diff options
Diffstat (limited to 'ffmpeg/libavutil/fifo.c')
| -rw-r--r-- | ffmpeg/libavutil/fifo.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/ffmpeg/libavutil/fifo.c b/ffmpeg/libavutil/fifo.c new file mode 100644 index 0000000..bafa9e9 --- /dev/null +++ b/ffmpeg/libavutil/fifo.c @@ -0,0 +1,182 @@ +/* + * a very simple circular buffer FIFO implementation + * Copyright (c) 2000, 2001, 2002 Fabrice Bellard + * Copyright (c) 2006 Roman Shaposhnik + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ +#include "common.h" +#include "fifo.h" + +AVFifoBuffer *av_fifo_alloc(unsigned int size) +{ + AVFifoBuffer *f= av_mallocz(sizeof(AVFifoBuffer)); + if (!f) + return NULL; + f->buffer = av_malloc(size); + f->end = f->buffer + size; + av_fifo_reset(f); + if (!f->buffer) + av_freep(&f); + return f; +} + +void av_fifo_free(AVFifoBuffer *f) +{ + if (f) { + av_freep(&f->buffer); + av_free(f); + } +} + +void av_fifo_reset(AVFifoBuffer *f) +{ + f->wptr = f->rptr = f->buffer; + f->wndx = f->rndx = 0; +} + +int av_fifo_size(AVFifoBuffer *f) +{ + return (uint32_t)(f->wndx - f->rndx); +} + +int av_fifo_space(AVFifoBuffer *f) +{ + return f->end - f->buffer - av_fifo_size(f); +} + +int av_fifo_realloc2(AVFifoBuffer *f, unsigned int new_size) +{ + unsigned int old_size = f->end - f->buffer; + + if (old_size < new_size) { + int len = av_fifo_size(f); + AVFifoBuffer *f2 = av_fifo_alloc(new_size); + + if (!f2) + return AVERROR(ENOMEM); + av_fifo_generic_read(f, f2->buffer, len, NULL); + f2->wptr += len; + f2->wndx += len; + av_free(f->buffer); + *f = *f2; + av_free(f2); + } + return 0; +} + +int av_fifo_grow(AVFifoBuffer *f, unsigned int size) +{ + unsigned int old_size = f->end - f->buffer; + if(size + (unsigned)av_fifo_size(f) < size) + return AVERROR(EINVAL); + + size += av_fifo_size(f); + + if (old_size < size) + return av_fifo_realloc2(f, FFMAX(size, 2*size)); + return 0; +} + +// src must NOT be const as it can be a context for func that may need updating (like a pointer or byte counter) +int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int)) +{ + int total = size; + uint32_t wndx= f->wndx; + uint8_t *wptr= f->wptr; + + do { + int len = FFMIN(f->end - wptr, size); + if (func) { + if (func(src, wptr, len) <= 0) + break; + } else { + memcpy(wptr, src, len); + src = (uint8_t*)src + len; + } +// Write memory barrier needed for SMP here in theory + wptr += len; + if (wptr >= f->end) + wptr = f->buffer; + wndx += len; + size -= len; + } while (size > 0); + f->wndx= wndx; + f->wptr= wptr; + return total - size; +} + + +int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int)) +{ +// Read memory barrier needed for SMP here in theory + do { + int len = FFMIN(f->end - f->rptr, buf_size); + if(func) func(dest, f->rptr, len); + else{ + memcpy(dest, f->rptr, len); + dest = (uint8_t*)dest + len; + } +// memory barrier needed for SMP here in theory + av_fifo_drain(f, len); + buf_size -= len; + } while (buf_size > 0); + return 0; +} + +/** Discard data from the FIFO. */ +void av_fifo_drain(AVFifoBuffer *f, int size) +{ + f->rptr += size; + if (f->rptr >= f->end) + f->rptr -= f->end - f->buffer; + f->rndx += size; +} + +#ifdef TEST + +int main(void) +{ + /* create a FIFO buffer */ + AVFifoBuffer *fifo = av_fifo_alloc(13 * sizeof(int)); + int i, j, n; + + /* fill data */ + for (i = 0; av_fifo_space(fifo) >= sizeof(int); i++) + av_fifo_generic_write(fifo, &i, sizeof(int), NULL); + + /* peek at FIFO */ + n = av_fifo_size(fifo)/sizeof(int); + for (i = -n+1; i < n; i++) { + int *v = (int *)av_fifo_peek2(fifo, i*sizeof(int)); + printf("%d: %d\n", i, *v); + } + printf("\n"); + + /* read data */ + for (i = 0; av_fifo_size(fifo) >= sizeof(int); i++) { + av_fifo_generic_read(fifo, &j, sizeof(int), NULL); + printf("%d ", j); + } + printf("\n"); + + av_fifo_free(fifo); + + return 0; +} + +#endif |