Author:

• Name: David Goodenough
  Location: ZZ - Unknown location
  
  

To build:

make all

To use:

echo foo bar | ./dg

Try:

./try.sh

Judges’ remarks:

Some C preprocessors got confused about single quotes in certain cases. In particular, the following source line:

b12(ase(bco(acp(bi(acp(bcp(acp(bpl(aqu(bqu(A))))))))))))))))))))))))))))))

sometimes has to be changed to:

b12(ase(bco(acp(bi(acp(bcp(acp(bpl('A'))))))))))))))))))))))))))))

particularly if the C preprocessor botches single quotes in cpp expansions, which we have done for the wider audience.

Author’s remarks:

If my preprocessor could hack it, I could write this as one single line rather than 4, but when I do that I get a complaint “defines nested too deeply”.

Obfuscation spoiler:

This is another rot13 job (believe it or not) - the #defines are a novel way of adding tokens: #define b12(x) 12 x means that at some point in the source a 12 is followed by the compressed nested #defines. The b12 gets the previous compression as an argument, and prepends the 12, thus making another step in the recreation of the source. The axx() #defines do the same, but add tokens after.

As for the rot13 algorithm, it relies on index(3) to find if the character is in the set A-Za-z. l[] is an array that gets filled with:

"nopqrstuvwxyzzzzabcdefghijklmmmmNOPQRSTUVWXYZZZZABCDEFGHIJKLMMMM"

If index(3) says the char is in the alphabet, then XOR the offset with 16 to translate, and output, otherwise pass it unchanged.

Inventory for 1990/dg

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Primary files

• dg.c - entry source
• Makefile - entry Makefile
• dg.orig.c - original source
• try.sh - how to run
• 1990_dg.tar.bz2 - download entry source

Secondary files

• index.html - entry home page
• README.md - markdown source for index.html
• .entry.json - description of entry in JSON
• .gitignore - list of files that should not be committed under git
• .path - directory path from top directory