/* A splay-tree datatype.
- Copyright (C) 1998 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.
+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 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.
+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.
+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, 51 Franklin Street - Fifth Floor,
+Boston, MA 02110-1301, USA. */
- For an easily readable description of splay-trees, see:
+/* 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
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+
+#include <stdio.h>
+
#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*));
+static void splay_tree_delete_helper (splay_tree, splay_tree_node);
+static inline void rotate_left (splay_tree_node *,
+ splay_tree_node, splay_tree_node);
+static inline void rotate_right (splay_tree_node *,
+ splay_tree_node, splay_tree_node);
+static void splay_tree_splay (splay_tree, splay_tree_key);
+static int splay_tree_foreach_helper (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;
+splay_tree_delete_helper (splay_tree sp, splay_tree_node node)
{
+ splay_tree_node pending = 0;
+ splay_tree_node active = 0;
+
if (!node)
return;
- splay_tree_delete_helper (sp, node->left);
- splay_tree_delete_helper (sp, node->right);
+#define KDEL(x) if (sp->delete_key) (*sp->delete_key)(x);
+#define VDEL(x) if (sp->delete_value) (*sp->delete_value)(x);
- if (sp->delete_key)
- (*sp->delete_key)(node->key);
- if (sp->delete_value)
- (*sp->delete_value)(node->value);
+ KDEL (node->key);
+ VDEL (node->value);
- free ((char*) node);
-}
+ /* We use the "key" field to hold the "next" pointer. */
+ node->key = (splay_tree_key)pending;
+ pending = (splay_tree_node)node;
-/* Help splay SP around KEY. PARENT and GRANDPARENT are the parent
- and grandparent, respectively, of NODE. */
+ /* Now, keep processing the pending list until there aren't any
+ more. This is a little more complicated than just recursing, but
+ it doesn't toast the stack for large trees. */
-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)
+ while (pending)
{
- /* 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
+ active = pending;
+ pending = 0;
+ while (active)
{
- *node = n->left;
- n->left = *parent;
+ splay_tree_node temp;
+
+ /* active points to a node which has its key and value
+ deallocated, we just need to process left and right. */
+
+ if (active->left)
+ {
+ KDEL (active->left->key);
+ VDEL (active->left->value);
+ active->left->key = (splay_tree_key)pending;
+ pending = (splay_tree_node)(active->left);
+ }
+ if (active->right)
+ {
+ KDEL (active->right->key);
+ VDEL (active->right->value);
+ active->right->key = (splay_tree_key)pending;
+ pending = (splay_tree_node)(active->right);
+ }
+
+ temp = active;
+ active = (splay_tree_node)(temp->key);
+ (*sp->deallocate) ((char*) temp, sp->allocate_data);
}
- *parent = n;
- return n;
}
+#undef KDEL
+#undef VDEL
+}
- /* 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;
- }
+/* Rotate the edge joining the left child N with its parent P. PP is the
+ grandparents' pointer to P. */
- /* 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;
- }
+static inline void
+rotate_left (splay_tree_node *pp, splay_tree_node p, splay_tree_node n)
+{
+ splay_tree_node tmp;
+ tmp = n->right;
+ n->right = p;
+ p->left = tmp;
+ *pp = n;
+}
+
+/* Rotate the edge joining the right child N with its parent P. PP is the
+ grandparents' pointer to P. */
+
+static inline void
+rotate_right (splay_tree_node *pp, splay_tree_node p, splay_tree_node n)
+{
+ splay_tree_node tmp;
+ tmp = n->left;
+ n->left = p;
+ p->right = tmp;
+ *pp = n;
}
-/* Splay SP around KEY. */
+/* Bottom up splay of key. */
static void
-splay_tree_splay (sp, key)
- splay_tree sp;
- splay_tree_key key;
+splay_tree_splay (splay_tree sp, splay_tree_key key)
{
if (sp->root == 0)
return;
- splay_tree_splay_helper (sp, key, &sp->root,
- /*grandparent=*/0, /*parent=*/0);
+ do {
+ int cmp1, cmp2;
+ splay_tree_node n, c;
+
+ n = sp->root;
+ cmp1 = (*sp->comp) (key, n->key);
+
+ /* Found. */
+ if (cmp1 == 0)
+ return;
+
+ /* Left or right? If no child, then we're done. */
+ if (cmp1 < 0)
+ c = n->left;
+ else
+ c = n->right;
+ if (!c)
+ return;
+
+ /* Next one left or right? If found or no child, we're done
+ after one rotation. */
+ cmp2 = (*sp->comp) (key, c->key);
+ if (cmp2 == 0
+ || (cmp2 < 0 && !c->left)
+ || (cmp2 > 0 && !c->right))
+ {
+ if (cmp1 < 0)
+ rotate_left (&sp->root, n, c);
+ else
+ rotate_right (&sp->root, n, c);
+ return;
+ }
+
+ /* Now we have the four cases of double-rotation. */
+ if (cmp1 < 0 && cmp2 < 0)
+ {
+ rotate_left (&n->left, c, c->left);
+ rotate_left (&sp->root, n, n->left);
+ }
+ else if (cmp1 > 0 && cmp2 > 0)
+ {
+ rotate_right (&n->right, c, c->right);
+ rotate_right (&sp->root, n, n->right);
+ }
+ else if (cmp1 < 0 && cmp2 > 0)
+ {
+ rotate_right (&n->left, c, c->right);
+ rotate_left (&sp->root, n, n->left);
+ }
+ else if (cmp1 > 0 && cmp2 < 0)
+ {
+ rotate_left (&n->right, c, c->left);
+ rotate_right (&sp->root, n, n->right);
+ }
+ } while (1);
}
/* Call FN, passing it the DATA, for every node below NODE, all of
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;
+static int
+splay_tree_foreach_helper (splay_tree sp, splay_tree_node node,
+ splay_tree_foreach_fn fn, void *data)
{
int val;
return splay_tree_foreach_helper (sp, node->right, fn, data);
}
+
+/* An allocator and deallocator based on xmalloc. */
+static void *
+splay_tree_xmalloc_allocate (int size, void *data ATTRIBUTE_UNUSED)
+{
+ return (void *) xmalloc (size);
+}
+
+static void
+splay_tree_xmalloc_deallocate (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. Use xmalloc to allocate the splay tree structure, and any
+ nodes added. */
+
+splay_tree
+splay_tree_new (splay_tree_compare_fn compare_fn,
+ splay_tree_delete_key_fn delete_key_fn,
+ splay_tree_delete_value_fn delete_value_fn)
+{
+ 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 (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_new_with_allocator (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) xmalloc (sizeof (struct splay_tree));
+ 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;
}
/* Deallocate SP. */
void
-splay_tree_delete (sp)
- splay_tree sp;
+splay_tree_delete (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
previous node with the indicated KEY exists, its data is replaced
- with the new value. */
+ with the new value. Returns the new node. */
-void
-splay_tree_insert (sp, key, value)
- splay_tree sp;
- splay_tree_key key;
- splay_tree_value value;
+splay_tree_node
+splay_tree_insert (splay_tree sp, splay_tree_key key, splay_tree_value value)
{
- int comparison;
+ int comparison = 0;
splay_tree_splay (sp, key);
/* 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 (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. */
splay_tree_node
-splay_tree_lookup (sp, key)
- splay_tree sp;
- splay_tree_key key;
+splay_tree_lookup (splay_tree sp, splay_tree_key key)
{
splay_tree_splay (sp, key);
return 0;
}
+/* Return the node in SP with the greatest key. */
+
+splay_tree_node
+splay_tree_max (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 (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 (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 (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.
Otherwise, this function returns 0. */
int
-splay_tree_foreach (sp, fn, data)
- splay_tree sp;
- splay_tree_foreach_fn fn;
- void *data;
+splay_tree_foreach (splay_tree sp, splay_tree_foreach_fn fn, void *data)
{
return splay_tree_foreach_helper (sp, sp->root, fn, data);
}
+
+/* Splay-tree comparison function, treating the keys as ints. */
+
+int
+splay_tree_compare_ints (splay_tree_key k1, splay_tree_key k2)
+{
+ if ((int) k1 < (int) k2)
+ return -1;
+ else if ((int) k1 > (int) k2)
+ return 1;
+ else
+ return 0;
+}
+
+/* Splay-tree comparison function, treating the keys as pointers. */
+
+int
+splay_tree_compare_pointers (splay_tree_key k1, splay_tree_key k2)
+{
+ if ((char*) k1 < (char*) k2)
+ return -1;
+ else if ((char*) k1 > (char*) k2)
+ return 1;
+ else
+ return 0;
+}
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