MemMapped.h

/*
Pharmit
Copyright (c) David Ryan Koes, University of Pittsburgh and contributors.
All rights reserved.

Pharmit is licensed under both the BSD 3-clause license and the GNU
Public License version 2. Any use of the code that retains its reliance
on the GPL-licensed OpenBabel library is subject to the terms of the GPL2.

Use of the Pharmit code independently of OpenBabel (or any other
GPL2 licensed software) may choose between the BSD or GPL licenses.

See the LICENSE file provided with the distribution for more information.

*/
/*
 * MemMapped.h
 *
 *  Created on: Oct 19, 2011
 *      Author: dkoes
 *
 *  A wrapper for a memory mapped file.  I use this instead of boost
 *  since this way I have more control over the posix settings and
 *  a mroe convenient interface
 */

#ifndef MEMMAPPED_H_
#define MEMMAPPED_H_

#include "GSSTypes.h"
#include <string>

class MemMapped
{
	void *addr;
	unsigned long sz;
public:
	MemMapped(): addr(NULL), sz(0) {}
	~MemMapped() {} //does not unmap, must explicitly clear

	//map a file into memory
	bool map(const string& fname, bool readOnly, bool sequential, bool populate=false, bool readonce=false);

	const unsigned char& operator[](unsigned i) const { return ((unsigned char*)addr)[i]; }
	operator void*() const { return addr; }

	const char * begin() const { return (const char*)addr; }
	const char * end() const { return (const char*)addr + sz; }
	void clear();
	unsigned long size() const { return sz; }
};

#endif /* MEMMAPPED_H_ */