100 lines
2.7 KiB
C++
100 lines
2.7 KiB
C++
/*
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* Copyright (c) 2018-2020 Atmosphère-NX
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include <array>
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#include <bit>
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#include "common/alignment.h"
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#include "common/bit_util.h"
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#include "common/common_types.h"
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namespace Common {
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namespace impl {
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template <typename Storage, size_t N>
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class BitSet {
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public:
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constexpr BitSet() = default;
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constexpr void SetBit(size_t i) {
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this->words[i / FlagsPerWord] |= GetBitMask(i % FlagsPerWord);
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}
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constexpr void ClearBit(size_t i) {
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this->words[i / FlagsPerWord] &= ~GetBitMask(i % FlagsPerWord);
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}
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constexpr size_t CountLeadingZero() const {
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for (size_t i = 0; i < NumWords; i++) {
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if (this->words[i]) {
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return FlagsPerWord * i + CountLeadingZeroImpl(this->words[i]);
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}
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}
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return FlagsPerWord * NumWords;
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}
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constexpr size_t GetNextSet(size_t n) const {
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for (size_t i = (n + 1) / FlagsPerWord; i < NumWords; i++) {
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Storage word = this->words[i];
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if (!IsAligned(n + 1, FlagsPerWord)) {
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word &= GetBitMask(n % FlagsPerWord) - 1;
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}
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if (word) {
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return FlagsPerWord * i + CountLeadingZeroImpl(word);
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}
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}
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return FlagsPerWord * NumWords;
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}
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private:
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static_assert(std::is_unsigned_v<Storage>);
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static_assert(sizeof(Storage) <= sizeof(u64));
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static constexpr size_t FlagsPerWord = BitSize<Storage>();
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static constexpr size_t NumWords = AlignUp(N, FlagsPerWord) / FlagsPerWord;
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static constexpr auto CountLeadingZeroImpl(Storage word) {
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return std::countl_zero(static_cast<unsigned long long>(word)) -
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(BitSize<unsigned long long>() - FlagsPerWord);
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}
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static constexpr Storage GetBitMask(size_t bit) {
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return Storage(1) << (FlagsPerWord - 1 - bit);
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}
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std::array<Storage, NumWords> words{};
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};
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} // namespace impl
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template <size_t N>
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using BitSet8 = impl::BitSet<u8, N>;
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template <size_t N>
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using BitSet16 = impl::BitSet<u16, N>;
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template <size_t N>
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using BitSet32 = impl::BitSet<u32, N>;
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template <size_t N>
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using BitSet64 = impl::BitSet<u64, N>;
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} // namespace Common
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