PageFreeList

The list of free pages of a page store. The format of a free list trunk page is:

• page type: byte (0)
• checksum: short (1-2)
• data (3-)

Methods
static PageFreeList	create(PageStore store, int pageId) Create a new free-list page.
static PageFreeList	create(PageStore store, int pageId) Create a new free-list page. Parameters: store - the page store pageId - the page id Returns: the page
static int	getPagesAddressed(int pageSize) Get the number of pages that can fit in a free list.
static int	getPagesAddressed(int pageSize) Get the number of pages that can fit in a free list. Parameters: pageSize - the page size Returns: the number of pages
static PageFreeList	read(PageStore store, Data data, int pageId) Read a free-list page.
static PageFreeList	read(PageStore store, Data data, int pageId) Read a free-list page. Parameters: store - the page store data - the data pageId - the page id Returns: the page
int	allocate(BitField exclude, int first) Allocate a page from the free list.
int	allocate(BitField exclude, int first) Allocate a page from the free list. Parameters: exclude - the exclude list or null first - the first page to look for Returns: the page, or -1 if all pages are used
void	allocate(int pageId) Mark a page as used.
void	allocate(int pageId) Mark a page as used. Parameters: pageId - the page id
boolean	canMove()
boolean	canMove()
boolean	canRemove()
boolean	canRemove()
void	free(int pageId) Add a page to the free list.
void	free(int pageId) Add a page to the free list. Parameters: pageId - the page id to add
int	getFirstFree(int first) Get the first free page starting at the given offset.
int	getFirstFree(int first) Get the first free page starting at the given offset. Parameters: first - the page number to start the search Returns: the page number, or -1
int	getLastUsed()
int	getLastUsed()
int	getMemory() Get the estimated memory size.
int	getMemory() Get the estimated memory size. Returns: number of double words (4 bytes)
boolean	isUsed(int pageId) Check if a page is already in use.
boolean	isUsed(int pageId) Check if a page is already in use. Parameters: pageId - the page to check Returns: true if it is in use
void	moveTo(Session session, int newPos)
void	moveTo(Session session, int newPos)
String	toString()
String	toString()
void	write()
void	write()