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