操作系统:ubuntu10.04
前言:
在嵌入式开发中,只要是带操作系统的,在其上开发产品应用,基本都需要用到多线程。
为了提高效率,尽可能的提高并发率。因此,线程之间的通信就是问题的核心。
根据当前产品需要,使用 环形缓冲区 解决。
一,环形缓冲区的实现
1,cbuf.h
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#ifndef __cbuf_h__
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#define __cbuf_h__
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#ifdef __cplusplus
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extern "c" {
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#endif
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/* define to prevent recursive inclusion
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-------------------------------------*/
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#include "types.h"
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#include "thread.h"
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typedef struct _cbuf
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{
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int32_t size; /* 当前缓冲区中存放的数据的个数 */
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int32_t next_in; /* 缓冲区中下一个保存数据的位置 */
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int32_t next_out; /* 从缓冲区中取出下一个数据的位置 */
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int32_t capacity; /* 这个缓冲区的可保存的数据的总个数 */
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mutex_t mutex; /* lock the structure */
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cond_t not_full; /* full -> not full condition */
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cond_t not_empty; /* empty -> not empty condition */
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void *data[cbuf_max];/* 缓冲区中保存的数据指针 */
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}cbuf_t;
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/* 初始化环形缓冲区 */
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extern int32_t cbuf_init(cbuf_t *c);
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/* 销毁环形缓冲区 */
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extern void cbuf_destroy(cbuf_t *c);
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/* 压入数据 */
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extern int32_t cbuf_enqueue(cbuf_t *c,void *data);
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/* 取出数据 */
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extern void* cbuf_dequeue(cbuf_t *c);
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/* 判断缓冲区是否为满 */
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extern bool cbuf_full(cbuf_t *c);
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/* 判断缓冲区是否为空 */
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extern bool cbuf_empty(cbuf_t *c);
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/* 获取缓冲区可存放的元素的总个数 */
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extern int32_t cbuf_capacity(cbuf_t *c);
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#ifdef __cplusplus
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}
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#endif
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#endif
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/* end of file
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---------------------------------------------------------------*/
2,cbuf.c
二,辅助文件
为了提高程序的
移植性,对线程相关进行封装。
1,thread.h
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#ifndef __thread_h__
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#define __thread_h__
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#ifdef __cplusplus
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extern "c" {
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#endif
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/* define to prevent recursive inclusion
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-------------------------------------*/
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#include "types.h"
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typedef struct _mutex
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{
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pthread_mutex_t mutex;
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}mutex_t;
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typedef struct _cond
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{
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pthread_cond_t cond;
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}cond_t;
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typedef pthread_t tid_t;
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typedef pthread_attr_t attr_t;
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typedef void* (* thread_fun_t)(void*);
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typedef struct _thread
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{
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tid_t tid;
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cond_t *cv;
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int32_t state;
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int32_t stack_size;
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attr_t attr;
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thread_fun_t fun;
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}thread_t;
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/* mutex */
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extern int32_t mutex_init(mutex_t *m);
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extern int32_t mutex_destroy(mutex_t *m);
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extern int32_t mutex_lock(mutex_t *m);
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extern int32_t mutex_unlock(mutex_t *m);
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/* cond */
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extern int32_t cond_init(cond_t *c);
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extern int32_t cond_destroy(cond_t *c);
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extern int32_t cond_signal(cond_t *c);
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extern int32_t cond_wait(cond_t *c,mutex_t *m);
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/* thread */
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/* 线程的创建,其属性的设置等都封装在里面 */
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extern int32_t thread_create(thread_t *t);
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//extern int32_t thread_init(thread_t *t);
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#define thread_join(t, p) pthread_join(t, p)
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#define thread_self() pthread_self()
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#define thread_sigmask pthread_sigmask
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#ifdef __cplusplus
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}
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#endif
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#endif
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/* end of file
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---------------------------------------------------------------*/
2,thread.c
三,测试
1,测试代码
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/*
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* cbuf begin
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*/
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#define over (-1)
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static cbuf_t cmd;
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static int line_1[200];
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static int line_2[200];
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//static int temp = 0;
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static bool line1_finish = false;
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static bool line2_finish = false;
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void* producer_1(void *data)
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{
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int32_t i = 0;
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for(i = 0; i < 200; i)
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{
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line_1[i] = i1000;
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cbuf_enqueue(&cmd, &line_1[i]);
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if(0 == (i % 9)) sleep(1);
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}
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line1_finish = true;
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return null;
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}
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void* producer_2(void *data)
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{
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int32_t i = 0;
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for(i = 0; i < 200; i)
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{
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line_2[i] = i20000;
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cbuf_enqueue(&cmd, &line_2[i]);
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if(0 == (i % 9)) sleep(1);
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}
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line2_finish = true;
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return null;
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}
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void* consumer(void *data)
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{
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int32_t *ptr = null;
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while(1)
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{
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ptr = cbuf_dequeue(&cmd);
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printf("%d\n",*ptr);
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if(cbuf_empty(&cmd) && line2_finish && line1_finish)
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{
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printf("quit\n");
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break;
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}
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}
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return null;
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}
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void test_cbuf_oper(void)
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{
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pthread_t l_1;
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pthread_t l_2;
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pthread_t c;
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cbuf_init(&cmd);
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pthread_create(&l_1,null,producer_1,0);
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pthread_create(&l_2,null,producer_2,0);
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pthread_create(&c,null,consumer,0);
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pthread_join(l_1,null);
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pthread_join(l_2,null);
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pthread_join(c,null);
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cbuf_destroy(&cmd);
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}
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void test_cbuf(void)
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{
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test_cbuf_oper();
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}
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/*
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* cbuf end
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*/
2,测试结果
四,参考文件
1,《bareos-master》源码
2,《nginx》源码
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