sl@0: /* boost random/shuffle_output.hpp header file
sl@0:  *
sl@0:  * Copyright Jens Maurer 2000-2001
sl@0:  * Distributed under the Boost Software License, Version 1.0. (See
sl@0:  * accompanying file LICENSE_1_0.txt or copy at
sl@0:  * http://www.boost.org/LICENSE_1_0.txt)
sl@0:  *
sl@0:  * See http://www.boost.org for most recent version including documentation.
sl@0:  *
sl@0:  * $Id: shuffle_output.hpp,v 1.10 2005/08/25 16:27:22 johnmaddock Exp $
sl@0:  *
sl@0:  * Revision history
sl@0:  *  2001-02-18  moved to individual header files
sl@0:  */
sl@0: 
sl@0: #ifndef BOOST_RANDOM_SHUFFLE_OUTPUT_HPP
sl@0: #define BOOST_RANDOM_SHUFFLE_OUTPUT_HPP
sl@0: 
sl@0: #include <iostream>
sl@0: #include <algorithm>     // std::copy
sl@0: #include <cassert>
sl@0: #include <boost/config.hpp>
sl@0: #include <boost/limits.hpp>
sl@0: #include <boost/static_assert.hpp>
sl@0: #include <boost/cstdint.hpp>
sl@0: #include <boost/random/linear_congruential.hpp>
sl@0: 
sl@0: namespace boost {
sl@0: namespace random {
sl@0: 
sl@0: // Carter Bays and S.D. Durham 1979
sl@0: template<class UniformRandomNumberGenerator, int k,
sl@0: #ifndef BOOST_NO_DEPENDENT_TYPES_IN_TEMPLATE_VALUE_PARAMETERS
sl@0:   typename UniformRandomNumberGenerator::result_type 
sl@0: #else
sl@0:   uint32_t
sl@0: #endif
sl@0:   val = 0>
sl@0: class shuffle_output
sl@0: {
sl@0: public:
sl@0:   typedef UniformRandomNumberGenerator base_type;
sl@0:   typedef typename base_type::result_type result_type;
sl@0: 
sl@0:   BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
sl@0:   BOOST_STATIC_CONSTANT(int, buffer_size = k);
sl@0: 
sl@0:   shuffle_output() : _rng() { init(); }
sl@0: #if defined(BOOST_MSVC) && _MSC_VER < 1300
sl@0:   // MSVC does not implicitly generate the copy constructor here
sl@0:   shuffle_output(const shuffle_output & x)
sl@0:     : _rng(x._rng), y(x.y) { std::copy(x.v, x.v+k, v); }
sl@0: #endif
sl@0:   template<class T>
sl@0:   explicit shuffle_output(T seed) : _rng(seed) { init(); }
sl@0:   explicit shuffle_output(const base_type & rng) : _rng(rng) { init(); }
sl@0:   template<class It> shuffle_output(It& first, It last)
sl@0:     : _rng(first, last) { init(); }
sl@0:   void seed() { _rng.seed(); init(); }
sl@0:   template<class T>
sl@0:   void seed(T s) { _rng.seed(s); init(); }
sl@0:   template<class It> void seed(It& first, It last)
sl@0:   {
sl@0:     _rng.seed(first, last);
sl@0:     init();
sl@0:   }
sl@0: 
sl@0:   const base_type& base() const { return _rng; }
sl@0: 
sl@0:   result_type operator()() {
sl@0:     // calculating the range every time may seem wasteful.  However, this
sl@0:     // makes the information locally available for the optimizer.
sl@0:     result_type range = (max)()-(min)()+1;
sl@0:     int j = k*(y-(min)())/range;
sl@0:     // assert(0 <= j && j < k);
sl@0:     y = v[j];
sl@0:     v[j] = _rng();
sl@0:     return y;
sl@0:   }
sl@0: 
sl@0:   result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return (_rng.min)(); }
sl@0:   result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return (_rng.max)(); }
sl@0:   static bool validation(result_type x) { return val == x; }
sl@0: 
sl@0: #ifndef BOOST_NO_OPERATORS_IN_NAMESPACE
sl@0: 
sl@0: #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
sl@0:   template<class CharT, class Traits>
sl@0:   friend std::basic_ostream<CharT,Traits>&
sl@0:   operator<<(std::basic_ostream<CharT,Traits>& os, const shuffle_output& s)
sl@0:   {
sl@0:     os << s._rng << " " << s.y << " ";
sl@0:     for(int i = 0; i < s.buffer_size; ++i)
sl@0:       os << s.v[i] << " ";
sl@0:     return os;
sl@0:   }
sl@0: 
sl@0:   template<class CharT, class Traits>
sl@0:   friend std::basic_istream<CharT,Traits>&
sl@0:   operator>>(std::basic_istream<CharT,Traits>& is, shuffle_output& s)
sl@0:   {
sl@0:     is >> s._rng >> std::ws >> s.y >> std::ws;
sl@0:     for(int i = 0; i < s.buffer_size; ++i)
sl@0:       is >> s.v[i] >> std::ws;
sl@0:     return is;
sl@0:   }
sl@0: #endif
sl@0: 
sl@0:   friend bool operator==(const shuffle_output& x, const shuffle_output& y)
sl@0:   { return x._rng == y._rng && x.y == y.y && std::equal(x.v, x.v+k, y.v); }
sl@0:   friend bool operator!=(const shuffle_output& x, const shuffle_output& y)
sl@0:   { return !(x == y); }
sl@0: #else
sl@0:   // Use a member function; Streamable concept not supported.
sl@0:   bool operator==(const shuffle_output& rhs) const
sl@0:   { return _rng == rhs._rng && y == rhs.y && std::equal(v, v+k, rhs.v); }
sl@0:   bool operator!=(const shuffle_output& rhs) const
sl@0:   { return !(*this == rhs); }
sl@0: #endif
sl@0: private:
sl@0:   void init()
sl@0:   {
sl@0: #ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
sl@0:     BOOST_STATIC_ASSERT(std::numeric_limits<result_type>::is_integer);
sl@0: #endif
sl@0:     result_type range = (max)()-(min)();
sl@0:     assert(range > 0);      // otherwise there would be little choice
sl@0:     if(static_cast<unsigned long>(k * range) < 
sl@0:        static_cast<unsigned long>(range))  // not a sufficient condition
sl@0:       // likely overflow with bucket number computation
sl@0:       assert(!"overflow will occur");
sl@0: 
sl@0:     // we cannot use std::generate, because it uses pass-by-value for _rng
sl@0:     for(result_type * p = v; p != v+k; ++p)
sl@0:       *p = _rng();
sl@0:     y = _rng();
sl@0:   }
sl@0: 
sl@0:   base_type _rng;
sl@0:   result_type v[k];
sl@0:   result_type y;
sl@0: };
sl@0: 
sl@0: #ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
sl@0: //  A definition is required even for integral static constants
sl@0: template<class UniformRandomNumberGenerator, int k, 
sl@0: #ifndef BOOST_NO_DEPENDENT_TYPES_IN_TEMPLATE_VALUE_PARAMETERS
sl@0:   typename UniformRandomNumberGenerator::result_type 
sl@0: #else
sl@0:   uint32_t
sl@0: #endif
sl@0:   val>
sl@0: const bool shuffle_output<UniformRandomNumberGenerator, k, val>::has_fixed_range;
sl@0: 
sl@0: template<class UniformRandomNumberGenerator, int k, 
sl@0: #ifndef BOOST_NO_DEPENDENT_TYPES_IN_TEMPLATE_VALUE_PARAMETERS
sl@0:   typename UniformRandomNumberGenerator::result_type 
sl@0: #else
sl@0:   uint32_t
sl@0: #endif
sl@0:   val>
sl@0: const int shuffle_output<UniformRandomNumberGenerator, k, val>::buffer_size;
sl@0: #endif
sl@0: 
sl@0: } // namespace random
sl@0: 
sl@0: // validation by experiment from Harry Erwin's generator.h (private e-mail)
sl@0: typedef random::shuffle_output<
sl@0:     random::linear_congruential<uint32_t, 1366, 150889, 714025, 0>,
sl@0:   97, 139726> kreutzer1986;
sl@0: 
sl@0: 
sl@0: } // namespace boost
sl@0: 
sl@0: #endif // BOOST_RANDOM_SHUFFLE_OUTPUT_HPP