SpecialRow Class Reference

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Detailed Description

Abstract class that represents an Special Row.

A Special Row is a row (or column) stored to be used in the further stages. This class permit that subclasses store the special row in any possible area (e.g.: disk, memory, database, etc.).

Definition at line 41 of file SpecialRow.hpp.

#include <SpecialRow.hpp>

Inheritance diagram for SpecialRow:

List of all members.

Public Member Functions
	SpecialRow ()
	Default Constructor.
virtual	~SpecialRow ()
	Default Destructor.
void	open (bool readOnly, int length=0)
	Opens the special rows for read-only or write-only.
virtual int	write (const cell_t *buf, int len)
	Writes data in the row serially.
virtual int	read (cell_t *buf, int len)
	Reads data from the row serially.
virtual int	getType ()
void	seek (int offset)
	Defines the next position to be read.
int	getOffset ()
	Returns the current reading position.
int	getId ()
	Returns the ID of the row.
virtual void	close ()=0
	Closes the special row for writing.
virtual void	truncateRow (int size)=0
	Truncate the size of the row.
Static Public Member Functions
static int	sortById (SpecialRow *a, SpecialRow *b)
	Function that sorts the special rows by ID.
Protected Member Functions
void	setId (int id)
	Defines the ID of the row, i.e., the number of the row it represents.
Private Member Functions
virtual void	initialize (bool readOnly, int length=0)=0
	Initializes the row with specific data.
virtual int	write (const cell_t *buf, int offset, int len)=0
	Stores the vector in a given offset.
virtual int	read (cell_t *buf, int offset, int len)=0
	Stores the vector in a given offset.
Private Attributes
int	id
	The number of the row that this object represents.
int	offset
	Current reading position.
bool	readOnly
	Indicates if the row is in reading or writing mode.

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Constructor & Destructor Documentation

SpecialRow::SpecialRow

(

)

Default Constructor.

Definition at line 29 of file SpecialRow.cpp.

SpecialRow::~SpecialRow

(

)

[virtual]

Default Destructor.

Definition at line 36 of file SpecialRow.cpp.

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Member Function Documentation

virtual void SpecialRow::close

(

)

[pure virtual]

Closes the special row for writing.

Implements CellsWriter.

Implemented in SpecialRowFile, FirstRow, and SpecialRowRAM.

int SpecialRow::getId

(

)

Returns the ID of the row.

Returns:

the number of the row (i-coordinate).

Definition at line 62 of file SpecialRow.cpp.

int SpecialRow::getOffset

(

)

[virtual]

Returns the current reading position.

Returns:

the index of the next cell to be read.

Implements SeekableCellsReader.

Definition at line 92 of file SpecialRow.cpp.

int SpecialRow::getType

(

)

[virtual]

Implements CellsReader.

Definition at line 48 of file SpecialRow.cpp.

virtual void SpecialRow::initialize	(	bool	readOnly,
		int	length = 0
	)		[private, pure virtual]

Initializes the row with specific data.

Parameters:

readOnly	if true, indicates that the row will be used only for read access. Otherwise, the row will only be used for write access. Each subclass must implement this method with specific code.
length	the maximum length of this row. The subclass may consider this as the initial size, for faster allocation.

Implemented in FirstRow, SpecialRowFile, and SpecialRowRAM.

void SpecialRow::open	(	bool	readOnly,
		int	length = 0
	)

Opens the special rows for read-only or write-only.

Parameters:

readOnly	if true, indicates that the row will be used only for read access. Otherwise, the row will only be used for write access.
length	the maximum length of this row.

Definition at line 43 of file SpecialRow.cpp.

int SpecialRow::read	(	cell_t *	buf,
		int	len
	)		[virtual]

Reads data from the row serially.

The read access is done in the reverse direction, from the end to the beginning. Before reading, the SpecialRow::setOffset must defines the start position to be read.

Parameters:

buf	vector that will receive the cells read from the row.
len	length of the vector.

Returns:

The number of cells read.

Implements CellsReader.

Definition at line 119 of file SpecialRow.cpp.

virtual int SpecialRow::read	(	cell_t *	buf,
		int	offset,
		int	len
	)		[private, pure virtual]

Stores the vector in a given offset.

It is guaranteed that the offset is serially decremented. Each subclass must implement this method with specific code.

Parameters:

buf	vector containing the cells to be read. The data read will be stored in the first byte of this vector.
offset	the position that the data must be read.
len	length of the vector.

Returns:

The number of cells read.

Implemented in FirstRow, SpecialRowFile, and SpecialRowRAM.

void SpecialRow::seek

(

int

offset

)

[virtual]

Defines the next position to be read.

Parameters:

offset

The reading position.

Implements SeekableCellsReader.

Definition at line 81 of file SpecialRow.cpp.

void SpecialRow::setId

(

int

id

)

[protected]

Defines the ID of the row, i.e., the number of the row it represents.

Parameters:

id	the number of the row (i-coordinate).

Definition at line 55 of file SpecialRow.cpp.

int SpecialRow::sortById	(	SpecialRow *	a,
		SpecialRow *	b
	)		[static]

Function that sorts the special rows by ID.

Definition at line 69 of file SpecialRow.cpp.

virtual void SpecialRow::truncateRow

(

int

size

)

[pure virtual]

Truncate the size of the row.

If the size is zero, the row must be completely deleted. Each subclass must implement this method with specific code.

Parameters:

size	the number of cells to keep after truncation.

Implemented in SpecialRowFile, FirstRow, and SpecialRowRAM.

int SpecialRow::write	(	const cell_t *	buf,
		int	len
	)		[virtual]

Writes data in the row serially.

Parameters:

buf	vector containing the cells to be appended to the row.
len	length of the vector.

Returns:

The number of cells written.

Implements CellsWriter.

Definition at line 99 of file SpecialRow.cpp.

virtual int SpecialRow::write	(	const cell_t *	buf,
		int	offset,
		int	len
	)		[private, pure virtual]

Stores the vector in a given offset.

It is guaranteed that the offset is serially incremented. Each subclass must implement this method with specific code.

Parameters:

buf	vector containing the cells to be saved.
offset	the position that the vector must be stored.
len	length of the vector.

Returns:

The number of cells stored.

Implemented in FirstRow, SpecialRowFile, and SpecialRowRAM.

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Member Data Documentation

int SpecialRow::id [private]

The number of the row that this object represents.

Definition at line 134 of file SpecialRow.hpp.

int SpecialRow::offset [private]

Current reading position.

Definition at line 137 of file SpecialRow.hpp.

bool SpecialRow::readOnly [private]

Indicates if the row is in reading or writing mode.

Definition at line 140 of file SpecialRow.hpp.

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

• SpecialRow.hpp
• SpecialRow.cpp