fairport::data_block Class Reference

A block which represents end user data. More...

#include <node.h>

Inheritance diagram for fairport::data_block:

Collaboration diagram for fairport::data_block:

List of all members.

Public Member Functions
	data_block (const shared_db_ptr &db, const block_info &info, size_t total_size)
	Constructor for a data_block.
virtual	~data_block ()
size_t	read (std::vector< byte > &buffer, ulong offset) const
	Read data from this block.
template<typename T >
T	read (ulong offset) const
	Read data from this block.
virtual size_t	read_raw (byte *pdest_buffer, size_t size, ulong offset) const =0
	Read data from this block.
virtual uint	get_page_count () const =0
	Get the number of physical pages in this data_block.
virtual std::tr1::shared_ptr < external_block >	get_page (uint page_num) const =0
	Get a specific page of this data_block.
size_t	get_total_size () const
	Get the total logical size of this block.
Protected Attributes
size_t	m_total_size
	the total or logical size (sum of all external child blocks)

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Detailed Description

A block which represents end user data.

This class is the base class of both extended_block and external_block. This base class exists to abstract away their differences, so a node can treat a given block (be it extended or external) simply as a stream of bytes.

Definition at line 486 of file node.h.

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Constructor & Destructor Documentation

fairport::data_block::data_block	(	const shared_db_ptr &	db,
		const block_info &	info,
		size_t	total_size
	)		[inline]

Constructor for a data_block.

Parameters:

[in]	db	The database context
[in]	info	Information about this block
[in]	total_size	The total logical size of this block

Definition at line 493 of file node.h.

virtual fairport::data_block::~data_block

(

)

[inline, virtual]

Definition at line 495 of file node.h.

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Member Function Documentation

virtual std::tr1::shared_ptr<external_block> fairport::data_block::get_page

(

uint

page_num

)

const [pure 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

Implemented in fairport::external_block, and fairport::extended_block.

virtual uint fairport::data_block::get_page_count

(

)

const [pure 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

Implemented in fairport::external_block, and fairport::extended_block.

size_t fairport::data_block::get_total_size

(

)

const [inline]

Get the total logical size of this block.

Returns:

The total logical size of this block

Definition at line 535 of file node.h.

size_t fairport::data_block::read	(	std::vector< byte > &	buffer,
		ulong	offset
	)		const [inline]

Read data from this block.

Fills the specified buffer with data starting at the specified offset. The size of the buffer indicates how much data to read.

Parameters:

[in,out]	buffer	The buffer to fill
[in]	offset	The location to read from

Returns:

The amount of data read

Definition at line 895 of file node.h.

template<typename T >

T fairport::data_block::read

(

ulong

offset

)

const [inline]

Read data from this block.

Returns a "T" located as the specified offset

Template Parameters:

T	The type to read

Parameters:

[in]

offset

The location to read from

Returns:

The type read

Definition at line 911 of file node.h.

virtual size_t fairport::data_block::read_raw	(	byte *	pdest_buffer,
		size_t	size,
		ulong	offset
	)		const [pure 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

Implemented in fairport::external_block, and fairport::extended_block.

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Member Data Documentation

size_t fairport::data_block::m_total_size [protected]

the total or logical size (sum of all external child blocks)

Definition at line 538 of file node.h.

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

• fairport/ndb/node.h