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 "lossless_videoencdsp.h"
22#include "mathops.h"
23
24// 0x7f7f7f7f or 0x7f7f7f7f7f7f7f7f or whatever, depending on the cpu's native arithmetic size
25#define pb_7f (~0UL / 255 * 0x7f)
26#define pb_80 (~0UL / 255 * 0x80)
27
28static void diff_bytes_c(uint8_t *dst, const uint8_t *src1, const uint8_t *src2, intptr_t w)
29{
30    long i;
31
32#if !HAVE_FAST_UNALIGNED
33    if (((long)src1 | (long)src2) & (sizeof(long) - 1)) {
34        for (i = 0; i + 7 < w; i += 8) {
35            dst[i + 0] = src1[i + 0] - src2[i + 0];
36            dst[i + 1] = src1[i + 1] - src2[i + 1];
37            dst[i + 2] = src1[i + 2] - src2[i + 2];
38            dst[i + 3] = src1[i + 3] - src2[i + 3];
39            dst[i + 4] = src1[i + 4] - src2[i + 4];
40            dst[i + 5] = src1[i + 5] - src2[i + 5];
41            dst[i + 6] = src1[i + 6] - src2[i + 6];
42            dst[i + 7] = src1[i + 7] - src2[i + 7];
43        }
44    } else
45#endif
46    for (i = 0; i <= w - (int) sizeof(long); i += sizeof(long)) {
47        long a = *(long *) (src1 + i);
48        long b = *(long *) (src2 + i);
49        *(long *) (dst + i) = ((a | pb_80) - (b & pb_7f)) ^
50                              ((a ^ b ^ pb_80) & pb_80);
51    }
52    for (; i < w; i++)
53        dst[i + 0] = src1[i + 0] - src2[i + 0];
54}
55
56static void sub_median_pred_c(uint8_t *dst, const uint8_t *src1,
57                              const uint8_t *src2, intptr_t w,
58                              int *left, int *left_top)
59{
60    int i;
61    uint8_t l, lt;
62
63    l  = *left;
64    lt = *left_top;
65
66    for (i = 0; i < w; i++) {
67        const int pred = mid_pred(l, src1[i], (l + src1[i] - lt) & 0xFF);
68        lt     = src1[i];
69        l      = src2[i];
70        dst[i] = l - pred;
71    }
72
73    *left     = l;
74    *left_top = lt;
75}
76
77static void sub_left_predict_c(uint8_t *dst, uint8_t *src,
78                               ptrdiff_t stride, ptrdiff_t width, int height)
79{
80    int i, j;
81    uint8_t prev = 0x80; /* Set the initial value */
82    for (j = 0; j < height; j++) {
83        for (i = 0; i < width; i++) {
84            *dst++ = src[i] - prev;
85            prev   = src[i];
86        }
87        src += stride;
88    }
89}
90
91av_cold void ff_llvidencdsp_init(LLVidEncDSPContext *c)
92{
93    c->diff_bytes      = diff_bytes_c;
94    c->sub_median_pred = sub_median_pred_c;
95    c->sub_left_predict = sub_left_predict_c;
96
97#if ARCH_X86
98    ff_llvidencdsp_init_x86(c);
99#endif
100}
101