FFmpeg
exrdsp.c
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1 /*
2  * This file is part of FFmpeg.
3  *
4  * Copyright (c) 2006 Industrial Light & Magic, a division of Lucas Digital Ltd. LLC
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include <stdint.h>
22 
23 #include "libavutil/attributes.h"
24 #include "exrdsp.h"
25 #include "config.h"
26 
27 static void reorder_pixels_scalar(uint8_t *dst, const uint8_t *src, ptrdiff_t size)
28 {
29  const uint8_t *t1 = src;
30  int half_size = size / 2;
31  const uint8_t *t2 = src + half_size;
32  uint8_t *s = dst;
33  int i;
34 
35  for (i = 0; i < half_size; i++) {
36  *(s++) = *(t1++);
37  *(s++) = *(t2++);
38  }
39 }
40 
41 static void predictor_scalar(uint8_t *src, ptrdiff_t size)
42 {
43  /* Unrolled: `src[i + 1] += src[i] - 128;` */
44  if ((size & 1) == 0) {
45  src[1] += src[0] ^ 0x80;
46  src++;
47  size--;
48  }
49 
50  for (ptrdiff_t i = 1; i < size; i += 2) {
51  uint8_t a = src[i] + src[i - 1];
52 
53  src[i] = a;
54  src[i + 1] += a;
55  src[i] ^= 0x80;
56  }
57 }
58 
60 {
61  c->reorder_pixels = reorder_pixels_scalar;
62  c->predictor = predictor_scalar;
63 
64 #if ARCH_RISCV
66 #elif ARCH_X86
68 #endif
69 }
reorder_pixels_scalar
static void reorder_pixels_scalar(uint8_t *dst, const uint8_t *src, ptrdiff_t size)
Definition: exrdsp.c:27
ExrDSPContext
Definition: exrdsp.h:25
av_cold
#define av_cold
Definition: attributes.h:90
s
#define s(width, name)
Definition: cbs_vp9.c:198
exrdsp.h
ff_exrdsp_init
av_cold void ff_exrdsp_init(ExrDSPContext *c)
Definition: exrdsp.c:59
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
dst
uint8_t ptrdiff_t const uint8_t ptrdiff_t int intptr_t intptr_t int int16_t * dst
Definition: dsp.h:83
ff_exrdsp_init_x86
void ff_exrdsp_init_x86(ExrDSPContext *c)
Definition: exrdsp_init.c:35
size
int size
Definition: twinvq_data.h:10344
a
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:41
predictor_scalar
static void predictor_scalar(uint8_t *src, ptrdiff_t size)
Definition: exrdsp.c:41
attributes.h
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:256
ff_exrdsp_init_riscv
void ff_exrdsp_init_riscv(ExrDSPContext *c)
Definition: exrdsp_init.c:29
src
#define src
Definition: vp8dsp.c:248