BufferMap Class Reference

#include <bufmgr.h>

Public Member Functions
	BufferMap ()
	Constructor for BufferMap.
	~BufferMap ()
	Destructor for BufferMap.
FrameId	get (PageId page_id)
	Returns FrameId corresponding to the given PageId. More...
bool	contains (PageId page_id)
	Returns true if the map contains the given PageId, else false. More...
void	insert (PageId page_id, FrameId frame_id)
	Inserts the pair <page_id, frame_id> into the map. More...
void	remove (PageId page_id)
	Removes the key-value pair corresponding to the given PageId from the map. More...

Private Attributes
std::unordered_map< PageId, FrameId, BufHash >	buf_map

Detailed Description

BufferMap is a wrapper class for std::unordered_map<PageId, FrameId> that maps PageIds to a Frame index in the buffer pool. Has different method names from std::unordered_map. Have get(), contains(), insert(), and remove() methods.

Member Function Documentation

contains()

bool BufferMap::contains

(

PageId

page_id

)

Returns true if the map contains the given PageId, else false.

Precondition

A lock is held on the map. A PageId is provided.

Postcondition

Returns true if the map contains the PageId, else false. Lock is still held on the map.

Parameters

page_id

A PageId to be searched in the map.

Returns

bool indicating whether the given PageId exists in the BufferMap.

get()

FrameId BufferMap::get

(

PageId

page_id

)

Returns FrameId corresponding to the given PageId.

Precondition

A lock is held on the map. This map contains the given PageId.

Postcondition

Returns the corresponding FrameId. Lock is still held on the map.

Parameters

page_id

A PageId for which the corresponding FrameId will be returned.

Returns

FrameId which correspond to the given PageId.

Exceptions

PageNotFoundBufMgr

if the given PageId is not in the map.

insert()

void BufferMap::insert	(	PageId	page_id,
		FrameId	frame_id
	)

Inserts the pair <page_id, frame_id> into the map.

Precondition

A lock is held on the map. A PageId and FrameId are provided as input.

Postcondition

Adds a new <PageId, FrameId> pair to the map. If the map contains page_id, then it throws an exception. Lock is still held on the map.

Parameters

page_id	A PageId key.
frame_id	A FrameId value.

Exceptions

throw

PageAlreadyLoadedBufMgr if a page with this PageId is already in the Buffer Pool

remove()

void BufferMap::remove

(

PageId

page_id

)

Removes the key-value pair corresponding to the given PageId from the map.

Precondition

A lock is held on the map. The given PageId is in the map.

Postcondition

The key-value pair searched by page_id is removed from the map.

Parameters

page_id

The PageId key for the key-value pair to be removed.

Exceptions

PageIdNotFoundBufMgr

If page_id is not in the map.

Member Data Documentation

buf_map

std::unordered_map<PageId,FrameId,BufHash> BufferMap::buf_map

private

The underlying std::unordered_map for storing the map information

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The documentation for this class was generated from the following file:

• bufmgr.h