acliu@skat.usc.edu (Alex C. Liu) (12/10/89)
FILE: help binary.formats LAST CHANGE: Dec 8th, 1989 VERSION: UX-Maze Server V2.0c UX-Maze Encoded Binary File Formats =================================== In order for one to be able to send binary data over 7bit connections such as the ones in mail, one must be able to conver the Binary data into a more printable format and be able to put it back into binary. One good think about computers, is that all standards aren't standard, so this server provides 3 different methods for encoding binary information: uuencode This is the USENet's and UNIX's standard for sending binary data over mail connections. This is method is the default for the server. File's are expanded by 35% though. Source code for decodeing uuencoded files is available through this server in the file: unix-support uuencode btoa This is a nice encoding programming originally distributed with the Unix Compress package. It is like uuencode, but it will expand the files only 25%. And also trys to compress strings of zeros into a single character. The source for this method is in: unix-support btoa hex This is a format I made up in order to help people who don't have Unix or uudecoding capablities handy. It is a very simple encoding method, involving Binary->Hex conversion and some extra checksums added just because I wanted the protocol to look fancy. Basicly, a encoded file has the following form: ________________ |Beginning of file |Some extra garbage | |hexf filename <- Indicates that a hex file |:082345677667D87D8BC93 begins (Pretty much like Hex en- |:03449A87C837F874B8374FF the "begin" line in coded |:033045BD311F34559302 uuencoding binary |:0300040484993FA884BA6D data |:1233BBC3349B33DFF4844 | ^^|<----up to---->|^^ || 35 bytes || Numbers <=++ in hex ++=> Checksum of bytes in Mod256 addition of all line (without) bytes in the line w/o including including the chksum the byte count |:082345677667D87D8BC93 |:03449A87C837F874B8374FF |:033045BD311F34559302 |:0300040484993FA884BA6D |:1233BBC3349B33DFF4844 |end <- Indicates the end of the |Some more trailing garbage hex file |________________ This encoding method was design to be simple and at the same time robust. So users from almost any o.s. will be able to write a decoder. If you have any questions on this method, don't hesitate to ask. Also, a sample BASIC decoding program can be found in: help unhexf.bas --- Alex C. Liu acliu%skat@usc.edu acliu@skat.usc.edu (Simple .signature, $CHEAP$)