61.多线程检索内存

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
#include <string.h>
#include <memory.h>
#include <process.h>
#include <Windows.h>

char *path = "dangdangwang.txt";

#define N 13180820

//存储所有的行的信息
char ** g_pp;
//创建线程的数组
struct threads *pthread;

//初始化全局变量g_pp
void  init(char *path)
{
    printf("init start");
    g_pp = malloc(sizeof(char*)*N);
    memset(g_pp, '\0', sizeof(char*)*N);//清空内容
    FILE *pf = fopen(path, "r");

    if (pf==NULL)
    {
        printf("init  fail");
    } 
    else
    {
        for (int i = 0; i < N;i++)
        {
            char str[1024] = { 0 };
            //读取字符串
            fgets(str, 1024, pf);
            //获取长度
            int length = strlen(str);
            if (length >= 1)
            {
                //分配内存
                g_pp[i] = malloc(sizeof(char)*(length + 1));
                //清空内容
                memset(g_pp[i], '\0', length + 1);
                if (g_pp[i]!=NULL)
                {
                    //拷贝
                    strcpy(g_pp[i], str);
                }
            }
        }
        fclose(pf);
    }
    printf("init end");
}

//线性查找
void  search(char*str)
{

    for (int i = 0; i < N;i++)
    {
        if (g_pp[i]!=NULL)
        {
            char *p = strstr(g_pp[i], str);
            if (p != NULL)
            {
                printf("%s\n", g_pp[i]);//找到打印
            }
        }    
    }
}

//创建线程数组
struct threads
{
    //指针数组的起始地址,指向的是一部分字符串,所以是二级指针
    //(二级指针指向很多个一级指针)
    char **ppstart;
    //负责索引的长度
    int length;
    //线程编号
    int id;
    //查找的字符串
    char *pstr;
};

//线程查找,传递的是线程结构体的信息
void searchthread(void *p)
{
    //类型转换
    struct threads *pinfo = p;
    //遍历查找
    for (int i = 0; i < pinfo->length;i++)
    {
        if (pinfo->ppstart[i]!=NULL)
        {
            char *p = strstr(pinfo->ppstart[i], pinfo->pstr);//查找
            if (p!=NULL)
            {
                printf("线程%d找到%s\n", pinfo->id,pinfo->ppstart[i]);//找到
            }
        }
    }
}

//创建线程,并且查找
void  searchwiththread(char*str)
{
    //线程是CPU核心的倍数
    int num = 23;
    //堆上开辟,线程结构体的信息
    pthread = malloc(sizeof(struct threads) * 23);
    //内存清零
    memset(pthread, '\0', sizeof(struct threads )* 23);
    //线程句柄分配内存
    HANDLE *phd = malloc(sizeof(HANDLE) * 23);

    //如果能够整除
    if (N%num == 0)
    {
        for (int i = 0; i < num;i++)
        {
            pthread[i].id = i;
            pthread[i].pstr = str;
            //长度分配
            pthread[i].length = N/num; 
            //起始地址
            pthread[i].ppstart = g_pp+i*(N/num);
            //创建线程
            phd[i] = _beginthread(searchthread, 0, &pthread[i]);
        }
    } 
    //如果不能被整除
    else
    {
        for (int i = 0; i < num-1; i++)
        {
            pthread[i].id = i;
            pthread[i].pstr = str;
            pthread[i].length = N / (num-1); 
            //起始地址
            pthread[i].ppstart = g_pp + i*(N / (num-1));
            //创建线程
            phd[i] = _beginthread(searchthread, 0, &pthread[i]);
        }
        //处理最后一个
        {
            int i = num - 1;
            pthread[i].id = i;
            pthread[i].pstr = str;
            pthread[i].length = N%(num-1);
            //起始地址
            pthread[i].ppstart = g_pp + i*(N / (num - 1));
            //创建线程
            phd[i] = _beginthread(searchthread, 0, &pthread[i]);
        }
    }
    //等待所有线程退出
    WaitForMultipleObjects(num, phd, TRUE, INFINITE);
}

//获取文件有多少行
int getN(char *path)
{
    FILE *pf = fopen(path, "r");
    if (pf == NULL)
    {
        return -1;
    }
    else
    {
        int i = 0;
        while (!feof(pf))
        {
            char str[256] = { 0 };
            fgets(str, 256, pf);
            i++;
        }
        fclose(pf);
        return i;
    }
}

void main()
{
    //初始化全局变量g_pp
    init(path);
    while (1)
    {
        char str[128] = { 0 };
        scanf("%s", str);
        //多线程查找
        searchwiththread(str);
    }
    system("pause");
}