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/* See LICENSE file for copyright and license details. */
#ifndef TYPES_RING_H
#define TYPES_RING_H
#include <stdlib.h>
#ifndef GCC_ONLY
# if defined(__GNUC__) && !defined(__clang__)
# define GCC_ONLY(...) __VA_ARGS__
# else
# define GCC_ONLY(...) /* nothing */
# endif
#endif
/**
* Ring buffer
*/
struct ring {
/**
* Buffer for the data
*/
char *restrict buffer;
/**
* The first set byte in `.buffer`
*/
size_t start;
/**
* The last set byte in `.buffer`, plus 1
*/
size_t end;
/**
* The size of `.buffer`
*/
size_t size;
};
/**
* Initialise a ring buffer
*
* @param this The ring buffer
*/
GCC_ONLY(__attribute__((__nonnull__)))
void ring_initialise(struct ring *restrict this);
/**
* Marshal a ring buffer
*
* @param this The ring buffer
* @param buf Output buffer for the marshalled data,
* `NULL` to only measure how large buffer
* is needed
* @return The number of marshalled bytes
*/
GCC_ONLY(__attribute__((__nonnull__(1))))
size_t ring_marshal(const struct ring *restrict this, void *restrict buf);
/**
* Unmarshal a ring buffer
*
* @param this Output parameter for the ring buffer
* @param buf Buffer with the marshalled data
* @return The number of unmarshalled bytes, 0 on error
*/
GCC_ONLY(__attribute__((__nonnull__)))
size_t ring_unmarshal(struct ring *restrict this, const void *restrict buf);
/**
* Append data to a ring buffer
*
* @param this The ring buffer
* @param data The new data
* @param n The number of bytes in `data`
* @return Zero on success, -1 on error
*/
GCC_ONLY(__attribute__((__nonnull__(1))))
int ring_push(struct ring *restrict this, void *restrict data, size_t n);
/**
* Get queued data from a ring buffer
*
* It can take up to two calls (with `ring_pop` between)
* to get all queued data
*
* @param this The ring buffer
* @param n Output parameter for the length
* of the returned segment
* @return The beginning of the queued data,
* `NULL` if there is nothing more
*/
GCC_ONLY(__attribute__((__nonnull__)))
void *ring_peek(struct ring *restrict this, size_t *restrict n);
/**
* Dequeue data from a ring bubber
*
* @param this The ring buffer
* @param n The number of bytes to dequeue
*/
GCC_ONLY(__attribute__((__nonnull__)))
void ring_pop(struct ring *restrict this, size_t n);
/**
* Release resource allocated to a ring buffer
*
* @param this The ring buffer
*/
GCC_ONLY(__attribute__((__nonnull__)))
static inline void
ring_destroy(struct ring *restrict this)
{
free(this->buffer);
}
/**
* Check whether there is more data waiting
* in a ring buffer
*
* @param this The ring buffer
* @return 1 if there is more data, 0 otherwise
*/
GCC_ONLY(__attribute__((__nonnull__)))
static inline int
ring_have_more(struct ring *restrict this)
{
return !!this->buffer;
}
#endif
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