send_big_file.h

文件传输

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <iostream>
using namespace std;
#define BACKLOG 10
#define MAX_LEN 1024*1024
#define DOT_PERIOD 50
#define NAME_LEN 20

//读文件块到缓冲区，用标准I／O
ssize_t readall(int fd, void* buf,size_t *len){
   size_t nleft;
   ssize_t nread;
   ssize_t total;
   char *ptr;
   ptr = (char*)buf;
   nleft = *len;
   total = 0;
   while( nleft > 0){
      if((nread = read(fd,ptr,*len)) == -1){
         perror("readall");
         break;
      }
      if(nread ==0)
         break;
      nleft -= nread;
      ptr += nread;
      total += nread;
      *len = nleft;
   }
   *len = total;
   return (nread==-1)?-1:0;
}
//读取文件块到缓冲区，用文件I／O
ssize_t readall(FILE * stream, void* buf,size_t *len){
   size_t nread;
   char *ptr;
   ptr = (char*)buf;
   if((nread = fread(ptr, sizeof(char), *len, stream)) == -1){
         perror("readall");
         exit(1);
   }
   *len = nread;
   return (nread==-1)?-1:0;
}

//把缓冲区内容写进文件，用标准I／O
ssize_t writeall(int fd, void* buf,size_t *len){
   size_t nleft;
   ssize_t nwrite;
   ssize_t total;
   const char *ptr;
   ptr = (char*)buf;
   nleft = *len;
   total = 0;
   while( nleft > 0){
      if((nwrite = write(fd,ptr,*len))== -1){
         perror("write all");
         break;
      }
      nleft -= nwrite;
      ptr += nwrite;
      total += nwrite;
      *len = nleft;
   }
   *len = total;
   return (nwrite==-1)?-1:0;
}
//把缓冲区内容写进文件，用文件I／O
ssize_t writeall(FILE * stream, void* buf,size_t *len){
   const char *ptr;
   ptr = (char*)buf;
   int nwrite;
   if((nwrite = fwrite(ptr,sizeof(char),*len,stream))== -1){
         perror("write all");
         exit(1);
   }
   *len = nwrite;
   return (nwrite==-1)?-1:0;
}
//读入将要传送的文件名
int read_cmd(int sockfd,char* cmd_buf,int len){
   char line[NAME_LEN];
   int my_len = 0;
   if(len > MAX_LEN)
         len = MAX_LEN;
   if((my_len = read(sockfd, line,len))<0 ){
            perror("read");
            return -1;
   }
   line[my_len] = '\0';
   strcpy(cmd_buf, line);
   printf("Client requests file: %s\n",cmd_buf);
   return 0;
}
//传送文件
int send_file(int sockfd,char *file_name){
    int file_fd;
    int file_size;
    int read_left;
    size_t len;
    FILE * filename;
    int error_flag;
    size_t readlen;
    struct stat file_state;
    char buffer[MAX_LEN];
    int dot_number = 0;
     if((file_fd = open(file_name,O_RDONLY)) == -1){
        perror("open");
        return -1;
    }
    filename = fopen(file_name,"r");
    if(fstat(file_fd, &file_state)==-1){
        perror("fstat");
        return -1;
    }
    file_size = file_state.st_size;
    read_left = file_size;
    len = MAX_LEN;
    while(read_left > 0){
        readlen = MAX_LEN;
        error_flag = readall(filename,buffer,&readlen);
        if(error_flag<0 ){
            return -1;
        }
        if(readlen ==0 && read_left!=0){
            printf("the file is not read fully!\n");
            return -1;
        }
        read_left -= readlen;
        len = readlen;
        error_flag = writeall(sockfd,buffer,&len);
        if(error_flag == -1){
            return -1;
        }
        if(read_left ==0){
            printf("\nServer send file over!\n");
        }
    }
    close(file_fd);
    return 0;
}