tomato-testing/toxav/ring_buffer.c
Green Sky 227425b90e Squashed 'external/toxcore/c-toxcore/' content from commit 67badf69
git-subtree-dir: external/toxcore/c-toxcore
git-subtree-split: 67badf69416a74e74f6d7eb51dd96f37282b8455
2023-07-25 11:53:09 +02:00

116 lines
2.0 KiB
C

/* SPDX-License-Identifier: GPL-3.0-or-later
* Copyright © 2016-2018 The TokTok team.
* Copyright © 2013 Tox project.
* Copyright © 2013 plutooo
*/
#include "ring_buffer.h"
#include <stdlib.h>
#include "../toxcore/ccompat.h"
struct RingBuffer {
uint16_t size; /* Max size */
uint16_t start;
uint16_t end;
void **data;
};
bool rb_full(const RingBuffer *b)
{
return (b->end + 1) % b->size == b->start;
}
bool rb_empty(const RingBuffer *b)
{
return b->end == b->start;
}
/**
* @retval NULL on success
* @return input value "p" on failure, so caller can free on failed rb_write
*/
void *rb_write(RingBuffer *b, void *p)
{
if (b == nullptr) {
return p;
}
void *rc = nullptr;
if ((b->end + 1) % b->size == b->start) { /* full */
rc = b->data[b->start];
}
b->data[b->end] = p;
b->end = (b->end + 1) % b->size;
if (b->end == b->start) {
b->start = (b->start + 1) % b->size;
}
return rc;
}
bool rb_read(RingBuffer *b, void **p)
{
if (b->end == b->start) { /* Empty */
*p = nullptr;
return false;
}
*p = b->data[b->start];
b->start = (b->start + 1) % b->size;
return true;
}
RingBuffer *rb_new(int size)
{
RingBuffer *buf = (RingBuffer *)calloc(1, sizeof(RingBuffer));
if (buf == nullptr) {
return nullptr;
}
buf->size = size + 1; /* include empty elem */
buf->data = (void **)calloc(buf->size, sizeof(void *));
if (buf->data == nullptr) {
free(buf);
return nullptr;
}
return buf;
}
void rb_kill(RingBuffer *b)
{
if (b != nullptr) {
free(b->data);
free(b);
}
}
uint16_t rb_size(const RingBuffer *b)
{
if (rb_empty(b)) {
return 0;
}
return
b->end > b->start ?
b->end - b->start :
(b->size - b->start) + b->end;
}
uint16_t rb_data(const RingBuffer *b, void **dest)
{
uint16_t i;
for (i = 0; i < rb_size(b); ++i) {
dest[i] = b->data[(b->start + i) % b->size];
}
return i;
}