文本处理或拷贝

#include <stdio.h>#include <stdlib.h>#include <errno.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#define MAXLINE 1024/*每次读入一行文本，包括换行符*/ssize_t readline(int fd, void *vptr, size_t maxlen){ssize_t n, rc;char c, *ptr;ptr = vptr;for(n = 1; n < maxlen; n++){if((rc = read(fd, &c, 1)) == 1){*ptr++ = c;if(c == '/n')break;}else if(rc == 0){*ptr = 0;return (n-1);}else{if(errno == EINTR)continue;return -1;}}*ptr = 0;return (n);}int main(int argc, char *argv[]){int from_fd, to_fd;char *from_file;char *to_file;char buffer[MAXLINE];int start = 0, end = 0;memset(buffer, 0, sizeof(buffer));/*检查参数的合法性*/if(argc < 3){printf("%s <source file> <dst file>/n", argv[0]);exit(1);}/*获取文件名*/from_file = argv[1];to_file = argv[2];/*打开源文件*/if((from_fd = open(from_file, O_RDONLY)) == -1){fprintf(stderr, "Open %s Error: %s/n", from_file, strerror(errno));exit(1);}/*创建目标文件*/if((to_fd = open(to_file, O_WRONLY|O_CREAT, S_IRUSR|S_IWUSR)) == -1){fprintf(stderr, "Open %s Error: %s/n", to_file, strerror(errno));exit(1);}/*行处理，然后再写入目标文件*/while(readline(from_fd, buffer, MAXLINE)){/*int str_buf_len = strlen(buffer);for(end = 0; end < str_buf_len + 1; end++){if(buffer[end] == ']')start = end + 3;if(buffer[end] == '|')buffer[end] = '/t';}*///to do somethingint write_len = 0;if((write_len=write(to_fd, buffer+start, strlen(buffer+start))) == -1){fprintf(stderr, "write %s Error: %s/n", to_file, strerror(errno));exit(1);}//printf("%d/n", write_len);memset(buffer, 0, sizeof(buffer));}close(to_fd);close(from_fd);return 0;}