| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP___RANDOM_LINEAR_CONGRUENTIAL_ENGINE_H |
| #define _LIBCPP___RANDOM_LINEAR_CONGRUENTIAL_ENGINE_H |
| |
| #include <__config> |
| #include <__random/is_seed_sequence.h> |
| #include <cstdint> |
| #include <iosfwd> |
| #include <type_traits> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_PUSH_MACROS |
| #include <__undef_macros> |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| template <unsigned long long __a, unsigned long long __c, |
| unsigned long long __m, unsigned long long _Mp, |
| bool _MightOverflow = (__a != 0 && __m != 0 && __m-1 > (_Mp-__c)/__a), |
| bool _OverflowOK = ((__m | (__m-1)) > __m), // m = 2^n |
| bool _SchrageOK = (__a != 0 && __m != 0 && __m % __a <= __m / __a)> // r <= q |
| struct __lce_alg_picker |
| { |
| static_assert(__a != 0 || __m != 0 || !_MightOverflow || _OverflowOK || _SchrageOK, |
| "The current values of a, c, and m cannot generate a number " |
| "within bounds of linear_congruential_engine."); |
| |
| static _LIBCPP_CONSTEXPR const bool __use_schrage = _MightOverflow && |
| !_OverflowOK && |
| _SchrageOK; |
| }; |
| |
| template <unsigned long long __a, unsigned long long __c, |
| unsigned long long __m, unsigned long long _Mp, |
| bool _UseSchrage = __lce_alg_picker<__a, __c, __m, _Mp>::__use_schrage> |
| struct __lce_ta; |
| |
| // 64 |
| |
| template <unsigned long long __a, unsigned long long __c, unsigned long long __m> |
| struct __lce_ta<__a, __c, __m, (unsigned long long)(~0), true> |
| { |
| typedef unsigned long long result_type; |
| _LIBCPP_INLINE_VISIBILITY |
| static result_type next(result_type __x) |
| { |
| // Schrage's algorithm |
| const result_type __q = __m / __a; |
| const result_type __r = __m % __a; |
| const result_type __t0 = __a * (__x % __q); |
| const result_type __t1 = __r * (__x / __q); |
| __x = __t0 + (__t0 < __t1) * __m - __t1; |
| __x += __c - (__x >= __m - __c) * __m; |
| return __x; |
| } |
| }; |
| |
| template <unsigned long long __a, unsigned long long __m> |
| struct __lce_ta<__a, 0, __m, (unsigned long long)(~0), true> |
| { |
| typedef unsigned long long result_type; |
| _LIBCPP_INLINE_VISIBILITY |
| static result_type next(result_type __x) |
| { |
| // Schrage's algorithm |
| const result_type __q = __m / __a; |
| const result_type __r = __m % __a; |
| const result_type __t0 = __a * (__x % __q); |
| const result_type __t1 = __r * (__x / __q); |
| __x = __t0 + (__t0 < __t1) * __m - __t1; |
| return __x; |
| } |
| }; |
| |
| template <unsigned long long __a, unsigned long long __c, unsigned long long __m> |
| struct __lce_ta<__a, __c, __m, (unsigned long long)(~0), false> |
| { |
| typedef unsigned long long result_type; |
| _LIBCPP_INLINE_VISIBILITY |
| static result_type next(result_type __x) |
| { |
| return (__a * __x + __c) % __m; |
| } |
| }; |
| |
| template <unsigned long long __a, unsigned long long __c> |
| struct __lce_ta<__a, __c, 0, (unsigned long long)(~0), false> |
| { |
| typedef unsigned long long result_type; |
| _LIBCPP_INLINE_VISIBILITY |
| static result_type next(result_type __x) |
| { |
| return __a * __x + __c; |
| } |
| }; |
| |
| // 32 |
| |
| template <unsigned long long _Ap, unsigned long long _Cp, unsigned long long _Mp> |
| struct __lce_ta<_Ap, _Cp, _Mp, unsigned(~0), true> |
| { |
| typedef unsigned result_type; |
| _LIBCPP_INLINE_VISIBILITY |
| static result_type next(result_type __x) |
| { |
| const result_type __a = static_cast<result_type>(_Ap); |
| const result_type __c = static_cast<result_type>(_Cp); |
| const result_type __m = static_cast<result_type>(_Mp); |
| // Schrage's algorithm |
| const result_type __q = __m / __a; |
| const result_type __r = __m % __a; |
| const result_type __t0 = __a * (__x % __q); |
| const result_type __t1 = __r * (__x / __q); |
| __x = __t0 + (__t0 < __t1) * __m - __t1; |
| __x += __c - (__x >= __m - __c) * __m; |
| return __x; |
| } |
| }; |
| |
| template <unsigned long long _Ap, unsigned long long _Mp> |
| struct __lce_ta<_Ap, 0, _Mp, unsigned(~0), true> |
| { |
| typedef unsigned result_type; |
| _LIBCPP_INLINE_VISIBILITY |
| static result_type next(result_type __x) |
| { |
| const result_type __a = static_cast<result_type>(_Ap); |
| const result_type __m = static_cast<result_type>(_Mp); |
| // Schrage's algorithm |
| const result_type __q = __m / __a; |
| const result_type __r = __m % __a; |
| const result_type __t0 = __a * (__x % __q); |
| const result_type __t1 = __r * (__x / __q); |
| __x = __t0 + (__t0 < __t1) * __m - __t1; |
| return __x; |
| } |
| }; |
| |
| template <unsigned long long _Ap, unsigned long long _Cp, unsigned long long _Mp> |
| struct __lce_ta<_Ap, _Cp, _Mp, unsigned(~0), false> |
| { |
| typedef unsigned result_type; |
| _LIBCPP_INLINE_VISIBILITY |
| static result_type next(result_type __x) |
| { |
| const result_type __a = static_cast<result_type>(_Ap); |
| const result_type __c = static_cast<result_type>(_Cp); |
| const result_type __m = static_cast<result_type>(_Mp); |
| return (__a * __x + __c) % __m; |
| } |
| }; |
| |
| template <unsigned long long _Ap, unsigned long long _Cp> |
| struct __lce_ta<_Ap, _Cp, 0, unsigned(~0), false> |
| { |
| typedef unsigned result_type; |
| _LIBCPP_INLINE_VISIBILITY |
| static result_type next(result_type __x) |
| { |
| const result_type __a = static_cast<result_type>(_Ap); |
| const result_type __c = static_cast<result_type>(_Cp); |
| return __a * __x + __c; |
| } |
| }; |
| |
| // 16 |
| |
| template <unsigned long long __a, unsigned long long __c, unsigned long long __m, bool __b> |
| struct __lce_ta<__a, __c, __m, (unsigned short)(~0), __b> |
| { |
| typedef unsigned short result_type; |
| _LIBCPP_INLINE_VISIBILITY |
| static result_type next(result_type __x) |
| { |
| return static_cast<result_type>(__lce_ta<__a, __c, __m, unsigned(~0)>::next(__x)); |
| } |
| }; |
| |
| template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m> |
| class _LIBCPP_TEMPLATE_VIS linear_congruential_engine; |
| |
| template <class _CharT, class _Traits, |
| class _Up, _Up _Ap, _Up _Cp, _Up _Np> |
| _LIBCPP_INLINE_VISIBILITY |
| basic_ostream<_CharT, _Traits>& |
| operator<<(basic_ostream<_CharT, _Traits>& __os, |
| const linear_congruential_engine<_Up, _Ap, _Cp, _Np>&); |
| |
| template <class _CharT, class _Traits, |
| class _Up, _Up _Ap, _Up _Cp, _Up _Np> |
| basic_istream<_CharT, _Traits>& |
| operator>>(basic_istream<_CharT, _Traits>& __is, |
| linear_congruential_engine<_Up, _Ap, _Cp, _Np>& __x); |
| |
| template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m> |
| class _LIBCPP_TEMPLATE_VIS linear_congruential_engine |
| { |
| public: |
| // types |
| typedef _UIntType result_type; |
| |
| private: |
| result_type __x_; |
| |
| static _LIBCPP_CONSTEXPR const result_type _Mp = result_type(~0); |
| |
| static_assert(__m == 0 || __a < __m, "linear_congruential_engine invalid parameters"); |
| static_assert(__m == 0 || __c < __m, "linear_congruential_engine invalid parameters"); |
| static_assert(is_unsigned<_UIntType>::value, "_UIntType must be unsigned type"); |
| public: |
| static _LIBCPP_CONSTEXPR const result_type _Min = __c == 0u ? 1u : 0u; |
| static _LIBCPP_CONSTEXPR const result_type _Max = __m - _UIntType(1u); |
| static_assert(_Min < _Max, "linear_congruential_engine invalid parameters"); |
| |
| // engine characteristics |
| static _LIBCPP_CONSTEXPR const result_type multiplier = __a; |
| static _LIBCPP_CONSTEXPR const result_type increment = __c; |
| static _LIBCPP_CONSTEXPR const result_type modulus = __m; |
| _LIBCPP_INLINE_VISIBILITY |
| static _LIBCPP_CONSTEXPR result_type min() {return _Min;} |
| _LIBCPP_INLINE_VISIBILITY |
| static _LIBCPP_CONSTEXPR result_type max() {return _Max;} |
| static _LIBCPP_CONSTEXPR const result_type default_seed = 1u; |
| |
| // constructors and seeding functions |
| #ifndef _LIBCPP_CXX03_LANG |
| _LIBCPP_INLINE_VISIBILITY |
| linear_congruential_engine() : linear_congruential_engine(default_seed) {} |
| _LIBCPP_INLINE_VISIBILITY |
| explicit linear_congruential_engine(result_type __s) { seed(__s); } |
| #else |
| _LIBCPP_INLINE_VISIBILITY |
| explicit linear_congruential_engine(result_type __s = default_seed) { |
| seed(__s); |
| } |
| #endif |
| template<class _Sseq> |
| _LIBCPP_INLINE_VISIBILITY |
| explicit linear_congruential_engine(_Sseq& __q, |
| typename enable_if<__is_seed_sequence<_Sseq, linear_congruential_engine>::value>::type* = 0) |
| {seed(__q);} |
| _LIBCPP_INLINE_VISIBILITY |
| void seed(result_type __s = default_seed) |
| {seed(integral_constant<bool, __m == 0>(), |
| integral_constant<bool, __c == 0>(), __s);} |
| template<class _Sseq> |
| _LIBCPP_INLINE_VISIBILITY |
| typename enable_if |
| < |
| __is_seed_sequence<_Sseq, linear_congruential_engine>::value, |
| void |
| >::type |
| seed(_Sseq& __q) |
| {__seed(__q, integral_constant<unsigned, |
| 1 + (__m == 0 ? (sizeof(result_type) * __CHAR_BIT__ - 1)/32 |
| : (__m > 0x100000000ull))>());} |
| |
| // generating functions |
| _LIBCPP_INLINE_VISIBILITY |
| result_type operator()() |
| {return __x_ = static_cast<result_type>(__lce_ta<__a, __c, __m, _Mp>::next(__x_));} |
| _LIBCPP_INLINE_VISIBILITY |
| void discard(unsigned long long __z) {for (; __z; --__z) operator()();} |
| |
| friend _LIBCPP_INLINE_VISIBILITY |
| bool operator==(const linear_congruential_engine& __x, |
| const linear_congruential_engine& __y) |
| {return __x.__x_ == __y.__x_;} |
| friend _LIBCPP_INLINE_VISIBILITY |
| bool operator!=(const linear_congruential_engine& __x, |
| const linear_congruential_engine& __y) |
| {return !(__x == __y);} |
| |
| private: |
| |
| _LIBCPP_INLINE_VISIBILITY |
| void seed(true_type, true_type, result_type __s) {__x_ = __s == 0 ? 1 : __s;} |
| _LIBCPP_INLINE_VISIBILITY |
| void seed(true_type, false_type, result_type __s) {__x_ = __s;} |
| _LIBCPP_INLINE_VISIBILITY |
| void seed(false_type, true_type, result_type __s) {__x_ = __s % __m == 0 ? |
| 1 : __s % __m;} |
| _LIBCPP_INLINE_VISIBILITY |
| void seed(false_type, false_type, result_type __s) {__x_ = __s % __m;} |
| |
| template<class _Sseq> |
| void __seed(_Sseq& __q, integral_constant<unsigned, 1>); |
| template<class _Sseq> |
| void __seed(_Sseq& __q, integral_constant<unsigned, 2>); |
| |
| template <class _CharT, class _Traits, |
| class _Up, _Up _Ap, _Up _Cp, _Up _Np> |
| friend |
| basic_ostream<_CharT, _Traits>& |
| operator<<(basic_ostream<_CharT, _Traits>& __os, |
| const linear_congruential_engine<_Up, _Ap, _Cp, _Np>&); |
| |
| template <class _CharT, class _Traits, |
| class _Up, _Up _Ap, _Up _Cp, _Up _Np> |
| friend |
| basic_istream<_CharT, _Traits>& |
| operator>>(basic_istream<_CharT, _Traits>& __is, |
| linear_congruential_engine<_Up, _Ap, _Cp, _Np>& __x); |
| }; |
| |
| template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m> |
| _LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type |
| linear_congruential_engine<_UIntType, __a, __c, __m>::multiplier; |
| |
| template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m> |
| _LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type |
| linear_congruential_engine<_UIntType, __a, __c, __m>::increment; |
| |
| template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m> |
| _LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type |
| linear_congruential_engine<_UIntType, __a, __c, __m>::modulus; |
| |
| template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m> |
| _LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type |
| linear_congruential_engine<_UIntType, __a, __c, __m>::default_seed; |
| |
| template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m> |
| template<class _Sseq> |
| void |
| linear_congruential_engine<_UIntType, __a, __c, __m>::__seed(_Sseq& __q, |
| integral_constant<unsigned, 1>) |
| { |
| const unsigned __k = 1; |
| uint32_t __ar[__k+3]; |
| __q.generate(__ar, __ar + __k + 3); |
| result_type __s = static_cast<result_type>(__ar[3] % __m); |
| __x_ = __c == 0 && __s == 0 ? result_type(1) : __s; |
| } |
| |
| template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m> |
| template<class _Sseq> |
| void |
| linear_congruential_engine<_UIntType, __a, __c, __m>::__seed(_Sseq& __q, |
| integral_constant<unsigned, 2>) |
| { |
| const unsigned __k = 2; |
| uint32_t __ar[__k+3]; |
| __q.generate(__ar, __ar + __k + 3); |
| result_type __s = static_cast<result_type>((__ar[3] + |
| ((uint64_t)__ar[4] << 32)) % __m); |
| __x_ = __c == 0 && __s == 0 ? result_type(1) : __s; |
| } |
| |
| template <class _CharT, class _Traits, |
| class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m> |
| inline _LIBCPP_INLINE_VISIBILITY |
| basic_ostream<_CharT, _Traits>& |
| operator<<(basic_ostream<_CharT, _Traits>& __os, |
| const linear_congruential_engine<_UIntType, __a, __c, __m>& __x) |
| { |
| __save_flags<_CharT, _Traits> __lx(__os); |
| typedef basic_ostream<_CharT, _Traits> _Ostream; |
| __os.flags(_Ostream::dec | _Ostream::left); |
| __os.fill(__os.widen(' ')); |
| return __os << __x.__x_; |
| } |
| |
| template <class _CharT, class _Traits, |
| class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m> |
| basic_istream<_CharT, _Traits>& |
| operator>>(basic_istream<_CharT, _Traits>& __is, |
| linear_congruential_engine<_UIntType, __a, __c, __m>& __x) |
| { |
| __save_flags<_CharT, _Traits> __lx(__is); |
| typedef basic_istream<_CharT, _Traits> _Istream; |
| __is.flags(_Istream::dec | _Istream::skipws); |
| _UIntType __t; |
| __is >> __t; |
| if (!__is.fail()) |
| __x.__x_ = __t; |
| return __is; |
| } |
| |
| typedef linear_congruential_engine<uint_fast32_t, 16807, 0, 2147483647> |
| minstd_rand0; |
| typedef linear_congruential_engine<uint_fast32_t, 48271, 0, 2147483647> |
| minstd_rand; |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| _LIBCPP_POP_MACROS |
| |
| #endif // _LIBCPP___RANDOM_LINEAR_CONGRUENTIAL_ENGINE_H |
