Re: ASCII to ASCII compression.

On 06/06/2024 17:56, Ben Bacarisse wrote:

Malcolm McLean <malcolm.arthur.mclean@gmail.com> writes:
 

Not strictly a C programming question, but smart people will see the
relavance to the topicality, which is portability.

 I must not be smart as I can't see any connection to the topic of this
group!
 

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?

 Obviously such algorithms exist.  One that is used a lot is just base64
encoding of binary compressed text, but that won't beat something
specifically crafted for the task which is presumably what you are
asking for.  I don't know of anything aimed at that task specifically.
 One thing you should specify is whether you need it to work on small
texts, or, even better, at what sort of size you want the pay-off to
start to kick in.  For example, the xz+base64 encoding of the complete
works of Shakespeare is still less than 40% of the size of the original
but your single line will end up much larger using that off-the-shelf
scheme.
 

What I was thing of was using Huffman codes to convert ASCII to a string of of bits. Then use isgraph characters to chop the code up into six bits. Then you have a special character to represent end of line. So if the compressed text gets corrupted, you only lose a single line.
The idea is that the compressed data can then be embedded in C source.
Or stored in text files. A bit like uuencoding. But for text, not binary.
--
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