138 lines
3.2 KiB
C
138 lines
3.2 KiB
C
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/* ring_buffer.c */
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#include "ring_buffer.h"
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#include <stdlib.h>
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#include <string.h>
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bool rb_init(RingBuffer *rb, size_t capacity, size_t elem_size) {
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rb->buffer = malloc(capacity * elem_size);
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if (!rb->buffer) return false;
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rb->max = capacity;
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rb->sz = elem_size;
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rb->head = 0;
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rb->tail = 0;
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rb->full = false;
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return true;
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}
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void rb_free(RingBuffer *rb) {
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free(rb->buffer);
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rb->buffer = NULL;
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}
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void rb_reset(RingBuffer *rb) {
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rb->head = rb->tail = 0;
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rb->full = false;
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}
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bool rb_empty(const RingBuffer *rb) {
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return (!rb->full && (rb->head == rb->tail));
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}
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bool rb_full(const RingBuffer *rb) {
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return rb->full;
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}
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bool rb_put(RingBuffer *rb, const void *data) {
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if (rb->full) return false;
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memcpy((char*)rb->buffer + (rb->head * rb->sz), data, rb->sz);
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rb->head = (rb->head + 1) % rb->max;
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rb->full = (rb->head == rb->tail);
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return true;
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}
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bool rb_get(RingBuffer *rb, void *data) {
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if (rb_empty(rb)) return false;
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memcpy(data, (char*)rb->buffer + (rb->tail * rb->sz), rb->sz);
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rb->full = false;
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rb->tail = (rb->tail + 1) % rb->max;
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return true;
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}
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size_t rb_size(const RingBuffer *rb) {
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size_t size = rb->max;
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if (!rb->full) {
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if (rb->head >= rb->tail) {
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size = rb->head - rb->tail;
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} else {
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size = rb->max + rb->head - rb->tail;
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}
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}
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return size;
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}
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size_t rb_get_bulk(RingBuffer *rb, void *data, size_t len) {
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if (rb_empty(rb)) {
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return 0;
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}
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size_t curr_size = rb_size(rb);
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size_t to_read = len < curr_size ? len : curr_size;
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// 第一次拷贝：从 tail 到缓冲区末尾
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size_t cnt1 = rb->max - rb->tail;
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if (cnt1 > to_read) cnt1 = to_read;
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memcpy(data,
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(char*)rb->buffer + rb->tail * rb->sz,
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cnt1 * rb->sz);
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// 第二次拷贝：如果需要，从缓冲区开头继续读取
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size_t cnt2 = to_read - cnt1;
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if (cnt2 > 0) {
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memcpy((char*)data + cnt1 * rb->sz,
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rb->buffer,
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cnt2 * rb->sz);
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}
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rb->tail = (rb->tail + to_read) % rb->max;
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rb->full = false;
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return to_read;
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}
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size_t rb_put_bulk(RingBuffer *rb, const void *data, size_t len) {
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// 如果缓冲区已满，直接返回 0
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if (rb->full) {
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return 0;
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}
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// 计算当前可用空间（元素数）
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size_t curr_size = rb_size(rb);
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size_t avail = rb->max - curr_size;
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// 实际要写入的元素数
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size_t to_write = len < avail ? len : avail;
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if (to_write == 0) {
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return 0;
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}
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// 第一次拷贝：从 head 开始直到缓冲区末尾
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size_t cnt1 = rb->max - rb->head;
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if (cnt1 > to_write) {
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cnt1 = to_write;
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}
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memcpy((char*)rb->buffer + rb->head * rb->sz,
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data,
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cnt1 * rb->sz);
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// 第二次拷贝：如果还要写入，则回绕到缓冲区开头
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size_t cnt2 = to_write - cnt1;
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if (cnt2 > 0) {
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memcpy(rb->buffer,
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(const char*)data + cnt1 * rb->sz,
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cnt2 * rb->sz);
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}
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// 更新 head 索引
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rb->head = (rb->head + to_write) % rb->max;
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// 如果写满，则置 full
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if (to_write == avail) {
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rb->full = true;
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}
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return to_write;
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}
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