chromium/third_party/libc++/src/include/__random/linear_congruential_engine.h

//===----------------------------------------------------------------------===//
//
// 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 <__type_traits/enable_if.h>
#include <__type_traits/integral_constant.h>
#include <__type_traits/is_unsigned.h>
#include <cstdint>
#include <iosfwd>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

_LIBCPP_PUSH_MACROS
#include <__undef_macros>

_LIBCPP_BEGIN_NAMESPACE_STD

enum __lce_alg_type { … };

template <unsigned long long __a,
          unsigned long long __c,
          unsigned long long __m,
          unsigned long long _Mp,
          bool _HasOverflow = (__a != 0ull && (__m & (__m - 1ull)) != 0ull),      // a != 0, m != 0, m != 2^n
          bool _Full        = (!_HasOverflow || __m - 1ull <= (_Mp - __c) / __a), // (a * x + c) % m works
          bool _Part        = (!_HasOverflow || __m - 1ull <= _Mp / __a),         // (a * x) % m works
          bool _Schrage     = (_HasOverflow && __m % __a <= __m / __a)>               // r <= q
struct __lce_alg_picker { … };

template <unsigned long long __a,
          unsigned long long __c,
          unsigned long long __m,
          unsigned long long _Mp,
          __lce_alg_type _Mode = __lce_alg_picker<__a, __c, __m, _Mp>::__mode>
struct __lce_ta;

// 64

#ifndef _LIBCPP_HAS_NO_INT128
__lce_ta<_Ap, _Cp, _Mp, (unsigned long long)(-1), _LCE_Promote>;
#endif

__lce_ta<__a, __c, __m, (unsigned long long)(-1), _LCE_Schrage>;

__lce_ta<__a, 0ULL, __m, (unsigned long long)(-1), _LCE_Schrage>;

__lce_ta<__a, __c, __m, (unsigned long long)(-1), _LCE_Part>;

__lce_ta<__a, __c, __m, (unsigned long long)(-1), _LCE_Full>;

__lce_ta<__a, __c, 0ULL, (unsigned long long)(-1), _LCE_Full>;

// 32

__lce_ta<__a, __c, __m, unsigned int(-1), _LCE_Promote>;

__lce_ta<_Ap, _Cp, _Mp, unsigned int(-1), _LCE_Schrage>;

__lce_ta<_Ap, 0ULL, _Mp, unsigned int(-1), _LCE_Schrage>;

__lce_ta<_Ap, _Cp, _Mp, unsigned int(-1), _LCE_Part>;

__lce_ta<_Ap, _Cp, _Mp, unsigned int(-1), _LCE_Full>;

__lce_ta<_Ap, _Cp, 0ULL, unsigned int(-1), _LCE_Full>;

// 16

__lce_ta<__a, __c, __m, (unsigned short)(-1), __mode>;

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_HIDE_FROM_ABI 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>
_LIBCPP_HIDE_FROM_ABI 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 { … };

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>) { … }

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>) { … }

template <class _CharT, class _Traits, class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
inline _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
operator<<(basic_ostream<_CharT, _Traits>& __os, const linear_congruential_engine<_UIntType, __a, __c, __m>& __x) { … }

template <class _CharT, class _Traits, class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
_LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
operator>>(basic_istream<_CharT, _Traits>& __is, linear_congruential_engine<_UIntType, __a, __c, __m>& __x) { … }

minstd_rand0;
minstd_rand;

_LIBCPP_END_NAMESPACE_STD

_LIBCPP_POP_MACROS

#endif // _LIBCPP___RANDOM_LINEAR_CONGRUENTIAL_ENGINE_H