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/** @file cjk-tokenizer.h
* @brief Tokenise CJK text as n-grams
*/
/* Copyright (c) 2007, 2008 Yung-chung Lin (henearkrxern@gmail.com)
* Copyright (c) 2011 Richard Boulton (richard@tartarus.org)
* Copyright (c) 2011 Brandon Schaefer (brandontschaefer@gmail.com)
* Copyright (c) 2011 Olly Betts
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#ifndef XAPIAN_INCLUDED_CJK_TOKENIZER_H
#define XAPIAN_INCLUDED_CJK_TOKENIZER_H
#include "xapian/unicode.h"
#include <string>
namespace CJK {
/** Should we use the CJK n-gram code?
*
* The first time this is called it reads the environmental variable
* XAPIAN_CJK_NGRAM and returns true if it is set to a non-empty value.
* Subsequent calls cache and return the same value.
*/
bool is_cjk_enabled();
bool codepoint_is_cjk(unsigned codepoint);
std::string get_cjk(Xapian::Utf8Iterator &it);
}
class CJKTokenIterator {
Xapian::Utf8Iterator it;
mutable Xapian::Utf8Iterator p;
mutable unsigned len;
mutable std::string current_token;
public:
explicit CJKTokenIterator(const std::string & s)
: it(s) { }
explicit CJKTokenIterator(const Xapian::Utf8Iterator & it_)
: it(it_) { }
CJKTokenIterator()
: it() { }
const std::string & operator*() const;
CJKTokenIterator & operator++();
/// Get the length of the current token in Unicode characters.
unsigned get_length() const { return len; }
friend bool operator==(const CJKTokenIterator &, const CJKTokenIterator &);
};
inline bool
operator==(const CJKTokenIterator & a, const CJKTokenIterator & b)
{
// We only really care about comparisons where one or other is an end
// iterator.
return a.it == b.it;
}
inline bool
operator!=(const CJKTokenIterator & a, const CJKTokenIterator & b)
{
return !(a == b);
}
#endif // XAPIAN_INCLUDED_CJK_TOKENIZER_H
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