zipios::InflateInputStreambuf Class Reference

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 (InflateInputStreambuf const &rhs)=delete
	InflateInputStreambuf (std::streambuf *inbuf, offset_t s_pos=-1)
	Initialize a InflateInputStreambuf.
virtual	~InflateInputStreambuf ()
	Clean up the InflateInputStreambuf object.
InflateInputStreambuf &	operator= (InflateInputStreambuf const &rhs)=delete
bool	reset (offset_t stream_position=-1)
	Initializes the stream buffer.

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

Protected Attributes
std::streambuf *	m_inbuf = nullptr
std::vector< char >	m_outvec = std::vector<char>()

Private Attributes
std::vector< char >	m_invec = std::vector<char>()
z_stream	m_zs = z_stream()
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

InflateInputStreambuf() [1/2]

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 reset().

InflateInputStreambuf() [2/2]

zipios::InflateInputStreambuf::InflateInputStreambuf ( InflateInputStreambuf const &  rhs )

delete

~InflateInputStreambuf()

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 92 of file inflateinputstreambuf.cpp.

References m_zs.

Member Function Documentation

operator=()

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

delete

reset()

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 207 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().

underflow()

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. For now we throw. 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 123 of file inflateinputstreambuf.cpp.

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

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

Member Data Documentation

m_inbuf

std::streambuf* zipios::FilterInputStreambuf::m_inbuf = nullptr

protectedinherited

Definition at line 47 of file filterinputstreambuf.hpp.

Referenced by zipios::FilterInputStreambuf::FilterInputStreambuf(), zipios::ZipInputStreambuf::ZipInputStreambuf(), reset(), underflow(), and zipios::ZipInputStreambuf::underflow().

m_invec

std::vector<char> zipios::InflateInputStreambuf::m_invec = std::vector<char>()

private

Definition at line 66 of file inflateinputstreambuf.hpp.

Referenced by reset(), and underflow().

m_outvec

std::vector<char> zipios::InflateInputStreambuf::m_outvec = std::vector<char>()

protected

Todo:

Consider design?

Definition at line 63 of file inflateinputstreambuf.hpp.

Referenced by zipios::ZipInputStreambuf::ZipInputStreambuf(), reset(), underflow(), and zipios::ZipInputStreambuf::underflow().

m_zs

z_stream zipios::InflateInputStreambuf::m_zs = z_stream()

private

Definition at line 68 of file inflateinputstreambuf.hpp.

Referenced by ~InflateInputStreambuf(), reset(), and underflow().

m_zs_initialized

bool zipios::InflateInputStreambuf::m_zs_initialized = false

private

Definition at line 69 of file inflateinputstreambuf.hpp.

Referenced by reset().

---

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

• inflateinputstreambuf.hpp
• inflateinputstreambuf.cpp