120 lines
3.6 KiB
C++
120 lines
3.6 KiB
C++
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the
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* Free Software Foundation, Inc.,
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* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifndef _TEXTSPLIT_H_INCLUDED_
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#define _TEXTSPLIT_H_INCLUDED_
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/* @(#$Id: textsplit.h,v 1.20 2007-10-04 12:21:52 dockes Exp $ (C) 2004 J.F.Dockes */
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#include <string>
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#ifndef NO_NAMESPACES
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using std::string;
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#endif
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/**
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* Function class whose takeword method is called for every detected word while * splitting text.
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*/
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class TextSplitCB {
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public:
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virtual ~TextSplitCB() {}
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virtual bool takeword(const string& term,
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int pos, // term pos
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int bts, // byte offset of first char in term
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int bte // byte offset of first char after term
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) = 0;
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};
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class Utf8Iter;
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/**
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* Split text into words.
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* See comments at top of .cpp for more explanations.
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* This uses a callback function. It could be done with an iterator instead,
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* but 'ts much simpler this way...
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*/
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class TextSplit {
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public:
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// Should we activate special processing of Chinese characters ? This
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// needs a little more cpu, so it can be turned off globally.
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static bool o_processCJK;
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static unsigned int o_CJKNgramLen;
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static const unsigned int o_CJKMaxNgramLen = 5;
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static void cjkProcessing(bool onoff, unsigned int ngramlen = 2)
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{
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o_processCJK = onoff;
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o_CJKNgramLen = ngramlen <= o_CJKMaxNgramLen ?
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ngramlen : o_CJKMaxNgramLen;
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}
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enum Flags {TXTS_NONE = 0,
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TXTS_ONLYSPANS = 1, // Only return maximum spans (a@b.com)
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TXTS_NOSPANS = 2, // Only return atomic words (a, b, com)
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TXTS_KEEPWILD = 4 // Handle wildcards as letters
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};
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/**
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* Constructor: just store callback object
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*/
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TextSplit(TextSplitCB *t, Flags flags = Flags(TXTS_NONE))
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: m_flags(flags), m_cb(t), m_maxWordLength(40),
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m_prevpos(-1)
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{
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}
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/**
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* Split text, emit words and positions.
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*/
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bool text_to_words(const string &in);
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// Utility functions : these does not need the user to setup a callback
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// etc.
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static int countWords(const string &in, Flags flgs = TXTS_ONLYSPANS);
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private:
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Flags m_flags;
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TextSplitCB *m_cb;
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int m_maxWordLength;
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// Current span. Might be jf.dockes@wanadoo.f
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string m_span;
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// Current word: no punctuation at all in there. Byte offset
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// relative to the current span and byte length
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int m_wordStart;
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unsigned int m_wordLen;
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// Currently inside number
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bool m_inNumber;
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// Term position of current word and span
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int m_wordpos;
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int m_spanpos;
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// It may happen that our cleanup would result in emitting the
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// same term twice. We try to avoid this
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int m_prevpos;
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unsigned int m_prevlen;
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// This processes cjk text:
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bool cjk_to_words(Utf8Iter *it, unsigned int *cp);
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bool emitterm(bool isspan, string &term, int pos, int bs, int be);
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bool doemit(bool spanerase, int bp);
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};
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#endif /* _TEXTSPLIT_H_INCLUDED_ */
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