97 lines
3.2 KiB
C
97 lines
3.2 KiB
C
/* A splay-tree datatype.
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Copyright 1998, 1999, 2000, 2002, 2004 Free Software Foundation, Inc.
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Contributed by Mark Mitchell (mark@markmitchell.com).
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Adapted for libmudflap from libiberty by Frank Ch. Eigler <fche@redhat.com>.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to
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the Free Software Foundation, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/* For an easily readable description of splay-trees, see:
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Lewis, Harry R. and Denenberg, Larry. Data Structures and Their
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Algorithms. Harper-Collins, Inc. 1991.
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The major feature of splay trees is that all basic tree operations
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are amortized O(log n) time for a tree with n nodes.
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This version has been further modified to periodically rebalance
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the entire tree, should degenerate access patterns result in a very
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lopsided tree.
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*/
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#ifndef _SPLAY_TREE_H
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#define _SPLAY_TREE_H
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/* Use typedefs for the key and data types to facilitate changing
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these types, if necessary. These types should be sufficiently wide
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that any pointer or scalar can be cast to these types, and then
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cast back, without loss of precision. */
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typedef uintptr_t splay_tree_key;
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typedef void *splay_tree_value;
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/* Forward declaration for a node in the tree. */
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typedef struct splay_tree_node_s *splay_tree_node;
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/* The type of a function used to iterate over the tree. */
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typedef int (*splay_tree_foreach_fn) (splay_tree_node, void *);
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/* The nodes in the splay tree. */
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struct splay_tree_node_s
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{
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/* Data. */
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splay_tree_key key;
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splay_tree_value value;
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/* Children. */
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splay_tree_node left;
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splay_tree_node right;
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};
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/* The splay tree itself. */
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struct splay_tree_s
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{
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/* The root of the tree. */
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splay_tree_node root;
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/* The last key value for which the tree has been splayed, but not
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since modified. */
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splay_tree_key last_splayed_key;
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int last_splayed_key_p;
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/* Statistics. */
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unsigned num_keys;
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/* Traversal recursion control flags. */
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unsigned max_depth;
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unsigned depth;
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unsigned rebalance_p;
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};
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typedef struct splay_tree_s *splay_tree;
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extern splay_tree splay_tree_new (void);
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extern splay_tree_node splay_tree_insert (splay_tree, splay_tree_key, splay_tree_value);
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extern void splay_tree_remove (splay_tree, splay_tree_key);
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extern splay_tree_node splay_tree_lookup (splay_tree, splay_tree_key);
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extern splay_tree_node splay_tree_predecessor (splay_tree, splay_tree_key);
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extern splay_tree_node splay_tree_successor (splay_tree, splay_tree_key);
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extern splay_tree_node splay_tree_max (splay_tree);
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extern splay_tree_node splay_tree_min (splay_tree);
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extern int splay_tree_foreach (splay_tree, splay_tree_foreach_fn, void *);
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extern void splay_tree_rebalance (splay_tree sp);
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#endif /* _SPLAY_TREE_H */
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