/* A splay-tree datatype.
- Copyright (C) 1998, 1999 Free Software Foundation, Inc.
+ Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
Contributed by Mark Mitchell (mark@markmitchell.com).
This file is part of GNU CC.
#include <stdlib.h>
#endif
+#include <stdio.h>
+
#include "libiberty.h"
#include "splay-tree.h"
if (sp->delete_value)
(*sp->delete_value)(node->value);
- free ((char*) node);
+ (*sp->deallocate) ((char*) node, sp->allocate_data);
}
/* Help splay SP around KEY. PARENT and GRANDPARENT are the parent
return splay_tree_foreach_helper (sp, node->right, fn, data);
}
+
+/* An allocator and deallocator based on xmalloc. */
+static void *
+splay_tree_xmalloc_allocate (size, data)
+ int size;
+ void *data ATTRIBUTE_UNUSED;
+{
+ return (void *) xmalloc (size);
+}
+
+static void
+splay_tree_xmalloc_deallocate (object, data)
+ void *object;
+ void *data ATTRIBUTE_UNUSED;
+{
+ free (object);
+}
+
+
/* Allocate a new splay tree, using COMPARE_FN to compare nodes,
DELETE_KEY_FN to deallocate keys, and DELETE_VALUE_FN to deallocate
- values. */
+ values. Use xmalloc to allocate the splay tree structure, and any
+ nodes added. */
splay_tree
splay_tree_new (compare_fn, delete_key_fn, delete_value_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));
+ return (splay_tree_new_with_allocator
+ (compare_fn, delete_key_fn, delete_value_fn,
+ splay_tree_xmalloc_allocate, splay_tree_xmalloc_deallocate, 0));
+}
+
+
+/* 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_with_allocator (compare_fn, delete_key_fn, delete_value_fn,
+ allocate_fn, deallocate_fn, allocate_data)
+ splay_tree_compare_fn compare_fn;
+ splay_tree_delete_key_fn delete_key_fn;
+ splay_tree_delete_value_fn delete_value_fn;
+ splay_tree_allocate_fn allocate_fn;
+ splay_tree_deallocate_fn deallocate_fn;
+ void *allocate_data;
+{
+ splay_tree sp = (splay_tree) (*allocate_fn) (sizeof (struct splay_tree_s),
+ allocate_data);
sp->root = 0;
sp->comp = compare_fn;
sp->delete_key = delete_key_fn;
sp->delete_value = delete_value_fn;
+ sp->allocate = allocate_fn;
+ sp->deallocate = deallocate_fn;
+ sp->allocate_data = allocate_data;
return sp;
}
splay_tree sp;
{
splay_tree_delete_helper (sp, sp->root);
- free ((char*) sp);
+ (*sp->deallocate) ((char*) sp, sp->allocate_data);
}
/* Insert a new node (associating KEY with DATA) into SP. If a
/* 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 = ((splay_tree_node)
+ (*sp->allocate) (sizeof (struct splay_tree_node_s),
+ sp->allocate_data));
node->key = key;
node->value = value;
node->right->left = 0;
}
- sp->root = node;
- }
+ sp->root = node;
+ }
return sp->root;
}
+/* Remove KEY from SP. It is not an error if it did not exist. */
+
+void
+splay_tree_remove (sp, key)
+ splay_tree sp;
+ splay_tree_key key;
+{
+ splay_tree_splay (sp, key);
+
+ if (sp->root && (*sp->comp) (sp->root->key, key) == 0)
+ {
+ splay_tree_node left, right;
+
+ left = sp->root->left;
+ right = sp->root->right;
+
+ /* Delete the root node itself. */
+ if (sp->delete_value)
+ (*sp->delete_value) (sp->root->value);
+ (*sp->deallocate) (sp->root, sp->allocate_data);
+
+ /* One of the children is now the root. Doesn't matter much
+ which, so long as we preserve the properties of the tree. */
+ if (left)
+ {
+ sp->root = left;
+
+ /* If there was a right child as well, hang it off the
+ right-most leaf of the left child. */
+ if (right)
+ {
+ while (left->right)
+ left = left->right;
+ left->right = right;
+ }
+ }
+ else
+ sp->root = right;
+ }
+}
+
/* Lookup KEY in SP, returning VALUE if present, and NULL
otherwise. */
return 0;
}
+/* Return the node in SP with the greatest key. */
+
+splay_tree_node
+splay_tree_max (sp)
+ splay_tree sp;
+{
+ splay_tree_node n = sp->root;
+
+ if (!n)
+ return NULL;
+
+ while (n->right)
+ n = n->right;
+
+ return n;
+}
+
+/* Return the node in SP with the smallest key. */
+
+splay_tree_node
+splay_tree_min (sp)
+ splay_tree sp;
+{
+ splay_tree_node n = sp->root;
+
+ if (!n)
+ return NULL;
+
+ while (n->left)
+ n = n->left;
+
+ return n;
+}
+
+/* Return the immediate predecessor KEY, or NULL if there is no
+ predecessor. KEY need not be present in the tree. */
+
+splay_tree_node
+splay_tree_predecessor (sp, key)
+ splay_tree sp;
+ splay_tree_key key;
+{
+ int comparison;
+ splay_tree_node node;
+
+ /* If the tree is empty, there is certainly no predecessor. */
+ if (!sp->root)
+ return NULL;
+
+ /* Splay the tree around KEY. That will leave either the KEY
+ itself, its predecessor, or its successor at the root. */
+ splay_tree_splay (sp, key);
+ comparison = (*sp->comp)(sp->root->key, key);
+
+ /* If the predecessor is at the root, just return it. */
+ if (comparison < 0)
+ return sp->root;
+
+ /* Otherwise, find the rightmost element of the left subtree. */
+ node = sp->root->left;
+ if (node)
+ while (node->right)
+ node = node->right;
+
+ return node;
+}
+
+/* Return the immediate successor KEY, or NULL if there is no
+ successor. KEY need not be present in the tree. */
+
+splay_tree_node
+splay_tree_successor (sp, key)
+ splay_tree sp;
+ splay_tree_key key;
+{
+ int comparison;
+ splay_tree_node node;
+
+ /* If the tree is empty, there is certainly no successor. */
+ if (!sp->root)
+ return NULL;
+
+ /* Splay the tree around KEY. That will leave either the KEY
+ itself, its predecessor, or its successor at the root. */
+ splay_tree_splay (sp, key);
+ comparison = (*sp->comp)(sp->root->key, key);
+
+ /* If the successor is at the root, just return it. */
+ if (comparison > 0)
+ return sp->root;
+
+ /* Otherwise, find the leftmost element of the right subtree. */
+ node = sp->root->right;
+ if (node)
+ while (node->left)
+ node = node->left;
+
+ return node;
+}
+
/* 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.
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