diff options
Diffstat (limited to 'libavutil/fifo.c')
| -rw-r--r-- | libavutil/fifo.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/libavutil/fifo.c b/libavutil/fifo.c index 55621f0dca..0001ccbd43 100644 --- a/libavutil/fifo.c +++ b/libavutil/fifo.c @@ -26,6 +26,232 @@ #include "common.h" #include "fifo.h" +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; +}; + +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; + + return f; +} + +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 = f->nb_elems + copy; + } + + f->nb_elems += inc; + + return 0; +} + +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 = f->offset_w; + int ret = 0; + + if (to_write > av_fifo_can_write(f)) + return AVERROR(ENOSPC); + + 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); + } +} + + #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) |