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/*
** PJL C++ Library
** file_vector.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 file_vector_H
#define file_vector_H
// standard
#include <iostream.h>
#include <iterator>
#include <sys/types.h> /* for off_t */
// local
#include "fake_ansi.h"
class file_vector_base {
public:
typedef off_t size_type;
typedef ptrdiff_t difference_type;
file_vector_base() { init(); }
file_vector_base( char const *path, ios::open_mode mode = ios::in ) {
init();
open( path, mode );
}
~file_vector_base() { close(); }
bool open( char const *path, ios::open_mode = ios::in );
void close();
bool empty() const { return !size_; }
int error() const { return error_; }
size_type max_size() const { return size_; }
size_type size() const { return size_; }
operator bool() const { return !error_; }
protected:
void* base() const { return addr_; }
private:
size_type size_;
int fd_; // Unix file descriptor
void *addr_;
int error_;
void init();
};
//*****************************************************************************
//
// SYNOPSYS
//
// file_vector< T >
//
// DESCRIPTION
//
// A file_vector is an object that maps a file into memory (via the Unix
// system call mmap(2)) allowing it to be accessed via iterators.
// Processing a file, especially files accessed randomly, is MUCH faster
// than standard I/O. The type T is usually a character type, but could
// be a numeric type for reading vectors or matricies of, say, long or
// double.
//
// SEE ALSO
//
// mmap(2)
//
//*****************************************************************************
template< class T > class file_vector : public file_vector_base {
public:
////////// typedefs ///////////////////////////////////////////////////
typedef T value_type;
typedef value_type* pointer;
typedef value_type const* const_pointer;
typedef value_type& reference;
typedef value_type const& const_reference;
////////// constructors ///////////////////////////////////////////////
file_vector() { }
file_vector( char const *path, ios::open_mode mode = ios::in ) :
file_vector_base( path, mode ) { }
////////// iterators //////////////////////////////////////////////////
typedef pointer iterator;
typedef const_pointer const_iterator;
typedef reverse_bidirectional_iterator<
iterator, value_type, reference, difference_type
> reverse_iterator;
typedef reverse_bidirectional_iterator<
const_iterator, value_type, const_reference, difference_type
> const_reverse_iterator;
iterator begin() { return (iterator)base(); }
const_iterator begin() const { return (const_iterator)base(); }
iterator end() { return begin() + size(); }
const_iterator end() const { return begin() + size(); }
reverse_iterator rbegin() {
return reverse_iterator( end() );
}
reverse_iterator rend() {
return reverse_iterator( begin() );
}
const_reverse_iterator rbegin() const {
return const_reverse_iterator( end() );
}
const_reverse_iterator rend() const {
return const_reverse_iterator( begin() );
}
////////// element access /////////////////////////////////////////////
reference back() { return *( end() - 1 ); }
const_reference back() const { return *( end() - 1 ); }
reference front() { return *begin(); }
const_reference front() const { return *begin(); }
reference operator[]( size_type i ) {
return *( begin() + i );
}
const_reference operator[]( size_type i ) const {
return *( begin() + i );
}
};
#endif /* file_vector_H */
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