зеркало из https://github.com/microsoft/STL.git
152 строки
5.2 KiB
C++
152 строки
5.2 KiB
C++
// bit standard header (core)
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// Copyright (c) Microsoft Corporation.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#pragma once
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#ifndef _BIT_
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#define _BIT_
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#include <yvals_core.h>
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#if _STL_COMPILER_PREPROCESSOR
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#if !_HAS_CXX20
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#pragma message("The contents of <bit> are available only with C++20 or later.")
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#else // ^^^ !_HAS_CXX20 / _HAS_CXX20 vvv
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#include <limits>
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#include <type_traits>
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#pragma pack(push, _CRT_PACKING)
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#pragma warning(push, _STL_WARNING_LEVEL)
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#pragma warning(disable : _STL_DISABLED_WARNINGS)
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_STL_DISABLE_CLANG_WARNINGS
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#pragma push_macro("new")
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#undef new
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_STD_BEGIN
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enum class endian { little = 0, big = 1, native = little };
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#ifdef __cpp_lib_bitops // TRANSITION, VSO-1020212
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template <class _Ty>
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inline constexpr bool _Is_standard_unsigned_integer =
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_Is_any_of_v<remove_cv_t<_Ty>, unsigned char, unsigned short, unsigned int, unsigned long, unsigned long long>;
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template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> = 0>
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_NODISCARD constexpr int countl_zero(_Ty _Val) noexcept;
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template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> = 0>
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_NODISCARD constexpr bool ispow2(const _Ty _Val) noexcept {
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return _Val != 0 && (_Val & (_Val - 1)) == 0;
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}
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template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> = 0>
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_NODISCARD constexpr _Ty ceil2(const _Ty _Val) noexcept /* strengthened */ {
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if (_Val == 0) {
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return 1;
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}
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return static_cast<_Ty>(_Ty{1} << (numeric_limits<_Ty>::digits - _STD countl_zero(static_cast<_Ty>(_Val - 1))));
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}
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template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> = 0>
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_NODISCARD constexpr _Ty floor2(const _Ty _Val) noexcept {
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if (_Val == 0) {
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return 0;
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}
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return static_cast<_Ty>(_Ty{1} << (numeric_limits<_Ty>::digits - 1 - _STD countl_zero(_Val)));
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}
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template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> = 0>
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_NODISCARD constexpr _Ty bit_length(const _Ty _Val) noexcept {
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return static_cast<_Ty>(numeric_limits<_Ty>::digits - _STD countl_zero(_Val));
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}
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template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> = 0>
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_NODISCARD constexpr _Ty rotr(_Ty _Val, int _Rotation) noexcept;
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template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> = 0>
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_NODISCARD constexpr _Ty rotl(const _Ty _Val, const int _Rotation) noexcept {
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constexpr auto _Digits = numeric_limits<_Ty>::digits;
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const auto _Remainder = _Rotation % _Digits;
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if (_Remainder > 0) {
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return static_cast<_Ty>(
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static_cast<_Ty>(_Val << _Remainder) | static_cast<_Ty>(_Val >> (_Digits - _Remainder)));
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} else if (_Remainder == 0) {
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return _Val;
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} else { // _Remainder < 0
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return _STD rotr(_Val, -_Remainder);
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}
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}
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template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> _Enabled>
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_NODISCARD constexpr _Ty rotr(const _Ty _Val, const int _Rotation) noexcept {
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constexpr auto _Digits = numeric_limits<_Ty>::digits;
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const auto _Remainder = _Rotation % _Digits;
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if (_Remainder > 0) {
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return static_cast<_Ty>(
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static_cast<_Ty>(_Val >> _Remainder) | static_cast<_Ty>(_Val << (_Digits - _Remainder)));
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} else if (_Remainder == 0) {
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return _Val;
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} else { // _Remainder < 0
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return _STD rotl(_Val, -_Remainder);
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}
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}
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template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> _Enabled>
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_NODISCARD constexpr int countl_zero(const _Ty _Val) noexcept {
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constexpr int _Digits = numeric_limits<_Ty>::digits;
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if (_Val == 0) {
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return _Digits;
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}
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if constexpr (sizeof(_Ty) <= sizeof(unsigned int)) {
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return __builtin_clz(_Val) - (numeric_limits<unsigned int>::digits - _Digits);
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} else {
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return __builtin_clzll(_Val) - (numeric_limits<unsigned long long>::digits - _Digits);
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}
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}
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template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> = 0>
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_NODISCARD constexpr int countl_one(const _Ty _Val) noexcept {
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return _STD countl_zero(static_cast<_Ty>(~_Val));
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}
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template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> = 0>
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_NODISCARD constexpr int countr_zero(const _Ty _Val) noexcept {
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if (_Val == 0) {
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return numeric_limits<_Ty>::digits;
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}
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if constexpr (sizeof(_Ty) <= sizeof(unsigned int)) {
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return __builtin_ctz(_Val);
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} else {
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return __builtin_ctzll(_Val);
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}
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}
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template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> _Enabled = 0>
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_NODISCARD constexpr int countr_one(const _Ty _Val) noexcept {
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return _STD countr_zero(static_cast<_Ty>(~_Val));
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}
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template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> _Enabled = 0>
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_NODISCARD constexpr int popcount(const _Ty _Val) noexcept {
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if constexpr (sizeof(_Ty) <= sizeof(unsigned int)) {
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return __builtin_popcount(_Val);
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} else {
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return __builtin_popcountll(_Val);
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}
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}
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#endif // __cpp_lib_bitops
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_STD_END
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#pragma pop_macro("new")
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_STL_RESTORE_CLANG_WARNINGS
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#pragma warning(pop)
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#pragma pack(pop)
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#endif // _HAS_CXX20
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#endif // _STL_COMPILER_PREPROCESSOR
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#endif // _BIT_
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