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/*
** PJL C++ Library
** mmap_file.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 mmap_file_H
#define mmap_file_H
// standard
#include <cstddef> /* for ptrdiff_t, size_t */
#include <fstream> /* for openmode */
#include <iterator>
#include <sys/types.h> /* needed by FreeBSD systems */
#include <sys/mman.h> /* for mmap(2) */
//
// Some C headers on some implementations define open/close as macros to remap
// them to functions that handle files larger than 2 GB. This works fine in C,
// but can break C++ where classes have open/close member functions. Undefine
// them and live with the consequence of not being able to deal with large
// files on such (brain-damaged) implementations.
//
#ifdef open
#undef open
#endif
#ifdef close
#undef close
#endif
// local
#include "platform.h"
namespace PJL {
//*****************************************************************************
//
// SYNOPSYS
//
class mmap_file
//
// DESCRIPTION
//
// An mmap_file 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.
//
// SEE ALSO
//
// mmap(2)
//
// W. Richard Stevens. "Advanced Programming in the Unix Environment,"
// Addison-Wesley, Reading, MA, 1993. pp. 407-413
//
//*****************************************************************************
{
public:
////////// typedefs ///////////////////////////////////////////////////////
typedef size_t size_type;
typedef ptrdiff_t difference_type;
typedef char value_type;
typedef value_type* pointer;
typedef value_type const* const_pointer;
typedef value_type& reference;
typedef value_type const& const_reference;
enum behavior_type {
#ifdef PJL_NO_MADVISE
bt_normal,
bt_random,
bt_sequential
#else
bt_normal = MADV_NORMAL,
bt_random = MADV_RANDOM,
bt_sequential = MADV_SEQUENTIAL
#endif
};
////////// constructors & destructor //////////////////////////////////////
mmap_file() { init(); }
mmap_file( char const *path, std::ios::openmode mode = std::ios::in ) {
init();
open( path, mode );
}
~mmap_file() { close(); }
////////// iterators //////////////////////////////////////////////////////
typedef pointer iterator;
typedef const_pointer const_iterator;
#ifndef __SUNPRO_CC
//
// There's a known bug with the reverse_iterator definition in the STL
// headers that Sun's CC compiler uses. Since we don't actually use
// reverse_iterator in SWISH++, just leave it out.
//
typedef std::reverse_iterator< iterator > reverse_iterator;
typedef std::reverse_iterator< const_iterator > const_reverse_iterator;
#endif
iterator begin() { return (iterator)addr_; }
const_iterator begin() const { return (const_iterator)addr_; }
iterator end() { return begin() + size_; }
const_iterator end() const { return begin() + size_; }
#ifndef __SUNPRO_CC
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() );
}
#endif /* __SUNPRO_CC */
////////// member functions ///////////////////////////////////////////////
operator bool() const { return !errno_; }
reference back() { return *( end() - 1 ); }
const_reference back() const { return *( end() - 1 ); }
int behavior( behavior_type ) const;
reference front() { return *begin(); }
const_reference front() const { return *begin(); }
bool open( char const *path, std::ios::openmode = std::ios::in );
void close();
bool empty() const { return !size_; }
int error() const { return errno_; }
size_type max_size() const { return size_; }
size_type size() const { return size_; }
reference operator[]( size_type i ) {
return *( begin() + i );
}
const_reference operator[]( size_type i ) const {
return *( begin() + i );
}
private:
size_type size_;
int fd_; // Unix file descriptor
void *addr_;
mutable int errno_;
void init();
};
} // namespace PJL
#endif /* mmap_file_H */
/* vim:set et sw=4 ts=4: */
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