1/*
2 * This file is part of FFmpeg.
3 *
4 * FFmpeg is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * FFmpeg is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19#include "config.h"
20#include "libavutil/attributes.h"
21#include "huffyuvencdsp.h"
22#include "mathops.h"
23
24// 0x00010001 or 0x0001000100010001 or whatever, depending on the cpu's native arithmetic size
25#define pw_1 (ULONG_MAX / UINT16_MAX)
26
27static void diff_int16_c(uint16_t *dst, const uint16_t *src1, const uint16_t *src2, unsigned mask, int w){
28    long i;
29#if !HAVE_FAST_UNALIGNED
30    if((long)src2 & (sizeof(long)-1)){
31        for(i=0; i+3<w; i+=4){
32            dst[i+0] = (src1[i+0]-src2[i+0]) & mask;
33            dst[i+1] = (src1[i+1]-src2[i+1]) & mask;
34            dst[i+2] = (src1[i+2]-src2[i+2]) & mask;
35            dst[i+3] = (src1[i+3]-src2[i+3]) & mask;
36        }
37    }else
38#endif
39    {
40        unsigned long pw_lsb = (mask >> 1) * pw_1;
41        unsigned long pw_msb = pw_lsb +  pw_1;
42
43        for (i = 0; i <= w - (int)sizeof(long)/2; i += sizeof(long)/2) {
44            long a = *(long*)(src1+i);
45            long b = *(long*)(src2+i);
46            *(long*)(dst+i) = ((a|pw_msb) - (b&pw_lsb)) ^ ((a^b^pw_msb)&pw_msb);
47        }
48    }
49    for (; i<w; i++)
50        dst[i] = (src1[i] - src2[i]) & mask;
51}
52
53static 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){
54    int i;
55    uint16_t l, lt;
56
57    l  = *left;
58    lt = *left_top;
59
60    for(i=0; i<w; i++){
61        const int pred = mid_pred(l, src1[i], (l + src1[i] - lt) & mask);
62        lt = src1[i];
63        l  = src2[i];
64        dst[i] = (l - pred) & mask;
65    }
66
67    *left     = l;
68    *left_top = lt;
69}
70
71av_cold void ff_huffyuvencdsp_init(HuffYUVEncDSPContext *c, AVCodecContext *avctx)
72{
73    c->diff_int16           = diff_int16_c;
74    c->sub_hfyu_median_pred_int16 = sub_hfyu_median_pred_int16_c;
75
76#if ARCH_X86
77    ff_huffyuvencdsp_init_x86(c, avctx);
78#endif
79}
80