Atmosphere/libraries/libvapours/include/vapours/util/util_bitutil.hpp
2020-02-22 23:05:14 -08:00

77 lines
2.3 KiB
C++

/*
* 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 <vapours/common.hpp>
#include <vapours/assert.hpp>
namespace ams::util {
template <typename T>
class BitsOf {
private:
static_assert(std::is_integral<T>::value);
static constexpr ALWAYS_INLINE int GetLsbPos(T v) {
return __builtin_ctzll(static_cast<u64>(v));
}
T value;
public:
/* Note: GCC has a bug in constant-folding here. Workaround: wrap entire caller with constexpr. */
constexpr ALWAYS_INLINE BitsOf(T value = T(0u)) : value(value) {
/* ... */
}
constexpr ALWAYS_INLINE bool operator==(const BitsOf &other) const {
return this->value == other.value;
}
constexpr ALWAYS_INLINE bool operator!=(const BitsOf &other) const {
return this->value != other.value;
}
constexpr ALWAYS_INLINE int operator*() const {
return GetLsbPos(this->value);
}
constexpr ALWAYS_INLINE BitsOf &operator++() {
this->value &= ~(T(1u) << GetLsbPos(this->value));
return *this;
}
constexpr ALWAYS_INLINE BitsOf &operator++(int) {
BitsOf ret(this->value);
++(*this);
return ret;
}
constexpr ALWAYS_INLINE BitsOf begin() const {
return *this;
}
constexpr ALWAYS_INLINE BitsOf end() const {
return BitsOf(T(0u));
}
};
template<typename T = u64, typename ...Args>
constexpr ALWAYS_INLINE T CombineBits(Args... args) {
return (... | (T(1u) << args));
}
}