Andrew's git - gitweb.git/blob - t/helper/test-genrandom.c

   1/*
   2 * Simple random data generator used to create reproducible test files.
   3 * This is inspired from POSIX.1-2001 implementation example for rand().
   4 * Copyright (C) 2007 by Nicolas Pitre, licensed under the GPL version 2.
   5 */
   6
   7#include "git-compat-util.h"
   8
   9int cmd_main(int argc, const char **argv)
  10{
  11        unsigned long count, next = 0;
  12        unsigned char *c;
  13
  14        if (argc < 2 || argc > 3) {
  15                fprintf(stderr, "usage: %s <seed_string> [<size>]\n", argv[0]);
  16                return 1;
  17        }
  18
  19        c = (unsigned char *) argv[1];
  20        do {
  21                next = next * 11 + *c;
  22        } while (*c++);
  23
  24        count = (argc == 3) ? strtoul(argv[2], NULL, 0) : -1L;
  25
  26        while (count--) {
  27                next = next * 1103515245 + 12345;
  28                if (putchar((next >> 16) & 0xff) == EOF)
  29                        return -1;
  30        }
  31
  32        return 0;
  33}