libcruft-util/bitwise.hpp

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