Green Sky
227425b90e
git-subtree-dir: external/toxcore/c-toxcore git-subtree-split: 67badf69416a74e74f6d7eb51dd96f37282b8455
116 lines
2.0 KiB
C
116 lines
2.0 KiB
C
/* SPDX-License-Identifier: GPL-3.0-or-later
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* Copyright © 2016-2018 The TokTok team.
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* Copyright © 2013 Tox project.
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* Copyright © 2013 plutooo
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*/
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#include "ring_buffer.h"
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#include <stdlib.h>
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#include "../toxcore/ccompat.h"
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struct RingBuffer {
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uint16_t size; /* Max size */
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uint16_t start;
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uint16_t end;
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void **data;
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};
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bool rb_full(const RingBuffer *b)
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{
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return (b->end + 1) % b->size == b->start;
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}
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bool rb_empty(const RingBuffer *b)
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{
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return b->end == b->start;
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}
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/**
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* @retval NULL on success
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* @return input value "p" on failure, so caller can free on failed rb_write
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*/
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void *rb_write(RingBuffer *b, void *p)
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{
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if (b == nullptr) {
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return p;
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}
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void *rc = nullptr;
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if ((b->end + 1) % b->size == b->start) { /* full */
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rc = b->data[b->start];
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}
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b->data[b->end] = p;
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b->end = (b->end + 1) % b->size;
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if (b->end == b->start) {
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b->start = (b->start + 1) % b->size;
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}
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return rc;
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}
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bool rb_read(RingBuffer *b, void **p)
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{
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if (b->end == b->start) { /* Empty */
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*p = nullptr;
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return false;
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}
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*p = b->data[b->start];
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b->start = (b->start + 1) % b->size;
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return true;
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}
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RingBuffer *rb_new(int size)
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{
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RingBuffer *buf = (RingBuffer *)calloc(1, sizeof(RingBuffer));
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if (buf == nullptr) {
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return nullptr;
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}
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buf->size = size + 1; /* include empty elem */
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buf->data = (void **)calloc(buf->size, sizeof(void *));
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if (buf->data == nullptr) {
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free(buf);
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return nullptr;
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}
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return buf;
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}
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void rb_kill(RingBuffer *b)
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{
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if (b != nullptr) {
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free(b->data);
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free(b);
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}
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}
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uint16_t rb_size(const RingBuffer *b)
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{
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if (rb_empty(b)) {
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return 0;
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}
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return
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b->end > b->start ?
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b->end - b->start :
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(b->size - b->start) + b->end;
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}
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uint16_t rb_data(const RingBuffer *b, void **dest)
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{
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uint16_t i;
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for (i = 0; i < rb_size(b); ++i) {
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dest[i] = b->data[(b->start + i) % b->size];
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}
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return i;
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}
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