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/* Simple Plugin API
*
* Copyright © 2018 Wim Taymans
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#ifndef SPA_RINGBUFFER_H
#define SPA_RINGBUFFER_H
#ifdef __cplusplus
extern "C" {
#endif
/**
* \defgroup spa_ringbuffer Ringbuffer
* Ring buffer implementation
*/
/**
* \addtogroup spa_ringbuffer
* \{
*/
struct spa_ringbuffer;
#include <string.h>
#include <spa/utils/defs.h>
/**
* A ringbuffer type.
*/
struct spa_ringbuffer {
uint32_t readindex; /*< the current read index */
uint32_t writeindex; /*< the current write index */
};
#define SPA_RINGBUFFER_INIT() (struct spa_ringbuffer) { 0, 0 }
/**
* Initialize a spa_ringbuffer with \a size.
*
* \param rbuf a spa_ringbuffer
*/
static inline void spa_ringbuffer_init(struct spa_ringbuffer *rbuf)
{
*rbuf = SPA_RINGBUFFER_INIT();
}
/**
* Sets the pointers so that the ringbuffer contains \a size bytes.
*
* \param rbuf a spa_ringbuffer
* \param size the target size of \a rbuf
*/
static inline void spa_ringbuffer_set_avail(struct spa_ringbuffer *rbuf, uint32_t size)
{
rbuf->readindex = 0;
rbuf->writeindex = size;
}
/**
* Get the read index and available bytes for reading.
*
* \param rbuf a spa_ringbuffer
* \param index the value of readindex, should be taken modulo the size of the
* ringbuffer memory to get the offset in the ringbuffer memory
* \return number of available bytes to read. values < 0 mean
* there was an underrun. values > rbuf->size means there
* was an overrun.
*/
static inline int32_t spa_ringbuffer_get_read_index(struct spa_ringbuffer *rbuf, uint32_t *index)
{
*index = __atomic_load_n(&rbuf->readindex, __ATOMIC_RELAXED);
return (int32_t) (__atomic_load_n(&rbuf->writeindex, __ATOMIC_ACQUIRE) - *index);
}
/**
* Read \a len bytes from \a rbuf starting \a offset. \a offset must be taken
* modulo \a size and len should be smaller than \a size.
*
* \param rbuf a struct \ref spa_ringbuffer
* \param buffer memory to read from
* \param size the size of \a buffer
* \param offset offset in \a buffer to read from
* \param data destination memory
* \param len number of bytes to read
*/
static inline void
spa_ringbuffer_read_data(struct spa_ringbuffer *rbuf,
const void *buffer, uint32_t size,
uint32_t offset, void *data, uint32_t len)
{
uint32_t l0 = SPA_MIN(len, size - offset), l1 = len - l0;
spa_memcpy(data, SPA_PTROFF(buffer, offset, void), l0);
if (SPA_UNLIKELY(l1 > 0))
spa_memcpy(SPA_PTROFF(data, l0, void), buffer, l1);
}
/**
* Update the read pointer to \a index.
*
* \param rbuf a spa_ringbuffer
* \param index new index
*/
static inline void spa_ringbuffer_read_update(struct spa_ringbuffer *rbuf, int32_t index)
{
__atomic_store_n(&rbuf->readindex, index, __ATOMIC_RELEASE);
}
/**
* Get the write index and the number of bytes inside the ringbuffer.
*
* \param rbuf a spa_ringbuffer
* \param index the value of writeindex, should be taken modulo the size of the
* ringbuffer memory to get the offset in the ringbuffer memory
* \return the fill level of \a rbuf. values < 0 mean
* there was an underrun. values > rbuf->size means there
* was an overrun. Subtract from the buffer size to get
* the number of bytes available for writing.
*/
static inline int32_t spa_ringbuffer_get_write_index(struct spa_ringbuffer *rbuf, uint32_t *index)
{
*index = __atomic_load_n(&rbuf->writeindex, __ATOMIC_RELAXED);
return (int32_t) (*index - __atomic_load_n(&rbuf->readindex, __ATOMIC_ACQUIRE));
}
/**
* Write \a len bytes to \a buffer starting \a offset. \a offset must be taken
* modulo \a size and len should be smaller than \a size.
*
* \param rbuf a spa_ringbuffer
* \param buffer memory to write to
* \param size the size of \a buffer
* \param offset offset in \a buffer to write to
* \param data source memory
* \param len number of bytes to write
*/
static inline void
spa_ringbuffer_write_data(struct spa_ringbuffer *rbuf,
void *buffer, uint32_t size,
uint32_t offset, const void *data, uint32_t len)
{
uint32_t l0 = SPA_MIN(len, size - offset), l1 = len - l0;
spa_memcpy(SPA_PTROFF(buffer, offset, void), data, l0);
if (SPA_UNLIKELY(l1 > 0))
spa_memcpy(buffer, SPA_PTROFF(data, l0, void), l1);
}
/**
* Update the write pointer to \a index
*
* \param rbuf a spa_ringbuffer
* \param index new index
*/
static inline void spa_ringbuffer_write_update(struct spa_ringbuffer *rbuf, int32_t index)
{
__atomic_store_n(&rbuf->writeindex, index, __ATOMIC_RELEASE);
}
/**
* \}
*/
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* SPA_RINGBUFFER_H */