Statistics
| Branch: | Revision:

ffmpeg / libavutil / fifo.c @ 870a12d1

History | View | Annotate | Download (3.28 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
int av_fifo_init(AVFifoBuffer *f, int size)
26
{
27
    f->buffer = av_malloc(size);
28
    if (!f->buffer)
29
        return -1;
30
    f->end = f->buffer + size;
31
    f->wptr = f->rptr = f->buffer;
32
    return 0;
33
}
34

    
35
void av_fifo_free(AVFifoBuffer *f)
36
{
37
    av_free(f->buffer);
38
}
39

    
40
int av_fifo_size(AVFifoBuffer *f)
41
{
42
    int size = f->wptr - f->rptr;
43
    if (size < 0)
44
        size += f->end - f->buffer;
45
    return size;
46
}
47

    
48
/**
49
 * Get data from the fifo (returns -1 if not enough data).
50
 */
51
int av_fifo_read(AVFifoBuffer *f, uint8_t *buf, int buf_size)
52
{
53
    int size = av_fifo_size(f);
54

    
55
    if (size < buf_size)
56
        return -1;
57
    while (buf_size > 0) {
58
        int len = FFMIN(f->end - f->rptr, buf_size);
59
        memcpy(buf, f->rptr, len);
60
        buf += len;
61
        f->rptr += len;
62
        if (f->rptr >= f->end)
63
            f->rptr = f->buffer;
64
        buf_size -= len;
65
    }
66
    return 0;
67
}
68

    
69
/**
70
 * Resizes a FIFO.
71
 */
72
void av_fifo_realloc(AVFifoBuffer *f, unsigned int new_size) {
73
    unsigned int old_size= f->end - f->buffer;
74

    
75
    if(old_size < new_size){
76
        uint8_t *old= f->buffer;
77

    
78
        f->buffer= av_realloc(f->buffer, new_size);
79

    
80
        f->rptr += f->buffer - old;
81
        f->wptr += f->buffer - old;
82

    
83
        if(f->wptr < f->rptr){
84
            memmove(f->rptr + new_size - old_size, f->rptr, f->buffer + old_size - f->rptr);
85
            f->rptr += new_size - old_size;
86
        }
87
        f->end= f->buffer + new_size;
88
    }
89
}
90

    
91
void av_fifo_write(AVFifoBuffer *f, const uint8_t *buf, int size)
92
{
93
    while (size > 0) {
94
        int len = FFMIN(f->end - f->wptr, size);
95
        memcpy(f->wptr, buf, len);
96
        f->wptr += len;
97
        if (f->wptr >= f->end)
98
            f->wptr = f->buffer;
99
        buf += len;
100
        size -= len;
101
    }
102
}
103

    
104

    
105
/* get data from the fifo (return -1 if not enough data) */
106
int av_fifo_generic_read(AVFifoBuffer *f, int buf_size, void (*func)(void*, void*, int), void* dest)
107
{
108
    int size = av_fifo_size(f);
109

    
110
    if (size < buf_size)
111
        return -1;
112
    while (buf_size > 0) {
113
        int len = FFMIN(f->end - f->rptr, buf_size);
114
        func(dest, f->rptr, len);
115
        f->rptr += len;
116
        if (f->rptr >= f->end)
117
            f->rptr = f->buffer;
118
        buf_size -= len;
119
    }
120
    return 0;
121
}
122

    
123
/* discard data from the fifo */
124
void av_fifo_drain(AVFifoBuffer *f, int size)
125
{
126
    f->rptr += size;
127
    if (f->rptr >= f->end)
128
        f->rptr -= f->end - f->buffer;
129
}