CompuServe Messages

Shmuel, I've done it, and I talk about it in the upcoming June 1990 issue, but I didn't include any source code. Here's how I do it. Keys in a b-tree node are in collated sequence. The first key in a node is always whole, that is it contains all its ASCII characters. If the next key repeats any of the leading characters of the first, the repeated characters are replaced by an escape sequence that specifies how many characters repeat. This is a form of run-length-encoding. So if you had these keys: program, programmed, programmer, progress, progressive the compressed form would be: program, <7>med, <9>r, <5>ess, <8>ive The bracketed digits represent the count which must take a form that distinguishes them from valid characters. A tree navigator must be serial. It must start at the first key in order to reconstruct any subsequent compressed keys. Al Stevens