1.demo2.c
主要解决内存满了问题和读写速度不一致问题即读的比写的快。
#include <stdio.h>
#include <pthread.h>
#include <string.h>
#include "demo2.h"
#define MAX_BUFFER_NUM 5
#define MAX_DATA_LENGTH 1024
/* 设置句柄类 */
typedef struct {
char abyBuf[MAX_DATA_LENGTH]; /* 存放的数据量 */
int nBufferldx;
int nBufferEnable; /* buffer是否被占用 */
int nWriteBufferLength; /* buffer内写入的数据量此buffer最多可以
写入2的32次方减一的数据 */
int nReadBufferLength;/* buffer内读出的数据 */
int bWait; /* 条件等待标志位 */
pthread_mutex_t tBufferMutex; /* buffer访问时线程锁 */
pthread_cond_t tBufferReadCond; /* 条件变量 */
}TBufferlnf;
static TBufferlnf g_tBufferInf[MAX_BUFFER_NUM];/* 缓冲池的最大数量为结构体数组 */
/* 1. 创建buffer
* 2. 销毁buffer
* 3. 往buffer送数据
* 4. 往buffer取数据
* 5. 获取buffer状态
*
*/
/* 主要解决问题 */
/* 1.读的比写的快怎么办,Buffer满了怎么办 */
/* 显示当前Buffer的状态 */
void show_Buffer_Inf(void **pptHandle)
{
TBufferlnf *ptHandle = (TBufferlnf *)*pptHandle;
printf("nIdx=%d\n", ptHandle->nBufferldx);
printf("nEnable=%d\n", ptHandle->nBufferEnable);
printf("data nReadBufferLength=%d\n", ptHandle->nReadBufferLength);
printf("data nWriteBufferLength=%d\n", ptHandle->nWriteBufferLength);
}
int get_Data_From_Buffer(void **pptHandle, void *data,
int nDataLength) /* data为主函数将要拷贝到的内存块 */
{
TBufferlnf *ptHandle = (TBufferlnf *)*pptHandle;
int nReadLength;
int nNowDataLocation;
int nDiff;
if ((pptHandle == NULL) || (data == NULL))
{
printf("input param error, ptHandle=%p, data=%p\n", ptHandle, data);
return -1;
}
if (nDataLength >= MAX_DATA_LENGTH) /* 如果获得的数据大于等于可以存放的数据量 */
{
printf("input param error, nDataLength=%d", nDataLength);
return -2;
}
pthread_mutex_lock(&(ptHandle->tBufferMutex)); /* 读的数据一定要比写的慢 */
nDiff = ptHandle->nWriteBufferLength - ptHandle->nReadBufferLength; /* 写的数据与读的数据只差 */
if (nDiff > MAX_DATA_LENGTH) /* 如果差大于内存块大小则报错 */
{
printf(" nDiff error, nDiff=%d\n", nDiff);
return -3;
}
while (ptHandle->nWriteBufferLength < ptHandle->nReadBufferLength) /* 因为读的数据一定要比写的慢所以当写的数据少于
读的数据时条件等待等待数据生产 */
{
ptHandle->bWait = 1;
printf("waiting for product\n");
pthread_cond_wait(&(ptHandle->tBufferReadCond), &(ptHandle->tBufferMutex));
}
nNowDataLocation = (ptHandle->nReadBufferLength) % MAX_DATA_LENGTH; /* 数据的当前位置长度 */
ptHandle->nReadBufferLength += nDataLength;
if (ptHandle->nReadBufferLength >= MAX_DATA_LENGTH)
{
nReadLength = (ptHandle->nReadBufferLength) % MAX_DATA_LENGTH;
memcpy((char *)data, &(ptHandle->abyBuf[nNowDataLocation]), (MAX_DATA_LENGTH-nNowDataLocation));
memcpy(((char *)data + MAX_DATA_LENGTH - nNowDataLocation), &(ptHandle->abyBuf[0]),
nReadLength);
}
else
{
memcpy((char *)data, &(ptHandle->abyBuf[nNowDataLocation]), nDataLength);
}
pthread_mutex_unlock(&(ptHandle->tBufferMutex));
return 0;
}
int send_Data_To_Buffer(void **pptHandle, void *data,
int nDataLength)
{
TBufferlnf *ptHandle = (TBufferlnf *)*pptHandle;
int nNowDataLocation; /* 未存入数据时的位置 */
int nWriteLength; /* 越界开始从头写入的数据量 */
if ((pptHandle == NULL) || (data == NULL))
{
printf("input param error, ptHandle=%p, data=%p\n", ptHandle,
data);
return -1;
}
if ((nDataLength <= 0) || (nDataLength >= MAX_DATA_LENGTH)) /* 如果获得的数据大于等于可以存放的数据量 */
{
printf("input param error, nDataLength=%d\n", nDataLength);
return -2;
}
pthread_mutex_lock(&(ptHandle->tBufferMutex));
nNowDataLocation = (ptHandle->nWriteBufferLength) % MAX_DATA_LENGTH; /* 比如说原来的数据245取余是245得到 ，
ptHandle->nWriteBufferLength比MAX_DATA_LENGTH小时取余算出的是当前自已的值 */
ptHandle->nWriteBufferLength += nDataLength;
if (ptHandle->nWriteBufferLength >= MAX_DATA_LENGTH) /* 如果拷贝数据加上原有数据大于等于buffer长度 */
{
nWriteLength = (ptHandle->nWriteBufferLength) % MAX_DATA_LENGTH; /* 取余算出超出来的数据，
ptHandle->nWriteBufferLength比MAX_DATA_LENGTH大时取余算出超出的部分*/
memcpy(&(ptHandle->abyBuf[nNowDataLocation]), (char *)data, (MAX_DATA_LENGTH - nNowDataLocation)); /* 先拷贝内存中剩下可以容纳的数据量 */
memcpy(&(ptHandle->abyBuf[0]), ((char *)data + MAX_DATA_LENGTH - nNowDataLocation), nWriteLength); /* 接着拷贝超出的数据，也就是data剩下的数据 */
}
else
{
memcpy(&(ptHandle->abyBuf[nNowDataLocation]), (char *)data, nDataLength);
}
if (ptHandle->bWait == 1) /* 防止一开始发送信号，一开始写数据比读数据多有信号，下一秒数据消耗比读数据少时
会认为已经有了信号出BUG，所以先要有条件判断 */
{
if (ptHandle->nWriteBufferLength > ptHandle->nReadBufferLength)
{
printf("send signal to consumer\n");
ptHandle->bWait = 0;
pthread_cond_signal(&(ptHandle->tBufferReadCond)); /* 发送信号的过程，假如上一秒发送信号，
下一秒写数据量少于读数据量又去接收到信号继续拷贝数据,所以常常伴随条件变量bWait */
}
}
pthread_mutex_unlock(&(ptHandle->tBufferMutex));
return 0;
}
int destory_Buffer(void **pptHandle)
{
if (*pptHandle == NULL) /* 内存块空就报错 */
{
return -1;
}
TBufferlnf *ptHandle = (TBufferlnf*)(*pptHandle);
ptHandle->nBufferEnable = 0;
return 0;
}
/* pptHandle是二级指针保存一级指针的地址，*pptHandle可以得到一级指针变量里面存的内容即变量的地址，**pptHandle得到原本变量里面的值 */
int create_Buffer(void **pptHandle)
{
int nIdx = 0;
*pptHandle = NULL;
for (nIdx = 0; nIdx < MAX_BUFFER_NUM; nIdx++) /* 寻找未被占用的buffer */
{
pthread_mutex_lock(&(g_tBufferInf[nIdx].tBufferMutex));
if (!g_tBufferInf[nIdx].nBufferEnable) /* 内存块没有被占用时 */
{
*pptHandle = &g_tBufferInf[nIdx]; /* 取*一次就是内存块变量地址 */
g_tBufferInf[nIdx].nBufferEnable = 1;/* 代表内存块被占用 */
pthread_mutex_unlock(&(g_tBufferInf[nIdx].tBufferMutex));
break; /* 找到后跳出 */
}
}
if (*pptHandle == NULL) /* 内存块空就报错 */
{
return -1;
}
return 0;
}
/* 初始化Buffer，清空buffer和定义互斥条件变量 */
void buffer_Init()
{
int nIdx = 0;
memset(&g_tBufferInf[0], 0, sizeof(TBufferlnf)*MAX_BUFFER_NUM);
for (nIdx = 0; nIdx < MAX_BUFFER_NUM; nIdx++)
{
pthread_mutex_init(&(g_tBufferInf[nIdx].tBufferMutex), NULL);
pthread_cond_init(&(g_tBufferInf[nIdx].tBufferReadCond), NULL);
}
}
2.demo2.h
#ifndef _BUFFER_H
#define _BUFFER_H
void show_Buffer_Inf(void **pptHandle);
int get_Data_From_Buffer(void **pptHandle, void *data,
int nDataLength);
int send_Data_To_Buffer(void **pptHandle, void *data,
int nDataLength);
int destory_Buffer(void **pptHandle);
int create_Buffer(void **pptHandle);
void buffer_Init();
#endif
3.main.c
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>
#include "demo2.h"
/* 全局变量pHandle */
void *pHandle = NULL;
/* 生产速度比消费速度快 */
void *WorkProduct(void *arg)
{
printf("This is product\n");
while(1)
{
send_Data_To_Buffer(&pHandle, "nixu", 4);
sleep(1);
}
return NULL;
}
void *WorkConsmue(void *arg)
{
printf("This is consume\n");
char readBuf[128];
while(1)
{
get_Data_From_Buffer(&pHandle, &readBuf[0], 3);
sleep(1);
printf("readBuf=%s\n", readBuf);
}
return NULL;
}
int main()
{
int nRet = 0;
pthread_t tCons;
pthread_t tProd;
buffer_Init();
nRet = create_Buffer(&pHandle);
if (nRet)
{
printf(" create_buffer error nRet=%d", nRet);
return -1;
}
pthread_create(&tCons, NULL, WorkProduct, NULL);
pthread_create(&tProd, NULL, WorkConsmue, NULL);
pthread_join(tCons, NULL);
pthread_join(tProd, NULL);
return 0;
}
2.编译时出现的报错
(1).||要加括号否则出现错误
2.GDB调试
