1 | /* boost random/xor_combine.hpp header file |
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2 | * |
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3 | * Copyright Jens Maurer 2002 |
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4 | * Distributed under the Boost Software License, Version 1.0. (See |
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5 | * accompanying file LICENSE_1_0.txt or copy at |
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6 | * http://www.boost.org/LICENSE_1_0.txt) |
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7 | * |
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8 | * See http://www.boost.org for most recent version including documentation. |
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9 | * |
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10 | * $Id: xor_combine.hpp,v 1.13 2005/05/21 15:57:00 dgregor Exp $ |
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11 | * |
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12 | */ |
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13 | |
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14 | #ifndef BOOST_RANDOM_XOR_COMBINE_HPP |
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15 | #define BOOST_RANDOM_XOR_COMBINE_HPP |
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16 | |
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17 | #include <iostream> |
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18 | #include <cassert> |
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19 | #include <algorithm> // for std::min and std::max |
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20 | #include <boost/config.hpp> |
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21 | #include <boost/limits.hpp> |
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22 | #include <boost/static_assert.hpp> |
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23 | #include <boost/cstdint.hpp> // uint32_t |
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24 | |
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25 | |
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26 | namespace boost { |
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27 | namespace random { |
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28 | |
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29 | template<class URNG1, int s1, class URNG2, int s2, |
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30 | #ifndef BOOST_NO_DEPENDENT_TYPES_IN_TEMPLATE_VALUE_PARAMETERS |
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31 | typename URNG1::result_type |
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32 | #else |
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33 | uint32_t |
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34 | #endif |
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35 | val = 0> |
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36 | class xor_combine |
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37 | { |
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38 | public: |
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39 | typedef URNG1 base1_type; |
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40 | typedef URNG2 base2_type; |
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41 | typedef typename base1_type::result_type result_type; |
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42 | |
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43 | BOOST_STATIC_CONSTANT(bool, has_fixed_range = false); |
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44 | BOOST_STATIC_CONSTANT(int, shift1 = s1); |
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45 | BOOST_STATIC_CONSTANT(int, shfit2 = s2); |
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46 | |
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47 | xor_combine() : _rng1(), _rng2() |
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48 | { } |
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49 | xor_combine(const base1_type & rng1, const base2_type & rng2) |
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50 | : _rng1(rng1), _rng2(rng2) { } |
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51 | template<class It> xor_combine(It& first, It last) |
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52 | : _rng1(first, last), _rng2( /* advanced by other call */ first, last) { } |
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53 | void seed() { _rng1.seed(); _rng2.seed(); } |
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54 | template<class It> void seed(It& first, It last) |
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55 | { |
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56 | _rng1.seed(first, last); |
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57 | _rng2.seed(first, last); |
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58 | } |
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59 | |
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60 | const base1_type& base1() { return _rng1; } |
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61 | const base2_type& base2() { return _rng2; } |
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62 | |
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63 | result_type operator()() |
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64 | { |
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65 | // MSVC fails BOOST_STATIC_ASSERT with std::numeric_limits at class scope |
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66 | #if !defined(BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS) && !(defined(BOOST_MSVC) && BOOST_MSVC <= 1300) |
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67 | BOOST_STATIC_ASSERT(std::numeric_limits<typename base1_type::result_type>::is_integer); |
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68 | BOOST_STATIC_ASSERT(std::numeric_limits<typename base2_type::result_type>::is_integer); |
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69 | BOOST_STATIC_ASSERT(std::numeric_limits<typename base1_type::result_type>::digits >= std::numeric_limits<typename base2_type::result_type>::digits); |
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70 | #endif |
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71 | return (_rng1() << s1) ^ (_rng2() << s2); |
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72 | } |
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73 | |
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74 | result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return std::min BOOST_PREVENT_MACRO_SUBSTITUTION((_rng1.min)(), (_rng2.min)()); } |
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75 | result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return std::max BOOST_PREVENT_MACRO_SUBSTITUTION((_rng1.min)(), (_rng2.max)()); } |
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76 | static bool validation(result_type x) { return val == x; } |
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77 | |
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78 | #ifndef BOOST_NO_OPERATORS_IN_NAMESPACE |
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79 | |
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80 | #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS |
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81 | template<class CharT, class Traits> |
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82 | friend std::basic_ostream<CharT,Traits>& |
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83 | operator<<(std::basic_ostream<CharT,Traits>& os, const xor_combine& s) |
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84 | { |
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85 | os << s._rng1 << " " << s._rng2 << " "; |
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86 | return os; |
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87 | } |
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88 | |
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89 | template<class CharT, class Traits> |
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90 | friend std::basic_istream<CharT,Traits>& |
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91 | operator>>(std::basic_istream<CharT,Traits>& is, xor_combine& s) |
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92 | { |
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93 | is >> s._rng1 >> std::ws >> s._rng2 >> std::ws; |
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94 | return is; |
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95 | } |
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96 | #endif |
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97 | |
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98 | friend bool operator==(const xor_combine& x, const xor_combine& y) |
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99 | { return x._rng1 == y._rng1 && x._rng2 == y._rng2; } |
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100 | friend bool operator!=(const xor_combine& x, const xor_combine& y) |
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101 | { return !(x == y); } |
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102 | #else |
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103 | // Use a member function; Streamable concept not supported. |
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104 | bool operator==(const xor_combine& rhs) const |
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105 | { return _rng1 == rhs._rng1 && _rng2 == rhs._rng2; } |
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106 | bool operator!=(const xor_combine& rhs) const |
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107 | { return !(*this == rhs); } |
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108 | #endif |
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109 | |
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110 | private: |
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111 | base1_type _rng1; |
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112 | base2_type _rng2; |
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113 | }; |
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114 | |
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115 | #ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION |
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116 | // A definition is required even for integral static constants |
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117 | template<class URNG1, int s1, class URNG2, int s2, |
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118 | #ifndef BOOST_NO_DEPENDENT_TYPES_IN_TEMPLATE_VALUE_PARAMETERS |
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119 | typename URNG1::result_type |
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120 | #else |
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121 | uint32_t |
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122 | #endif |
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123 | val> |
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124 | const bool xor_combine<URNG1, s1, URNG2, s2, val>::has_fixed_range; |
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125 | #endif |
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126 | |
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127 | } // namespace random |
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128 | } // namespace boost |
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129 | |
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130 | #endif // BOOST_RANDOM_XOR_COMBINE_HPP |
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