GoKawiilData Compression Explained
Matt Mahoney
Copyright (C) 2010-2012, Dell, Inc. You are permitted to copy and distribute material from this book provided (1) any material you distribute includes this license, (2) the material is not modified, and (3) you do not charge a fee or require any other considerations for copies or for any works that incorporate material from this book. These restrictions do not apply to normal "fair use", defined as cited quotations totaling less than one page. This book may be downloaded without charge from http://mattmahoney.net/dc/dce.html.
Last update: Apr. 15, 2013.
e-reader translations by Alejo Sanchez, Oct. 29, 2011: mobi (Kindle) and epub (other readers).
About this Book
This book is for the reader who wants to understand how data compression works, or who wants to write data compression software. Prior programming ability and some math skills will be needed. Specific topics include:
This book is intended to be self contained. Sources are linked when appropriate, but you don't need to click on them to understand the material.
1. Information Theory
Data compression is the art of reducing the number of bits needed to store or transmit data. Compression can be either lossless or lossy. Losslessly compressed data can be decompressed to exactly its original value. An example is 1848 Morse Code. Each letter of the alphabet is coded as a sequence of dots and dashes. The most common letters in English like E and T receive the shortest codes. The least common like J, Q, X, and Z are assigned the longest codes.
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