#include <Pt/ZBuffer.h>

Stream buffer that inflates on read and deflates on write. More...

Public Types
enum	Format { Zlib = 0 , Gzip }
	Compression/decompression format. More...

Public Member Functions
	ZBuffer (Format fmt=Zlib)
	Default Constructor.
	ZBuffer (std::ios &ios, Format fmt=Zlib)
	Construct with target stream.
virtual	~ZBuffer ()
	Destructor.
void	attach (std::ios &target)
	Attach to target stream.
void	detach ()
	Detach from target stream.
void	discard ()
	Discards the buffer content and resets the state.
void	reset ()
	Detach from target stream, discard the buffer and reset the state.
void	reset (std::ios &target)
	Attach to target stream, discard the buffer and reset the state.
void	finish ()
	Finish and flush remaining data to the target stream.
std::size_t	zcount () const
	Returns the total number of decompressed bytes produced so far.
std::streamsize	import (std::streamsize maxImport=0)
	Import data from the target stream.
std::streamsize	speekn (char *buffer, std::streamsize size)
	Peeks characters in the stream buffer.
std::streamsize	out_avail ()
	Returns the number of characters buffered for output.

Protected Member Functions
virtual std::streamsize	showfull ()
	Returns the number of characters buffered for output.

Detailed Description

ZBuffer is the buffer in the Zlib Streams model. It is a BasicStreamBuffer of char attached to a target std::ios. Reading inflates compressed bytes from the target. Writing deflates uncompressed bytes into the target.

Format selects zlib or gzip wrapping at construction and must match the target data. attach() sets the target. detach() drops it without finishing a frame. reset() discards buffered data and begins a new zlib stream, optionally with a new target. discard() resets the state and keeps the target. finish() flushes remaining compressed bytes and ends the stream.

zcount() is the total number of uncompressed bytes produced by inflate. The buffer does not own the target; keep the target alive until detach() or destruction.

Member Enumeration Documentation

◆ Format

enum Format

Enumerator
Zlib	zlib header/trailer with Adler-32 checksum.
Gzip	gzip header/trailer with CRC-32 checksum (RFC 1952).

Member Function Documentation

◆ import()

std::streamsize import ( std::streamsize maxImport = 0 )

Returns the number of bytes consumed from the underlyig stream.

◆ speekn()

std::streamsize speekn	(	char *	buffer,
		std::streamsize	size )

inherited

The number of characters that can be peeked depends on the current get area and may be less than requested, similar to istream::readsome(). The characters are not consumed.

Public Types