Decompressor Class Reference

This class decompresses compressed(.huf) files to its original form. More...

#include <Decompressor.h>

Classes
struct	fileInfo
	Structure to hold file metadata. More...

Public Member Functions
	Decompressor ()
	~Decompressor ()
void	decompressFile (const std::string &infileName)
	Decompresses the compressed(.huf) file to its original form. More...

Private Member Functions
void	clear ()
	Resets all the attributes for next decompression operation. More...
void	deleteTree (BinNode *node)
	Frees all heap storage associated with the Huffman Tree. More...
void	readHeader (const std::string &infileName, std::ifstream &infile)
	Reads the header section from compressed file. More...
BinNode *	readTree (std::ifstream &reader)
	Reads the entire Huffman tree in to the file header section using a pre-order traversal algorithm. More...
void	writeIntoFile (const std::string &infileName)
	Decodes encoded characters using the tree obtained from header section. More...

Private Attributes
Queue< fileInfo >	files
	Queue of input file(s) to be decompressed. More...
std::ifstream	infile
	Instance of ifstream class for reading encoded characters from compressed file. More...
BinNode *	rootNode
	Root node for Huffman tree. More...

Detailed Description

This class decompresses compressed(.huf) files to its original form.

It decompresses those files and folders which was compressed using Huffman Compression Algorithm.

Definition at line 23 of file Decompressor.h.

Constructor & Destructor Documentation

Decompressor()

Decompressor::Decompressor

(

)

Definition at line 3 of file Decompressor.cpp.

~Decompressor()

Decompressor::~Decompressor

(

)

Definition at line 5 of file Decompressor.cpp.

Member Function Documentation

clear()

void Decompressor::clear ( )

private

Resets all the attributes for next decompression operation.

Definition at line 9 of file Decompressor.cpp.

decompressFile()

void Decompressor::decompressFile

(

const std::string &

infileName

)

Decompresses the compressed(.huf) file to its original form.

Parameters

infileName

compressed file path to be decompressed.

Definition at line 134 of file Decompressor.cpp.

deleteTree()

void Decompressor::deleteTree ( BinNode *  node )

private

Frees all heap storage associated with the Huffman Tree.

Definition at line 15 of file Decompressor.cpp.

readHeader()

void Decompressor::readHeader ( const std::string &  infileName, std::ifstream &  infile  )

private

Reads the header section from compressed file.

Header section of compressed file contains tree and other metaData required during decompression. Meta data includes number of input files, each file size and file path

Read total number of files

Read total number of characters in each file, filename and directories

Definition at line 44 of file Decompressor.cpp.

readTree()

BinNode * Decompressor::readTree ( std::ifstream &  reader )

private

Reads the entire Huffman tree in to the file header section using a pre-order traversal algorithm.

when the program reads a bit 1, it can read the next 8 bits and wrap the char in a binary leaf node. When the program reads a bit 0, it create a new internal node and connect the two nodes as left and right child.

Definition at line 24 of file Decompressor.cpp.

writeIntoFile()

void Decompressor::writeIntoFile ( const std::string &  infileName )

private

Decodes encoded characters using the tree obtained from header section.

Traverses the tree and on reaching the leaf node, write the character present in leaf node to output file till all the characters are decoded.

If output file size becomes equal to the fileSize known from file header section, it flush and closes the file and creates a new output file from the files queue till it becomes empty.

Definition at line 83 of file Decompressor.cpp.

Member Data Documentation

files

Queue<fileInfo> Decompressor::files

private

Queue of input file(s) to be decompressed.

Definition at line 42 of file Decompressor.h.

infile

std::ifstream Decompressor::infile

private

Instance of ifstream class for reading encoded characters from compressed file.

Definition at line 45 of file Decompressor.h.

rootNode

BinNode* Decompressor::rootNode

private

Root node for Huffman tree.

Definition at line 48 of file Decompressor.h.