/* CVS info   */
/* $Date: 2005/10/04 17:52:00 $     */
/* $Revision: 1.1 $ */
/* $RCSfile: gen_file.c,v $  */
/* $Name: rel_7 $     */
/*
  This is a simple program to produce files of a given size.
  The file is filled with a sequence of lower case letters.
  File sizes ending in k or K indicate KBytes 1024.
  File sizes ending in m or M indicate MBytes 1024*1024.
*/

#include <stdio.h>
#include <string.h>


// 1 K bytes
char data[ 1024 ];

int main(int argc, char** argv){

  FILE* File_ptr;
  char* filename;
  int  fsize;         // in KBs
  int len;
  int scale = 1;
  char t;
  int sh = 1;
  
  static char cvs_info[] = "BMARKGRP $Date: 2005/10/04 17:52:00 $ $Revision: 1.1 $ $RCSfile: gen_file.c,v $ $Name: rel_7 $";


  // Fill with letters a-z
  for(int i=0; i<1024; i++){
    data[i] = (char)((int)'a'+(i%26));
  }

  filename = argv[1];
  if (argc == 2){
    fsize = 1;
    sh = 0;
  }else{
    len = strlen(argv[2]);

    // KBytes
    t = argv[2][len-1];
    if ( (t=='k') | (t=='K') ){
      scale = 1;
      argv[2][len-1] = 0;
      sh = 0;
    }
    // MBytes
    if ( (t=='m') | (t=='M') ){
      scale = 1024;
      argv[2][len-1] = 0;
      sh = 0;
    }
    // GBytes
    if ( (t=='g') | (t=='G') ){
      scale = 1024*1024;
      argv[2][len-1] = 0;
      sh = 0;
    }
    fsize = atoi(argv[2])*scale;
  }

  // Open the file for appending
  if( (File_ptr = fopen(filename, "a") ) == NULL){
    printf("open\n");
    exit( 2 );
  }

  if (sh){
    for (long i=0; i<fsize; i++){
      fwrite( &data[i] , 1, 1, File_ptr );  // Writes number of bytes
    }
  }else{
    for (long i=0; i<fsize; i++){
      fwrite( data , 1024, 1, File_ptr );  // Writes KB or MB blocks
    }
  }

  // Close the file
  if ( fclose( File_ptr ) == EOF ){
    exit( 4 );
  }

  return 0;
} // End Main