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279 lines
6.6 KiB
C++
279 lines
6.6 KiB
C++
#pragma once
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#include <string.h>
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#include <city.h>
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#include <string>
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#include <vector>
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#include <functional>
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#include <ostream>
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#include <emmintrin.h>
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/// Штука, чтобы не создавать строки для поиска подстроки в хэш таблице.
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struct StringRef
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{
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const char * data = nullptr;
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size_t size = 0;
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StringRef(const char * data_, size_t size_) : data(data_), size(size_) {}
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StringRef(const unsigned char * data_, size_t size_) : data(reinterpret_cast<const char *>(data_)), size(size_) {}
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StringRef(const std::string & s) : data(s.data()), size(s.size()) {}
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StringRef() {}
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std::string toString() const { return std::string(data, size); }
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};
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typedef std::vector<StringRef> StringRefs;
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/** Сравнение строк на равенство.
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* Подход является спорным и выигрывает не во всех случаях.
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* Подробнее смотрите hash_map_string_2.cpp
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*/
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inline bool compareSSE2(const char * p1, const char * p2)
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{
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return 0xFFFF == _mm_movemask_epi8(_mm_cmpeq_epi8(
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_mm_loadu_si128(reinterpret_cast<const __m128i *>(p1)),
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_mm_loadu_si128(reinterpret_cast<const __m128i *>(p2))));
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}
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inline bool memequalSSE2Wide(const char * p1, const char * p2, size_t size)
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{
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while (size >= 64)
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{
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if ( compareSSE2(p1, p2)
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&& compareSSE2(p1 + 16, p2 + 16)
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&& compareSSE2(p1 + 32, p2 + 32)
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&& compareSSE2(p1 + 40, p2 + 40))
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{
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p1 += 64;
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p2 += 64;
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size -= 64;
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}
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else
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return false;
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}
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switch ((size % 64) / 16)
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{
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case 3: if (!compareSSE2(p1 + 32, p2 + 32)) return false;
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case 2: if (!compareSSE2(p1 + 16, p2 + 16)) return false;
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case 1: if (!compareSSE2(p1 , p2 )) return false;
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case 0: break;
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}
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p1 += (size % 64) / 16 * 16;
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p2 += (size % 64) / 16 * 16;
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switch (size % 16)
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{
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case 15: if (p1[14] != p2[14]) return false;
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case 14: if (p1[13] != p2[13]) return false;
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case 13: if (p1[12] != p2[12]) return false;
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case 12: if (reinterpret_cast<const uint32_t *>(p1)[2] == reinterpret_cast<const uint32_t *>(p2)[2]) goto l8; else return false;
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case 11: if (p1[10] != p2[10]) return false;
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case 10: if (p1[9] != p2[9]) return false;
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case 9: if (p1[8] != p2[8]) return false;
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l8: case 8: return reinterpret_cast<const uint64_t *>(p1)[0] == reinterpret_cast<const uint64_t *>(p2)[0];
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case 7: if (p1[6] != p2[6]) return false;
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case 6: if (p1[5] != p2[5]) return false;
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case 5: if (p1[4] != p2[4]) return false;
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case 4: return reinterpret_cast<const uint32_t *>(p1)[0] == reinterpret_cast<const uint32_t *>(p2)[0];
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case 3: if (p1[2] != p2[2]) return false;
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case 2: return reinterpret_cast<const uint16_t *>(p1)[0] == reinterpret_cast<const uint16_t *>(p2)[0];
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case 1: if (p1[0] != p2[0]) return false;
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case 0: break;
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}
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return true;
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}
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inline bool operator== (StringRef lhs, StringRef rhs)
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{
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if (lhs.size != rhs.size)
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return false;
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if (lhs.size == 0)
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return true;
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return memequalSSE2Wide(lhs.data, rhs.data, lhs.size);
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}
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inline bool operator!= (StringRef lhs, StringRef rhs)
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{
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return !(lhs == rhs);
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}
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inline bool operator< (StringRef lhs, StringRef rhs)
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{
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int cmp = memcmp(lhs.data, rhs.data, std::min(lhs.size, rhs.size));
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return cmp < 0 || (cmp == 0 && lhs.size < rhs.size);
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}
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inline bool operator> (StringRef lhs, StringRef rhs)
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{
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int cmp = memcmp(lhs.data, rhs.data, std::min(lhs.size, rhs.size));
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return cmp > 0 || (cmp == 0 && lhs.size > rhs.size);
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}
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/** Хэш-функции.
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* Можно использовать либо CityHash64,
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* либо функцию на основе инструкции crc32,
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* которая является заведомо менее качественной, но на реальных наборах данных,
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* при использовании в хэш-таблице, работает существенно быстрее.
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* Подробнее см. hash_map_string_3.cpp
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*/
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#ifdef __SSE4_1__
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#include <smmintrin.h>
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#else
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inline uint64 _mm_crc32_u64(uint64 crc, uint64 value)
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{
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asm("crc32q %[value], %[crc]\n" : [crc] "+r" (crc) : [value] "rm" (value));
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return crc;
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}
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#endif
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/// Кусочки взяты из CityHash.
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inline uint64 hashLen16(uint64 u, uint64 v)
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{
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return Hash128to64(uint128(u, v));
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}
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inline uint64 shiftMix(uint64 val)
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{
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return val ^ (val >> 47);
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}
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inline uint64 rotateByAtLeast1(uint64 val, int shift)
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{
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return (val >> shift) | (val << (64 - shift));
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}
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inline size_t hashLessThan8(const char * data, size_t size)
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{
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static constexpr uint64 k2 = 0x9ae16a3b2f90404fULL;
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static constexpr uint64 k3 = 0xc949d7c7509e6557ULL;
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if (size >= 4)
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{
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uint64 a = *reinterpret_cast<const uint32_t *>(data);;
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return hashLen16(size + (a << 3), *reinterpret_cast<const uint32_t *>(data + size - 4));
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}
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if (size > 0)
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{
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uint8 a = data[0];
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uint8 b = data[size >> 1];
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uint8 c = data[size - 1];
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uint32 y = static_cast<uint32>(a) + (static_cast<uint32>(b) << 8);
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uint32 z = size + (static_cast<uint32>(c) << 2);
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return shiftMix(y * k2 ^ z * k3) * k2;
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}
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return k2;
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}
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inline size_t hashLessThan16(const char * data, size_t size)
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{
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if (size > 8)
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{
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uint64 a = *reinterpret_cast<const uint64_t *>(data);
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uint64 b = *reinterpret_cast<const uint64_t *>(data + size - 8);
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return hashLen16(a, rotateByAtLeast1(b + size, size)) ^ b;
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}
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return hashLessThan8(data, size);
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}
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struct CRC32Hash
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{
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size_t operator() (StringRef x) const
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{
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const char * pos = x.data;
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size_t size = x.size;
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if (size == 0)
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return 0;
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if (size < 8)
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{
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return hashLessThan8(x.data, x.size);
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}
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const char * end = pos + size;
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size_t res = -1ULL;
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do
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{
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uint64_t word = *reinterpret_cast<const uint64_t *>(pos);
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res = _mm_crc32_u64(res, word);
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pos += 8;
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} while (pos + 8 < end);
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uint64_t word = *reinterpret_cast<const uint64_t *>(end - 8); /// Не уверен, что это нормально.
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res = _mm_crc32_u64(res, word);
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return res;
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}
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};
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#if 1
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struct StringRefHash : CRC32Hash {};
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#else
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struct StringRefHash
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{
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size_t operator() (StringRef x) const
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{
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return CityHash64(x.data, x.size);
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}
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};
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#endif
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namespace std
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{
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template <>
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struct hash<StringRef> : public StringRefHash {};
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}
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namespace ZeroTraits
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{
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inline bool check(StringRef x) { return 0 == x.size; }
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inline void set(StringRef & x) { x.size = 0; }
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};
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inline bool operator==(StringRef lhs, const char * rhs)
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{
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for (size_t pos = 0; pos < lhs.size; ++pos)
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if (!rhs[pos] || lhs.data[pos] != rhs[pos])
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return false;
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return true;
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}
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inline std::ostream & operator<<(std::ostream & os, const StringRef & str)
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{
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if (str.data)
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os.write(str.data, str.size);
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return os;
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}
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