string convert_cyr_string (string str, string from, string to)
This function converts the given string from one Cyrillic character set to another. The from and to arguments are single characters that represent the source and target Cyrillic character sets. The supported types are:
k - koi8-r
w - windows-1251
i - iso8859-5
a - x-cp866
d - x-cp866
m - x-mac-cyrillic