[deliverable/binutils-gdb.git] / libiberty / splay-tree.c

/* A splay-tree datatype.  
   Copyright (C) 1998, 1999 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, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, 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.  */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif

#include <stdio.h>

#include "libiberty.h"
#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.  */

static 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_s));
  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.  Returns the new node.  */

splay_tree_node
splay_tree_insert (sp, key, value)
     splay_tree sp;
     splay_tree_key key;
     splay_tree_value value;
{
  int comparison = 0;

  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_s));
      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;
  }

  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);
      free (sp->root);

      /* 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_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);
}

/* Splay-tree comparison function, treating the keys as ints.  */

int
splay_tree_compare_ints (k1, k2)
     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 (k1, k2)
     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;
}
Commit	Line	Data
252b5132	1	/* A splay-tree datatype.
af32ff69	2	Copyright (C) 1998, 1999 Free Software Foundation, Inc.
252b5132 RH	3	Contributed by Mark Mitchell (mark@markmitchell.com).
	4
	5	This file is part of GNU CC.
	6
	7	GNU CC is free software; you can redistribute it and/or modify it
	8	under the terms of the GNU General Public License as published by
	9	the Free Software Foundation; either version 2, or (at your option)
	10	any later version.
	11
	12	GNU CC is distributed in the hope that it will be useful, but
	13	WITHOUT ANY WARRANTY; without even the implied warranty of
	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	15	General Public License for more details.
	16
	17	You should have received a copy of the GNU General Public License
	18	along with GNU CC; see the file COPYING. If not, write to
	19	the Free Software Foundation, 59 Temple Place - Suite 330,
	20	Boston, MA 02111-1307, USA. */
	21
	22	/* For an easily readable description of splay-trees, see:
	23
	24	Lewis, Harry R. and Denenberg, Larry. Data Structures and Their
	25	Algorithms. Harper-Collins, Inc. 1991. */
	26
	27	#ifdef HAVE_CONFIG_H
	28	#include "config.h"
	29	#endif
	30
	31	#ifdef HAVE_STDLIB_H
	32	#include <stdlib.h>
	33	#endif
	34
60c64519 DD	35	#include <stdio.h>
60c64519 DD	36
252b5132 RH	37	#include "libiberty.h"
	38	#include "splay-tree.h"
	39
	40	static void splay_tree_delete_helper PARAMS((splay_tree,
	41	splay_tree_node));
	42	static void splay_tree_splay PARAMS((splay_tree,
	43	splay_tree_key));
	44	static splay_tree_node splay_tree_splay_helper
	45	PARAMS((splay_tree,
	46	splay_tree_key,
	47	splay_tree_node*,
	48	splay_tree_node*,
	49	splay_tree_node*));
	50	static int splay_tree_foreach_helper PARAMS((splay_tree,
	51	splay_tree_node,
	52	splay_tree_foreach_fn,
	53	void*));
	54
	55	/* Deallocate NODE (a member of SP), and all its sub-trees. */
	56
	57	static void
	58	splay_tree_delete_helper (sp, node)
	59	splay_tree sp;
	60	splay_tree_node node;
	61	{
	62	if (!node)
	63	return;
	64
	65	splay_tree_delete_helper (sp, node->left);
	66	splay_tree_delete_helper (sp, node->right);
	67
	68	if (sp->delete_key)
	69	(*sp->delete_key)(node->key);
	70	if (sp->delete_value)
	71	(*sp->delete_value)(node->value);
	72
	73	free ((char*) node);
	74	}
	75
	76	/* Help splay SP around KEY. PARENT and GRANDPARENT are the parent
	77	and grandparent, respectively, of NODE. */
	78
	79	static splay_tree_node
	80	splay_tree_splay_helper (sp, key, node, parent, grandparent)
	81	splay_tree sp;
	82	splay_tree_key key;
	83	splay_tree_node *node;
	84	splay_tree_node *parent;
	85	splay_tree_node *grandparent;
	86	{
	87	splay_tree_node *next;
	88	splay_tree_node n;
	89	int comparison;
	90
	91	n = *node;
	92
	93	if (!n)
	94	return *parent;
	95
	96	comparison = (*sp->comp) (key, n->key);
	97
	98	if (comparison == 0)
	99	/* We've found the target. */
	100	next = 0;
101	else if (comparison < 0)
102	/* The target is to the left. */
103	next = &n->left;
104	else
105	/* The target is to the right. */
106	next = &n->right;
107
108	if (next)
109	{
110	/* Continue down the tree. */
111	n = splay_tree_splay_helper (sp, key, next, node, parent);
112
113	/* The recursive call will change the place to which NODE
114	points. */
115	if (*node != n)
116	return n;
117	}
118
119	if (!parent)
120	/* NODE is the root. We are done. */
121	return n;
122
123	/* First, handle the case where there is no grandparent (i.e.,
124	PARENT is the root of the tree.) /
125	if (!grandparent)
126	{
127	if (n == (*parent)->left)
128	{
129	*node = n->right;
130	n->right = *parent;
131	}
132	else
133	{
134	*node = n->left;
135	n->left = *parent;
136	}
137	*parent = n;
138	return n;
139	}
140
141	/* Next handle the cases where both N and *PARENT are left children,
142	or where both are right children. */
143	if (n == (parent)->left && parent == (*grandparent)->left)
144	{
145	splay_tree_node p = *parent;
146
147	(*grandparent)->left = p->right;
148	p->right = *grandparent;
149	p->left = n->right;
150	n->right = p;
151	*grandparent = n;
152	return n;
153	}
154	else if (n == (parent)->right && parent == (*grandparent)->right)
155	{
156	splay_tree_node p = *parent;
157
158	(*grandparent)->right = p->left;
159	p->left = *grandparent;
160	p->right = n->left;
161	n->left = p;
162	*grandparent = n;
163	return n;
164	}
165
166	/* Finally, deal with the case where N is a left child, but *PARENT
167	is a right child, or vice versa. */
168	if (n == (*parent)->left)
169	{
170	(*parent)->left = n->right;
171	n->right = *parent;
172	(*grandparent)->right = n->left;
173	n->left = *grandparent;
174	*grandparent = n;
175	return n;
176	}
177	else
178	{
179	(*parent)->right = n->left;
180	n->left = *parent;
181	(*grandparent)->left = n->right;
182	n->right = *grandparent;
183	*grandparent = n;
184	return n;
185	}
186	}
187
188	/* Splay SP around KEY. */
189
190	static void
191	splay_tree_splay (sp, key)
192	splay_tree sp;
193	splay_tree_key key;
194	{
195	if (sp->root == 0)
196	return;
197
198	splay_tree_splay_helper (sp, key, &sp->root,
199	/grandparent=/0, /parent=/0);
200	}
201
202	/* Call FN, passing it the DATA, for every node below NODE, all of
203	which are from SP, following an in-order traversal. If FN every
204	returns a non-zero value, the iteration ceases immediately, and the
205	value is returned. Otherwise, this function returns 0. */
206
207	static int
208	splay_tree_foreach_helper (sp, node, fn, data)
209	splay_tree sp;
210	splay_tree_node node;
211	splay_tree_foreach_fn fn;
212	void* data;
213	{
214	int val;
215
216	if (!node)
217	return 0;
218
219	val = splay_tree_foreach_helper (sp, node->left, fn, data);
220	if (val)
221	return val;
222
223	val = (*fn)(node, data);
224	if (val)
225	return val;
226
227	return splay_tree_foreach_helper (sp, node->right, fn, data);
228	}
229
230	/* Allocate a new splay tree, using COMPARE_FN to compare nodes,
231	DELETE_KEY_FN to deallocate keys, and DELETE_VALUE_FN to deallocate
232	values. */
233
234	splay_tree
235	splay_tree_new (compare_fn, delete_key_fn, delete_value_fn)
236	splay_tree_compare_fn compare_fn;
237	splay_tree_delete_key_fn delete_key_fn;
238	splay_tree_delete_value_fn delete_value_fn;
239	{
0c0a36a4	240	splay_tree sp = (splay_tree) xmalloc (sizeof (struct splay_tree_s));
252b5132 RH	241	sp->root = 0;
	242	sp->comp = compare_fn;
	243	sp->delete_key = delete_key_fn;
	244	sp->delete_value = delete_value_fn;
	245
	246	return sp;
	247	}
	248
	249	/* Deallocate SP. */
	250
	251	void
	252	splay_tree_delete (sp)
	253	splay_tree sp;
	254	{
	255	splay_tree_delete_helper (sp, sp->root);
	256	free ((char*) sp);
	257	}
	258
	259	/* Insert a new node (associating KEY with DATA) into SP. If a
	260	previous node with the indicated KEY exists, its data is replaced
0c0a36a4	261	with the new value. Returns the new node. */
252b5132	262
0c0a36a4	263	splay_tree_node
252b5132 RH	264	splay_tree_insert (sp, key, value)
	265	splay_tree sp;
	266	splay_tree_key key;
	267	splay_tree_value value;
	268	{
af32ff69	269	int comparison = 0;
252b5132 RH	270
	271	splay_tree_splay (sp, key);
	272
	273	if (sp->root)
	274	comparison = (*sp->comp)(sp->root->key, key);
	275
	276	if (sp->root && comparison == 0)
	277	{
	278	/* If the root of the tree already has the indicated KEY, just
	279	replace the value with VALUE. */
	280	if (sp->delete_value)
	281	(*sp->delete_value)(sp->root->value);
	282	sp->root->value = value;
	283	}
	284	else
	285	{
	286	/* Create a new node, and insert it at the root. */
	287	splay_tree_node node;
	288
0c0a36a4	289	node = (splay_tree_node) xmalloc (sizeof (struct splay_tree_node_s));
252b5132 RH	290	node->key = key;
	291	node->value = value;
	292
	293	if (!sp->root)
	294	node->left = node->right = 0;
	295	else if (comparison < 0)
	296	{
	297	node->left = sp->root;
	298	node->right = node->left->right;
	299	node->left->right = 0;
	300	}
	301	else
	302	{
	303	node->right = sp->root;
	304	node->left = node->right->left;
	305	node->right->left = 0;
	306	}
	307
	308	sp->root = node;
	309	}
0c0a36a4 ILT	310
0c0a36a4 ILT	311	return sp->root;
252b5132 RH	312	}
252b5132 RH	313
afe36a78 RH	314	/* Remove KEY from SP. It is not an error if it did not exist. */
	315
	316	void
	317	splay_tree_remove (sp, key)
	318	splay_tree sp;
	319	splay_tree_key key;
	320	{
	321	splay_tree_splay (sp, key);
	322
	323	if (sp->root && (*sp->comp) (sp->root->key, key) == 0)
	324	{
	325	splay_tree_node left, right;
	326
	327	left = sp->root->left;
	328	right = sp->root->right;
	329
	330	/* Delete the root node itself. */
	331	if (sp->delete_value)
	332	(*sp->delete_value) (sp->root->value);
	333	free (sp->root);
	334
	335	/* One of the children is now the root. Doesn't matter much
	336	which, so long as we preserve the properties of the tree. */
	337	if (left)
	338	{
	339	sp->root = left;
	340
	341	/* If there was a right child as well, hang it off the
	342	right-most leaf of the left child. */
	343	if (right)
	344	{
	345	while (left->right)
	346	left = left->right;
	347	left->right = right;
	348	}
	349	}
	350	else
	351	sp->root = right;
	352	}
	353	}
	354
252b5132 RH	355	/* Lookup KEY in SP, returning VALUE if present, and NULL
	356	otherwise. */
	357
	358	splay_tree_node
	359	splay_tree_lookup (sp, key)
	360	splay_tree sp;
	361	splay_tree_key key;
	362	{
	363	splay_tree_splay (sp, key);
	364
	365	if (sp->root && (*sp->comp)(sp->root->key, key) == 0)
	366	return sp->root;
	367	else
	368	return 0;
	369	}
	370
	371	/* Call FN, passing it the DATA, for every node in SP, following an
	372	in-order traversal. If FN every returns a non-zero value, the
	373	iteration ceases immediately, and the value is returned.
	374	Otherwise, this function returns 0. */
	375
	376	int
	377	splay_tree_foreach (sp, fn, data)
	378	splay_tree sp;
	379	splay_tree_foreach_fn fn;
	380	void *data;
	381	{
	382	return splay_tree_foreach_helper (sp, sp->root, fn, data);
	383	}
	384
	385	/* Splay-tree comparison function, treating the keys as ints. */
	386
	387	int
	388	splay_tree_compare_ints (k1, k2)
	389	splay_tree_key k1;
	390	splay_tree_key k2;
	391	{
	392	if ((int) k1 < (int) k2)
	393	return -1;
	394	else if ((int) k1 > (int) k2)
	395	return 1;
	396	else
	397	return 0;
	398	}
	399
	400	/* Splay-tree comparison function, treating the keys as pointers. */
	401
	402	int
	403	splay_tree_compare_pointers (k1, k2)
	404	splay_tree_key k1;
	405	splay_tree_key k2;
	406	{
	407	if ((char) k1 < (char) k2)
	408	return -1;
	409	else if ((char) k1 > (char) k2)
	410	return 1;
	411	else
	412	return 0;
	413	}