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Posted

I was toying around with AutoIt using it for simple automation until I got an assignment, which was basically to implement some data compression scheme and to comment on the compression ratio etc.

I have never done any project like this-which gives a finished product-on any programming language, though I'm decently conversed with C++ and a little bit with AutoIt.

So this time around I thought of using AutoIt for implementing the Lempel-Ziv algorithm. I got the code ready and it compiled okay, but the output wasn't what I expected. Then as a part of trouble shooting i got the generated code table and found that except for the first one, there's only one type of code - equivalent to the ASCII of "O".

Can anybody tell me where I'm going wrong ?

I looked around a lot, but cant figure out why I'm not able to generate different codes. So i'm attaching the code. Any help is appreciated.

Lempel_Ziv.au3

Note: The code for the algorithm itself is not "complete" in the sense that a few exceptions have not been covered yet.

Thanks in advance.

Posted

I haven't tested the code, but looking through it, you have made an incorrect assumption in regards to FileRead. FileRead($ipfile, 1) reads in one CHARACTER, not one bit.

If I posted any code, assume that code was written using the latest release version unless stated otherwise. Also, if it doesn't work on XP I can't help with that because I don't have access to XP, and I'm not going to.
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I hereby grant any person the right to use any code I post, that I am the original author of, on the autoitscript.com forums, unless I've specifically stated otherwise in the code or the thread post. If you do use my code all I ask, as a courtesy, is to make note of where you got it from.

Back up and restore Windows user files _Array.au3 - Modified array functions that include support for 2D arrays.  -  ColorChooser - An add-on for SciTE that pops up a color dialog so you can select and paste a color code into a script.  -  Customizable Splashscreen GUI w/Progress Bar - Create a custom "splash screen" GUI with a progress bar and custom label.  -  _FileGetProperty - Retrieve the properties of a file  -  SciTE Toolbar - A toolbar demo for use with the SciTE editor  -  GUIRegisterMsg demo - Demo script to show how to use the Windows messages to interact with controls and your GUI.  -   Latin Square password generator

Posted

I haven't tested the code, but looking through it, you have made an incorrect assumption in regards to FileRead. FileRead($ipfile, 1) reads in one CHARACTER, not one bit.

Thanks for pointing out the mistake. :)

Is there some way I can get the script to read the file bit by bit instead of reading one byte at a time?

Posted

Is there some way I can get the script to read the file bit by bit instead of reading one byte at a time?

No. A Byte is the minimum data size for FileRead().

- You will need to use additional code to get at the bits of a Byte. (Give forum search a try, as there are some topics on that subject.)

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