90 lines
2.2 KiB
C
90 lines
2.2 KiB
C
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/******************************************************************************
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* @brief 环形缓冲区管理(参考linux/kfifo)
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*
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* Copyright (c) 2016~2020, <morro_luo@163.com>
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Change Logs:
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* Date Author Notes
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* 2016-05-30 Morro 初版完成
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******************************************************************************/
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#include "ringbuffer.h"
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#include <string.h>
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#include <stddef.h>
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#define min(a,b) ( (a) < (b) )? (a):(b)
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/*
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*@brief 构造一个空环形缓冲区
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*@param[in] r - 环形缓冲区管理器
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*@param[in] buf - 数据缓冲区
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*@param[in] len - buf长度(必须是2的N次幂)
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*@retval bool
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*/
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bool ring_buf_init(ring_buf_t *r,unsigned char *buf, unsigned int len)
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{
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r->buf = buf;
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r->size = len;
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r->front = r->rear = 0;
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return (buf != NULL) && ((len & len -1) == 0);
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}
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/*
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*@brief 清空环形缓冲区
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*@param[in] r - 待清空的环形缓冲区
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*@retval none
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*/
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void ring_buf_clr(ring_buf_t *r)
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{
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r->front = r->rear = 0;
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}
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/*
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*@brief 获取环形缓冲区数据长度
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*@retval 环形缓冲区中有效字节数
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*/
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int ring_buf_len(ring_buf_t *r)
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{
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return r->rear - r->front;
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}
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/*
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*@brief 将指定长度的数据放到环形缓冲区中
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*@param[in] buf - 数据缓冲区
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* len - 缓冲区长度
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*@retval 实际放到中的数据
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*/
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int ring_buf_put(ring_buf_t *r,unsigned char *buf,unsigned int len)
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{
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unsigned int i;
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unsigned int left;
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left = r->size + r->front - r->rear;
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len = min(len , left);
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i = min(len, r->size - (r->rear & r->size - 1));
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memcpy(r->buf + (r->rear & r->size - 1), buf, i);
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memcpy(r->buf, buf + i, len - i);
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r->rear += len;
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return len;
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}
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/*
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*@brief 从环形缓冲区中读取指定长度的数据
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*@param[in] len - 读取长度
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*@param[out] buf - 输出数据缓冲区
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*@retval 实际读取长度
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*/
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int ring_buf_get(ring_buf_t *r,unsigned char *buf,unsigned int len)
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{
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unsigned int i;
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unsigned int left;
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left = r->rear - r->front;
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len = min(len , left);
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i = min(len, r->size - (r->front & r->size - 1));
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memcpy(buf, r->buf + (r->front & r->size - 1), i);
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memcpy(buf + i, r->buf, len - i);
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r->front += len;
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return len;
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}
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