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Diffstat (limited to 'libavutil/fifo.h')
| -rw-r--r-- | libavutil/fifo.h | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/libavutil/fifo.h b/libavutil/fifo.h index f4fd291e59..f455022e3c 100644 --- a/libavutil/fifo.h +++ b/libavutil/fifo.h @@ -28,6 +28,185 @@ #include "avutil.h" #include "attributes.h" +typedef struct AVFifo AVFifo; + +/** + * Callback for writing or reading from a FIFO, passed to (and invoked from) the + * av_fifo_*_cb() functions. It may be invoked multiple times from a single + * av_fifo_*_cb() call and may process less data than the maximum size indicated + * by nb_elems. + * + * @param opaque the opaque pointer provided to the av_fifo_*_cb() function + * @param buf the buffer for reading or writing the data, depending on which + * av_fifo_*_cb function is called + * @param nb_elems On entry contains the maximum number of elements that can be + * read from / written into buf. On success, the callback should + * update it to contain the number of elements actually written. + * + * @return 0 on success, a negative error code on failure (will be returned from + * the invoking av_fifo_*_cb() function) + */ +typedef int AVFifoCB(void *opaque, void *buf, size_t *nb_elems); + +/** + * Allocate and initialize an AVFifo with a given element size. + * + * @param elems initial number of elements that can be stored in the FIFO + * @param elem_size Size in bytes of a single element. Further operations on + * the returned FIFO will implicitly use this element size. + * @param flags currently unused, must be 0 + * + * @return newly-allocated AVFifo on success, a negative error code on failure + */ +AVFifo *av_fifo_alloc2(size_t elems, size_t elem_size, + unsigned int flags); + +/** + * @return Element size for FIFO operations. This element size is set at + * FIFO allocation and remains constant during its lifetime + */ +size_t av_fifo_elem_size(const AVFifo *f); + +/** + * @return number of elements available for reading from the given FIFO. + */ +size_t av_fifo_can_read(const AVFifo *f); + +/** + * @return number of elements that can be written into the given FIFO. + */ +size_t av_fifo_can_write(const AVFifo *f); + +/** + * Enlarge an AVFifo. + * + * On success, the FIFO will be large enough to hold exactly + * inc + av_fifo_can_read() + av_fifo_can_write() + * elements. In case of failure, the old FIFO is kept unchanged. + * + * @param f AVFifo to resize + * @param inc number of elements to allocate for, in addition to the current + * allocated size + * @return a non-negative number on success, a negative error code on failure + */ +int av_fifo_grow2(AVFifo *f, size_t inc); + +/** + * Write data into a FIFO. + * + * In case nb_elems > av_fifo_can_write(f), nothing is written and an error + * is returned. + * + * @param f the FIFO buffer + * @param buf Data to be written. nb_elems * av_fifo_elem_size(f) bytes will be + * read from buf on success. + * @param nb_elems number of elements to write into FIFO + * + * @return a non-negative number on success, a negative error code on failure + */ +int av_fifo_write(AVFifo *f, const void *buf, size_t nb_elems); + +/** + * Write data from a user-provided callback into a FIFO. + * + * @param f the FIFO buffer + * @param read_cb Callback supplying the data to the FIFO. May be called + * multiple times. + * @param opaque opaque user data to be provided to read_cb + * @param nb_elems Should point to the maximum number of elements that can be + * written. Will be updated to contain the number of elements + * actually written. + * + * @return non-negative number on success, a negative error code on failure + */ +int av_fifo_write_from_cb(AVFifo *f, AVFifoCB read_cb, + void *opaque, size_t *nb_elems); + +/** + * Read data from a FIFO. + * + * In case nb_elems > av_fifo_can_read(f), nothing is read and an error + * is returned. + * + * @param f the FIFO buffer + * @param buf Buffer to store the data. nb_elems * av_fifo_elem_size(f) bytes + * will be written into buf on success. + * @param nb_elems number of elements to read from FIFO + * + * @return a non-negative number on success, a negative error code on failure + */ +int av_fifo_read(AVFifo *f, void *buf, size_t nb_elems); + +/** + * Feed data from a FIFO into a user-provided callback. + * + * @param f the FIFO buffer + * @param write_cb Callback the data will be supplied to. May be called + * multiple times. + * @param opaque opaque user data to be provided to write_cb + * @param nb_elems Should point to the maximum number of elements that can be + * read. Will be updated to contain the total number of elements + * actually sent to the callback. + * + * @return non-negative number on success, a negative error code on failure + */ +int av_fifo_read_to_cb(AVFifo *f, AVFifoCB write_cb, + void *opaque, size_t *nb_elems); + +/** + * Read data from a FIFO without modifying FIFO state. + * + * Returns an error if an attempt is made to peek to nonexistent elements + * (i.e. if offset + nb_elems is larger than av_fifo_can_read(f)). + * + * @param f the FIFO buffer + * @param buf Buffer to store the data. nb_elems * av_fifo_elem_size(f) bytes + * will be written into buf. + * @param nb_elems number of elements to read from FIFO + * @param offset number of initial elements to skip. + * + * @return a non-negative number on success, a negative error code on failure + */ +int av_fifo_peek(AVFifo *f, void *buf, size_t nb_elems, size_t offset); + +/** + * Feed data from a FIFO into a user-provided callback. + * + * @param f the FIFO buffer + * @param write_cb Callback the data will be supplied to. May be called + * multiple times. + * @param opaque opaque user data to be provided to write_cb + * @param nb_elems Should point to the maximum number of elements that can be + * read. Will be updated to contain the total number of elements + * actually sent to the callback. + * @param offset number of initial elements to skip; offset + *nb_elems must not + * be larger than av_fifo_can_read(f). + * + * @return a non-negative number on success, a negative error code on failure + */ +int av_fifo_peek_to_cb(AVFifo *f, AVFifoCB write_cb, void *opaque, + size_t *nb_elems, size_t offset); + +/** + * Discard the specified amount of data from an AVFifo. + * @param size number of elements to discard, MUST NOT be larger than + * av_fifo_can_read(f) + */ +void av_fifo_drain2(AVFifo *f, size_t size); + +/* + * Empty the AVFifo. + * @param f AVFifo to reset + */ +void av_fifo_reset2(AVFifo *f); + +/** + * Free an AVFifo and reset pointer to NULL. + * @param f Pointer to an AVFifo to free. *f == NULL is allowed. + */ +void av_fifo_freep2(AVFifo **f); + + typedef struct AVFifoBuffer { uint8_t *buffer; uint8_t *rptr, *wptr, *end; |