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From: Malcolm McLean <malcolm.arthur.mclean@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: ASCII to ASCII compression.
Date: Fri, 7 Jun 2024 13:43:50 +0100
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On 07/06/2024 10:36, David Brown wrote:
> On 06/06/2024 21:02, Malcolm McLean wrote:
>> On 06/06/2024 17:55, bart wrote:
>>> On 06/06/2024 17:25, Malcolm McLean wrote:
>>>>
>>>> Not strictly a C programming question, but smart people will see the 
>>>> relavance to the topicality, which is portability.
>>>>
>>>> Is there a compresiion algorthim which converts human language ASCII 
>>>> text to compressed ASCII, preferably only "isgraph" characters?
>>>>
>>>> So "Mary had a little lamb, its fleece was white as snow".
>>>>
>>>> Would become
>>>>
>>>> QWE£$543GtT£$"||x|VVBB?
>>>
>>> What's the problem with compressing to binary (using existing, 
>>> efficient utilities), then turning that binary into ASCII (like Mime 
>>> or Base64)?
>>>
>> Because if a single bit flips in a zip archive, it's likely the entire 
>> archive will be lost. This scheme is robust. We can emed compressed 
>> text in programs, and if it is corruped, only a single line will 
>> become unreadable.
> 
> Ah, you want something that will work like your newsreader program that 
> randomly changes letters or otherwise corrupts your spelling while 
> leaving most of it readable?  :-)
> 
> Pass the data through a compressor and then add forward error checking 
> mechanisms such as Reed-Solomon codes.  Then convert to ASCII base64 or 
> similar.
> 
Yes, exactly.

I want a system for compression which is robust to corruption, can be 
stored as text, and with a compressor / decompressor which can be 
written by a child hobby programmer with only a very little bit of 
experience of programming.

That's what I need for Baby X. The FileSystem XML files can get very 
large, and of course Baby X programmers are going to ask about 
compression. And I don't think there is an existing system, and so I 
shall devise one.

-- 
Check out Basic Algorithms and my other books:
https://www.lulu.com/spotlight/bgy1mm