/* boost random/discard_block.hpp header file * * Copyright Jens Maurer 2002 * 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: discard_block.hpp,v 1.12 2005/05/21 15:57:00 dgregor Exp $ * * Revision history * 2001-03-02 created */ #ifndef BOOST_RANDOM_DISCARD_BLOCK_HPP #define BOOST_RANDOM_DISCARD_BLOCK_HPP #include <iostream> #include <boost/config.hpp> #include <boost/limits.hpp> #include <boost/static_assert.hpp> namespace boost { namespace random { template<class UniformRandomNumberGenerator, unsigned int p, unsigned int r> class discard_block { public: typedef UniformRandomNumberGenerator base_type; typedef typename base_type::result_type result_type; BOOST_STATIC_CONSTANT(bool, has_fixed_range = false); BOOST_STATIC_CONSTANT(unsigned int, total_block = p); BOOST_STATIC_CONSTANT(unsigned int, returned_block = r); #ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS BOOST_STATIC_ASSERT(total_block >= returned_block); #endif discard_block() : _rng(), _n(0) { } explicit discard_block(const base_type & rng) : _rng(rng), _n(0) { } template<class It> discard_block(It& first, It last) : _rng(first, last), _n(0) { } void seed() { _rng.seed(); _n = 0; } template<class T> void seed(T s) { _rng.seed(s); _n = 0; } template<class It> void seed(It& first, It last) { _n = 0; _rng.seed(first, last); } const base_type& base() const { return _rng; } result_type operator()() { if(_n >= returned_block) { // discard values of random number generator for( ; _n < total_block; ++_n) _rng(); _n = 0; } ++_n; return _rng(); } result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return (_rng.min)(); } result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return (_rng.max)(); } static bool validation(result_type x) { return true; } // dummy #ifndef BOOST_NO_OPERATORS_IN_NAMESPACE #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS template<class CharT, class Traits> friend std::basic_ostream<CharT,Traits>& operator<<(std::basic_ostream<CharT,Traits>& os, const discard_block& s) { os << s._rng << " " << s._n << " "; return os; } template<class CharT, class Traits> friend std::basic_istream<CharT,Traits>& operator>>(std::basic_istream<CharT,Traits>& is, discard_block& s) { is >> s._rng >> std::ws >> s._n >> std::ws; return is; } #endif friend bool operator==(const discard_block& x, const discard_block& y) { return x._rng == y._rng && x._n == y._n; } friend bool operator!=(const discard_block& x, const discard_block& y) { return !(x == y); } #else // Use a member function; Streamable concept not supported. bool operator==(const discard_block& rhs) const { return _rng == rhs._rng && _n == rhs._n; } bool operator!=(const discard_block& rhs) const { return !(*this == rhs); } #endif private: base_type _rng; unsigned int _n; }; #ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION // A definition is required even for integral static constants template<class UniformRandomNumberGenerator, unsigned int p, unsigned int r> const bool discard_block<UniformRandomNumberGenerator, p, r>::has_fixed_range; template<class UniformRandomNumberGenerator, unsigned int p, unsigned int r> const unsigned int discard_block<UniformRandomNumberGenerator, p, r>::total_block; template<class UniformRandomNumberGenerator, unsigned int p, unsigned int r> const unsigned int discard_block<UniformRandomNumberGenerator, p, r>::returned_block; #endif } // namespace random } // namespace boost #endif // BOOST_RANDOM_DISCARD_BLOCK_HPP