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