80 lines
2.2 KiB
C++
80 lines
2.2 KiB
C++
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Copyright 2011 Danny Robson <danny@nerdcruft.net>
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*/
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#ifndef __UTIL_BITWISE_HPP
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#define __UTIL_BITWISE_HPP
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#include <type_traits>
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#include <cstdint>
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namespace util {
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const uint8_t BITMASK_1BITS = 0x01;
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const uint8_t BITMASK_2BITS = 0x03;
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const uint8_t BITMASK_3BITS = 0x07;
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const uint8_t BITMASK_4BITS = 0x0F;
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const uint8_t BITMASK_5BITS = 0x1F;
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const uint8_t BITMASK_6BITS = 0x3F;
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const uint8_t BITMASK_7BITS = 0x7F;
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const uint8_t BITMASK_8BITS = 0xFF;
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///////////////////////////////////////////////////////////////////////////
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template <typename T>
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constexpr T
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rotatel [[gnu::pure]] (const T value, std::size_t magnitude)
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{
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return (value << magnitude) | (value >> sizeof (value) * 8 - magnitude);
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}
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template <typename T>
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constexpr T
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rotater [[gnu::pure]] (const T value, std::size_t magnitude)
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{
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return (value >> magnitude) | (value << sizeof (value) * 8 - magnitude);
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}
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///////////////////////////////////////////////////////////////////////////
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// TODO: make constexpr for C++14
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template <typename T>
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T
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reverse (T value) {
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T out = value;
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std::size_t bits = sizeof (value) * 8 - 1;
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for (value >>= 1; value; value >>= 1) {
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out <<= 1;
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out |= value & 0x01;
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--bits;
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}
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out <<= bits;
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return out;
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}
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///////////////////////////////////////////////////////////////////////////
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template <typename T>
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constexpr T
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popcount (std::enable_if_t<std::is_integral<T>::value,T> t)
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{
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return __builtin_popcount (t);
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}
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}
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#endif
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