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lavu/fifo: return errors on trying to read/write too much 

Trying to write too much will currently overwrite previous data. Trying
to read too much will either av_assert2() in av_fifo_drain() or return
old data. Trying to peek too much will either av_assert2() in
av_fifo_generic_peek_at() or return old data.

Return an error code in all these cases, which is safer and more
consistent.
This commit is contained in:
Anton Khirnov 2021-12-31 11:41:11 +01:00
parent 53f513c60b
commit f480c43dfa
2 changed files with 18 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
libavutil/fifo.c
View File

@ -134,6 +134,9 @@ int av_fifo_generic_write(AVFifoBuffer *f, void *src, int 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) {
@ -159,13 +162,8 @@ int av_fifo_generic_peek_at(AVFifoBuffer *f, void *dest, int offset, int buf_siz
{
uint8_t *rptr = f->rptr;
av_assert2(offset >= 0);
/*
* *ndx are indexes modulo 2^32, they are intended to overflow,
* to handle *ndx greater than 4gb.
*/
av_assert2(buf_size + (unsigned)offset <= f->wndx - f->rndx);
if (offset < 0 || buf_size > av_fifo_size(f) - offset)
return AVERROR(EINVAL);
if (offset >= f->end - rptr)
rptr += offset - (f->end - f->buffer);
@ -198,6 +196,9 @@ int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size,
{
uint8_t *rptr = f->rptr;
if (buf_size > av_fifo_size(f))
return AVERROR(EINVAL);
do {
int len = FFMIN(f->end - rptr, buf_size);
if (func)
@ -218,6 +219,9 @@ int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size,
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)

8
libavutil/fifo.h
View File

@ -91,6 +91,8 @@ int av_fifo_space(const AVFifoBuffer *f);
* @param buf_size number of bytes to read
* @param func generic read function
* @param dest data destination
*
* @return a non-negative number on success, a negative error code on failure
*/
int av_fifo_generic_peek_at(AVFifoBuffer *f, void *dest, int offset, int buf_size, void (*func)(void*, void*, int));
@ -101,6 +103,8 @@ int av_fifo_generic_peek_at(AVFifoBuffer *f, void *dest, int offset, int buf_siz
* @param buf_size number of bytes to read
* @param func generic read function
* @param dest data destination
*
* @return a non-negative number on success, a negative error code on failure
*/
int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
@ -110,6 +114,8 @@ int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size, void (*func)
* @param buf_size number of bytes to read
* @param func generic read function
* @param dest data destination
*
* @return a non-negative number on success, a negative error code on failure
*/
int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
@ -124,7 +130,7 @@ int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)
* func must return the number of bytes written to dest_buf, or <= 0 to
* indicate no more data available to write.
* If func is NULL, src is interpreted as a simple byte array for source data.
* @return the number of bytes written to the FIFO
* @return the number of bytes written to the FIFO or a negative error code on failure
*/
int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));