fairport::extended_block Class Reference

A data block which refers to other data blocks, in order to extend the physical size limit (8k) to a larger logical size. More...

#include <node.h>

Inheritance diagram for fairport::extended_block:

Collaboration diagram for fairport::extended_block:

List of all members.

Public Member Functions
	extended_block (const shared_db_ptr &db, const block_info &info, ushort level, size_t total_size, size_t child_max_total_size, ulong page_max_count, ulong child_page_max_count, std::vector< block_id > bi)
	Construct an extended_block from disk.
size_t	read_raw (byte *pdest_buffer, size_t size, ulong offset) const
	Read data from this block.
uint	get_page_count () const
	Get the number of physical pages in this data_block.
std::tr1::shared_ptr < external_block >	get_page (uint page_num) const
	Get a specific page of this data_block.
ushort	get_level () const
	Get the "level" of this extended_block.
bool	is_internal () const
	Returns the blocks internal/external state.

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Detailed Description

A data block which refers to other data blocks, in order to extend the physical size limit (8k) to a larger logical size.

An extended_block is essentially a list of block_ids of other data_block, which themselves may be an extended_block or an external_block. Ultimately they form a "data tree", the leafs of which form the "logical" contents of the block.

This class is an in memory representation of the disk::extended_block structure.

See also:

[MS-PST] 2.2.2.8.3.2

Definition at line 553 of file node.h.

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Constructor & Destructor Documentation

fairport::extended_block::extended_block	(	const shared_db_ptr &	db,
		const block_info &	info,
		ushort	level,
		size_t	total_size,
		size_t	child_max_total_size,
		ulong	page_max_count,
		ulong	child_page_max_count,
		std::vector< block_id >	bi
	)		[inline]

Construct an extended_block from disk.

Parameters:

[in]	db	The database context
[in]	info	Information about this block
[in]	level	The level of this extended block (1 or 2)
[in]	total_size	The total logical size of this block
[in]	child_max_total_size	The maximum logical size of a child block
[in]	page_max_count	The maximum number of external blocks that can be contained in this block
[in]	child_page_max_count	The maximum number of external blocks that can be contained in a child block
[in]	bi	The block_info for all child blocks

Definition at line 568 of file node.h.

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Member Function Documentation

ushort fairport::extended_block::get_level

(

)

const [inline]

Get the "level" of this extended_block.

A level 1 extended_block (or "xblock") points to external blocks. A level 2 extended_block (or "xxblock") points to other extended_blocks

Returns:

1 for an xblock, 2 for an xxblock

Definition at line 585 of file node.h.

std::tr1::shared_ptr< fairport::external_block > fairport::extended_block::get_page

(

uint

page_num

)

const [inline, virtual]

Get a specific page of this data_block.

Note:

In this context, "page" refers to an external_block

Exceptions:

out_of_range

If page_num >= get_page_count()

Parameters:

[in]

page_num

The ordinal of the external_block to get, zero based

Returns:

The requested external_block

Implements fairport::data_block.

Definition at line 947 of file node.h.

fairport::uint fairport::extended_block::get_page_count

(

)

const [inline, virtual]

Get the number of physical pages in this data_block.

Note:

In this context, "page" refers to an external_block

Returns:

The total number of external_blocks under this data_block

Implements fairport::data_block.

Definition at line 924 of file node.h.

bool fairport::extended_block::is_internal

(

)

const [inline, virtual]

Returns the blocks internal/external state.

Returns:

true if this is an internal block, false otherwise

Implements fairport::block.

Definition at line 586 of file node.h.

size_t fairport::extended_block::read_raw	(	byte *	pdest_buffer,
		size_t	size,
		ulong	offset
	)		const [inline, virtual]

Read data from this block.

Parameters:

[out]	pdest_buffer	The location to read the data into
[in]	size	The amount of data to read
[in]	offset	The location to read from

Returns:

The amount of data read

Implements fairport::data_block.

Definition at line 975 of file node.h.

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

• fairport/ndb/node.h