Utilities

All the following utilities read from stdin and output the results to stdout.
There are some samples at the end that show how they can be used.

mapascii.c - Map uppercase ASCII alphabet to zero-based character indexing.
remapascii.c - Inverse of the above.

mapfi.c - Map uppercase Finnish special characters to end of uppercase ASCII alphabet.
remapfi.c - Inverse of the above.

subst.c - Substitute a byte for an other byte.
bottom.c - Map bytes in an interval to a given bottom byte.
gcd.c - Compute greatest common divisor of two numbers.
chtable.c - Show all tuples of Chinese remainders for two moduli.

Samples

caesarall - List all 25 Caesar decryptions, bash script.
caesarallfi - List all 28 Caesar decryptions for Finnish alphabet, bash script.
paramgcd - Parametric input for gcd above.