Shrinkler

[Blueberry]

A new version of Shrinkler has just been released: Shrinkler 4.7!

There are various new features and improvements this time:

• The Amiga Shrinkler executable is now built using Amiga-GCC. This makes it compress about 15% faster, and it no longer needs ixemul.library.
  
  
• A new option (--commandline, -c) to support commandline parameters. This was always supposed to work, but only actually worked with the default header. It now works with all headers when you specify the option, and the header is a few bytes smaller if you don't.
  
  
• A new option (--bytes, -b) to disable the parity context for data compression. This usually gives better results for data that is not word-oriented. The 6502 decruncher already supports this format, and its documentation points to a special Shrinkler build for this. Now you can use the standard Shrinkler.
  
  
• The output size for data crunching is no longer rounded up to a multiple of 4 bytes, as the decompressor now reads the data one byte at a time. This also means that the crunched data no longer has to be word-aligned on 68000.
  
  
• A new option (--header, -w) to write a header before the crunched data. This header contains imformation about compressed and uncompressed size, safety margin and whether parity context were enabled for the compression. To accompany this, the decompressor source code is extended with some utility code to load a Shrinkler-compressed file from disk, automatically allocating the right amount of memory for overlapped decompression.
  
  
• Finally, the default compression preset was upped from -2 to -3, since this is usually a more suitable sweet spot between size and speed, and it's the maximum number of iterations that can be printed in an Amiga console with a width of 77 characters.

You are all welcome to ask questions here, on Pouet or on GitHub.

[ross]

Thanks.

Originally Posted by Blueberry

[*]A new option (--bytes, -b) to disable the parity context for data compression. This usually gives better results for data that is not word-oriented. The 6502 decruncher already supports this format, and its documentation points to a special Shrinkler build for this. Now you can use the standard Shrinkler.

Is there an estimate for this? For example for normal ASCII text.

As for 68k code, I think the parity context is unbeatable in all cases, and that's what I've always appreciated in

Shrinkler

.

[Blueberry]

Originally Posted by ross

Is there an estimate for this? For example for normal ASCII text.

For small text files (a few kilobytes) it looks like it typically improves the size by about 1%. For larger files it makes less of a difference, since the dual contexts will converge towards the same distribution eventually.

[pink^abyss]

Originally Posted by Blueberry

A new version of Shrinkler has just been released: Shrinkler 4.7!

You are all welcome to ask questions here, on Pouet or on GitHub.

Thanks Blueberry for improving!