"Your code removes control characters and certain punctuation but does not remove non-ASCII characters. Is this intentional?"

Well, I really didn't have to include that line, but I did anyway just to be consistent. If I'm going to disallow certain characters in a file name when reading, then I would do the same for creating a file just to be consistent. The reason I chose to ban these characters is because they may be used for bad purposes when reading a file, and they're illegal anyway if you look at the file system specs. The NTFS and FAT file systems disallow creating files with characters 0x00-0x1F and you also can't have files that include: > < * ? | " but it's ok to have a file which contains characters from the extended ASCII chart (0x80-0xFF).