ClickHouse/dbms/include/DB/Core/StringRef.h
Vladimir Smirnov d36f52502e Make it compilable on OS X
It's still hackish and dirty, but server and client compies.

Server starts, but throwes meaningless exception on any query.

Client seems to be working fine.

Linux compilation might (but shouldn't) be broken (not tested).
2016-11-01 17:59:21 +01:00

313 lines
7.5 KiB
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#pragma once
#include <string.h>
#include <city.h>
#include <string>
#include <vector>
#include <functional>
#include <ostream>
#if defined(__x86_64__)
#include <emmintrin.h>
#endif
#include <DB/Core/Types.h>
#include <DB/Common/unaligned.h>
/// Штука, чтобы не создавать строки для поиска подстроки в хэш таблице.
struct StringRef
{
const char * data = nullptr;
size_t size = 0;
StringRef(const char * data_, size_t size_) : data(data_), size(size_) {}
StringRef(const unsigned char * data_, size_t size_) : data(reinterpret_cast<const char *>(data_)), size(size_) {}
StringRef(const std::string & s) : data(s.data()), size(s.size()) {}
StringRef() = default;
std::string toString() const { return std::string(data, size); }
explicit operator std::string() const { return toString(); }
};
using StringRefs = std::vector<StringRef>;
using UInt64 = DB::UInt64;
#if defined(__x86_64__)
/** Сравнение строк на равенство.
* Подход является спорным и выигрывает не во всех случаях.
* Подробнее смотрите hash_map_string_2.cpp
*/
inline bool compareSSE2(const char * p1, const char * p2)
{
return 0xFFFF == _mm_movemask_epi8(_mm_cmpeq_epi8(
_mm_loadu_si128(reinterpret_cast<const __m128i *>(p1)),
_mm_loadu_si128(reinterpret_cast<const __m128i *>(p2))));
}
inline bool compareSSE2x4(const char * p1, const char * p2)
{
return 0xFFFF == _mm_movemask_epi8(
_mm_and_si128(
_mm_and_si128(
_mm_cmpeq_epi8(
_mm_loadu_si128(reinterpret_cast<const __m128i *>(p1)),
_mm_loadu_si128(reinterpret_cast<const __m128i *>(p2))),
_mm_cmpeq_epi8(
_mm_loadu_si128(reinterpret_cast<const __m128i *>(p1) + 1),
_mm_loadu_si128(reinterpret_cast<const __m128i *>(p2) + 1))),
_mm_and_si128(
_mm_cmpeq_epi8(
_mm_loadu_si128(reinterpret_cast<const __m128i *>(p1) + 2),
_mm_loadu_si128(reinterpret_cast<const __m128i *>(p2) + 2)),
_mm_cmpeq_epi8(
_mm_loadu_si128(reinterpret_cast<const __m128i *>(p1) + 3),
_mm_loadu_si128(reinterpret_cast<const __m128i *>(p2) + 3)))));
}
inline bool memequalSSE2Wide(const char * p1, const char * p2, size_t size)
{
while (size >= 64)
{
if (compareSSE2x4(p1, p2))
{
p1 += 64;
p2 += 64;
size -= 64;
}
else
return false;
}
switch ((size % 64) / 16)
{
case 3: if (!compareSSE2(p1 + 32, p2 + 32)) return false;
case 2: if (!compareSSE2(p1 + 16, p2 + 16)) return false;
case 1: if (!compareSSE2(p1 , p2 )) return false;
case 0: break;
}
p1 += (size % 64) / 16 * 16;
p2 += (size % 64) / 16 * 16;
switch (size % 16)
{
case 15: if (p1[14] != p2[14]) return false;
case 14: if (p1[13] != p2[13]) return false;
case 13: if (p1[12] != p2[12]) return false;
case 12: if (reinterpret_cast<const uint32_t *>(p1)[2] == reinterpret_cast<const uint32_t *>(p2)[2]) goto l8; else return false;
case 11: if (p1[10] != p2[10]) return false;
case 10: if (p1[9] != p2[9]) return false;
case 9: if (p1[8] != p2[8]) return false;
l8: case 8: return reinterpret_cast<const UInt64 *>(p1)[0] == reinterpret_cast<const UInt64 *>(p2)[0];
case 7: if (p1[6] != p2[6]) return false;
case 6: if (p1[5] != p2[5]) return false;
case 5: if (p1[4] != p2[4]) return false;
case 4: return reinterpret_cast<const uint32_t *>(p1)[0] == reinterpret_cast<const uint32_t *>(p2)[0];
case 3: if (p1[2] != p2[2]) return false;
case 2: return reinterpret_cast<const uint16_t *>(p1)[0] == reinterpret_cast<const uint16_t *>(p2)[0];
case 1: if (p1[0] != p2[0]) return false;
case 0: break;
}
return true;
}
#endif
inline bool operator== (StringRef lhs, StringRef rhs)
{
if (lhs.size != rhs.size)
return false;
if (lhs.size == 0)
return true;
#if defined(__x86_64__)
return memequalSSE2Wide(lhs.data, rhs.data, lhs.size);
#else
return 0 == memcmp(lhs.data, rhs.data, lhs.size);
#endif
}
inline bool operator!= (StringRef lhs, StringRef rhs)
{
return !(lhs == rhs);
}
inline bool operator< (StringRef lhs, StringRef rhs)
{
int cmp = memcmp(lhs.data, rhs.data, std::min(lhs.size, rhs.size));
return cmp < 0 || (cmp == 0 && lhs.size < rhs.size);
}
inline bool operator> (StringRef lhs, StringRef rhs)
{
int cmp = memcmp(lhs.data, rhs.data, std::min(lhs.size, rhs.size));
return cmp > 0 || (cmp == 0 && lhs.size > rhs.size);
}
/** Хэш-функции.
* Можно использовать либо CityHash64,
* либо функцию на основе инструкции crc32,
* которая является заведомо менее качественной, но на реальных наборах данных,
* при использовании в хэш-таблице, работает существенно быстрее.
* Подробнее см. hash_map_string_3.cpp
*/
struct StringRefHash64
{
size_t operator() (StringRef x) const
{
return CityHash64(x.data, x.size);
}
};
#if defined(__x86_64__)
#ifdef __SSE4_1__
#include <smmintrin.h>
#else
inline UInt64 _mm_crc32_u64(UInt64 crc, UInt64 value)
{
asm("crc32q %[value], %[crc]\n" : [crc] "+r" (crc) : [value] "rm" (value));
return crc;
}
#endif
/// Кусочки взяты из CityHash.
inline UInt64 hashLen16(UInt64 u, UInt64 v)
{
return Hash128to64(uint128(u, v));
}
inline UInt64 shiftMix(UInt64 val)
{
return val ^ (val >> 47);
}
inline UInt64 rotateByAtLeast1(UInt64 val, int shift)
{
return (val >> shift) | (val << (64 - shift));
}
inline size_t hashLessThan8(const char * data, size_t size)
{
static constexpr UInt64 k2 = 0x9ae16a3b2f90404fULL;
static constexpr UInt64 k3 = 0xc949d7c7509e6557ULL;
if (size >= 4)
{
UInt64 a = unalignedLoad<uint32_t>(data);
return hashLen16(size + (a << 3), unalignedLoad<uint32_t>(data + size - 4));
}
if (size > 0)
{
uint8 a = data[0];
uint8 b = data[size >> 1];
uint8 c = data[size - 1];
uint32 y = static_cast<uint32>(a) + (static_cast<uint32>(b) << 8);
uint32 z = size + (static_cast<uint32>(c) << 2);
return shiftMix(y * k2 ^ z * k3) * k2;
}
return k2;
}
inline size_t hashLessThan16(const char * data, size_t size)
{
if (size > 8)
{
UInt64 a = unalignedLoad<UInt64>(data);
UInt64 b = unalignedLoad<UInt64>(data + size - 8);
return hashLen16(a, rotateByAtLeast1(b + size, size)) ^ b;
}
return hashLessThan8(data, size);
}
struct CRC32Hash
{
size_t operator() (StringRef x) const
{
const char * pos = x.data;
size_t size = x.size;
if (size == 0)
return 0;
if (size < 8)
{
return hashLessThan8(x.data, x.size);
}
const char * end = pos + size;
size_t res = -1ULL;
do
{
UInt64 word = unalignedLoad<UInt64>(pos);
res = _mm_crc32_u64(res, word);
pos += 8;
} while (pos + 8 < end);
UInt64 word = unalignedLoad<UInt64>(end - 8); /// Не уверен, что это нормально.
res = _mm_crc32_u64(res, word);
return res;
}
};
struct StringRefHash : CRC32Hash {};
#else
struct StringRefHash : StringRefHash64 {};
#endif
namespace std
{
template <>
struct hash<StringRef> : public StringRefHash {};
}
namespace ZeroTraits
{
inline bool check(StringRef x) { return 0 == x.size; }
inline void set(StringRef & x) { x.size = 0; }
};
inline bool operator==(StringRef lhs, const char * rhs)
{
for (size_t pos = 0; pos < lhs.size; ++pos)
if (!rhs[pos] || lhs.data[pos] != rhs[pos])
return false;
return true;
}
inline std::ostream & operator<<(std::ostream & os, const StringRef & str)
{
if (str.data)
os.write(str.data, str.size);
return os;
}