test_write_pipe.cpp

/*
Copyright 2007, 2008, 2009, 2010, 2011 Instituto de Sistemas e Robotica, Instituto Superior Tecnico

This file is part of MeRMaID.

MeRMaID is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

MeRMaID is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with MeRMaID.  If not, see <http://www.gnu.org/licenses/>.
*/



#include "config.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <assert.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <assert.h>

#define PIPE_NAME "/tmp/test_write_pipe"
#define FILE_NAME "test_file.txt"
#define SIZE 1000

int main()
{
  // create named pipe
  mkfifo (PIPE_NAME, S_IRUSR);
  
#ifdef DEBUG
  puts ("Named pipe created.");
#endif
  
  // open named pipe
  int fd_pipe = open (PIPE_NAME, O_RDONLY, S_IRUSR);
  FILE* fd_file = fopen (FILE_NAME, "r");
  
  if (fd_pipe == -1 || fd_file == 0) {
#ifdef DEBUG
    printf ("Error opening pipe. fd_pipe: %d errno: %d\n", fd_pipe, errno);
#endif
    return -1;
  }
  
  fseek (fd_file, 0, SEEK_END);
  int fsize = ftell (fd_file);
  fseek (fd_file, 0, SEEK_SET);
  
#ifdef DEBUG
  printf ("fsize: %d\n", fsize);
#endif
  
  //puts("Named pipe opened sucessfully.");
  
  while (1) {
    char buf_pipe[SIZE], buf_file[SIZE];
    int bytes_read_pipe = read (fd_pipe, buf_pipe, sizeof (buf_pipe));
    
    int bytes_read_file = fread (buf_file, 1, bytes_read_pipe, fd_file);
    fsize -= bytes_read_file;
    
    // error
    if (memcmp (buf_file, buf_pipe, bytes_read_pipe) || bytes_read_pipe != bytes_read_file) {
#ifdef DEBUG
      puts ("dont match");
#endif
      return -1;
    }
    
    // transmission is over
    if (bytes_read_pipe == 0) {
#ifdef DEBUG
      puts ("transmission is over");
#endif
      if (fsize == 0) {// read every single byte from the file
        return 0;
      }
#ifdef DEBUG
      puts ("bytes not read");
#endif
      return -1; // there were more bytes to be received
    }
#ifdef DEBUG
    for (int i = 0; i < bytes_read_pipe; i++)
      putchar (buf_pipe[i]);
    putchar ('\n');
#endif
  }
  
  close (fd_pipe);
  fclose (fd_file);
  return 0;
}