drwnCompressionBuffer Class Reference

Utility class for compressing data using the zlib library. More...

Public Member Functions
unsigned int	originalBytes () const
	number of uncompressed bytes
unsigned int	compressedBytes () const
	number of compressed bytes
void	compress (const unsigned char *data, unsigned int size)
	compress size bytes of data into buffer
void	decompress (unsigned char *data) const
	decompress buffer into data
size_t	numBytesOnDisk () const
	number of bytes required to store buffer contents on disk
bool	write (ostream &os) const
	write compression buffer to output stream
bool	read (istream &is)
	read compression buffer from input stream
drwnCompressionBuffer	clone () const
	clone the buffer
void	free ()
	free all memory associated with the buffer

Protected Attributes
unsigned char *	_data
unsigned int	_bytesAllocated
unsigned int	_bytesOriginal
unsigned int	_bytesCompressed

Detailed Description

Utility class for compressing data using the zlib library.

The class holds compressed data. Copying the buffer does not copy the data (i.e., a shallow copy is performed). To copy the data use the clone member function. When decompressing data enough space must be allocated in output buffer. The following code snippet shows example usage:

// compress a string
string inputStr = getStringToCompress();
drwnCompressionBuffer buffer;
buffer.compress((unsigned char *)inputStr.c_str(), inputStr.size());

DRWN_LOG_MESSAGE("compressed " << buffer.originalBytes() << " bytes to " 
    << buffer.compressedBytes() << " bytes");

// decompress a string
string recoveredStr;
recoveredStr.resize(buffer.originalBytes());
buffer.decompress((unsigned char *)&recoveredStr[0]);

Warning

This class will simply copy data without compressing if compiled without DRWN_HAS_ZLIB defined.

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

• drwnCompressionBuffer.h
• drwnCompressionBuffer.cpp