US 7,490,101 B2
Method and structure for deleting leaves in tree table structures
Claude Basso, Raleigh, N.C. (US); Jean L. Calvignac, Cary, N.C. (US); Gordon T. Davis, Chapel Hill, N.C. (US); Marco Heddes, Lawrence, Mass. (US); Piyush C. Patel, Cary, N.C. (US); Steven R. Perrin, Raleigh, N.C. (US); Grayson W. Randall, Cary, N.C. (US); and Sonia K. Rovner, Chapel Hill, N.C. (US)
Assigned to International Business Machines Corporation, Armonk, N.Y. (US)
Filed on Aug. 04, 2006, as Appl. No. 11/462,404.
Application 11/462404 is a continuation of application No. 10/453245, filed on Jun. 03, 2003, granted, now 7,149,749, filed on Dec. 12, 2006.
Prior Publication US 2006/0271576 A1, Nov. 30, 2006
This patent is subject to a terminal disclaimer.
Int. Cl. G06F 7/00 (2006.01); G06F 17/00 (2006.01); G06F 17/30 (2006.01)
U.S. Cl. 707—102  [707/6; 707/100; 707/101] 8 Claims
OG exemplary drawing
 
1. A method of deleting a leaf in a patricia tree leaf structure without interrupting the functioning of the patricia tree, comprising:
providing a patricia tree leaf having a plurality of leaf keys, each of the keys having a pattern x bits in length wherein x is a positive integer;
the patricia tree further comprising a plurality of pattern search control blocks, each of the pattern search control blocks configured to decode m bits and store 2m possible combinations of bits, wherein m is a positive integer;
each of the pattern search control blocks containing a prefix and either an end-of-trail leaf or a pointer to another of the pattern search control blocks;
placing each of the prefixes in a tree prefix table;
searching for a key in the patricia tree;
if the patricia tree searching does not find the key in the patricia tree, searching for the key in the prefix table and if the key is not found in the prefix table confirming that the key is deleted; and
if the patricia tree searching finds the key, deleting the key from one of the pattern search control blocks and collapsing the patricia tree by eliminating the left most pattern search control block from the patricia tree.