add support for downmixing to stereo or mono
[ffmpeg-lucabe.git] / libavutil / fifo.c
blob8ac3a0cb55ca4c3a1eb35f2368ff07b51ad9e2be
1 /*
2 * A very simple circular buffer FIFO implementation
3 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
4 * Copyright (c) 2006 Roman Shaposhnik
6 * This file is part of FFmpeg.
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.
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.
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
22 #include "common.h"
23 #include "fifo.h"
25 int av_fifo_init(AVFifoBuffer *f, int size)
27 f->wptr = f->rptr =
28 f->buffer = av_malloc(size);
29 f->end = f->buffer + size;
30 if (!f->buffer)
31 return -1;
32 return 0;
35 void av_fifo_free(AVFifoBuffer *f)
37 av_free(f->buffer);
40 int av_fifo_size(AVFifoBuffer *f)
42 int size = f->wptr - f->rptr;
43 if (size < 0)
44 size += f->end - f->buffer;
45 return size;
48 /**
49 * Get data from the fifo (returns -1 if not enough data).
51 int av_fifo_read(AVFifoBuffer *f, uint8_t *buf, int buf_size)
53 return av_fifo_generic_read(f, buf_size, NULL, buf);
56 /**
57 * Resizes a FIFO.
59 void av_fifo_realloc(AVFifoBuffer *f, unsigned int new_size) {
60 unsigned int old_size= f->end - f->buffer;
62 if(old_size < new_size){
63 int len= av_fifo_size(f);
64 AVFifoBuffer f2;
66 av_fifo_init(&f2, new_size);
67 av_fifo_read(f, f2.buffer, len);
68 f2.wptr += len;
69 av_free(f->buffer);
70 *f= f2;
74 void av_fifo_write(AVFifoBuffer *f, const uint8_t *buf, int size)
76 do {
77 int len = FFMIN(f->end - f->wptr, size);
78 memcpy(f->wptr, buf, len);
79 f->wptr += len;
80 if (f->wptr >= f->end)
81 f->wptr = f->buffer;
82 buf += len;
83 size -= len;
84 } while (size > 0);
88 /** get data from the fifo (return -1 if not enough data) */
89 int av_fifo_generic_read(AVFifoBuffer *f, int buf_size, void (*func)(void*, void*, int), void* dest)
91 int size = av_fifo_size(f);
93 if (size < buf_size)
94 return -1;
95 do {
96 int len = FFMIN(f->end - f->rptr, buf_size);
97 if(func) func(dest, f->rptr, len);
98 else{
99 memcpy(dest, f->rptr, len);
100 dest = (uint8_t*)dest + len;
102 av_fifo_drain(f, len);
103 buf_size -= len;
104 } while (buf_size > 0);
105 return 0;
108 /** discard data from the fifo */
109 void av_fifo_drain(AVFifoBuffer *f, int size)
111 f->rptr += size;
112 if (f->rptr >= f->end)
113 f->rptr -= f->end - f->buffer;