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/*
** SWISH++
** word_index.h
**
** Copyright (C) 1998 Paul J. Lucas
**
** 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef word_index_H
#define word_index_H
// standard
#include <cstddef> /* for ptrdiff_t */
#include <iterator>
#include <sys/types.h> /* for off_t */
// local
#include "fake_ansi.h"
#include "file_vector.h"
//*****************************************************************************
//
// SYNOPSIS
//
class word_index;
//
// DESCRIPTION
//
// An instance of this class is used to access the word index portion of
// a generated index.
//
// By implementing fully-blown random access iterators for it, the STL
// algorithms work, in particular equal_range() that is used to look up
// words.
//
//*****************************************************************************
class word_index {
public:
////////// typedefs ///////////////////////////////////////////////////
typedef long size_type;
typedef ptrdiff_t difference_type;
typedef char* value_type;
typedef char** pointer;
typedef char const** const_pointer;
typedef char* reference;
typedef char const* const_reference;
////////// constructors ///////////////////////////////////////////////
word_index() { }
word_index( file_vector<char> const &file ) { set_index_file( file ); }
////////// members functions //////////////////////////////////////////
void set_index_file( file_vector<char> const& );
size_type size() const { return num_words_; }
////////// iterators //////////////////////////////////////////////////
class const_iterator;
friend class const_iterator;
class const_iterator :
public random_access_iterator< value_type, difference_type > {
public:
const_iterator() { }
const_reference operator*() const { return (*index_)[ word_ ]; }
const_iterator& operator++() {
return ++word_, *this;
}
const_iterator& operator--() {
return --word_, *this;
}
const_iterator operator++(int) {
return const_iterator( index_, word_++ );
}
const_iterator operator--(int) {
return const_iterator( index_, word_-- );
}
friend bool
operator==( const_iterator const &i, const_iterator const &j ) {
return i.word_ == j.word_;
}
friend bool
operator!=( const_iterator const &i, const_iterator const &j ) {
return !( i == j );
}
friend const_iterator
operator+( const_iterator const &i, int n ) {
return const_iterator( i.index_, i.word_ + n );
}
friend const_iterator
operator-( const_iterator const &i, int n ) {
return const_iterator( i.index_, i.word_ - n );
}
friend difference_type
operator-( const_iterator const &i, const_iterator const &j ) {
return i.word_ - j.word_;
}
private:
word_index const *index_;
long word_;
const_iterator( word_index const *index, long word_index ) :
index_( index ), word_( word_index ) { }
friend class word_index;
};
const_iterator begin() const {
return const_iterator( this, 0 );
}
const_iterator end() const {
return const_iterator( this, num_words_ );
}
const_reference operator[]( long i ) const {
return begin_ + offset_[ i ];
}
private:
file_vector<char>::const_iterator begin_;
size_type num_words_;
off_t const *offset_;
};
#endif /* word_index_H */
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