| /* |
| * 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 |
| */ |
| |
| /** |
| * @file |
| * @ingroup lavu_fifo |
| * A generic FIFO API |
| */ |
| |
| #ifndef AVUTIL_FIFO_H |
| #define AVUTIL_FIFO_H |
| |
| #include <stddef.h> |
| |
| /** |
| * @defgroup lavu_fifo AVFifo |
| * @ingroup lavu_data |
| * |
| * @{ |
| * A generic FIFO API |
| */ |
| |
| 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); |
| |
| /** |
| * Automatically resize the FIFO on writes, so that the data fits. This |
| * automatic resizing happens up to a limit that can be modified with |
| * av_fifo_auto_grow_limit(). |
| */ |
| #define AV_FIFO_FLAG_AUTO_GROW (1 << 0) |
| |
| /** |
| * 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 a combination of AV_FIFO_FLAG_* |
| * |
| * @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); |
| |
| /** |
| * Set the maximum size (in elements) to which the FIFO can be resized |
| * automatically. Has no effect unless AV_FIFO_FLAG_AUTO_GROW is used. |
| */ |
| void av_fifo_auto_grow_limit(AVFifo *f, size_t max_elems); |
| |
| /** |
| * @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 without |
| * growing it. |
| * |
| * In other words, this number of elements or less is guaranteed to fit |
| * into the FIFO. More data may be written when the |
| * AV_FIFO_FLAG_AUTO_GROW flag was specified at FIFO creation, but this |
| * may involve memory allocation, which can fail. |
| */ |
| 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) and the AV_FIFO_FLAG_AUTO_GROW flag |
| * was not specified at FIFO creation, nothing is written and an error |
| * is returned. |
| * |
| * Calling function is guaranteed to succeed if nb_elems <= av_fifo_can_write(f). |
| * |
| * @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(const 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(const 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); |
| |
| /** |
| * @} |
| */ |
| |
| #endif /* AVUTIL_FIFO_H */ |