu_median_pred_int16 = sub_hfyu_median_pred_int16_c;
if (ARCH_X86)
ff_huffyuvencdsp_init_x86(c, avctx);
}