c/c++ 替换文本文件中的字符串函数【方法二】linux、mac版本

#include <sys/mman.h>

#include <sys/types.h>

#include <fcntl.h>

#include<string>

#include<stdio.h>

#include <unistd.h>

#include <sys/dir.h>

#include <sys/stat.h>

#include <map>

using namespace std;

//求子串

char* substr(const char*str, unsigned long start, unsigned long end);

//替换文本. path:文件名, oriStr:将要替换的字符串、dstStr:替换的目的字符串

void replace(const char *path, const char *oriStr, const char *dstStr);

int main(int argc, char** argv)

{

    replace("/Users/zctech/Desktop/test/test.cpp", "void", "MUSTN'T");

}

//替换文本. path:文件名, oriStr:将要替换的字符串、dstStr:替换的目的字符串

void replace(const char *path, const char *oriStr, const char *dstStr)

{

    int fd = open(path, O_RDWR);

    

    //获取文件大小

    struct stat sb;

    fstat(fd, &sb);

    

    unsigned char *start = (unsigned char *)mmap(NULL, sb.st_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);

    if(start == MAP_FAILED) /* 判断是否映射成功 */

    {

        printf("映射失败，文件过大或者没有权限");

        return;

    }

    

    string str = "";

    unsigned long i = 0;

    while (i < sb.st_size)

    {

        

        if(0 == strcmp(oriStr, substr((char *)start, i, i + strlen(oriStr))))

        {

            str += dstStr;

            i += strlen(oriStr);

            continue;

        }

        str += *(start + i);

        i++;

    }

    

    close(fd);

    munmap(start, sb.st_size); /* 解除映射 */

    

    

    FILE *fp = fopen(path, "w");

    fwrite(str.c_str(), strlen(str.c_str()), sizeof(char), fp);

    fclose(fp);

}

//求子串

char* substr(const char*str, unsigned long start, unsigned long end)

{

    unsigned long n = end - start;

    static char stbuf[1024 * 1024];

    strncpy(stbuf, str + start, n);

    stbuf[n] = 0;                           //字串最后加上0

    return stbuf;

}