1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/epoc32/include/stdapis/boost/random/linear_feedback_shift.hpp Tue Mar 16 16:12:26 2010 +0000
1.3 @@ -0,0 +1,145 @@
1.4 +/* boost random/tausworthe.hpp header file
1.5 + *
1.6 + * Copyright Jens Maurer 2002
1.7 + * Distributed under the Boost Software License, Version 1.0. (See
1.8 + * accompanying file LICENSE_1_0.txt or copy at
1.9 + * http://www.boost.org/LICENSE_1_0.txt)
1.10 + *
1.11 + * See http://www.boost.org for most recent version including documentation.
1.12 + *
1.13 + * $Id: linear_feedback_shift.hpp,v 1.12 2005/05/21 15:57:00 dgregor Exp $
1.14 + *
1.15 + */
1.16 +
1.17 +#ifndef BOOST_RANDOM_LINEAR_FEEDBACK_SHIFT_HPP
1.18 +#define BOOST_RANDOM_LINEAR_FEEDBACK_SHIFT_HPP
1.19 +
1.20 +#include <iostream>
1.21 +#include <cassert>
1.22 +#include <stdexcept>
1.23 +#include <boost/config.hpp>
1.24 +#include <boost/static_assert.hpp>
1.25 +#include <boost/limits.hpp>
1.26 +
1.27 +namespace boost {
1.28 +namespace random {
1.29 +
1.30 +// Tausworte 1965
1.31 +template<class UIntType, int w, int k, int q, int s, UIntType val>
1.32 +class linear_feedback_shift
1.33 +{
1.34 +public:
1.35 + typedef UIntType result_type;
1.36 + // avoid the warning trouble when using (1<<w) on 32 bit machines
1.37 + BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
1.38 + BOOST_STATIC_CONSTANT(int, word_size = w);
1.39 + BOOST_STATIC_CONSTANT(int, exponent1 = k);
1.40 + BOOST_STATIC_CONSTANT(int, exponent2 = q);
1.41 + BOOST_STATIC_CONSTANT(int, step_size = s);
1.42 +
1.43 + result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return 0; }
1.44 + result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return wordmask; }
1.45 +
1.46 + // MSVC 6 and possibly others crash when encountering complicated integral
1.47 + // constant expressions. Avoid the checks for now.
1.48 + // BOOST_STATIC_ASSERT(w > 0);
1.49 + // BOOST_STATIC_ASSERT(q > 0);
1.50 + // BOOST_STATIC_ASSERT(k < w);
1.51 + // BOOST_STATIC_ASSERT(0 < 2*q && 2*q < k);
1.52 + // BOOST_STATIC_ASSERT(0 < s && s <= k-q);
1.53 +
1.54 + explicit linear_feedback_shift(UIntType s0 = 341) : wordmask(0)
1.55 + {
1.56 + // MSVC fails BOOST_STATIC_ASSERT with std::numeric_limits at class scope
1.57 +#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
1.58 + BOOST_STATIC_ASSERT(std::numeric_limits<UIntType>::is_integer);
1.59 + BOOST_STATIC_ASSERT(!std::numeric_limits<UIntType>::is_signed);
1.60 +#endif
1.61 +
1.62 + // avoid "left shift count >= with of type" warning
1.63 + for(int i = 0; i < w; ++i)
1.64 + wordmask |= (1u << i);
1.65 + seed(s0);
1.66 + }
1.67 +
1.68 + template<class It> linear_feedback_shift(It& first, It last) : wordmask(0)
1.69 + {
1.70 + // MSVC fails BOOST_STATIC_ASSERT with std::numeric_limits at class scope
1.71 +#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
1.72 + BOOST_STATIC_ASSERT(std::numeric_limits<UIntType>::is_integer);
1.73 + BOOST_STATIC_ASSERT(!std::numeric_limits<UIntType>::is_signed);
1.74 +#endif
1.75 +
1.76 + // avoid "left shift count >= with of type" warning
1.77 + for(int i = 0; i < w; ++i)
1.78 + wordmask |= (1u << i);
1.79 + seed(first, last);
1.80 + }
1.81 +
1.82 + void seed(UIntType s0 = 341) { assert(s0 >= (1 << (w-k))); value = s0; }
1.83 + template<class It> void seed(It& first, It last)
1.84 + {
1.85 + if(first == last)
1.86 + throw std::invalid_argument("linear_feedback_shift::seed");
1.87 + value = *first++;
1.88 + assert(value >= (1 << (w-k)));
1.89 + }
1.90 +
1.91 + result_type operator()()
1.92 + {
1.93 + const UIntType b = (((value << q) ^ value) & wordmask) >> (k-s);
1.94 + const UIntType mask = ( (~static_cast<UIntType>(0)) << (w-k) ) & wordmask;
1.95 + value = ((value & mask) << s) ^ b;
1.96 + return value;
1.97 + }
1.98 + bool validation(result_type x) const { return val == x; }
1.99 +
1.100 +#ifndef BOOST_NO_OPERATORS_IN_NAMESPACE
1.101 +
1.102 +#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
1.103 + template<class CharT, class Traits>
1.104 + friend std::basic_ostream<CharT,Traits>&
1.105 + operator<<(std::basic_ostream<CharT,Traits>& os, linear_feedback_shift x)
1.106 + { os << x.value; return os; }
1.107 +
1.108 + template<class CharT, class Traits>
1.109 + friend std::basic_istream<CharT,Traits>&
1.110 + operator>>(std::basic_istream<CharT,Traits>& is, linear_feedback_shift& x)
1.111 + { is >> x.value; return is; }
1.112 +#endif
1.113 +
1.114 + friend bool operator==(linear_feedback_shift x, linear_feedback_shift y)
1.115 + { return x.value == y.value; }
1.116 + friend bool operator!=(linear_feedback_shift x, linear_feedback_shift y)
1.117 + { return !(x == y); }
1.118 +#else
1.119 + // Use a member function; Streamable concept not supported.
1.120 + bool operator==(linear_feedback_shift rhs) const
1.121 + { return value == rhs.value; }
1.122 + bool operator!=(linear_feedback_shift rhs) const
1.123 + { return !(*this == rhs); }
1.124 +#endif
1.125 +
1.126 +private:
1.127 + UIntType wordmask; // avoid "left shift count >= width of type" warnings
1.128 + UIntType value;
1.129 +};
1.130 +
1.131 +#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
1.132 +// A definition is required even for integral static constants
1.133 +template<class UIntType, int w, int k, int q, int s, UIntType val>
1.134 +const bool linear_feedback_shift<UIntType, w, k, q, s, val>::has_fixed_range;
1.135 +template<class UIntType, int w, int k, int q, int s, UIntType val>
1.136 +const int linear_feedback_shift<UIntType, w, k, q, s, val>::word_size;
1.137 +template<class UIntType, int w, int k, int q, int s, UIntType val>
1.138 +const int linear_feedback_shift<UIntType, w, k, q, s, val>::exponent1;
1.139 +template<class UIntType, int w, int k, int q, int s, UIntType val>
1.140 +const int linear_feedback_shift<UIntType, w, k, q, s, val>::exponent2;
1.141 +template<class UIntType, int w, int k, int q, int s, UIntType val>
1.142 +const int linear_feedback_shift<UIntType, w, k, q, s, val>::step_size;
1.143 +#endif
1.144 +
1.145 +} // namespace random
1.146 +} // namespace boost
1.147 +
1.148 +#endif // BOOST_RANDOM_LINEAR_FEEDBACK_SHIFT_HPP