alex

/* *****************************************************************************
 * A.L.E (Arcade Learning Environment)
 * Copyright (c) 2009-2013 by Yavar Naddaf, Joel Veness, Marc G. Bellemare and
 *   the Reinforcement Learning and Artificial Intelligence Laboratory
 * Released under the GNU General Public License; see License.txt for details.
 *
 * Based on: Stella  --  "An Atari 2600 VCS Emulator"
 * Copyright (c) 1995-2007 by Bradford W. Mott and the Stella team
 *
 * *****************************************************************************
 *  misc_tools.h
 *
 *  A set of miscellaneous tools used in various places.
 **************************************************************************** */
#ifndef __MISC_TOOLS_H__
#define __MISC_TOOLS_H__

#include "Constants.h"

#if (defined(WIN32) || defined(__MINGW32__))
#include <sys/time.h>
#endif

namespace ale {

/* *****************************************************************************
    Inline C++ integer exponentiation routines
    Version 1.01
    Copyright (C) 1999-2004 John C. Bowman <bowman@math.ualberta.ca>
 **************************************************************************** */
inline int pow(int x, int p) {
  if (p == 0)
    return 1;
  if (x == 0 && p > 0)
    return 0;
  if (p < 0) {
    assert(x == 1 || x == -1);
    return (-p % 2) ? x : 1;
  }

  int r = 1;
  for (;;) {
    if (p & 1)
      r *= x;
    if ((p >>= 1) == 0)
      return r;
    x *= x;
  }
}

/* *****************************************************************************
    Makes x fit within the [uper, lower] bounds
 **************************************************************************** */
inline void bound(int& x, int lower_bound, int upper_bound) {
  if (x > upper_bound) {
    x = upper_bound;
  }
  if (x < lower_bound) {
    x = lower_bound;
  }
}

/* *****************************************************************************
    Return time in milliseconds.
 **************************************************************************** */
#if (defined(WIN32) || defined(__MINGW32__))

#include <windows.h>

inline long timeMillis() { return GetTickCount(); }

#else

inline long timeMillis() {
  struct timeval ts;
  gettimeofday(&ts, NULL);
  return ts.tv_sec * 1000 + ts.tv_usec / 1000;
}

#endif

}  // namespace ale

#endif  // __MISC_TOOLS_H__