LXR busybox/shell/random.h

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * $RANDOM support.
   4 *
   5 * Copyright (C) 2009 Denys Vlasenko
   6 *
   7 * Licensed under GPLv2, see file LICENSE in this source tree.
   8 */
   9#ifndef SHELL_RANDOM_H
  10#define SHELL_RANDOM_H 1
  11
  12PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
  13
  14typedef struct random_t {
  15        /* Random number generators */
  16        int32_t galois_LFSR; /* Galois LFSR (fast but weak). signed! */
  17        uint32_t LCG;        /* LCG (fast but weak) */
  18} random_t;
  19
  20#define UNINITED_RANDOM_T(rnd) \
  21        ((rnd)->galois_LFSR == 0)
  22
  23#define INIT_RANDOM_T(rnd, nonzero, v) \
  24        ((rnd)->galois_LFSR = (nonzero), (rnd)->LCG = (v))
  25
  26#define CLEAR_RANDOM_T(rnd) \
  27        ((rnd)->galois_LFSR = 0)
  28
  29uint32_t next_random(random_t *rnd) FAST_FUNC;
  30
  31POP_SAVED_FUNCTION_VISIBILITY
  32
  33#endif
  34