LookingGlass/common/include/common/ringbuffer.h
2023-10-20 15:36:34 +11:00

73 lines
3.2 KiB
C

/**
* Looking Glass
* Copyright © 2017-2023 The Looking Glass Authors
* https://looking-glass.io
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program 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 General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc., 59
* Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <stddef.h>
#include <stdbool.h>
typedef struct RingBuffer * RingBuffer;
RingBuffer ringbuffer_new(int length, size_t valueSize);
/* In an unbounded ring buffer, the read and write pointers are free to move
* independently of one another. This is useful if your input and output streams
* are progressing at the same rate on average, and you want to keep the
* latency stable in the event than an underrun or overrun occurs.
*
* If an underrun occurs (i.e., there is not enough data in the buffer to
* satisfy a read request), the missing values with be filled with zeros. When
* the writer catches up, the same number of values will be skipped from the
* input.
*
* If an overrun occurs (i.e., there is not enough free space in the buffer to
* satisfy a write request), excess values will be discarded. When the reader
* catches up, the same number of values will be zeroed in the output.
*/
RingBuffer ringbuffer_newUnbounded(int length, size_t valueSize);
void ringbuffer_free(RingBuffer * rb);
void ringbuffer_push(RingBuffer rb, const void * value);
void ringbuffer_reset(RingBuffer rb);
/* Note that the following functions are NOT thread-safe */
int ringbuffer_getLength(const RingBuffer rb);
int ringbuffer_getStart (const RingBuffer rb);
int ringbuffer_getCount (const RingBuffer rb);
void * ringbuffer_getValues(const RingBuffer rb);
/* Appends up to count values to the buffer returning the number of values
* appended. If the buffer is unbounded, the return value is always count;
* excess values will be discarded if the buffer is full. Pass a null values
* pointer to write zeros to the buffer. Count may be negative in unbounded mode
* to seek backwards.
* Note: This function is thread-safe */
int ringbuffer_append(const RingBuffer rb, const void * values, int count);
/* Consumes up to count values from the buffer returning the number of values
* consumed. If the buffer is unbounded, the return value is always count;
* excess values will be zeroed if there is not enough data in the buffer. Pass
* a null values pointer to move the read pointer without reading any data.
* Count may be negative in unbounded mode to seek backwards.
* Note: This function is thread-safe */
int ringbuffer_consume(const RingBuffer rb, void * values, int count);
typedef bool (*RingBufferIterator)(int index, void * value, void * udata);
void ringbuffer_forEach(const RingBuffer rb, RingBufferIterator fn,
void * udata, bool reverse);