jeanlemotan
103 lines
2.9 KiB
C++
103 lines
2.9 KiB
C++
#pragma once
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#include "tl/detail/prologue.h"
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#include "tl/functional.h"
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namespace tl
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{
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namespace algorithm
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{
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//////////////////////////////////////////////////////////////////////////
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/**
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* @brief Count the number of bit set for the given value.
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*/
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inline uint8_t bits_count(uint32_t i_value) noexcept
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{
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#if defined(_MSC_VER)
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return uint8_t(__popcnt(i_value));
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#elif defined(__clang__) || defined(__GNUC__)
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return uint8_t(__builtin_popcount(i_value));
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#else
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static_assert(!std::is_same_v<T, T>, "no-builtin function found for this compiler");
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#endif
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}
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//////////////////////////////////////////////////////////////////////////
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/**
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* @brief Count the number of bit set for the given value.
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*/
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inline uint64_t bits_count(uint64_t i_value) noexcept
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{
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#if defined(_MSC_VER)
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#if defined(TL_PLATFORM_64)
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return uint8_t(__popcnt64(i_value));
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#elif defined(TL_PLATFORM_32)
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return bits_count(uint32_t(i_value >> 32)) + bits_count(uint32_t(i_value & 0xffffffff));
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#else
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static_assert(!std::is_same_v<T, T>, "no-builtin function found for this compiler);");
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#endif // TL_PLATFORM_XX
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#elif defined(__clang__) || defined(__GNUC__)
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return uint8_t(__builtin_popcountl(i_value));
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#else
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static_assert(!std::is_same_v<T, T>, "no-builtin function found for this compiler");
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#endif
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}
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//////////////////////////////////////////////////////////////////////////
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/**
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* @brief Position of the top bit set to 1.
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* @param the given value
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* @return -1 in case value is 0 otherwise the position.
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*/
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inline int8_t top_bit(uint32_t i_value) noexcept
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{
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#if defined(_MSC_VER)
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unsigned long index = 0;
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return _BitScanReverse(&index, (unsigned long)i_value) ? uint8_t(index) : -1;
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#elif defined(__clang__) || defined(__GNUC__)
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return i_value ? 31u - __builtin_clzl(i_value) : -1;
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#else
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static_assert(!std::is_same_v<T, T>, "no-builtin function found for this compiler);");
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#endif
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}
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//////////////////////////////////////////////////////////////////////////
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/**
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* @brief Position of the top bit set to 1.
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* @param the given value
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* @return -1 in case value is 0 otherwise the position.
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*/
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inline int8_t top_bit(uint64_t i_value) noexcept
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{
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#if defined(_MSC_VER)
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unsigned long index = 0;
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#if defined(TL_PLATFORM_64)
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return _BitScanReverse64(&index, (unsigned long long)i_value) ? uint8_t(index) : -1;
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#elif defined(TL_PLATFORM_32)
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const int8_t position = top_bit(uint32_t(i_value >> 32));
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if (position > -1)
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{
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return position + 32;
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}
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return top_bit(uint32_t(i_value & 0xffffffff));
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#else
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static_assert(!std::is_same_v<T, T>, "no-builtin function found for this compiler);");
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#endif // TL_PLATFORM_XX
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#elif defined(__clang__) || defined(__GNUC__)
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return i_value ? 63u - __builtin_clzll(i_value) : -1;
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#else
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static_assert(!std::is_same_v<T, T>, "no-builtin function found for this compiler);");
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#endif
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}
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//////////////////////////////////////////////////////////////////////////
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} // namespace algorithm
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} // namespace tl
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