Gzipped file stream buffer class. More...

#include "gzfstream.h"

Inheritance diagram for gzfilebuf:

Public Member Functions
	gzfilebuf ()

virtual	~gzfilebuf ()

gzfilebuf *	attach (int fd, std::ios_base::openmode mode)
	Attach to already open gzipped file. More...

gzfilebuf *	close ()
	Close gzipped file. More...

bool	is_open () const
	Check if file is open. More...

gzfilebuf *	open (const char *name, std::ios_base::openmode mode)
	Open gzipped file. More...

int	setcompression (int comp_level, int comp_strategy=Z_DEFAULT_STRATEGY)
	Set compression level and strategy on the fly. More...

Protected Member Functions
bool	open_mode (std::ios_base::openmode mode, char *c_mode) const
	Convert ios open mode int to mode string used by zlib. More...

virtual int_type	overflow (int_type c=traits_type::eof())
	Write put area to gzipped file. More...

virtual int_type	pbackfail (int_type c=traits_type::eof())

virtual pos_type	seekoff (off_type off, std::ios_base::seekdir way, std::ios_base::openmode mode=std::ios_base::in\|std::ios_base::out)
	Alters the stream positions. More...

virtual pos_type	seekpos (pos_type sp, std::ios_base::openmode mode=std::ios_base::in\|std::ios_base::out)
	Alters the stream positions. More...

virtual std::streambuf *	setbuf (char_type *p, std::streamsize n)
	Installs external stream buffer. More...

virtual std::streamsize	showmanyc ()
	Number of characters available in stream buffer. More...

virtual int	sync ()
	Flush stream buffer to file. More...

virtual int_type	underflow ()
	Fill get area from gzipped file. More...

Detailed Description

Gzipped file stream buffer class.

This class implements basic_filebuf for gzipped files. It doesn't yet support seeking (allowed by zlib but slow/limited), putback and read/write access * (tricky). Otherwise, it attempts to be a drop-in replacement for the standard file streambuf.

Definition at line 55 of file gzfstream.h.

Constructor & Destructor Documentation

◆ gzfilebuf()

gzfilebuf::gzfilebuf ( )

Definition at line 59 of file gzfstream.cc.

◆ ~gzfilebuf()

gzfilebuf::~gzfilebuf ( )

virtual

Definition at line 68 of file gzfstream.cc.

References close(), and sync().

Member Function Documentation

◆ attach()

gzfilebuf * gzfilebuf::attach	(	int	fd,
		std::ios_base::openmode	mode
	)

Attach to already open gzipped file.

Parameters

fd	File descriptor.
mode	Open mode flags.

Returns: this on success, NULL on failure.

Definition at line 115 of file gzfstream.cc.

References is_open(), and open_mode().

Referenced by gzifstream::attach(), and gzofstream::attach().

◆ close()

gzfilebuf * gzfilebuf::close ( )

Close gzipped file.

Returns: this on success, NULL on failure.

Definition at line 142 of file gzfstream.cc.

References is_open(), and sync().

Referenced by ~gzfilebuf(), gzifstream::close(), and gzofstream::close().

◆ is_open()

bool gzfilebuf::is_open ( ) const

inline

Check if file is open.

Returns: True if file is open.

Definition at line 86 of file gzfstream.h.

Referenced by attach(), close(), gzifstream::is_open(), gzofstream::is_open(), open(), overflow(), pbackfail(), seekoff(), seekpos(), showmanyc(), and underflow().

◆ open()

gzfilebuf * gzfilebuf::open	(	const char *	name,
		std::ios_base::openmode	mode
	)

Open gzipped file.

Parameters

name	Filename.
mode	Open mode flags.

Returns: this on success, NULL on failure.

Definition at line 88 of file gzfstream.cc.

References is_open(), and open_mode().

Referenced by gzifstream::open(), and gzofstream::open().

◆ open_mode()

bool gzfilebuf::open_mode	(	std::ios_base::openmode	mode,
		char *	c_mode
	)		const

protected

Convert ios open mode int to mode string used by zlib.

Returns: True if valid mode flag combination.

Definition at line 166 of file gzfstream.cc.

References strlen(), and trunc().

Referenced by attach(), and open().

◆ overflow()

gzfilebuf::int_type gzfilebuf::overflow ( int_type c = traits_type::eof () )

protectedvirtual

Write put area to gzipped file.

Parameters

c	Extra character to add to buffer contents.

Returns: Non-EOF on success, EOF on error.

This actually writes characters in stream buffer to gzipped file. With unbuffered output this is done one character at a time.

Definition at line 303 of file gzfstream.cc.

References is_open().

Referenced by seekoff(), seekpos(), and sync().

◆ pbackfail()

gzfilebuf::int_type gzfilebuf::pbackfail ( int_type c = traits_type::eof () )

protectedvirtual

Definition at line 222 of file gzfstream.cc.

References is_open(), and SEEK_CUR.

◆ seekoff()

gzfilebuf::pos_type gzfilebuf::seekoff	(	off_type	off,
		std::ios_base::seekdir	way,
		std::ios_base::openmode	mode = `std::ios_base::in \| std::ios_base::out`
	)

protectedvirtual

Alters the stream positions.

Each derived class provides its own appropriate behavior.

Definition at line 467 of file gzfstream.cc.

References is_open(), overflow(), SEEK_CUR, SEEK_END, and SEEK_SET.

◆ seekpos()

gzfilebuf::pos_type gzfilebuf::seekpos	(	pos_type	sp,
		std::ios_base::openmode	mode = `std::ios_base::in \| std::ios_base::out`
	)

protectedvirtual

Alters the stream positions.

Each derived class provides its own appropriate behavior.

Definition at line 504 of file gzfstream.cc.

References is_open(), overflow(), and SEEK_SET.

◆ setbuf()

std::streambuf * gzfilebuf::setbuf	(	char_type *	p,
		std::streamsize	n
	)

protectedvirtual

Installs external stream buffer.

Parameters

p	Pointer to char buffer.
n	Size of external buffer.

Returns: this on success, NULL on failure.

Call setbuf(0,0) to enable unbuffered output.

Definition at line 356 of file gzfstream.cc.

References n, and sync().

◆ setcompression()

int gzfilebuf::setcompression	(	int	comp_level,
		int	comp_strategy = `Z_DEFAULT_STRATEGY`
	)

Set compression level and strategy on the fly.

Parameters

comp_level	Compression level (see zlib.h for allowed values)
comp_strategy	Compression strategy (see zlib.h for allowed values)

Returns: Z_OK on success, Z_STREAM_ERROR otherwise.

Unfortunately, these parameters cannot be modified separately, as the previous zfstream version assumed. Since the strategy is seldom changed, it can default and setcompression(level) then becomes like the old setcompressionlevel(level).

Definition at line 81 of file gzfstream.cc.

◆ showmanyc()

std::streamsize gzfilebuf::showmanyc ( )

protectedvirtual

Number of characters available in stream buffer.

Returns: Number of characters.

This indicates number of characters in get area of stream buffer. These characters can be read without accessing the gzipped file.

Definition at line 205 of file gzfstream.cc.

References is_open().

◆ sync()

int gzfilebuf::sync ( )

protectedvirtual

Flush stream buffer to file.

Returns: 0 on success, -1 on error.

This calls underflow(EOF) to do the job.

Definition at line 389 of file gzfstream.cc.

References overflow().

Referenced by ~gzfilebuf(), close(), and setbuf().

◆ underflow()

gzfilebuf::int_type gzfilebuf::underflow ( )

protectedvirtual

Fill get area from gzipped file.

Returns: First character in get area on success, EOF on error.

This actually reads characters from gzipped file to stream buffer. Always buffered.

Definition at line 260 of file gzfstream.cc.

References is_open(), and STASHED_CHARACTERS.

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

libinterp/corefcn/gzfstream.h
libinterp/corefcn/gzfstream.cc

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ gzfilebuf()

◆ ~gzfilebuf()

Member Function Documentation

◆ attach()

◆ close()

◆ is_open()

◆ open()

◆ open_mode()

◆ overflow()

◆ pbackfail()

◆ seekoff()

◆ seekpos()

◆ setbuf()

◆ setcompression()

◆ showmanyc()

◆ sync()

◆ underflow()