103 lines
2.8 KiB
C++
103 lines
2.8 KiB
C++
// Copyright 2017 Dolphin Emulator Project
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// Licensed under GPLv2+
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// Refer to the license.txt file included.
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#pragma once
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#include <climits>
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#include <cstddef>
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#include <type_traits>
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namespace Common
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{
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///
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/// Retrieves the size of a type in bits.
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///
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/// @tparam T Type to get the size of.
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///
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/// @return the size of the type in bits.
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///
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template <typename T>
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constexpr size_t BitSize() noexcept
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{
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return sizeof(T) * CHAR_BIT;
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}
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///
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/// Extracts a bit from a value.
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///
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/// @param src The value to extract a bit from.
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/// @param bit The bit to extract.
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///
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/// @tparam T The type of the value.
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///
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/// @return The extracted bit.
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///
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template <typename T>
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constexpr T ExtractBit(const T src, const size_t bit) noexcept
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{
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return (src >> bit) & static_cast<T>(1);
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}
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///
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/// Extracts a bit from a value.
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///
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/// @param src The value to extract a bit from.
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///
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/// @tparam bit The bit to extract.
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/// @tparam T The type of the value.
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///
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/// @return The extracted bit.
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///
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template <size_t bit, typename T>
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constexpr T ExtractBit(const T src) noexcept
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{
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static_assert(bit < BitSize<T>(), "Specified bit must be within T's bit width.");
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return ExtractBit(src, bit);
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}
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///
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/// Extracts a range of bits from a value.
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///
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/// @param src The value to extract the bits from.
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/// @param begin The beginning of the bit range. This is inclusive.
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/// @param end The ending of the bit range. This is inclusive.
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///
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/// @tparam T The type of the value.
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/// @tparam Result The returned result type. This is the unsigned analog
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/// of a signed type if a signed type is passed as T.
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///
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/// @return The extracted bits.
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///
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template <typename T, typename Result = std::make_unsigned_t<T>>
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constexpr Result ExtractBits(const T src, const size_t begin, const size_t end) noexcept
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{
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return static_cast<Result>(((static_cast<Result>(src) << ((BitSize<T>() - 1) - end)) >>
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(BitSize<T>() - end + begin - 1)));
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}
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///
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/// Extracts a range of bits from a value.
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///
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/// @param src The value to extract the bits from.
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///
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/// @tparam begin The beginning of the bit range. This is inclusive.
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/// @tparam end The ending of the bit range. This is inclusive.
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/// @tparam T The type of the value.
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/// @tparam Result The returned result type. This is the unsigned analog
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/// of a signed type if a signed type is passed as T.
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///
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/// @return The extracted bits.
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///
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template <size_t begin, size_t end, typename T, typename Result = std::make_unsigned_t<T>>
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constexpr Result ExtractBits(const T src) noexcept
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{
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static_assert(begin < end, "Beginning bit must be less than the ending bit.");
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static_assert(begin < BitSize<T>(), "Beginning bit is larger than T's bit width.");
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static_assert(end < BitSize<T>(), "Ending bit is larger than T's bit width.");
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return ExtractBits<T, Result>(src, begin, end);
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}
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} // namespace Common
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