/* * 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 <stdint.h> #include "avassert.h" #include "common.h" #include "fifo.h" // by default the FIFO can be auto-grown to 1MB #define AUTO_GROW_DEFAULT_BYTES (1024 * 1024) struct AVFifo { uint8_t *buffer; size_t elem_size, nb_elems; size_t offset_r, offset_w; // distinguishes the ambiguous situation offset_r == offset_w int is_empty; unsigned int flags; size_t auto_grow_limit; }; AVFifo *av_fifo_alloc2(size_t nb_elems, size_t elem_size, unsigned int flags) { AVFifo *f; void *buffer = NULL; if (!elem_size) return NULL; if (nb_elems) { buffer = av_realloc_array(NULL, nb_elems, elem_size); if (!buffer) return NULL; } f = av_mallocz(sizeof(*f)); if (!f) { av_free(buffer); return NULL; } f->buffer = buffer; f->nb_elems = nb_elems; f->elem_size = elem_size; f->is_empty = 1; f->flags = flags; f->auto_grow_limit = FFMAX(AUTO_GROW_DEFAULT_BYTES / elem_size, 1); return f; } void av_fifo_auto_grow_limit(AVFifo *f, size_t max_elems) { f->auto_grow_limit = max_elems; } size_t av_fifo_elem_size(const AVFifo *f) { return f->elem_size; } size_t av_fifo_can_read(const AVFifo *f) { if (f->offset_w <= f->offset_r && !f->is_empty) return f->nb_elems - f->offset_r + f->offset_w; return f->offset_w - f->offset_r; } size_t av_fifo_can_write(const AVFifo *f) { return f->nb_elems - av_fifo_can_read(f); } int av_fifo_grow2(AVFifo *f, size_t inc) { uint8_t *tmp; if (inc > SIZE_MAX - f->nb_elems) return AVERROR(EINVAL); tmp = av_realloc_array(f->buffer, f->nb_elems + inc, f->elem_size); if (!tmp) return AVERROR(ENOMEM); f->buffer = tmp; // move the data from the beginning of the ring buffer // to the newly allocated space if (f->offset_w <= f->offset_r && !f->is_empty) { const size_t copy = FFMIN(inc, f->offset_w); memcpy(tmp + f->nb_elems * f->elem_size, tmp, copy * f->elem_size); if (copy < f->offset_w) { memmove(tmp, tmp + copy * f->elem_size, (f->offset_w - copy) * f->elem_size); f->offset_w -= copy; } else f->offset_w = copy == inc ? 0 : f->nb_elems + copy; } f->nb_elems += inc; return 0; } static int fifo_check_space(AVFifo *f, size_t to_write) { const size_t can_write = av_fifo_can_write(f); const size_t need_grow = to_write > can_write ? to_write - can_write : 0; size_t can_grow; if (!need_grow) return 0; can_grow = f->auto_grow_limit > f->nb_elems ? f->auto_grow_limit - f->nb_elems : 0; if ((f->flags & AV_FIFO_FLAG_AUTO_GROW) && need_grow <= can_grow) { // allocate a bit more than necessary, if we can const size_t inc = (need_grow < can_grow / 2 ) ? need_grow * 2 : can_grow; return av_fifo_grow2(f, inc); } return AVERROR(ENOSPC); } static int fifo_write_common(AVFifo *f, const uint8_t *buf, size_t *nb_elems, AVFifoCB read_cb, void *opaque) { size_t to_write = *nb_elems; size_t offset_w; int ret = 0; ret = fifo_check_space(f, to_write); if (ret < 0) return ret; offset_w = f->offset_w; while (to_write > 0) { size_t len = FFMIN(f->nb_elems - offset_w, to_write); uint8_t *wptr = f->buffer + offset_w * f->elem_size; if (read_cb) { ret = read_cb(opaque, wptr, &len); if (ret < 0 || len == 0) break; } else { memcpy(wptr, buf, len * f->elem_size); buf += len * f->elem_size; } offset_w += len; if (offset_w >= f->nb_elems) offset_w = 0; to_write -= len; } f->offset_w = offset_w; if (*nb_elems != to_write) f->is_empty = 0; *nb_elems -= to_write; return ret; } int av_fifo_write(AVFifo *f, const void *buf, size_t nb_elems) { return fifo_write_common(f, buf, &nb_elems, NULL, NULL); } int av_fifo_write_from_cb(AVFifo *f, AVFifoCB read_cb, void *opaque, size_t *nb_elems) { return fifo_write_common(f, NULL, nb_elems, read_cb, opaque); } static int fifo_peek_common(const AVFifo *f, uint8_t *buf, size_t *nb_elems, size_t offset, AVFifoCB write_cb, void *opaque) { size_t to_read = *nb_elems; size_t offset_r = f->offset_r; size_t can_read = av_fifo_can_read(f); int ret = 0; if (offset > can_read || to_read > can_read - offset) { *nb_elems = 0; return AVERROR(EINVAL); } if (offset_r >= f->nb_elems - offset) offset_r -= f->nb_elems - offset; else offset_r += offset; while (to_read > 0) { size_t len = FFMIN(f->nb_elems - offset_r, to_read); uint8_t *rptr = f->buffer + offset_r * f->elem_size; if (write_cb) { ret = write_cb(opaque, rptr, &len); if (ret < 0 || len == 0) break; } else { memcpy(buf, rptr, len * f->elem_size); buf += len * f->elem_size; } offset_r += len; if (offset_r >= f->nb_elems) offset_r = 0; to_read -= len; } *nb_elems -= to_read; return ret; } int av_fifo_read(AVFifo *f, void *buf, size_t nb_elems) { int ret = fifo_peek_common(f, buf, &nb_elems, 0, NULL, NULL); av_fifo_drain2(f, nb_elems); return ret; } int av_fifo_read_to_cb(AVFifo *f, AVFifoCB write_cb, void *opaque, size_t *nb_elems) { int ret = fifo_peek_common(f, NULL, nb_elems, 0, write_cb, opaque); av_fifo_drain2(f, *nb_elems); return ret; } int av_fifo_peek(AVFifo *f, void *buf, size_t nb_elems, size_t offset) { return fifo_peek_common(f, buf, &nb_elems, offset, NULL, NULL); } int av_fifo_peek_to_cb(AVFifo *f, AVFifoCB write_cb, void *opaque, size_t *nb_elems, size_t offset) { return fifo_peek_common(f, NULL, nb_elems, offset, write_cb, opaque); } void av_fifo_drain2(AVFifo *f, size_t size) { const size_t cur_size = av_fifo_can_read(f); av_assert0(cur_size >= size); if (cur_size == size) f->is_empty = 1; if (f->offset_r >= f->nb_elems - size) f->offset_r -= f->nb_elems - size; else f->offset_r += size; } void av_fifo_reset2(AVFifo *f) { f->offset_r = f->offset_w = 0; f->is_empty = 1; } void av_fifo_freep2(AVFifo **f) { if (*f) { av_freep(&(*f)->buffer); av_freep(f); } } #if FF_API_FIFO_OLD_API FF_DISABLE_DEPRECATION_WARNINGS #define OLD_FIFO_SIZE_MAX (size_t)FFMIN3(INT_MAX, UINT32_MAX, SIZE_MAX) AVFifoBuffer *av_fifo_alloc_array(size_t nmemb, size_t size) { AVFifoBuffer *f; void *buffer; if (nmemb > OLD_FIFO_SIZE_MAX / size) return NULL; buffer = av_realloc_array(NULL, nmemb, size); if (!buffer) return NULL; f = av_mallocz(sizeof(AVFifoBuffer)); if (!f) { av_free(buffer); return NULL; } f->buffer = buffer; f->end = f->buffer + nmemb * size; av_fifo_reset(f); return f; } AVFifoBuffer *av_fifo_alloc(unsigned int size) { return av_fifo_alloc_array(size, 1); } void av_fifo_free(AVFifoBuffer *f) { if (f) { av_freep(&f->buffer); av_free(f); } } void av_fifo_freep(AVFifoBuffer **f) { if (f) { av_fifo_free(*f); *f = NULL; } } void av_fifo_reset(AVFifoBuffer *f) { f->wptr = f->rptr = f->buffer; f->wndx = f->rndx = 0; } int av_fifo_size(const AVFifoBuffer *f) { return (uint32_t)(f->wndx - f->rndx); } int av_fifo_space(const 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 (new_size > OLD_FIFO_SIZE_MAX) return AVERROR(EINVAL); if (old_size < new_size) { size_t offset_r = f->rptr - f->buffer; size_t offset_w = f->wptr - f->buffer; uint8_t *tmp; tmp = av_realloc(f->buffer, new_size); if (!tmp) return AVERROR(ENOMEM); // move the data from the beginning of the ring buffer // to the newly allocated space // the second condition distinguishes full vs empty fifo if (offset_w <= offset_r && av_fifo_size(f)) { const size_t copy = FFMIN(new_size - old_size, offset_w); memcpy(tmp + old_size, tmp, copy); if (copy < offset_w) { memmove(tmp, tmp + copy , offset_w - copy); offset_w -= copy; } else offset_w = old_size + copy; } f->buffer = tmp; f->end = f->buffer + new_size; f->rptr = f->buffer + offset_r; f->wptr = f->buffer + offset_w; } 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*old_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; if (size > av_fifo_space(f)) return AVERROR(ENOSPC); do { int len = FFMIN(f->end - wptr, size); if (func) { len = func(src, wptr, len); if (len <= 0) break; } else { memcpy(wptr, src, len); src = (uint8_t *)src + len; } 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_peek_at(AVFifoBuffer *f, void *dest, int offset, int buf_size, void (*func)(void*, void*, int)) { uint8_t *rptr = f->rptr; if (offset < 0 || buf_size > av_fifo_size(f) - offset) return AVERROR(EINVAL); if (offset >= f->end - rptr) rptr += offset - (f->end - f->buffer); else rptr += offset; while (buf_size > 0) { int len; if (rptr >= f->end) rptr -= f->end - f->buffer; len = FFMIN(f->end - rptr, buf_size); if (func) func(dest, rptr, len); else { memcpy(dest, rptr, len); dest = (uint8_t *)dest + len; } buf_size -= len; rptr += len; } return 0; } int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void *, void *, int)) { return av_fifo_generic_peek_at(f, dest, 0, buf_size, func); } int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void *, void *, int)) { if (buf_size > av_fifo_size(f)) return AVERROR(EINVAL); 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; } 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) { av_assert2(av_fifo_size(f) >= size); f->rptr += size; if (f->rptr >= f->end) f->rptr -= f->end - f->buffer; f->rndx += size; } FF_ENABLE_DEPRECATION_WARNINGS #endif