a very simple circular buffer FIFO implementation
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#include <stddef.h>
#include <stdint.h>
#include "attributes.h"
#include "version.h"
Go to the source code of this file.
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typedef struct AVFifo | AVFifo |
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typedef int | AVFifoCB(void *opaque, void *buf, size_t *nb_elems) |
| Callback for writing or reading from a FIFO, passed to (and invoked from) the av_fifo_*_cb() functions.
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AVFifo * | av_fifo_alloc2 (size_t elems, size_t elem_size, unsigned int flags) |
| Allocate and initialize an AVFifo with a given element size.
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size_t | av_fifo_elem_size (const AVFifo *f) |
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void | av_fifo_auto_grow_limit (AVFifo *f, size_t max_elems) |
| Set the maximum size (in elements) to which the FIFO can be resized automatically.
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size_t | av_fifo_can_read (const AVFifo *f) |
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size_t | av_fifo_can_write (const AVFifo *f) |
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int | av_fifo_grow2 (AVFifo *f, size_t inc) |
| Enlarge an AVFifo.
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int | av_fifo_write (AVFifo *f, const void *buf, size_t nb_elems) |
| Write data into a FIFO.
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int | av_fifo_write_from_cb (AVFifo *f, AVFifoCB read_cb, void *opaque, size_t *nb_elems) |
| Write data from a user-provided callback into a FIFO.
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int | av_fifo_read (AVFifo *f, void *buf, size_t nb_elems) |
| Read data from a FIFO.
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int | av_fifo_read_to_cb (AVFifo *f, AVFifoCB write_cb, void *opaque, size_t *nb_elems) |
| Feed data from a FIFO into a user-provided callback.
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int | av_fifo_peek (AVFifo *f, void *buf, size_t nb_elems, size_t offset) |
| Read data from a FIFO without modifying FIFO state.
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int | av_fifo_peek_to_cb (AVFifo *f, AVFifoCB write_cb, void *opaque, size_t *nb_elems, size_t offset) |
| Feed data from a FIFO into a user-provided callback.
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void | av_fifo_drain2 (AVFifo *f, size_t size) |
| Discard the specified amount of data from an AVFifo.
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void | av_fifo_reset2 (AVFifo *f) |
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void | av_fifo_freep2 (AVFifo **f) |
| Free an AVFifo and reset pointer to NULL.
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a very simple circular buffer FIFO implementation
Definition in file fifo.h.
◆ AV_FIFO_FLAG_AUTO_GROW
#define AV_FIFO_FLAG_AUTO_GROW (1 << 0) |
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().
Definition at line 58 of file fifo.h.
◆ AVFifo
◆ AVFifoCB
typedef int AVFifoCB(void *opaque, void *buf, size_t *nb_elems) |
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.
- Parameters
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opaque | the opaque pointer provided to the av_fifo_*_cb() function |
buf | the buffer for reading or writing the data, depending on which av_fifo_*_cb function is called |
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. |
- Returns
- 0 on success, a negative error code on failure (will be returned from the invoking av_fifo_*_cb() function)
Definition at line 51 of file fifo.h.
◆ av_fifo_alloc2()
AVFifo * av_fifo_alloc2 |
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size_t |
elems, |
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size_t |
elem_size, |
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unsigned int |
flags |
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) |
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Allocate and initialize an AVFifo with a given element size.
- Parameters
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elems | initial number of elements that can be stored in the FIFO |
elem_size | Size in bytes of a single element. Further operations on the returned FIFO will implicitly use this element size. |
flags | a combination of AV_FIFO_FLAG_* |
- Returns
- newly-allocated AVFifo on success, a negative error code on failure
◆ av_fifo_elem_size()
size_t av_fifo_elem_size |
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const AVFifo * |
f | ) |
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- Returns
- Element size for FIFO operations. This element size is set at FIFO allocation and remains constant during its lifetime
◆ av_fifo_auto_grow_limit()
void av_fifo_auto_grow_limit |
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AVFifo * |
f, |
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size_t |
max_elems |
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) |
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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.
◆ av_fifo_can_read()
size_t av_fifo_can_read |
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const AVFifo * |
f | ) |
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- Returns
- number of elements available for reading from the given FIFO.
◆ av_fifo_can_write()
size_t av_fifo_can_write |
( |
const AVFifo * |
f | ) |
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- Returns
- number of elements that can be written into the given FIFO.
◆ av_fifo_grow2()
int av_fifo_grow2 |
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AVFifo * |
f, |
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size_t |
inc |
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) |
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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.
- Parameters
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f | AVFifo to resize |
inc | number of elements to allocate for, in addition to the current allocated size |
- Returns
- a non-negative number on success, a negative error code on failure
◆ av_fifo_write()
int av_fifo_write |
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AVFifo * |
f, |
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const void * |
buf, |
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size_t |
nb_elems |
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) |
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Write data into a FIFO.
In case nb_elems > av_fifo_can_write(f), nothing is written and an error is returned.
- Parameters
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f | the FIFO buffer |
buf | Data to be written. nb_elems * av_fifo_elem_size(f) bytes will be read from buf on success. |
nb_elems | number of elements to write into FIFO |
- Returns
- a non-negative number on success, a negative error code on failure
◆ av_fifo_write_from_cb()
int av_fifo_write_from_cb |
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AVFifo * |
f, |
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AVFifoCB |
read_cb, |
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void * |
opaque, |
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size_t * |
nb_elems |
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) |
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Write data from a user-provided callback into a FIFO.
- Parameters
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f | the FIFO buffer |
read_cb | Callback supplying the data to the FIFO. May be called multiple times. |
opaque | opaque user data to be provided to read_cb |
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. |
- Returns
- non-negative number on success, a negative error code on failure
◆ av_fifo_read()
int av_fifo_read |
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AVFifo * |
f, |
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void * |
buf, |
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size_t |
nb_elems |
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) |
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Read data from a FIFO.
In case nb_elems > av_fifo_can_read(f), nothing is read and an error is returned.
- Parameters
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f | the FIFO buffer |
buf | Buffer to store the data. nb_elems * av_fifo_elem_size(f) bytes will be written into buf on success. |
nb_elems | number of elements to read from FIFO |
- Returns
- a non-negative number on success, a negative error code on failure
◆ av_fifo_read_to_cb()
int av_fifo_read_to_cb |
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AVFifo * |
f, |
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AVFifoCB |
write_cb, |
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void * |
opaque, |
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size_t * |
nb_elems |
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) |
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Feed data from a FIFO into a user-provided callback.
- Parameters
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f | the FIFO buffer |
write_cb | Callback the data will be supplied to. May be called multiple times. |
opaque | opaque user data to be provided to write_cb |
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. |
- Returns
- non-negative number on success, a negative error code on failure
◆ av_fifo_peek()
int av_fifo_peek |
( |
AVFifo * |
f, |
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void * |
buf, |
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size_t |
nb_elems, |
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size_t |
offset |
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) |
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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)).
- Parameters
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f | the FIFO buffer |
buf | Buffer to store the data. nb_elems * av_fifo_elem_size(f) bytes will be written into buf. |
nb_elems | number of elements to read from FIFO |
offset | number of initial elements to skip. |
- Returns
- a non-negative number on success, a negative error code on failure
◆ av_fifo_peek_to_cb()
int av_fifo_peek_to_cb |
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AVFifo * |
f, |
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AVFifoCB |
write_cb, |
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void * |
opaque, |
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size_t * |
nb_elems, |
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size_t |
offset |
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) |
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Feed data from a FIFO into a user-provided callback.
- Parameters
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f | the FIFO buffer |
write_cb | Callback the data will be supplied to. May be called multiple times. |
opaque | opaque user data to be provided to write_cb |
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. |
offset | number of initial elements to skip; offset + *nb_elems must not be larger than av_fifo_can_read(f). |
- Returns
- a non-negative number on success, a negative error code on failure
◆ av_fifo_drain2()
void av_fifo_drain2 |
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AVFifo * |
f, |
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size_t |
size |
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) |
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Discard the specified amount of data from an AVFifo.
- Parameters
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size | number of elements to discard, MUST NOT be larger than av_fifo_can_read(f) |
◆ av_fifo_reset2()
void av_fifo_reset2 |
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AVFifo * |
f | ) |
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◆ av_fifo_freep2()
void av_fifo_freep2 |
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AVFifo ** |
f | ) |
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Free an AVFifo and reset pointer to NULL.
- Parameters
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f | Pointer to an AVFifo to free. *f == NULL is allowed. |