/* boost random/uniform_01.hpp header file

 *

 * Copyright Jens Maurer 2000-2001

 * Distributed under the Boost Software License, Version 1.0. (See

 * accompanying file LICENSE_1_0.txt or copy at

 * http://www.boost.org/LICENSE_1_0.txt)

 *

 * See http://www.boost.org for most recent version including documentation.

 *

 * $Id: uniform_01.hpp 41369 2007-11-25 18:07:19Z bemandawes $

 *

 * Revision history

 *  2001-02-18  moved to individual header files

 */



#ifndef BOOST_RANDOM_UNIFORM_01_HPP

#define BOOST_RANDOM_UNIFORM_01_HPP



#include <iostream>

#include <boost/config.hpp>

#include <boost/limits.hpp>

#include <boost/static_assert.hpp>



namespace boost {



// Because it is so commonly used: uniform distribution on the real [0..1)

// range.  This allows for specializations to avoid a costly int -> float

// conversion plus float multiplication

template<class UniformRandomNumberGenerator, class RealType = double>

class uniform_01

{

public:

  typedef UniformRandomNumberGenerator base_type;

  typedef RealType result_type;



  BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);



#if !defined(BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS) && !(defined(BOOST_MSVC) && BOOST_MSVC <= 1300)

  BOOST_STATIC_ASSERT(!std::numeric_limits<RealType>::is_integer);

#endif



  explicit uniform_01(base_type rng)

    : _rng(rng),

      _factor(result_type(1) /

              (result_type((_rng.max)()-(_rng.min)()) +

               result_type(std::numeric_limits<base_result>::is_integer ? 1 : 0)))

  {

  }

  // compiler-generated copy ctor and copy assignment are fine



  result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return result_type(0); }

  result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return result_type(1); }

  base_type& base() { return _rng; }

  const base_type& base() const { return _rng; }

  void reset() { }



  result_type operator()() {

    for (;;) {

      result_type result = result_type(_rng() - (_rng.min)()) * _factor;

      if (result < result_type(1))

	return result;

    }

  }



#if !defined(BOOST_NO_OPERATORS_IN_NAMESPACE) && !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)

  template<class CharT, class Traits>

  friend std::basic_ostream<CharT,Traits>&

  operator<<(std::basic_ostream<CharT,Traits>& os, const uniform_01& u)

  {

    os << u._rng;

    return os;

  }



  template<class CharT, class Traits>

  friend std::basic_istream<CharT,Traits>&

  operator>>(std::basic_istream<CharT,Traits>& is, uniform_01& u)

  {

    is >> u._rng;

    return is;

  }

#endif



private:

  typedef typename base_type::result_type base_result;

  base_type _rng;

  result_type _factor;

};



#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION

//  A definition is required even for integral static constants

template<class UniformRandomNumberGenerator, class RealType>

const bool uniform_01<UniformRandomNumberGenerator, RealType>::has_fixed_range;

#endif



} // namespace boost



#endif // BOOST_RANDOM_UNIFORM_01_HPP

