CamelCase conversion to proper_c_style

I know it's probably heresy for a lot of coders, but does anyone know a function or class or regexp or somesuch which will scan through a PHP file and convert all the CamelCase code into proper C-type code? That is, "CamelCase" gets converted to "camel_case". I snagged a bunch of someone else's PHP code I'd like to modify, but it's coded the wrong way, so I'd like to fix it. (I'm teasing you CamelCase people. But I really would like to change this code around, because it doesn't happen to be my preference.) Paul -- Paul M. Foster