TAVLTREE REVISION HISTORY:

18-feb-91  First version released.

19-oct-91  1) TAVLtree library donated to the public domain.
              Registration is no longer requested; comments
              and feedback are.

           2) (Aug 31, 1991) Roberto Artigas, Jr. of Memphis, TN
              informs me that some Standard C compilers do not
              support signed bit fields.  Author BCH rewrote the
              structure "TAVL_NODE" to accomodate this fact.  By
              default, the flags "Lbit", "Rbit" and "bf" in
              TAVL_NODE are now chars.  To use bit fields instead
              of chars the library must be compiled with the variable
              "TAVL_USE_BIT_FIELDS" defined, either as a command line
              option ( -DTAVL_USE_BIT_FIELDS for Turbo C, Borland C++),
              or by editing the header file TAVLTREE.H.

              The space savings gained by using bit fields must be
              balanced against the more complex code emitted by the
              compiler; users can make their own choice.

           3) File TAVL_INS.C: around line 73:

              changed

                 if (replace) {
                   (*tree->free_item)(p->dataptr);
                   p->dataptr = (*tree->make_item)(item);
                 }

              to

                 if (replace) {
                     void *temp = (*tree->make_item)(item);
                     if (temp) {
                         (*tree->free_item)(p->dataptr);
                         p->dataptr = temp;
                     }
                     else p = NULL;
                 }

              This change prevents tree from being corrupted if
              there is insufficient dynamic memory to replace the
              data item.

           4) File TAVLREBL.C: lines 93 - 95
              Changed
                TAVL_nodeptr temp = c->Rptr;
                c->Rptr = a;
                a->Lptr = temp;
              to
                a->Lptr = c->Rptr;
                c->Rptr = a;

              and a similar change at lines 154 - 156.  The temporary
              variable is simply unnecessary in the new version.

  - Bert C. Hughes