A stream buffer to inflate data previous compressed with zlib. More...

#include <inflateinputstreambuf.hpp>

Inheritance diagram for zipios::InflateInputStreambuf:

Collaboration diagram for zipios::InflateInputStreambuf:

Public Member Functions
	InflateInputStreambuf (std::streambuf *inbuf, offset_t s_pos=-1)
	Initialize a InflateInputStreambuf. More...

	InflateInputStreambuf (InflateInputStreambuf const &src)=delete

virtual	~InflateInputStreambuf ()
	Clean up the InflateInputStreambuf object. More...

InflateInputStreambuf &	operator= (InflateInputStreambuf const &src)=delete

bool	reset (offset_t stream_position=-1)
	Initializes the stream buffer. More...

Protected Member Functions
virtual std::streambuf::int_type	underflow () override
	Called when more data is required. More...

Protected Attributes
std::streambuf *	m_inbuf

std::vector< char >	m_outvec

Private Attributes
std::vector< char >	m_invec

z_stream	m_zs

bool	m_zs_initialized = false

Detailed Description

The InflateInputStreambuf class is an input stream filter, that inflates the input from the attached input stream.

Deflation/Inflation is a compression/decompression method used in gzip and zip. The zlib library is used to perform the actual inflation, this class only wraps the functionality in an input stream filter.

Todo:: Add support for bzip2, lzma compressions.

Definition at line 47 of file inflateinputstreambuf.hpp.

Constructor & Destructor Documentation

zipios::InflateInputStreambuf::InflateInputStreambuf	(	std::streambuf *	inbuf,
		offset_t	start_pos = `-1`
	)

The constructor initializes the various stream buffers and setup the stream start position using the start_pos parameter.

Data will be inflated (decompressed using zlib) before being returned.

Parameters

[in,out]	inbuf	The streambuf to use for input.
[in]	start_pos	A position to reset the inbuf to before reading. Specify -1 to not change the position.

Definition at line 70 of file inflateinputstreambuf.cpp.

References m_zs, and reset().

zipios::InflateInputStreambuf::InflateInputStreambuf ( InflateInputStreambuf const & src )

delete

zipios::InflateInputStreambuf::~InflateInputStreambuf ( )

virtual

The destructor makes sure all allocated resources get cleaned up.

Todo:: Write an error callback interface and call that instead of using std::cerr...

Definition at line 99 of file inflateinputstreambuf.cpp.

References m_zs.

Member Function Documentation

InflateInputStreambuf& zipios::InflateInputStreambuf::operator= ( InflateInputStreambuf const & src )

delete

bool zipios::InflateInputStreambuf::reset ( offset_t stream_position = -1 )

This function resets the zlib stream and purges input and output buffers. It also repositions the input streambuf at stream_position.

Warning: This method is called in the constructor, so it must not read anything from the input streambuf m_inbuf (see notice in constructor.)

Parameters

[in] stream_position A position to reset the inbuf to before reading. Specify -1 to read from the current position.

See Also: InflateInputStreambuf()

Definition at line 215 of file inflateinputstreambuf.cpp.

References zipios::getBufferSize(), zipios::FilterInputStreambuf::m_inbuf, m_invec, m_outvec, m_zs, and m_zs_initialized.

Referenced by InflateInputStreambuf(), and zipios::ZipInputStreambuf::ZipInputStreambuf().

std::streambuf::int_type zipios::InflateInputStreambuf::underflow ( )

overrideprotectedvirtual

The function ensures that at least one byte is available in the input area by updating the pointers to the input area and reading more data in from the input sequence if required.

This function actually passes the data through the zlib library to decompress it.

Returns: The value of that character on success or std::streambuf::traits_type::eof() on failure.

Todo:: Add I/O error handling while inflating data from a file.

Todo:: Look at the error returned from inflate here, if there is some way to report it to the InflateInputStreambuf user. Until I find out I'll just print a warning to stdout. This at least throws, we probably want to create a log mechanism that the end user can connect to with a callback.

Reimplemented in zipios::ZipInputStreambuf.

Definition at line 130 of file inflateinputstreambuf.cpp.

References zipios::getBufferSize(), zipios::FilterInputStreambuf::m_inbuf, m_invec, m_outvec, and m_zs.

Referenced by zipios::ZipInputStreambuf::underflow().