YGP::extStreambuf Class Reference

Extended streambuf, designed to parse text. More...

Inherited by YGP::extStream< std::ifstream > [private], and YGP::extStream< T > [private].

List of all members.

Public Member Functions
	extStreambuf ()
	extStreambuf (std::streambuf &source)
	extStreambuf (std::streambuf *source)
virtual	~extStreambuf ()
Exception-handling
virtual int	overflow (int ch)
virtual int	underflow ()
virtual int	pbackfail (int c)
Position handling
virtual std::streampos	seekoff (std::streamoff, std::ios_base::seekdir, std::ios_base::openmode mode=std::ios::in|std::ios::out)
virtual std::streampos	seekpos (std::streampos pos, std::ios_base::openmode mode=std::ios::in|std::ios::out)
Setting of data-sink
void	setSource (std::streambuf *source)
void	setSource (std::streambuf &source)
Accessing stream values
unsigned int	getLine () const
unsigned int	getColumn () const

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Detailed Description

Extended streambuf, designed to parse text.

It overcomes two drawbacks of the original streambuf:

• Column and line information (which - to be fair - wouldn't make very much sense in the common streambuf anyway)
• A variable-sized putback-buffer. The common streambuf only stores one block (and a few bytes from the last), so a pushback beyond this border is not possible.

Note:

This buffer only works for input and needs a "real" data-sink as source, so provide another streambuf-object to get its data from with the constructor or with the setSource-method!

Also note that after repositionating in the stream (with seekoff/seekpos) the line-information might not reflect the truth anymore (and also not the column, at least til the next end-of-line is reached).

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Constructor & Destructor Documentation

YGP::extStreambuf::extStreambuf

(

)

Defaultconstructor; Although reading from this object should work and should also return some "random" data, to provide a "real" data-sink is highly recommended.

This method might be declared private (or at least protected) in the future.

YGP::extStreambuf::extStreambuf

(

std::streambuf &

source

)

Constructur; creates an extended streambuf which takes its input from the provided source.

Parameters:

source

Actual datasink to use

YGP::extStreambuf::extStreambuf

(

std::streambuf *

source

)

Constructur; creates an extended streambuf which takes its input from the provided source.

Parameters:

source

Actual datasink to use

YGP::extStreambuf::~extStreambuf

(

)

[virtual]

Destructor.

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Member Function Documentation

unsigned int YGP::extStreambuf::getColumn

(

)

const [inline]

Returns the actual column of the stream read from.

Reimplemented in YGP::extStream< T >, and YGP::extStream< std::ifstream >.

unsigned int YGP::extStreambuf::getLine

(

)

const [inline]

Returns the actual line of the stream read from.

Reimplemented in YGP::extStream< T >, and YGP::extStream< std::ifstream >.

int YGP::extStreambuf::overflow

(

int

ch

)

[virtual]

Called if output would cause the streambuf to overrun.

Because this class is designed for input, this method shouldn't be called.

Parameters:

ch

Char to write, causing the overflow

Returns:

int EOF in case of error

int YGP::extStreambuf::pbackfail

(

int

c

)

[virtual]

Manages the failure of a pushback of a character into the stream.

There are two reasons why this method could be called while pushing back characters:

• A character is pushed back which doesn't fit the read character. This is propably due to a programming failure and the pushback is not performed. For the sake of performance this the class ignores that case.
• A buffer underrun; caused by pushing characters back into the previous line (and - depending on the implementation of streambuf - maybe a few characters more). In this read-position of the data-sink is changed to the end of the previous line.

  Parameters:

  c

  Character to put back (not EOF)

  Returns:

  int Character putted back (EOF if an error occured)

  Remarks:

  For the sake of performance the check if the character pushed back matches the character in the stream is not performed (but the next read-operation returns the "right" character)!

std::streampos YGP::extStreambuf::seekoff	(	std::streamoff	off,
		std::ios_base::seekdir	dir,
		std::ios_base::openmode	mode = std::ios::in|std::ios::out
	)			[virtual]

Positionates the read pointer to the passed offset (either starting from the beginning or the end of the stream or from the current position).

Parameters:

	off	Offset to change in the stream
	dir	Direction to change offset to
	mode	Which pointer to move (get, put)

Returns:

std::streampos New position in the stream

std::streampos YGP::extStreambuf::seekpos	(	std::streampos	pos,
		std::ios_base::openmode	mode = std::ios::in|std::ios::out
	)			[virtual]

Positionates the read pointer to the passed position.

Parameters:

	pos	New position in the stream
	mode	Which pointer to move (get, put)

Returns:

std::streampos New position in the stream

void YGP::extStreambuf::setSource

(

std::streambuf &

source

)

[inline]

Sets the data sink to read from.

void YGP::extStreambuf::setSource

(

std::streambuf *

source

)

[inline]

Sets the data sink to read from.

int YGP::extStreambuf::underflow

(

)

[virtual]

Called if the object doesn't contain data in the input-buffer.

It then copies characters from its data-sink (the streambuf passed while constructing or defined with setSource) til the next line-feed character (10, 0x0a, '
') and sets this data as its input. This method is called automatically and should NOT be used. It also might be declared protected in the future.

Returns:

int EOF in case of an error, else 0

Precondition:

Readpointer equal or behind end-of-readbuffer

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

• XStrBuf.h
• XStrBuf.cpp