Octane v1.01.20 - The Open Compression Toolkit for C++

http://octane.sourceforge.net/

SampleCompressor Class Reference
[Compressors]

#include <samplecompressor.hpp>

Inheritance diagram for SampleCompressor:

List of all members.

---

Detailed Description

This Sample Statistical Compressor is a minimal example of how to coordinate the 3 components of the statistical compressor framework, a sample parser,modeler,and coder.

Definition at line 34 of file samplecompressor.hpp.

Public Member Functions
	SampleCompressor (bool registerme=false)
	constructor
	~SampleCompressor ()
	destructor
virtual std::string	GetClassName ()
	Get the assigned name of an instantiated compressor.
virtual std::string	GetDescription ()
	optionally provide a longer (maybe 20-60 characters) description
virtual OctaneCompressor *	MakeCompressorInstantiation ()
	Instantiate a compressor from this class (like a factory).
virtual void	ShowDebuggingInfo ()
	show any debugging info on request (used by various derived classes) [optional]
virtual unsigned int	GetMemoryUsed ()
	Report actual current memory usage (in bytes).
virtual unsigned int	GetDiskspaceUsed (bool fortempdecompressiononly)
	Report disk space (in bytes) that would be used when saving state to file (in bytes).
virtual std::string	GetParametersInformation ()
	Reports information about any parameters available.
virtual void	SetDefaultParameters ()
	Reset any parameters to their default values.
virtual bool	SetParameter (const std::string &parametername, const std::string &parametervalue)
	This function is called to set a variable value.
virtual bool	IsReadyToCompress ()
	is the compressor ready to compress? Normally this is false until a dictionary is built or loaded.
Protected Member Functions
virtual bool	DoProtectedCompress (bitreader &from, bitwriter &to)
	This is the member function which does the actual compression, and this is the function that should be subclasses by derived classes.
virtual bool	DoProtectedDecompress (bitreader &from, bitwriter &to)
	This is the member function which does the actual decompression, and this is the function that should be subclasses by derived classes.
virtual bool	DoProtectedCreateSymbolsAndModelsUsingStream (bitreader &from)
	This is the member function which does the actual training on an input in order to generate parsers/modelers/coders, and this is the function that should be subclasses by derived classes.
virtual bool	DoProtectedSaveState (bitwriter &to, bool fortempdecompressiononly)
	This is the member function which does the actual saving of state, and this is the function that should be subclasses by derived classes.
virtual bool	DoProtectedLoadState (bitreader &from)
	This is the member function which does the actual loading of state, and this is the function that should be subclasses by derived classes.
Protected Attributes
unsigned char	Parameter_xorbyte
	a byte which the sample compressor xors with incoming or outgoing bytes

---

Member Function Documentation

virtual std::string SampleCompressor::GetDescription (   )  [inline, virtual]

optionally provide a longer (maybe 20-60 characters) description Returns: a one line description Reimplemented from OctaneCompressor. Definition at line 48 of file samplecompressor.hpp. {return "Sample Compressor";}

bool SampleCompressor::SetParameter (  const std::string &  parametername, const std::string &  parametervalue )  [virtual]

This function is called to set a variable value. Note: this can be called with a variable not owned by this class, in which case the function should return false. Returns: true if the variable was found (whether it was set properly or not). Reimplemented from OctaneClass. Definition at line 87 of file samplecompressor.cpp. References Parameter_xorbyte, and OctaneClass::ParseParameter(). { // Generic function for user-interactive modification of parameters // Return true if we know this variable and use it bool bretv=false; // we have 1 variable we use, called xorbyte if (parametername=="xorbyte") bretv=ParseParameter(parametervalue,Parameter_xorbyte); // return success return bretv; }

bool SampleCompressor::IsReadyToCompress (   )  [virtual]

is the compressor ready to compress? Normally this is false until a dictionary is built or loaded. Returns: true on success Reimplemented from OctaneCompressor. Definition at line 105 of file samplecompressor.cpp. { // Are we ready to compress? // This sample compressor is always ready (needs no training) return true; }

bool SampleCompressor::DoProtectedCompress (  bitreader &  from, bitwriter &  to )  [protected, virtual]

This is the member function which does the actual compression, and this is the function that should be subclasses by derived classes. It is wrapped by the public API call Compress() which performs some measurements on compression speed and streamsize. Note: this function should never be called by an outside class - the API interface should be called instead. Returns: true on success Implements OctaneCompressor. Definition at line 117 of file samplecompressor.cpp. References bitreader::empty(), bitreader::get_byte(), Parameter_xorbyte, and bitwriter::put_byte(). { // Here is the main compression routine // Our sample compressor doesn't actually compress, instead it just xors // loop through input and 'compress' (xor) it unsigned char c; while (!from.empty()) { // grab a character from input c=from.get_byte(); // xor it with our parameter c= c ^ Parameter_xorbyte; // send it to output to.put_byte(c); } // return success return true; }

bool SampleCompressor::DoProtectedDecompress (  bitreader &  from, bitwriter &  to )  [protected, virtual]

This is the member function which does the actual decompression, and this is the function that should be subclasses by derived classes. It is wrapped by the public API call Decompress() which performs some measurements on decompression speed and streamsize. Note: this function should never be called by an outside class - the API interface should be called instead. Returns: true on success Implements OctaneCompressor. Definition at line 139 of file samplecompressor.cpp. References bitreader::empty(), bitreader::get_byte(), Parameter_xorbyte, and bitwriter::put_byte(). { // Here is the main decompression routine // Our sample compressor doesn't actually decompress, instead it just xors // loop through input and 'compress' (xor) it unsigned char c; while (!from.empty()) { // grab a character from input c=from.get_byte(); // xor it with our parameter c= Parameter_xorbyte ^ c; // send it to output to.put_byte(c); } // return success return true; }

bool SampleCompressor::DoProtectedCreateSymbolsAndModelsUsingStream (  bitreader &  from  )  [protected, virtual]

This is the member function which does the actual training on an input in order to generate parsers/modelers/coders, and this is the function that should be subclasses by derived classes. It is wrapped by the public API call CreateSymbolsAndModelsUsingStream() which performs some measurements on speed and streamsize. Note: this function should never be called by an outside class - the API interface should be called instead. Returns: true on success Reimplemented from OctaneCompressor. Definition at line 165 of file samplecompressor.cpp. References bitreader::empty(), and bitreader::get_byte(). { // OPTIONAL: this is called to 'train' a compressor, to let a compressor gather statistics from an input stream. // Our sample compressor does not need to implement this, but we include it here just for fun so you see what it looks like. // return false only on an error. // let's read the training input stream, just to show you how its done. unsigned char c; while (!from.empty()) { // grab a character, but we dont do anything with it. c=from.get_byte(); } // return success return true; }

bool SampleCompressor::DoProtectedSaveState (  bitwriter &  to, bool  fortempdecompressiononly )  [protected, virtual]

This is the member function which does the actual saving of state, and this is the function that should be subclasses by derived classes. It is wrapped by the public API call SaveState() which performs some measurements on speed and streamsize. Note: this function should never be called by an outside class - the API interface should be called instead. Returns: true on success Reimplemented from OctaneCompressor. Definition at line 183 of file samplecompressor.cpp. References Parameter_xorbyte, and bitwriter::put(). { // OPTIONAL: save any compressor internal state (like variables or learned statistics). // Many compressors have no interenal state to save, but this sample compressor has a variable // which should be saved. // The flag fortempdecompressiononly will be set if the state is being saved for decompression *only* // so that if there is some information is only needed for compression, we dont have to save it if we dont need it. // just tell the bitwriter to save the variables to.put(Parameter_xorbyte); // return true on success return true; }

bool SampleCompressor::DoProtectedLoadState (  bitreader &  from  )  [protected, virtual]

This is the member function which does the actual loading of state, and this is the function that should be subclasses by derived classes. It is wrapped by the public API call LoadState() which performs some measurements on speed and streamsize. Note: this function should never be called by an outside class - the API interface should be called instead. Returns: true on success Reimplemented from OctaneCompressor. Definition at line 198 of file samplecompressor.cpp. References bitreader::get(), and Parameter_xorbyte. { // OPTIONAL: load any compressor internal state (like variables or learned statistics). // Many compressors have no interenal state to save, but this sample compressor has a variable // which should be saved. // just tell the bitwriter to save the variables from.get(Parameter_xorbyte); // return true on success return true; }

---

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

• compressors/compressor_sample/samplecompressor.hpp
• compressors/compressor_sample/samplecompressor.cpp

 

Generated on 20 May 2004 by doxygen 1.3.3