splay-tree.c: New file.

	* splay-tree.c: New file.
	* Makefile.in (CFILES): Add it.
	(REQUIRED_OFILES): Likewise.
	(splay-tree.o): Add dependencies.

From-SVN: r23210

1 files changed, 331 insertions, 0 deletions

diff --git a/libiberty/splay-tree.c b/libiberty/splay-tree.c
new file mode 100644
index 00000000000..ed48116c063
--- /dev/null
+++ b/libiberty/splay-tree.c
@@ -0,0 +1,331 @@
+/* A splay-tree datatype.  
+   Copyright (C) 1998 Free Software Foundation, Inc.
+   Contributed by Mark Mitchell (mark@markmitchell.com).
+
+   This file is part of GNU CC.
+   
+   GNU CC is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   GNU CC is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with GNU CC; see the file COPYING.  If not, write to the Free
+   Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  
+
+   For an easily readable description of splay-trees, see:
+
+     Lewis, Harry R. and Denenberg, Larry.  Data Structures and Their
+     Algorithms.  Harper-Collins, Inc.  1991.  */
+
+#ifndef IN_GCC
+#include "libiberty.h"
+#endif /* IN_GCC */
+#include "splay-tree.h"
+
+static void splay_tree_delete_helper    PARAMS((splay_tree, 
+						splay_tree_node));
+static void splay_tree_splay            PARAMS((splay_tree,
+						splay_tree_key));
+static splay_tree_node splay_tree_splay_helper     
+                                        PARAMS((splay_tree,
+						splay_tree_key,
+						splay_tree_node*,
+						splay_tree_node*,
+						splay_tree_node*));
+static int splay_tree_foreach_helper    PARAMS((splay_tree,
+					        splay_tree_node,
+						splay_tree_foreach_fn,
+						void*));
+
+/* Deallocate NODE (a member of SP), and all its sub-trees.  */
+
+static void 
+splay_tree_delete_helper (sp, node)
+     splay_tree sp;
+     splay_tree_node node;
+{
+  if (!node)
+    return;
+
+  splay_tree_delete_helper (sp, node->left);
+  splay_tree_delete_helper (sp, node->right);
+
+  if (sp->delete_key)
+    (*sp->delete_key)(node->key);
+  if (sp->delete_value)
+    (*sp->delete_value)(node->value);
+
+  free ((char*) node);
+}
+
+/* Help splay SP around KEY.  PARENT and GRANDPARENT are the parent
+   and grandparent, respectively, of NODE.  */
+
+static splay_tree_node
+splay_tree_splay_helper (sp, key, node, parent, grandparent)
+     splay_tree sp;
+     splay_tree_key key;
+     splay_tree_node *node;
+     splay_tree_node *parent;
+     splay_tree_node *grandparent;
+{
+  splay_tree_node *next;
+  splay_tree_node n;
+  int comparison;
+  
+  n = *node;
+
+  if (!n)
+    return *parent;
+
+  comparison = (*sp->comp) (key, n->key);
+
+  if (comparison == 0)
+    /* We've found the target.  */
+    next = 0;
+  else if (comparison < 0)
+    /* The target is to the left.  */
+    next = &n->left;
+  else 
+    /* The target is to the right.  */
+    next = &n->right;
+
+  if (next)
+    {
+      /* Continue down the tree.  */
+      n = splay_tree_splay_helper (sp, key, next, node, parent);
+
+      /* The recursive call will change the place to which NODE
+	 points.  */
+      if (*node != n)
+	return n;
+    }
+
+  if (!parent)
+    /* NODE is the root.  We are done.  */
+    return n;
+
+  /* First, handle the case where there is no grandparent (i.e.,
+     *PARENT is the root of the tree.)  */
+  if (!grandparent) 
+    {
+      if (n == (*parent)->left)
+	{
+	  *node = n->right;
+	  n->right = *parent;
+	}
+      else
+	{
+	  *node = n->left;
+	  n->left = *parent;
+	}
+      *parent = n;
+      return n;
+    }
+
+  /* Next handle the cases where both N and *PARENT are left children,
+     or where both are right children.  */
+  if (n == (*parent)->left && *parent == (*grandparent)->left)
+    {
+      splay_tree_node p = *parent;
+
+      (*grandparent)->left = p->right;
+      p->right = *grandparent;
+      p->left = n->right;
+      n->right = p;
+      *grandparent = n;
+      return n; 
+    }
+  else if  (n == (*parent)->right && *parent == (*grandparent)->right)
+    {
+      splay_tree_node p = *parent;
+
+      (*grandparent)->right = p->left;
+      p->left = *grandparent;
+      p->right = n->left;
+      n->left = p;
+      *grandparent = n;
+      return n;
+    }
+
+  /* Finally, deal with the case where N is a left child, but *PARENT
+     is a right child, or vice versa.  */
+  if (n == (*parent)->left) 
+    {
+      (*parent)->left = n->right;
+      n->right = *parent;
+      (*grandparent)->right = n->left;
+      n->left = *grandparent;
+      *grandparent = n;
+      return n;
+    } 
+  else
+    {
+      (*parent)->right = n->left;
+      n->left = *parent;
+      (*grandparent)->left = n->right;
+      n->right = *grandparent;
+      *grandparent = n;
+      return n;
+    }
+}
+
+/* Splay SP around KEY.  */
+
+static void
+splay_tree_splay (sp, key)
+     splay_tree sp;
+     splay_tree_key key;
+{
+  if (sp->root == 0)
+    return;
+
+  splay_tree_splay_helper (sp, key, &sp->root, 
+			   /*grandparent=*/0, /*parent=*/0); 
+}
+
+/* Call FN, passing it the DATA, for every node below NODE, all of
+   which are from SP, following an in-order traversal.  If FN every
+   returns a non-zero value, the iteration ceases immediately, and the
+   value is returned.  Otherwise, this function returns 0.  */
+
+int
+splay_tree_foreach_helper (sp, node, fn, data)
+     splay_tree sp;
+     splay_tree_node node;
+     splay_tree_foreach_fn fn;
+     void* data;
+{
+  int val;
+
+  if (!node)
+    return 0;
+
+  val = splay_tree_foreach_helper (sp, node->left, fn, data);
+  if (val)
+    return val;
+
+  val = (*fn)(node, data);
+  if (val)
+    return val;
+
+  return splay_tree_foreach_helper (sp, node->right, fn, data);
+}
+
+/* Allocate a new splay tree, using COMPARE_FN to compare nodes,
+   DELETE_KEY_FN to deallocate keys, and DELETE_VALUE_FN to deallocate
+   values.  */
+
+splay_tree 
+splay_tree_new (compare_fn, delete_key_fn, delete_value_fn)
+     splay_tree_compare_fn compare_fn;
+     splay_tree_delete_key_fn delete_key_fn;
+     splay_tree_delete_value_fn delete_value_fn;
+{
+  splay_tree sp = (splay_tree) xmalloc (sizeof (struct splay_tree));
+  sp->root = 0;
+  sp->comp = compare_fn;
+  sp->delete_key = delete_key_fn;
+  sp->delete_value = delete_value_fn;
+
+  return sp;
+}
+
+/* Deallocate SP.  */
+
+void 
+splay_tree_delete (sp)
+     splay_tree sp;
+{
+  splay_tree_delete_helper (sp, sp->root);
+  free ((char*) sp);
+}
+
+/* Insert a new node (associating KEY with DATA) into SP.  If a
+   previous node with the indicated KEY exists, its data is replaced
+   with the new value.  */
+
+void 
+splay_tree_insert (sp, key, value)
+     splay_tree sp;
+     splay_tree_key key;
+     splay_tree_value value;
+{
+  int comparison;
+
+  splay_tree_splay (sp, key);
+
+  if (sp->root)
+    comparison = (*sp->comp)(sp->root->key, key);
+
+  if (sp->root && comparison == 0)
+    {
+      /* If the root of the tree already has the indicated KEY, just
+	 replace the value with VALUE.  */
+      if (sp->delete_value)
+	(*sp->delete_value)(sp->root->value);
+      sp->root->value = value;
+    } 
+  else 
+    {
+      /* Create a new node, and insert it at the root.  */
+      splay_tree_node node;
+      
+      node = (splay_tree_node) xmalloc (sizeof (struct splay_tree_node));
+      node->key = key;
+      node->value = value;
+      
+      if (!sp->root)
+	node->left = node->right = 0;
+      else if (comparison < 0)
+	{
+	  node->left = sp->root;
+	  node->right = node->left->right;
+	  node->left->right = 0;
+	}
+      else
+	{
+	  node->right = sp->root;
+	  node->left = node->right->left;
+	  node->right->left = 0;
+	}
+
+    sp->root = node;
+  }
+}
+
+/* Lookup KEY in SP, returning VALUE if present, and NULL 
+   otherwise.  */
+
+splay_tree_node
+splay_tree_lookup (sp, key)
+     splay_tree sp;
+     splay_tree_key key;
+{
+  splay_tree_splay (sp, key);
+
+  if (sp->root && (*sp->comp)(sp->root->key, key) == 0)
+    return sp->root;
+  else
+    return 0;
+}
+
+/* Call FN, passing it the DATA, for every node in SP, following an
+   in-order traversal.  If FN every returns a non-zero value, the
+   iteration ceases immediately, and the value is returned.
+   Otherwise, this function returns 0.  */
+
+int
+splay_tree_foreach (sp, fn, data)
+     splay_tree sp;
+     splay_tree_foreach_fn fn;
+     void *data;
+{
+  return splay_tree_foreach_helper (sp, sp->root, fn, data);
+}