Statistics
| Branch: | Revision:

ffmpeg / libavutil / fifo.c @ 17354407

History | View | Annotate | Download (3.42 KB)

1
/*
2
 * a very simple circular buffer FIFO implementation
3
 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
4
 * Copyright (c) 2006 Roman Shaposhnik
5
 *
6
 * This file is part of FFmpeg.
7
 *
8
 * FFmpeg is free software; you can redistribute it and/or
9
 * modify it under the terms of the GNU Lesser General Public
10
 * License as published by the Free Software Foundation; either
11
 * version 2.1 of the License, or (at your option) any later version.
12
 *
13
 * FFmpeg is distributed in the hope that it will be useful,
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
19
 * License along with FFmpeg; if not, write to the Free Software
20
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21
 */
22
#include "common.h"
23
#include "fifo.h"
24

    
25
AVFifoBuffer *av_fifo_alloc(unsigned int size)
26
{
27
    AVFifoBuffer *f= av_mallocz(sizeof(AVFifoBuffer));
28
    if(!f)
29
        return NULL;
30
    f->buffer = av_malloc(size);
31
    f->end = f->buffer + size;
32
    av_fifo_reset(f);
33
    if (!f->buffer)
34
        av_freep(&f);
35
    return f;
36
}
37

    
38
void av_fifo_free(AVFifoBuffer *f)
39
{
40
    if(f){
41
        av_freep(&f->buffer);
42
        av_free(f);
43
    }
44
}
45

    
46
void av_fifo_reset(AVFifoBuffer *f)
47
{
48
    f->wptr = f->rptr = f->buffer;
49
    f->wndx = f->rndx = 0;
50
}
51

    
52
int av_fifo_size(AVFifoBuffer *f)
53
{
54
    return (uint32_t)(f->wndx - f->rndx);
55
}
56

    
57
int av_fifo_space(AVFifoBuffer *f)
58
{
59
    return f->end - f->buffer - av_fifo_size(f);
60
}
61

    
62
int av_fifo_realloc2(AVFifoBuffer *f, unsigned int new_size) {
63
    unsigned int old_size= f->end - f->buffer;
64

    
65
    if(old_size < new_size){
66
        int len= av_fifo_size(f);
67
        AVFifoBuffer *f2= av_fifo_alloc(new_size);
68

    
69
        if (!f2)
70
            return -1;
71
        av_fifo_generic_read(f, f2->buffer, len, NULL);
72
        f2->wptr += len;
73
        f2->wndx += len;
74
        av_free(f->buffer);
75
        *f= *f2;
76
        av_free(f2);
77
    }
78
    return 0;
79
}
80

    
81
// src must NOT be const as it can be a context for func that may need updating (like a pointer or byte counter)
82
int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int))
83
{
84
    int total = size;
85
    do {
86
        int len = FFMIN(f->end - f->wptr, size);
87
        if(func) {
88
            if(func(src, f->wptr, len) <= 0)
89
                break;
90
        } else {
91
            memcpy(f->wptr, src, len);
92
            src = (uint8_t*)src + len;
93
        }
94
// Write memory barrier needed for SMP here in theory
95
        f->wptr += len;
96
        if (f->wptr >= f->end)
97
            f->wptr = f->buffer;
98
        f->wndx += len;
99
        size -= len;
100
    } while (size > 0);
101
    return total - size;
102
}
103

    
104

    
105
int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int))
106
{
107
// Read memory barrier needed for SMP here in theory
108
    do {
109
        int len = FFMIN(f->end - f->rptr, buf_size);
110
        if(func) func(dest, f->rptr, len);
111
        else{
112
            memcpy(dest, f->rptr, len);
113
            dest = (uint8_t*)dest + len;
114
        }
115
// memory barrier needed for SMP here in theory
116
        av_fifo_drain(f, len);
117
        buf_size -= len;
118
    } while (buf_size > 0);
119
    return 0;
120
}
121

    
122
/** Discard data from the FIFO. */
123
void 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;
128
    f->rndx += size;
129
}