text: /*
   * Copyright (c) 2007 Michael Niedermayer
   *
   * This file is part of Libav.
   *
   * Libav 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 2.1 of the License, or (at your option) any later version.
   *
   * Libav 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 Libav; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <inttypes.h>
  #include <errno.h>
  #include <string.h>
  
  static uint32_t state;
  static uint32_t ran(void)
  {
      return state = state * 1664525 + 1013904223;
  }
  
  int main(int argc, char **argv)
  {
      FILE *f;
      int count, maxburst, length;
  
      if (argc < 5) {
          printf("USAGE: trasher <filename> <count> <maxburst> <seed>\n");
          return 1;
      }
  
      f = fopen(argv[1], "rb+");
      if (!f) {
          perror(argv[1]);
          return 2;
      }
      count    = atoi(argv[2]);
      maxburst = atoi(argv[3]);
      state    = atoi(argv[4]);
  
      fseek(f, 0, SEEK_END);
      length = ftell(f);
      fseek(f, 0, SEEK_SET);
  
      while (count--) {
          int burst = 1 + ran() * (uint64_t) (abs(maxburst) - 1) / UINT32_MAX;
          int pos   = ran() * (uint64_t) length / UINT32_MAX;
          fseek(f, pos, SEEK_SET);
  
          if (maxburst < 0)
              burst = -maxburst;
  
          if (pos + burst > length)
              continue;
  
          while (burst--) {
              int val = ran() * 256ULL / UINT32_MAX;
  
              if (maxburst < 0)
                  val = 0;
  
              fwrite(&val, 1, 1, f);
          }
      }
  
      return 0;
  }
  