Segment deletion

A segment is deleted either by an application DLET call or because a segment is REPLaced with a different length.

Segment REPLace can cause a segment to move. Full Function handles segment length increases differently from DEDBs. In Full Function, an increased segment length that does not fit into the available free space is split, and the data is inserted away from the prefix. For DEDBs, if the replaced segment is changed, it is first deleted and then reinserted. The insertion process follows the normal space allocation rules.

The REPL call can cause a dependent overflow or an independent overflow CI to be freed if the last segment is deleted from the CI.