/*
 * Copyright 2008, Ingo Weinhold, ingo_weinhold@gmx.de.
 * Copyright 2004-2007, Axel Dörfler, axeld@pinc-software.de.
 * Distributed under the terms of the MIT License.
 *
 * Copyright 2001-2002, Travis Geiselbrecht. All rights reserved.
 * Distributed under the terms of the NewOS License.
 */
#ifndef _KERNEL_VM_STORE_ANONYMOUS_H
#define _KERNEL_VM_STORE_ANONYMOUS_H

#include <vm_types.h>


#if ENABLE_SWAP_SUPPORT

typedef page_num_t swap_addr_t;
struct swap_block;

extern "C" {
	void swap_init(void);
	void swap_init_post_modules(void);
	bool swap_free_page_swap_space(vm_page *page);
	uint32 swap_available_pages(void);
	uint32 swap_total_swap_pages(void);
}


class VMAnonymousCache : public VMCache {
public:
	virtual				~VMAnonymousCache();

			status_t	Init(bool canOvercommit, int32 numPrecommittedPages,
							int32 numGuardPages);

	virtual	status_t	Commit(off_t size);
	virtual	bool		HasPage(off_t offset);

	virtual	status_t	Read(off_t offset, const iovec *vecs, size_t count,
							size_t *_numBytes);
	virtual	status_t	Write(off_t offset, const iovec *vecs, size_t count,
							size_t *_numBytes);

	virtual	status_t	Fault(struct vm_address_space *aspace, off_t offset);

	virtual	void		MergeStore(VMCache* source);

private:
			void		_SwapBlockBuild(off_t pageIndex,
							swap_addr_t swapAddress, uint32 count);
			void        _SwapBlockFree(off_t pageIndex, uint32 count);
			swap_addr_t	_SwapBlockGetAddress(off_t pageIndex);
			status_t	_Commit(off_t size);

private:
	friend bool swap_free_page_swap_space(vm_page *page);

	bool	fCanOvercommit;
	bool	fHasPrecommitted;
	uint8	fPrecommittedPages;
	int32	fGuardedSize;
	off_t   fCommittedSwapSize;
	off_t   fAllocatedSwapSize;
};

#endif	// ENABLE_SWAP_SUPPORT

#endif	/* _KERNEL_VM_STORE_ANONYMOUS_H */