I've written code to do this. If you're lucky there will be a BOM (byte order mark) or MIME type to indicate the encoding form. In this case you know the encodi

I've written code to do this. If you're lucky there will be a BOM (byte order mark) or MIME type to indicate the encoding form. In this case you know the encoding. If you don't have this information, then you must guess the encoding. The issue is guessing may not produce accurate results, especially if you don't have enough bytes to go by. The program I wrote to guess the encoding would scan the bytes in multiple passes. Each pass would check if the bytes encoded valid characters in some specific encoding form. After a pass completed I would assign it a score based on how many successfully encoded characters were (or were not) found. After all passes completed I'd pick the highest score and assume that was the encoding. This approach ended up being reasonably reliable assuming there were enough bytes to go by.