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abbasahmad 19May2010 12:27

Data Compression
 
Can anybody help on this??? plz

The Burrows-Wheeler compression algorithm consists of three different algorithmic components, which are applied in succession:
1. Burrows-Wheeler transform. Given a typical English text file, transform it into a text file in
which sequences of the same character occur near each other many times.

2. Move-to-front encoding. Given a text file in which sequences of the same character occur near
each other many times, convert it into a text file in which certain characters appear more
frequently than others.

3. Huffman compression. Given a text file in which certain characters appear more frequently than
others, compress it by encoding frequently occurring characters with short codewords and rare
ones with long codewords. The only step that compresses the message is the final step. The
final step is particularly effective because the first two steps result in a text file in which certain
characters appear much more frequently than others.

Decompression : To expand a message, apply the inverse operations in reverse order: first apply the
Huffman expansion, then the move-to-front decoding, and finally the inverse Burrows-Wheeler trans-
form.


Inputs
For Compression: .txt file is given as an input .
For Decompression: .bwc file is given for decompression. Outputs
For Compression: decompressed file generated with .bwc extension.
For Decompression: original .txtfile generated from the input. Check List:
Correctness of algorithm: no data should be lost while compressing or decompressing.
Step-By-Step progress of algorithm: system should tell the intermediate products of each step in the process of compression and decompression.
List of data structures used for the solution
Bonus
Well designed user interface, and a look & feel of proper compression tool.

xpi0t0s 20May2010 13:26

Re: Data Compression
 
What help do you need? Do you understand the project?
When does it need to be in by?

shyam_oec 20May2010 14:31

Re: Data Compression
 
Quote:

sequences of the same character occur near each other many times.
what do u mean by this line ?

shabbir 20May2010 14:41

Re: Data Compression
 
Probably something like

ssssssssssjjjjjjjjjjjjjjjjjjffffffffffffffff
would become
s10j18f16


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