Author:

• Name: Volker Diels-Grabsch
  Location: DE - Federal Republic of Germany (Germany)

To build:

    make

To use:

    ./prog < file > file.Z

Try:

    ./try.sh

Judges’ remarks:

Finally, IOCCC now has its own text compression program, and it is short enough to qualify for the Best Short Program award! That said, can you compress it down to a one-liner, still producing files in the UNIX compress format, albeit sacrificing the compression ratio?

Can you explain why the /dev/zero file compresses identically by the entry and the standard compress(1) tool (see try.sh), but the text file compresses differently? The judges know. :)

Author’s remarks:

A tiny “compress” tool:

Usage:

    ./prog < input.txt > input.txt.Z

Example:

    ./prog < guidelines.txt > guidelines.txt.Z

Check for correctness:

    zcat guidelines.txt.Z > guidelines2.txt
    diff -s guidelines.txt guidelines2.txt

Of course you can also use 2015/mills2prog.c instead of zcat to verify the output file. The achieved compression ratio roughly matches that of the classic Unix compress(1) tool. And the source code is very compressed, too: It has exactly the same size as the paragraph you are reading right now. And exactly the same shape. Nevertheless, it is portable C99 code that runs on 32-bit and 64-bit platforms. It compiles without warnings on both GCC and Clang even with -Wextra and -Weverything.

2023 note: the above paragraph might not be true as far as number of bytes goes.

Primary files

• prog.c - entry source code
• Makefile - entry Makefile
• prog.orig.c - original source code
• guidelines.txt - 2018 IOCCC guidelines
• try.sh - script to try entry
• Shakespeare.txt - Coriolanus by Shakespeare

Secondary files

• 2019_diels-grabsch1.tar.bz2 - download entry tarball
• README.md - markdown source for this web page
• .entry.json - entry summary and manifest in JSON
• .gitignore - list of files that should not be committed under git
• .path - directory path from top level directory
• index.html - this web page

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