Question

I’m looking for pseudocode, or sample code, to convert higher bit ascii characters (like, Ü which is extended ascii 154) into U (which is ascii 85).

My initial guess is that since there are only about 25 ascii characters that are similar to 7bit ascii characters, a translation array would have to be used.

Let me know if you can think of anything else.

Answer 1

Indeed as proposed by unexist : ‘iconv’ function exists to handle all weird conversion for you, is available in almost all programming language and has a special option which tries to convert characters missing in the target set with approximations.

Use iconv to simply convert your input UTF-8 string to 7bit ASCII.

Otherwise, you’ll always end hitting corner case : a 8bit input using a different codepage with a different set of characters (thus not working at all with your conversion table), forgot to map one last stupid accented caracter (you mapped all grave/acute accent, but forgot to map Czech caron or the nordic ‘°’), etc.

Of course if you want to apply the solution to a small specific problem (making file-system friendly filenames for your music collection) the the look-up arrays are the way to go (either an array which for each code number above 128 maps an approximation under 128 as proposed by JeeBee, or the source/target pairs proposed by vIceBerg depending on which substitution functions are already available in your language of choice), because it’s quickly hacked together and quickly check for missing elements.