/* Copyright (C) 2004 J.F.Dockes
* 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_
#include <string>
#include <list>
#ifndef NO_NAMESPACES
using std::string;
using std::list;
#endif
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. This is set
// by rclconfig, changing it means reindexing
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;
}
// Are we indexing numbers ? Set by rclconfig. Change needs reindex
static bool o_noNumbers;
static void noNumbers()
{
o_noNumbers = true;
}
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
};
TextSplit(Flags flags = Flags(TXTS_NONE))
: m_flags(flags), m_maxWordLength(40), m_prevpos(-1)
{
}
virtual ~TextSplit() {}
/** Split text, emit words and positions. */
bool text_to_words(const string &in);
/** Process one output word: to be implemented by the actual user class */
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;
// Static utility functions:
/** Count words in string, as the splitter would generate them */
static int countWords(const string &in, Flags flgs = TXTS_ONLYSPANS);
/** Check if this is visibly not a single block of text */
static bool hasVisibleWhite(const string &in);
/** Split text span into strings, at white space, allowing for substrings
* quoted with " . Escaping with \ works as usual inside the quoted areas.
* This has to be kept separate from smallut.cpp's stringsToStrings, which
* basically works only if whitespace is ascii, and which processes
* non-utf-8 input (iso-8859 config files work ok). This hopefully
* handles all Unicode whitespace, but needs correct utf-8 input
*/
static bool stringToStrings(const string &s, list<string> &tokens);
/** Is char CJK ? */
static bool isCJK(int c);
private:
Flags m_flags;
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, bool spanemit=false);
};
#endif /* _TEXTSPLIT_H_INCLUDED_ */