Save the output stream buffer. More...

#include <gzipoutputstreambuf.hpp>

Inheritance diagram for zipios::GZIPOutputStreambuf:

Collaboration diagram for zipios::GZIPOutputStreambuf:

Public Member Functions
	GZIPOutputStreambuf (std::streambuf *outbuf, FileEntry::CompressionLevel compression_level)
	Initialize a GZIPOutputStreambuf object. More...

virtual	~GZIPOutputStreambuf () override
	Ensures that the stream gets closed properly. More...

void	close ()
	Close the stream. More...

void	closeStream ()
	Closing the stream. More...

void	finish ()
	Finishes the compression. More...

uint32_t	getCrc32 () const
	Get the CRC32 of the file. More...

size_t	getSize () const
	Retrieve the size of the file deflated. More...

bool	init (FileEntry::CompressionLevel compression_level)
	Initialize the zlib library. More...

void	setComment (std::string const &comment)

void	setFilename (std::string const &filename)

Protected Member Functions
virtual int	overflow (int c=EOF) override
	Handle an overflow. More...

virtual int	sync () override
	Synchronize the buffer. More...

Protected Attributes
std::vector< char >	m_invec

std::streambuf *	m_outbuf

uint32_t	m_overflown_bytes = 0

Private Member Functions
void	writeHeader ()

void	writeInt (uint32_t i)

void	writeTrailer ()

Private Attributes
std::string	m_comment

std::string	m_filename

bool	m_open = false

Detailed Description

This class is used to output the data of a file in a gzip stream including the necessary header and footer.

Definition at line 41 of file gzipoutputstreambuf.hpp.

Constructor & Destructor Documentation

zipios::GZIPOutputStreambuf::GZIPOutputStreambuf	(	std::streambuf *	outbuf,
		FileEntry::CompressionLevel	compression_level
	)

A newly constructed GZIPOutputStreambuf is ready to accept data.

Parameters

[in,out]	outbuf	The streambuf to use for output.
[in]	compression_level	The compression level to use to compress.

Definition at line 54 of file gzipoutputstreambuf.cpp.

References zipios::DeflateOutputStreambuf::init().

zipios::GZIPOutputStreambuf::~GZIPOutputStreambuf ( )

overridevirtual

This function makes sure that the stream gets closed properly which means that the compress terminates by calling finish() and the streams get closed.

Definition at line 71 of file gzipoutputstreambuf.cpp.

References finish().

Member Function Documentation

void zipios::GZIPOutputStreambuf::close ( )

This function ensures that the streams get closed.

Definition at line 93 of file gzipoutputstreambuf.cpp.

References finish().

void zipios::DeflateOutputStreambuf::closeStream ( )

inherited

This function is expected to be called once the stream is getting closed (the buffer is destroyed.)

It ensures that the zlib library last few bytes get flushed and then mark the class as closed.

Note that this function can be called to close the current zlib library stream and start a new one. It is actually called from the putNextEntry() function (via the closeEntry() function.)

Definition at line 205 of file deflateoutputstreambuf.cpp.

References zipios::DeflateOutputStreambuf::endDeflation(), zipios::DeflateOutputStreambuf::m_zs, and zipios::DeflateOutputStreambuf::m_zs_initialized.

Referenced by zipios::ZipOutputStreambuf::closeEntry(), finish(), and zipios::DeflateOutputStreambuf::~DeflateOutputStreambuf().

void zipios::GZIPOutputStreambuf::finish ( )

Write whatever is still necessary and close the streams.

Definition at line 103 of file gzipoutputstreambuf.cpp.

References zipios::DeflateOutputStreambuf::closeStream(), m_open, and writeTrailer().

Referenced by close(), and ~GZIPOutputStreambuf().

uint32_t zipios::DeflateOutputStreambuf::getCrc32 ( ) const

inherited

This function returns the CRC32 for the current file.

The returned value is the CRC for the data that has been compressed already (due to calls to overflow()). As DeflateOutputStreambuf may buffer an arbitrary amount of bytes until closeStream() has been invoked, the returned value is not very useful before closeStream() has been called.

Returns: The CRC32 of the last file that was passed through.

Definition at line 239 of file deflateoutputstreambuf.cpp.

References zipios::DeflateOutputStreambuf::m_crc32.

Referenced by zipios::ZipOutputStreambuf::updateEntryHeaderInfo(), and writeTrailer().

size_t zipios::DeflateOutputStreambuf::getSize ( ) const

inherited

This function returns the number of bytes written to the streambuf object and that were processed from the input buffer by the compressor. After closeStream() has been called this number is the total number of bytes written to the stream. In other words, the size of the uncompressed data.

Returns: The uncompressed size of the file that got written here.

Definition at line 256 of file deflateoutputstreambuf.cpp.

References zipios::DeflateOutputStreambuf::m_overflown_bytes.

Referenced by zipios::ZipOutputStreambuf::updateEntryHeaderInfo(), and writeTrailer().

bool zipios::DeflateOutputStreambuf::init ( FileEntry::CompressionLevel compression_level )

inherited

This method is called in the constructor, so it must not write anything to the output streambuf m_outbuf (see notice in constructor.)

It will initialize the output stream as required to accept data to be compressed using the zlib library. The compression level is expected to come from the FileEntry which is about to be saved in the file.

Returns: true if the initialization succeeded, false otherwise.

Definition at line 106 of file deflateoutputstreambuf.cpp.

References zipios::FileEntry::COMPRESSION_LEVEL_DEFAULT, zipios::FileEntry::COMPRESSION_LEVEL_FASTEST, zipios::FileEntry::COMPRESSION_LEVEL_MAXIMUM, zipios::FileEntry::COMPRESSION_LEVEL_MINIMUM, zipios::FileEntry::COMPRESSION_LEVEL_NONE, zipios::FileEntry::COMPRESSION_LEVEL_SMALLEST, zipios::getBufferSize(), zipios::DeflateOutputStreambuf::m_crc32, zipios::DeflateOutputStreambuf::m_invec, zipios::DeflateOutputStreambuf::m_outvec, zipios::DeflateOutputStreambuf::m_zs, and zipios::DeflateOutputStreambuf::m_zs_initialized.

Referenced by GZIPOutputStreambuf(), and zipios::ZipOutputStreambuf::putNextEntry().

int zipios::GZIPOutputStreambuf::overflow ( int c = EOF )

overrideprotectedvirtual

This function is called by the streambuf implementation whenever "too many bytes" are in the output buffer, ready to be compressed.

Exceptions

IOException This exception is raised whenever the overflow() function calls a zlib library function which returns an error.

Parameters

[in] c The character (byte) that overflowed the buffer.

Returns: Always zero (0).

Reimplemented from zipios::DeflateOutputStreambuf.

Definition at line 116 of file gzipoutputstreambuf.cpp.

References m_open, zipios::DeflateOutputStreambuf::overflow(), and writeHeader().

void zipios::GZIPOutputStreambuf::setComment ( std::string const & comment )

Definition at line 83 of file gzipoutputstreambuf.cpp.

References m_comment.

void zipios::GZIPOutputStreambuf::setFilename ( std::string const & filename )

Definition at line 77 of file gzipoutputstreambuf.cpp.

References m_filename.

int zipios::GZIPOutputStreambuf::sync ( )

overrideprotectedvirtual

The sync() function is expected to clear the input buffer so that any new data read from the input (i.e. a file) are re-read from disk. However, a call to sync() could break the filtering functionality so we do not implement it at all.

This means you are stuck with the existing buffer. But to make sure the system understands that, we always returns -1.

Reimplemented from zipios::DeflateOutputStreambuf.

Definition at line 128 of file gzipoutputstreambuf.cpp.

References zipios::DeflateOutputStreambuf::sync().

void zipios::GZIPOutputStreambuf::writeHeader ( )

private