1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___RANDOM_SUBTRACT_WITH_CARRY_ENGINE_H 10 #define _LIBCPP___RANDOM_SUBTRACT_WITH_CARRY_ENGINE_H 11 12 #include <__algorithm/equal.h> 13 #include <__algorithm/min.h> 14 #include <__config> 15 #include <__cstddef/size_t.h> 16 #include <__random/is_seed_sequence.h> 17 #include <__random/linear_congruential_engine.h> 18 #include <__type_traits/enable_if.h> 19 #include <cstdint> 20 #include <iosfwd> 21 #include <limits> 22 23 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 24 # pragma GCC system_header 25 #endif 26 27 _LIBCPP_PUSH_MACROS 28 #include <__undef_macros> 29 30 _LIBCPP_BEGIN_NAMESPACE_STD 31 32 template <class _UIntType, size_t __w, size_t __s, size_t __r> 33 class _LIBCPP_TEMPLATE_VIS subtract_with_carry_engine; 34 35 template <class _UInt, size_t _Wp, size_t _Sp, size_t _Rp> 36 _LIBCPP_HIDE_FROM_ABI bool operator==(const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x, 37 const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y); 38 39 template <class _UInt, size_t _Wp, size_t _Sp, size_t _Rp> 40 _LIBCPP_HIDE_FROM_ABI bool operator!=(const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x, 41 const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y); 42 43 template <class _CharT, class _Traits, class _UInt, size_t _Wp, size_t _Sp, size_t _Rp> 44 _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>& 45 operator<<(basic_ostream<_CharT, _Traits>& __os, const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x); 46 47 template <class _CharT, class _Traits, class _UInt, size_t _Wp, size_t _Sp, size_t _Rp> 48 _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>& 49 operator>>(basic_istream<_CharT, _Traits>& __is, subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x); 50 51 template <class _UIntType, size_t __w, size_t __s, size_t __r> 52 class _LIBCPP_TEMPLATE_VIS subtract_with_carry_engine { 53 public: 54 // types 55 typedef _UIntType result_type; 56 57 private: 58 result_type __x_[__r]; 59 result_type __c_; 60 size_t __i_; 61 62 static _LIBCPP_CONSTEXPR const result_type _Dt = numeric_limits<result_type>::digits; 63 static_assert(0 < __w, "subtract_with_carry_engine invalid parameters"); 64 static_assert(__w <= _Dt, "subtract_with_carry_engine invalid parameters"); 65 static_assert(0 < __s, "subtract_with_carry_engine invalid parameters"); 66 static_assert(__s < __r, "subtract_with_carry_engine invalid parameters"); 67 68 public: 69 static _LIBCPP_CONSTEXPR const result_type _Min = 0; 70 static _LIBCPP_CONSTEXPR const result_type _Max = 71 __w == _Dt ? result_type(~0) : (result_type(1) << __w) - result_type(1); 72 static_assert(_Min < _Max, "subtract_with_carry_engine invalid parameters"); 73 74 // engine characteristics 75 static inline _LIBCPP_CONSTEXPR const size_t word_size = __w; 76 static inline _LIBCPP_CONSTEXPR const size_t short_lag = __s; 77 static inline _LIBCPP_CONSTEXPR const size_t long_lag = __r; 78 _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR result_type min() { return _Min; } 79 _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR result_type max() { return _Max; } 80 static inline _LIBCPP_CONSTEXPR const result_type default_seed = 19780503u; 81 82 // constructors and seeding functions 83 #ifndef _LIBCPP_CXX03_LANG 84 _LIBCPP_HIDE_FROM_ABI subtract_with_carry_engine() : subtract_with_carry_engine(default_seed) {} 85 _LIBCPP_HIDE_FROM_ABI explicit subtract_with_carry_engine(result_type __sd) { seed(__sd); } 86 #else 87 _LIBCPP_HIDE_FROM_ABI explicit subtract_with_carry_engine(result_type __sd = default_seed) { seed(__sd); } 88 #endif 89 template <class _Sseq, __enable_if_t<__is_seed_sequence<_Sseq, subtract_with_carry_engine>::value, int> = 0> 90 _LIBCPP_HIDE_FROM_ABI explicit subtract_with_carry_engine(_Sseq& __q) { 91 seed(__q); 92 } 93 _LIBCPP_HIDE_FROM_ABI void seed(result_type __sd = default_seed) { 94 seed(__sd, integral_constant<unsigned, 1 + (__w - 1) / 32>()); 95 } 96 template <class _Sseq, __enable_if_t<__is_seed_sequence<_Sseq, subtract_with_carry_engine>::value, int> = 0> 97 _LIBCPP_HIDE_FROM_ABI void seed(_Sseq& __q) { 98 __seed(__q, integral_constant<unsigned, 1 + (__w - 1) / 32>()); 99 } 100 101 // generating functions 102 _LIBCPP_HIDE_FROM_ABI result_type operator()(); 103 _LIBCPP_HIDE_FROM_ABI void discard(unsigned long long __z) { 104 for (; __z; --__z) 105 operator()(); 106 } 107 108 template <class _UInt, size_t _Wp, size_t _Sp, size_t _Rp> 109 friend bool operator==(const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x, 110 const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y); 111 112 template <class _UInt, size_t _Wp, size_t _Sp, size_t _Rp> 113 friend bool operator!=(const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x, 114 const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y); 115 116 template <class _CharT, class _Traits, class _UInt, size_t _Wp, size_t _Sp, size_t _Rp> 117 friend basic_ostream<_CharT, _Traits>& 118 operator<<(basic_ostream<_CharT, _Traits>& __os, const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x); 119 120 template <class _CharT, class _Traits, class _UInt, size_t _Wp, size_t _Sp, size_t _Rp> 121 friend basic_istream<_CharT, _Traits>& 122 operator>>(basic_istream<_CharT, _Traits>& __is, subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x); 123 124 private: 125 _LIBCPP_HIDE_FROM_ABI void seed(result_type __sd, integral_constant<unsigned, 1>); 126 _LIBCPP_HIDE_FROM_ABI void seed(result_type __sd, integral_constant<unsigned, 2>); 127 template <class _Sseq> 128 _LIBCPP_HIDE_FROM_ABI void __seed(_Sseq& __q, integral_constant<unsigned, 1>); 129 template <class _Sseq> 130 _LIBCPP_HIDE_FROM_ABI void __seed(_Sseq& __q, integral_constant<unsigned, 2>); 131 }; 132 133 template <class _UIntType, size_t __w, size_t __s, size_t __r> 134 void subtract_with_carry_engine<_UIntType, __w, __s, __r>::seed(result_type __sd, integral_constant<unsigned, 1>) { 135 linear_congruential_engine<result_type, 40014u, 0u, 2147483563u> __e(__sd == 0u ? default_seed : __sd); 136 for (size_t __i = 0; __i < __r; ++__i) 137 __x_[__i] = static_cast<result_type>(__e() & _Max); 138 __c_ = __x_[__r - 1] == 0; 139 __i_ = 0; 140 } 141 142 template <class _UIntType, size_t __w, size_t __s, size_t __r> 143 void subtract_with_carry_engine<_UIntType, __w, __s, __r>::seed(result_type __sd, integral_constant<unsigned, 2>) { 144 linear_congruential_engine<result_type, 40014u, 0u, 2147483563u> __e(__sd == 0u ? default_seed : __sd); 145 for (size_t __i = 0; __i < __r; ++__i) { 146 result_type __e0 = __e(); 147 __x_[__i] = static_cast<result_type>((__e0 + ((uint64_t)__e() << 32)) & _Max); 148 } 149 __c_ = __x_[__r - 1] == 0; 150 __i_ = 0; 151 } 152 153 template <class _UIntType, size_t __w, size_t __s, size_t __r> 154 template <class _Sseq> 155 void subtract_with_carry_engine<_UIntType, __w, __s, __r>::__seed(_Sseq& __q, integral_constant<unsigned, 1>) { 156 const unsigned __k = 1; 157 uint32_t __ar[__r * __k]; 158 __q.generate(__ar, __ar + __r * __k); 159 for (size_t __i = 0; __i < __r; ++__i) 160 __x_[__i] = static_cast<result_type>(__ar[__i] & _Max); 161 __c_ = __x_[__r - 1] == 0; 162 __i_ = 0; 163 } 164 165 template <class _UIntType, size_t __w, size_t __s, size_t __r> 166 template <class _Sseq> 167 void subtract_with_carry_engine<_UIntType, __w, __s, __r>::__seed(_Sseq& __q, integral_constant<unsigned, 2>) { 168 const unsigned __k = 2; 169 uint32_t __ar[__r * __k]; 170 __q.generate(__ar, __ar + __r * __k); 171 for (size_t __i = 0; __i < __r; ++__i) 172 __x_[__i] = static_cast<result_type>((__ar[2 * __i] + ((uint64_t)__ar[2 * __i + 1] << 32)) & _Max); 173 __c_ = __x_[__r - 1] == 0; 174 __i_ = 0; 175 } 176 177 template <class _UIntType, size_t __w, size_t __s, size_t __r> 178 _UIntType subtract_with_carry_engine<_UIntType, __w, __s, __r>::operator()() { 179 const result_type& __xs = __x_[(__i_ + (__r - __s)) % __r]; 180 result_type& __xr = __x_[__i_]; 181 result_type __new_c = __c_ == 0 ? __xs < __xr : __xs != 0 ? __xs <= __xr : 1; 182 __xr = (__xs - __xr - __c_) & _Max; 183 __c_ = __new_c; 184 __i_ = (__i_ + 1) % __r; 185 return __xr; 186 } 187 188 template <class _UInt, size_t _Wp, size_t _Sp, size_t _Rp> 189 _LIBCPP_HIDE_FROM_ABI bool operator==(const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x, 190 const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y) { 191 if (__x.__c_ != __y.__c_) 192 return false; 193 if (__x.__i_ == __y.__i_) 194 return std::equal(__x.__x_, __x.__x_ + _Rp, __y.__x_); 195 if (__x.__i_ == 0 || __y.__i_ == 0) { 196 size_t __j = std::min(_Rp - __x.__i_, _Rp - __y.__i_); 197 if (!std::equal(__x.__x_ + __x.__i_, __x.__x_ + __x.__i_ + __j, __y.__x_ + __y.__i_)) 198 return false; 199 if (__x.__i_ == 0) 200 return std::equal(__x.__x_ + __j, __x.__x_ + _Rp, __y.__x_); 201 return std::equal(__x.__x_, __x.__x_ + (_Rp - __j), __y.__x_ + __j); 202 } 203 if (__x.__i_ < __y.__i_) { 204 size_t __j = _Rp - __y.__i_; 205 if (!std::equal(__x.__x_ + __x.__i_, __x.__x_ + (__x.__i_ + __j), __y.__x_ + __y.__i_)) 206 return false; 207 if (!std::equal(__x.__x_ + (__x.__i_ + __j), __x.__x_ + _Rp, __y.__x_)) 208 return false; 209 return std::equal(__x.__x_, __x.__x_ + __x.__i_, __y.__x_ + (_Rp - (__x.__i_ + __j))); 210 } 211 size_t __j = _Rp - __x.__i_; 212 if (!std::equal(__y.__x_ + __y.__i_, __y.__x_ + (__y.__i_ + __j), __x.__x_ + __x.__i_)) 213 return false; 214 if (!std::equal(__y.__x_ + (__y.__i_ + __j), __y.__x_ + _Rp, __x.__x_)) 215 return false; 216 return std::equal(__y.__x_, __y.__x_ + __y.__i_, __x.__x_ + (_Rp - (__y.__i_ + __j))); 217 } 218 219 template <class _UInt, size_t _Wp, size_t _Sp, size_t _Rp> 220 inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x, 221 const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y) { 222 return !(__x == __y); 223 } 224 225 template <class _CharT, class _Traits, class _UInt, size_t _Wp, size_t _Sp, size_t _Rp> 226 _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>& 227 operator<<(basic_ostream<_CharT, _Traits>& __os, const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x) { 228 __save_flags<_CharT, _Traits> __lx(__os); 229 typedef basic_ostream<_CharT, _Traits> _Ostream; 230 __os.flags(_Ostream::dec | _Ostream::left); 231 _CharT __sp = __os.widen(' '); 232 __os.fill(__sp); 233 __os << __x.__x_[__x.__i_]; 234 for (size_t __j = __x.__i_ + 1; __j < _Rp; ++__j) 235 __os << __sp << __x.__x_[__j]; 236 for (size_t __j = 0; __j < __x.__i_; ++__j) 237 __os << __sp << __x.__x_[__j]; 238 __os << __sp << __x.__c_; 239 return __os; 240 } 241 242 template <class _CharT, class _Traits, class _UInt, size_t _Wp, size_t _Sp, size_t _Rp> 243 _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>& 244 operator>>(basic_istream<_CharT, _Traits>& __is, subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x) { 245 __save_flags<_CharT, _Traits> __lx(__is); 246 typedef basic_istream<_CharT, _Traits> _Istream; 247 __is.flags(_Istream::dec | _Istream::skipws); 248 _UInt __t[_Rp + 1]; 249 for (size_t __i = 0; __i < _Rp + 1; ++__i) 250 __is >> __t[__i]; 251 if (!__is.fail()) { 252 for (size_t __i = 0; __i < _Rp; ++__i) 253 __x.__x_[__i] = __t[__i]; 254 __x.__c_ = __t[_Rp]; 255 __x.__i_ = 0; 256 } 257 return __is; 258 } 259 260 _LIBCPP_END_NAMESPACE_STD 261 262 _LIBCPP_POP_MACROS 263 264 #endif // _LIBCPP___RANDOM_SUBTRACT_WITH_CARRY_ENGINE_H 265