HuffmanDecoder Class Reference

#include <huffman.hpp>

Collaboration diagram for HuffmanDecoder:

Class Description

This class, together with sibling HuffmanEncoder implements the well known Huffman compression . The class uses type BitReader to read the bit stream from an underlying BitBuffer.

The use of this class is quite straight forward:

• Prepare a BitReader to point to the beginning of the bit stream generated with class HuffmanEncoder.
• Invoke method ReadTree once.
• For each encoded byte, invoke Read.

Note, that the length of the stream (the number of bytes to be decompressed) have to be known by the using software. This class is not responsible for storing this piece of information.

Definition at line 144 of file huffman.hpp.

Inner Classes
struct	Node

Public Methods
	HuffmanDecoder (BitReader &bitReader)
uint8_t	Read ()
ALIB_API void	ReadTree ()

Protected Static Fields
static constexpr int	MAX_NODES = 511
	The maximum number of nodes in the tree.

Protected Fields
BitReader &	br
	The bit reader given in the constructor.
Node	nodePool [MAX_NODES]
	Pre-allocated node objects.
int	npNext = 0
	The next node in nodePool to use.
Node	tree
	The root node of the symbol tree.

Constructor & Destructor Documentation

HuffmanDecoder()

HuffmanDecoder ( BitReader &  bitReader )

inline

Constructor.

Parameters

bitReader

The bit reader to read the huffman encoding table and then the encoded symbols from. (Stored in field br.)

Definition at line 175 of file huffman.hpp.

Member Function Documentation

Read()

uint8_t Read ( )

inline

Reads a symbol from the bit stream. This method has to be invoked for every symbol stored, after once reading the encoding information with method ReadTree.

Returns

The symbol read.

Definition at line 189 of file huffman.hpp.

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ReadTree()

void ReadTree

(

)

Reads the information to decode the data from the beginning of the bit stream. This method has to be invoked once prior to reading the symbols with method Read.

Definition at line 221 of file huffman.cpp.

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

• huffman.hpp
• huffman.cpp