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52 lines
1.2 KiB
C++
52 lines
1.2 KiB
C++
#pragma once
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#include <Common/PODArray.h>
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#include <Common/StringUtils/StringUtils.h>
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#include <Common/UTF8Helpers.h>
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#include <algorithm>
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#include <climits>
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#include <cstring>
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#include <memory>
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#include <utility>
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#ifdef __SSE4_2__
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# include <nmmintrin.h>
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#endif
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namespace DB
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{
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// used by FunctionsStringSimilarity and FunctionsStringHash
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// includes extracting ASCII ngram, UTF8 ngram, ASCII word and UTF8 word
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struct ExtractStringImpl
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{
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static ALWAYS_INLINE inline const UInt8 * readOneWord(const UInt8 *& pos, const UInt8 * end)
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{
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// jump separators
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while (pos < end && isUTF8Sep(*pos))
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++pos;
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// word start from here
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const UInt8 * word_start = pos;
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while (pos < end && !isUTF8Sep(*pos))
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++pos;
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return word_start;
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}
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// we use ASCII non-alphanum character as UTF8 separator
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static ALWAYS_INLINE inline bool isUTF8Sep(const UInt8 c) { return c < 128 && !isAlphaNumericASCII(c); }
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// read one UTF8 character
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static ALWAYS_INLINE inline void readOneUTF8Code(const UInt8 *& pos, const UInt8 * end)
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{
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size_t length = UTF8::seqLength(*pos);
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if (pos + length > end)
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length = end - pos;
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pos += length;
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}
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};
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}
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