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/*
Title: osomem.h - Interface to OS memory management
Copyright (c) 2006 David C.J. Matthews
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef OS_MEM_H_INCLUDED
#define OS_MEM_H_INCLUDED
// We need size_t so include these two here.
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
// This class provides access to the memory management provided by the
// operating system. It would be nice if we could always use malloc and
// free for this but we need to have execute permission on the code
// objects.
#define PERMISSION_READ 1
#define PERMISSION_WRITE 2
#define PERMISSION_EXEC 4
class OSMem
{
public:
// Allocate space and return a pointer to it. The size is the minimum
// size requested in bytes and it is updated with the actual space allocated.
// Returns NULL if it cannot allocate the space.
void *Allocate(size_t &bytes, unsigned permissions);
// Release the space previously allocated. This must free the whole of
// the segment. The space must be the size actually allocated.
bool Free(void *p, size_t space);
// Adjust the permissions on a segment. This must apply to the
// whole of a segment.
bool SetPermissions(void *p, size_t space, unsigned permissions);
};
extern OSMem *osMemoryManager;
#endif
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