Clarify non constness of src in av_fifo_generic_write()
[libav.git] / libavutil / fifo.c
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f5a478f6 1/*
89c9ff50 2 * a very simple circular buffer FIFO implementation
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3 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
4 * Copyright (c) 2006 Roman Shaposhnik
5 *
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6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
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9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
b78e7197 11 * version 2.1 of the License, or (at your option) any later version.
f5a478f6 12 *
b78e7197 13 * FFmpeg is distributed in the hope that it will be useful,
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14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
b78e7197 19 * License along with FFmpeg; if not, write to the Free Software
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20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22#include "common.h"
23#include "fifo.h"
24
41dd680d 25AVFifoBuffer *av_fifo_alloc(unsigned int size)
f5a478f6 26{
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27 AVFifoBuffer *f= av_mallocz(sizeof(AVFifoBuffer));
28 if(!f)
29 return NULL;
f5a478f6 30 f->buffer = av_malloc(size);
4497712f 31 f->end = f->buffer + size;
32b936d0 32 av_fifo_reset(f);
f5a478f6 33 if (!f->buffer)
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34 av_freep(&f);
35 return f;
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36}
37
38void av_fifo_free(AVFifoBuffer *f)
39{
41dd680d 40 if(f){
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41 av_free(f->buffer);
42 av_free(f);
41dd680d 43 }
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44}
45
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46void av_fifo_reset(AVFifoBuffer *f)
47{
48 f->wptr = f->rptr = f->buffer;
49 f->wndx = f->rndx = 0;
50}
51
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52int av_fifo_size(AVFifoBuffer *f)
53{
0a71e78c 54 return (uint32_t)(f->wndx - f->rndx);
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55}
56
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57int av_fifo_space(AVFifoBuffer *f)
58{
59 return f->end - f->buffer - av_fifo_size(f);
60}
61
8257b835 62int av_fifo_realloc2(AVFifoBuffer *f, unsigned int new_size) {
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63 unsigned int old_size= f->end - f->buffer;
64
0a71e78c 65 if(old_size < new_size){
96e39edc 66 int len= av_fifo_size(f);
41dd680d 67 AVFifoBuffer *f2= av_fifo_alloc(new_size);
f5a478f6 68
41dd680d 69 if (!f2)
8257b835 70 return -1;
3898eed8 71 av_fifo_generic_read(f, f2->buffer, len, NULL);
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72 f2->wptr += len;
73 f2->wndx += len;
96e39edc 74 av_free(f->buffer);
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75 *f= *f2;
76 av_free(f2);
f5a478f6 77 }
8257b835 78 return 0;
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79}
80
fc323a54 81// src must NOT be const as it can be a context for func that may need updating (like a pointer or byte counter)
95c76e11 82int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int))
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83{
84 int total = size;
50b44685 85 do {
870a12d1 86 int len = FFMIN(f->end - f->wptr, size);
49cec199 87 if(func) {
95c76e11 88 if(func(src, f->wptr, len) <= 0)
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89 break;
90 } else {
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91 memcpy(f->wptr, src, len);
92 src = (uint8_t*)src + len;
49cec199 93 }
a9364759 94// Write memory barrier needed for SMP here in theory
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95 f->wptr += len;
96 if (f->wptr >= f->end)
97 f->wptr = f->buffer;
0a71e78c 98 f->wndx += len;
f5a478f6 99 size -= len;
50b44685 100 } while (size > 0);
49cec199 101 return total - size;
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102}
103
104
3898eed8 105int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int))
f5a478f6 106{
a9364759 107// Read memory barrier needed for SMP here in theory
50b44685 108 do {
870a12d1 109 int len = FFMIN(f->end - f->rptr, buf_size);
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110 if(func) func(dest, f->rptr, len);
111 else{
112 memcpy(dest, f->rptr, len);
113 dest = (uint8_t*)dest + len;
114 }
a9364759 115// memory barrier needed for SMP here in theory
3da97cfd 116 av_fifo_drain(f, len);
f5a478f6 117 buf_size -= len;
50b44685 118 } while (buf_size > 0);
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119 return 0;
120}
121
89c9ff50 122/** Discard data from the FIFO. */
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123void av_fifo_drain(AVFifoBuffer *f, int size)
124{
125 f->rptr += size;
126 if (f->rptr >= f->end)
127 f->rptr -= f->end - f->buffer;
0a71e78c 128 f->rndx += size;
f5a478f6 129}