///-*-C++-*-//////////////////////////////////////////////////////////////////
//
// Hoard: A Fast, Scalable, and Memory-Efficient Allocator
//        for Shared-Memory Multiprocessors
// Contact author: Emery Berger, http://www.cs.utexas.edu/users/emery
//
// Copyright (c) 1998-2000, The University of Texas at Austin.
//
// This library is free software; you can redistribute it and/or modify
// it under the terms of the GNU Library General Public License as
// published by the Free Software Foundation, http://www.fsf.org.
//
// 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
// Library General Public License for more details.
//
//////////////////////////////////////////////////////////////////////////////

#ifndef _BLOCK_H_
#define _BLOCK_H_

#include "config.h"

#include "os/support/Debug.h"

//#include <assert.h>

namespace BPrivate {

class superblock;

class block {
	public:
		block(superblock * sb)
			:
#if HEAP_DEBUG
			_magic(FREE_BLOCK_MAGIC),
#endif
			_next(NULL), _mySuperblock(sb)
		{
		}

		block &
		operator=(const block & b)
		{
#if HEAP_DEBUG
			_magic = b._magic;
#endif
			_next = b._next;
			_mySuperblock = b._mySuperblock;
#if HEAP_FRAG_STATS
			_requestedSize = b._requestedSize;
#endif
			return *this;
		}

		enum {
			ALLOCATED_BLOCK_MAGIC = 0xcafecafe,
			FREE_BLOCK_MAGIC = 0xbabebabe
		};

		// Mark this block as free.
		inline void markFree(void);

		// Mark this block as allocated.
		inline void markAllocated(void);

		// Is this block valid? (i.e.,
		// does it have the right magic number?)
		inline const int isValid(void) const;

		// Return the block's superblock pointer.
		inline superblock *getSuperblock(void);

#if HEAP_FRAG_STATS
		void
		setRequestedSize(size_t s)
		{
			_requestedSize = s;
		}

		size_t
		getRequestedSize(void)
		{
			return _requestedSize;
		}
#endif

#if USE_PRIVATE_HEAPS
		void
		setActualSize(size_t s)
		{
			_actualSize = s;
		}

		size_t
		getActualSize(void)
		{
			return _actualSize;
		}
#endif
		void
		setNext(block * b)
		{
			_next = b;
		}

		block *
		getNext(void)
		{
			return _next;
		}

#if HEAP_LEAK_CHECK
		void
		setCallStack(int index, void *address)
		{
			_callStack[index] = address;
		}
		
		void *
		getCallStack(int index)
		{
			return _callStack[index];
		}
		
		void
		setAllocatedSize(size_t size)
		{
			_allocatedSize = size;
		}
		
		size_t
		getAllocatedSize()
		{
			return _allocatedSize;
		}
#endif

	private:
#if USE_PRIVATE_HEAPS
#if HEAP_DEBUG
		union {
			unsigned long _magic;
			double _d1;				// For alignment.
		};
#endif

		block *_next;				// The next block in a linked-list of blocks.
		size_t _actualSize;			// The actual size of the block.

		union {
			double _d2;				// For alignment.
			superblock *_mySuperblock;	// A pointer to my superblock.
		};
#else // ! USE_PRIVATE_HEAPS

#if HEAP_DEBUG
		union {
			unsigned long _magic;
			double _d3;				// For alignment.
		};
#endif

		block *_next;				// The next block in a linked-list of blocks.
		superblock *_mySuperblock;	// A pointer to my superblock.

#if defined(__i386__) && (__GNUC__ > 2)
		double _d5; // For alignment, make sure the whole structure is 16 byte
					// aligned
#endif

#endif // USE_PRIVATE_HEAPS

#if HEAP_LEAK_CHECK
		void *_callStack[HEAP_CALL_STACK_SIZE];
		size_t _allocatedSize;
#endif

#if HEAP_FRAG_STATS
		union {
			double _d4;				// This is just for alignment purposes.
			size_t _requestedSize;	// The amount of space requested (vs. allocated).
		};
#endif

		// Disable copying.
		block(const block &);
};

// Make sure the block size does not mess up the alignment of allocations, it
// must be a multiple of ALIGNMENT
#if __GNUC__ > 2
// The macro we use for legacy gcc doesn't work in the global context, only
// inside functions since it is wrapped in a do/while.
STATIC_ASSERT(sizeof(block) % HAIKU_MEMORY_ALIGNMENT == 0);
#endif


superblock *
block::getSuperblock(void)
{
#if HEAP_DEBUG
	assert(isValid());
#endif

	return _mySuperblock;
}


void
block::markFree(void)
{
#if HEAP_DEBUG
	assert(_magic == ALLOCATED_BLOCK_MAGIC);
	_magic = FREE_BLOCK_MAGIC;
#endif
}


void
block::markAllocated(void)
{
#if HEAP_DEBUG
	assert(_magic == FREE_BLOCK_MAGIC);
	_magic = ALLOCATED_BLOCK_MAGIC;
#endif
}


const int
block::isValid(void) const
{
#if HEAP_DEBUG
	return _magic == FREE_BLOCK_MAGIC
		|| _magic == ALLOCATED_BLOCK_MAGIC;
#else
	return 1;
#endif
}

}	// namespace BPrivate

#endif // _BLOCK_H_