We make some B2B software running on Windows, integrating with customer systems. We get a lot of interesting files. About a decade ago I wrote some utility cod

We make some B2B software running on Windows, integrating with customer systems. We get a lot of interesting files. About a decade ago I wrote some utility code for reading files, where it'll try to detect BOM first, if not scan for invalid UTF-8 sequences. If none are found assume UTF-8 else assume Windows-1252. Worked well for us so far. Still get the occasional flat file in Windows-1252 with one random field containing UTF-8, so some special handling is needed for those cases. But that's rare. Fortunately we don't have to worry about normalization for the most part. If we're parsing then any delimiters will be one of the usual suspects and the rest data.