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https://github.com/ClickHouse/ClickHouse.git
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b7ef5a699c
* Get rid of non-existent vectorclass * Move FastMemcpy to contribs * Restore comments * Disable FastMemcpy on non-Linux * Fix cmake file * Don't build FastMemcpy for ARM64 * Replace FastMemcpy submodule with its contents * Fix cmake file * Move widechar_width to contrib/ * Move sumbur to contrib/ * Move consistent-hashing to contrib/ * Fix UBSan tests
53 lines
1.8 KiB
C++
53 lines
1.8 KiB
C++
#pragma once
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#include <stdint.h>
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#include <limits>
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#include <type_traits>
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inline uint16_t LO_16(uint32_t x) { return static_cast<uint16_t>(x & 0x0000FFFF); }
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inline uint16_t HI_16(uint32_t x) { return static_cast<uint16_t>(x >> 16); }
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inline uint32_t LO_32(uint64_t x) { return static_cast<uint32_t>(x & 0x00000000FFFFFFFF); }
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inline uint32_t HI_32(uint64_t x) { return static_cast<uint32_t>(x >> 32); }
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/// Clang also defines __GNUC__
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#if defined(__GNUC__)
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inline unsigned GetValueBitCountImpl(unsigned int value) noexcept {
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// NOTE: __builtin_clz* have undefined result for zero.
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return std::numeric_limits<unsigned int>::digits - __builtin_clz(value);
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}
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inline unsigned GetValueBitCountImpl(unsigned long value) noexcept {
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return std::numeric_limits<unsigned long>::digits - __builtin_clzl(value);
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}
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inline unsigned GetValueBitCountImpl(unsigned long long value) noexcept {
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return std::numeric_limits<unsigned long long>::digits - __builtin_clzll(value);
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}
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#else
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/// Stupid implementation for non GCC-like compilers. Can use BSR from x86 instructions set.
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template <typename T>
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inline unsigned GetValueBitCountImpl(T value) noexcept {
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unsigned result = 1; // result == 0 - impossible value, since value cannot be zero
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value >>= 1;
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while (value) {
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value >>= 1;
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++result;
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}
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return result;
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}
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#endif
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/**
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* Returns the number of leading 0-bits in `value`, starting at the most significant bit position.
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* NOTE: value cannot be zero
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*/
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template <typename T>
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static inline unsigned GetValueBitCount(T value) noexcept {
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using TCvt = std::make_unsigned_t<std::decay_t<T>>;
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return GetValueBitCountImpl(static_cast<TCvt>(value));
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}
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