1*a9fa9459Szrj /* A splay-tree datatype.
2*a9fa9459Szrj Copyright (C) 1998, 1999, 2000, 2001, 2009,
3*a9fa9459Szrj 2010, 2011 Free Software Foundation, Inc.
4*a9fa9459Szrj Contributed by Mark Mitchell (mark@markmitchell.com).
5*a9fa9459Szrj
6*a9fa9459Szrj This file is part of GNU CC.
7*a9fa9459Szrj
8*a9fa9459Szrj GNU CC is free software; you can redistribute it and/or modify it
9*a9fa9459Szrj under the terms of the GNU General Public License as published by
10*a9fa9459Szrj the Free Software Foundation; either version 2, or (at your option)
11*a9fa9459Szrj any later version.
12*a9fa9459Szrj
13*a9fa9459Szrj GNU CC is distributed in the hope that it will be useful, but
14*a9fa9459Szrj WITHOUT ANY WARRANTY; without even the implied warranty of
15*a9fa9459Szrj MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16*a9fa9459Szrj General Public License for more details.
17*a9fa9459Szrj
18*a9fa9459Szrj You should have received a copy of the GNU General Public License
19*a9fa9459Szrj along with GNU CC; see the file COPYING. If not, write to
20*a9fa9459Szrj the Free Software Foundation, 51 Franklin Street - Fifth Floor,
21*a9fa9459Szrj Boston, MA 02110-1301, USA. */
22*a9fa9459Szrj
23*a9fa9459Szrj /* For an easily readable description of splay-trees, see:
24*a9fa9459Szrj
25*a9fa9459Szrj Lewis, Harry R. and Denenberg, Larry. Data Structures and Their
26*a9fa9459Szrj Algorithms. Harper-Collins, Inc. 1991. */
27*a9fa9459Szrj
28*a9fa9459Szrj #ifdef HAVE_CONFIG_H
29*a9fa9459Szrj #include "config.h"
30*a9fa9459Szrj #endif
31*a9fa9459Szrj
32*a9fa9459Szrj #ifdef HAVE_STDLIB_H
33*a9fa9459Szrj #include <stdlib.h>
34*a9fa9459Szrj #endif
35*a9fa9459Szrj
36*a9fa9459Szrj #include <stdio.h>
37*a9fa9459Szrj
38*a9fa9459Szrj #include "libiberty.h"
39*a9fa9459Szrj #include "splay-tree.h"
40*a9fa9459Szrj
41*a9fa9459Szrj static void splay_tree_delete_helper (splay_tree, splay_tree_node);
42*a9fa9459Szrj static inline void rotate_left (splay_tree_node *,
43*a9fa9459Szrj splay_tree_node, splay_tree_node);
44*a9fa9459Szrj static inline void rotate_right (splay_tree_node *,
45*a9fa9459Szrj splay_tree_node, splay_tree_node);
46*a9fa9459Szrj static void splay_tree_splay (splay_tree, splay_tree_key);
47*a9fa9459Szrj static int splay_tree_foreach_helper (splay_tree_node,
48*a9fa9459Szrj splay_tree_foreach_fn, void*);
49*a9fa9459Szrj
50*a9fa9459Szrj /* Deallocate NODE (a member of SP), and all its sub-trees. */
51*a9fa9459Szrj
52*a9fa9459Szrj static void
splay_tree_delete_helper(splay_tree sp,splay_tree_node node)53*a9fa9459Szrj splay_tree_delete_helper (splay_tree sp, splay_tree_node node)
54*a9fa9459Szrj {
55*a9fa9459Szrj splay_tree_node pending = 0;
56*a9fa9459Szrj splay_tree_node active = 0;
57*a9fa9459Szrj
58*a9fa9459Szrj if (!node)
59*a9fa9459Szrj return;
60*a9fa9459Szrj
61*a9fa9459Szrj #define KDEL(x) if (sp->delete_key) (*sp->delete_key)(x);
62*a9fa9459Szrj #define VDEL(x) if (sp->delete_value) (*sp->delete_value)(x);
63*a9fa9459Szrj
64*a9fa9459Szrj KDEL (node->key);
65*a9fa9459Szrj VDEL (node->value);
66*a9fa9459Szrj
67*a9fa9459Szrj /* We use the "key" field to hold the "next" pointer. */
68*a9fa9459Szrj node->key = (splay_tree_key)pending;
69*a9fa9459Szrj pending = (splay_tree_node)node;
70*a9fa9459Szrj
71*a9fa9459Szrj /* Now, keep processing the pending list until there aren't any
72*a9fa9459Szrj more. This is a little more complicated than just recursing, but
73*a9fa9459Szrj it doesn't toast the stack for large trees. */
74*a9fa9459Szrj
75*a9fa9459Szrj while (pending)
76*a9fa9459Szrj {
77*a9fa9459Szrj active = pending;
78*a9fa9459Szrj pending = 0;
79*a9fa9459Szrj while (active)
80*a9fa9459Szrj {
81*a9fa9459Szrj splay_tree_node temp;
82*a9fa9459Szrj
83*a9fa9459Szrj /* active points to a node which has its key and value
84*a9fa9459Szrj deallocated, we just need to process left and right. */
85*a9fa9459Szrj
86*a9fa9459Szrj if (active->left)
87*a9fa9459Szrj {
88*a9fa9459Szrj KDEL (active->left->key);
89*a9fa9459Szrj VDEL (active->left->value);
90*a9fa9459Szrj active->left->key = (splay_tree_key)pending;
91*a9fa9459Szrj pending = (splay_tree_node)(active->left);
92*a9fa9459Szrj }
93*a9fa9459Szrj if (active->right)
94*a9fa9459Szrj {
95*a9fa9459Szrj KDEL (active->right->key);
96*a9fa9459Szrj VDEL (active->right->value);
97*a9fa9459Szrj active->right->key = (splay_tree_key)pending;
98*a9fa9459Szrj pending = (splay_tree_node)(active->right);
99*a9fa9459Szrj }
100*a9fa9459Szrj
101*a9fa9459Szrj temp = active;
102*a9fa9459Szrj active = (splay_tree_node)(temp->key);
103*a9fa9459Szrj (*sp->deallocate) ((char*) temp, sp->allocate_data);
104*a9fa9459Szrj }
105*a9fa9459Szrj }
106*a9fa9459Szrj #undef KDEL
107*a9fa9459Szrj #undef VDEL
108*a9fa9459Szrj }
109*a9fa9459Szrj
110*a9fa9459Szrj /* Rotate the edge joining the left child N with its parent P. PP is the
111*a9fa9459Szrj grandparents' pointer to P. */
112*a9fa9459Szrj
113*a9fa9459Szrj static inline void
rotate_left(splay_tree_node * pp,splay_tree_node p,splay_tree_node n)114*a9fa9459Szrj rotate_left (splay_tree_node *pp, splay_tree_node p, splay_tree_node n)
115*a9fa9459Szrj {
116*a9fa9459Szrj splay_tree_node tmp;
117*a9fa9459Szrj tmp = n->right;
118*a9fa9459Szrj n->right = p;
119*a9fa9459Szrj p->left = tmp;
120*a9fa9459Szrj *pp = n;
121*a9fa9459Szrj }
122*a9fa9459Szrj
123*a9fa9459Szrj /* Rotate the edge joining the right child N with its parent P. PP is the
124*a9fa9459Szrj grandparents' pointer to P. */
125*a9fa9459Szrj
126*a9fa9459Szrj static inline void
rotate_right(splay_tree_node * pp,splay_tree_node p,splay_tree_node n)127*a9fa9459Szrj rotate_right (splay_tree_node *pp, splay_tree_node p, splay_tree_node n)
128*a9fa9459Szrj {
129*a9fa9459Szrj splay_tree_node tmp;
130*a9fa9459Szrj tmp = n->left;
131*a9fa9459Szrj n->left = p;
132*a9fa9459Szrj p->right = tmp;
133*a9fa9459Szrj *pp = n;
134*a9fa9459Szrj }
135*a9fa9459Szrj
136*a9fa9459Szrj /* Bottom up splay of key. */
137*a9fa9459Szrj
138*a9fa9459Szrj static void
splay_tree_splay(splay_tree sp,splay_tree_key key)139*a9fa9459Szrj splay_tree_splay (splay_tree sp, splay_tree_key key)
140*a9fa9459Szrj {
141*a9fa9459Szrj if (sp->root == 0)
142*a9fa9459Szrj return;
143*a9fa9459Szrj
144*a9fa9459Szrj do {
145*a9fa9459Szrj int cmp1, cmp2;
146*a9fa9459Szrj splay_tree_node n, c;
147*a9fa9459Szrj
148*a9fa9459Szrj n = sp->root;
149*a9fa9459Szrj cmp1 = (*sp->comp) (key, n->key);
150*a9fa9459Szrj
151*a9fa9459Szrj /* Found. */
152*a9fa9459Szrj if (cmp1 == 0)
153*a9fa9459Szrj return;
154*a9fa9459Szrj
155*a9fa9459Szrj /* Left or right? If no child, then we're done. */
156*a9fa9459Szrj if (cmp1 < 0)
157*a9fa9459Szrj c = n->left;
158*a9fa9459Szrj else
159*a9fa9459Szrj c = n->right;
160*a9fa9459Szrj if (!c)
161*a9fa9459Szrj return;
162*a9fa9459Szrj
163*a9fa9459Szrj /* Next one left or right? If found or no child, we're done
164*a9fa9459Szrj after one rotation. */
165*a9fa9459Szrj cmp2 = (*sp->comp) (key, c->key);
166*a9fa9459Szrj if (cmp2 == 0
167*a9fa9459Szrj || (cmp2 < 0 && !c->left)
168*a9fa9459Szrj || (cmp2 > 0 && !c->right))
169*a9fa9459Szrj {
170*a9fa9459Szrj if (cmp1 < 0)
171*a9fa9459Szrj rotate_left (&sp->root, n, c);
172*a9fa9459Szrj else
173*a9fa9459Szrj rotate_right (&sp->root, n, c);
174*a9fa9459Szrj return;
175*a9fa9459Szrj }
176*a9fa9459Szrj
177*a9fa9459Szrj /* Now we have the four cases of double-rotation. */
178*a9fa9459Szrj if (cmp1 < 0 && cmp2 < 0)
179*a9fa9459Szrj {
180*a9fa9459Szrj rotate_left (&n->left, c, c->left);
181*a9fa9459Szrj rotate_left (&sp->root, n, n->left);
182*a9fa9459Szrj }
183*a9fa9459Szrj else if (cmp1 > 0 && cmp2 > 0)
184*a9fa9459Szrj {
185*a9fa9459Szrj rotate_right (&n->right, c, c->right);
186*a9fa9459Szrj rotate_right (&sp->root, n, n->right);
187*a9fa9459Szrj }
188*a9fa9459Szrj else if (cmp1 < 0 && cmp2 > 0)
189*a9fa9459Szrj {
190*a9fa9459Szrj rotate_right (&n->left, c, c->right);
191*a9fa9459Szrj rotate_left (&sp->root, n, n->left);
192*a9fa9459Szrj }
193*a9fa9459Szrj else if (cmp1 > 0 && cmp2 < 0)
194*a9fa9459Szrj {
195*a9fa9459Szrj rotate_left (&n->right, c, c->left);
196*a9fa9459Szrj rotate_right (&sp->root, n, n->right);
197*a9fa9459Szrj }
198*a9fa9459Szrj } while (1);
199*a9fa9459Szrj }
200*a9fa9459Szrj
201*a9fa9459Szrj /* Call FN, passing it the DATA, for every node below NODE, all of
202*a9fa9459Szrj which are from SP, following an in-order traversal. If FN every
203*a9fa9459Szrj returns a non-zero value, the iteration ceases immediately, and the
204*a9fa9459Szrj value is returned. Otherwise, this function returns 0. */
205*a9fa9459Szrj
206*a9fa9459Szrj static int
splay_tree_foreach_helper(splay_tree_node node,splay_tree_foreach_fn fn,void * data)207*a9fa9459Szrj splay_tree_foreach_helper (splay_tree_node node,
208*a9fa9459Szrj splay_tree_foreach_fn fn, void *data)
209*a9fa9459Szrj {
210*a9fa9459Szrj int val;
211*a9fa9459Szrj splay_tree_node *stack;
212*a9fa9459Szrj int stack_ptr, stack_size;
213*a9fa9459Szrj
214*a9fa9459Szrj /* A non-recursive implementation is used to avoid filling the stack
215*a9fa9459Szrj for large trees. Splay trees are worst case O(n) in the depth of
216*a9fa9459Szrj the tree. */
217*a9fa9459Szrj
218*a9fa9459Szrj #define INITIAL_STACK_SIZE 100
219*a9fa9459Szrj stack_size = INITIAL_STACK_SIZE;
220*a9fa9459Szrj stack_ptr = 0;
221*a9fa9459Szrj stack = XNEWVEC (splay_tree_node, stack_size);
222*a9fa9459Szrj val = 0;
223*a9fa9459Szrj
224*a9fa9459Szrj for (;;)
225*a9fa9459Szrj {
226*a9fa9459Szrj while (node != NULL)
227*a9fa9459Szrj {
228*a9fa9459Szrj if (stack_ptr == stack_size)
229*a9fa9459Szrj {
230*a9fa9459Szrj stack_size *= 2;
231*a9fa9459Szrj stack = XRESIZEVEC (splay_tree_node, stack, stack_size);
232*a9fa9459Szrj }
233*a9fa9459Szrj stack[stack_ptr++] = node;
234*a9fa9459Szrj node = node->left;
235*a9fa9459Szrj }
236*a9fa9459Szrj
237*a9fa9459Szrj if (stack_ptr == 0)
238*a9fa9459Szrj break;
239*a9fa9459Szrj
240*a9fa9459Szrj node = stack[--stack_ptr];
241*a9fa9459Szrj
242*a9fa9459Szrj val = (*fn) (node, data);
243*a9fa9459Szrj if (val)
244*a9fa9459Szrj break;
245*a9fa9459Szrj
246*a9fa9459Szrj node = node->right;
247*a9fa9459Szrj }
248*a9fa9459Szrj
249*a9fa9459Szrj XDELETEVEC (stack);
250*a9fa9459Szrj return val;
251*a9fa9459Szrj }
252*a9fa9459Szrj
253*a9fa9459Szrj /* An allocator and deallocator based on xmalloc. */
254*a9fa9459Szrj static void *
splay_tree_xmalloc_allocate(int size,void * data ATTRIBUTE_UNUSED)255*a9fa9459Szrj splay_tree_xmalloc_allocate (int size, void *data ATTRIBUTE_UNUSED)
256*a9fa9459Szrj {
257*a9fa9459Szrj return (void *) xmalloc (size);
258*a9fa9459Szrj }
259*a9fa9459Szrj
260*a9fa9459Szrj static void
splay_tree_xmalloc_deallocate(void * object,void * data ATTRIBUTE_UNUSED)261*a9fa9459Szrj splay_tree_xmalloc_deallocate (void *object, void *data ATTRIBUTE_UNUSED)
262*a9fa9459Szrj {
263*a9fa9459Szrj free (object);
264*a9fa9459Szrj }
265*a9fa9459Szrj
266*a9fa9459Szrj
267*a9fa9459Szrj /* Allocate a new splay tree, using COMPARE_FN to compare nodes,
268*a9fa9459Szrj DELETE_KEY_FN to deallocate keys, and DELETE_VALUE_FN to deallocate
269*a9fa9459Szrj values. Use xmalloc to allocate the splay tree structure, and any
270*a9fa9459Szrj nodes added. */
271*a9fa9459Szrj
272*a9fa9459Szrj 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)273*a9fa9459Szrj splay_tree_new (splay_tree_compare_fn compare_fn,
274*a9fa9459Szrj splay_tree_delete_key_fn delete_key_fn,
275*a9fa9459Szrj splay_tree_delete_value_fn delete_value_fn)
276*a9fa9459Szrj {
277*a9fa9459Szrj return (splay_tree_new_with_allocator
278*a9fa9459Szrj (compare_fn, delete_key_fn, delete_value_fn,
279*a9fa9459Szrj splay_tree_xmalloc_allocate, splay_tree_xmalloc_deallocate, 0));
280*a9fa9459Szrj }
281*a9fa9459Szrj
282*a9fa9459Szrj
283*a9fa9459Szrj /* Allocate a new splay tree, using COMPARE_FN to compare nodes,
284*a9fa9459Szrj DELETE_KEY_FN to deallocate keys, and DELETE_VALUE_FN to deallocate
285*a9fa9459Szrj values. */
286*a9fa9459Szrj
287*a9fa9459Szrj splay_tree
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)288*a9fa9459Szrj splay_tree_new_with_allocator (splay_tree_compare_fn compare_fn,
289*a9fa9459Szrj splay_tree_delete_key_fn delete_key_fn,
290*a9fa9459Szrj splay_tree_delete_value_fn delete_value_fn,
291*a9fa9459Szrj splay_tree_allocate_fn allocate_fn,
292*a9fa9459Szrj splay_tree_deallocate_fn deallocate_fn,
293*a9fa9459Szrj void *allocate_data)
294*a9fa9459Szrj {
295*a9fa9459Szrj return
296*a9fa9459Szrj splay_tree_new_typed_alloc (compare_fn, delete_key_fn, delete_value_fn,
297*a9fa9459Szrj allocate_fn, allocate_fn, deallocate_fn,
298*a9fa9459Szrj allocate_data);
299*a9fa9459Szrj }
300*a9fa9459Szrj
301*a9fa9459Szrj /*
302*a9fa9459Szrj
303*a9fa9459Szrj @deftypefn Supplemental splay_tree splay_tree_new_with_typed_alloc @
304*a9fa9459Szrj (splay_tree_compare_fn @var{compare_fn}, @
305*a9fa9459Szrj splay_tree_delete_key_fn @var{delete_key_fn}, @
306*a9fa9459Szrj splay_tree_delete_value_fn @var{delete_value_fn}, @
307*a9fa9459Szrj splay_tree_allocate_fn @var{tree_allocate_fn}, @
308*a9fa9459Szrj splay_tree_allocate_fn @var{node_allocate_fn}, @
309*a9fa9459Szrj splay_tree_deallocate_fn @var{deallocate_fn}, @
310*a9fa9459Szrj void * @var{allocate_data})
311*a9fa9459Szrj
312*a9fa9459Szrj This function creates a splay tree that uses two different allocators
313*a9fa9459Szrj @var{tree_allocate_fn} and @var{node_allocate_fn} to use for allocating the
314*a9fa9459Szrj tree itself and its nodes respectively. This is useful when variables of
315*a9fa9459Szrj different types need to be allocated with different allocators.
316*a9fa9459Szrj
317*a9fa9459Szrj The splay tree will use @var{compare_fn} to compare nodes,
318*a9fa9459Szrj @var{delete_key_fn} to deallocate keys, and @var{delete_value_fn} to
319*a9fa9459Szrj deallocate values.
320*a9fa9459Szrj
321*a9fa9459Szrj @end deftypefn
322*a9fa9459Szrj
323*a9fa9459Szrj */
324*a9fa9459Szrj
325*a9fa9459Szrj splay_tree
splay_tree_new_typed_alloc(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 tree_allocate_fn,splay_tree_allocate_fn node_allocate_fn,splay_tree_deallocate_fn deallocate_fn,void * allocate_data)326*a9fa9459Szrj splay_tree_new_typed_alloc (splay_tree_compare_fn compare_fn,
327*a9fa9459Szrj splay_tree_delete_key_fn delete_key_fn,
328*a9fa9459Szrj splay_tree_delete_value_fn delete_value_fn,
329*a9fa9459Szrj splay_tree_allocate_fn tree_allocate_fn,
330*a9fa9459Szrj splay_tree_allocate_fn node_allocate_fn,
331*a9fa9459Szrj splay_tree_deallocate_fn deallocate_fn,
332*a9fa9459Szrj void * allocate_data)
333*a9fa9459Szrj {
334*a9fa9459Szrj splay_tree sp = (splay_tree) (*tree_allocate_fn)
335*a9fa9459Szrj (sizeof (struct splay_tree_s), allocate_data);
336*a9fa9459Szrj
337*a9fa9459Szrj sp->root = 0;
338*a9fa9459Szrj sp->comp = compare_fn;
339*a9fa9459Szrj sp->delete_key = delete_key_fn;
340*a9fa9459Szrj sp->delete_value = delete_value_fn;
341*a9fa9459Szrj sp->allocate = node_allocate_fn;
342*a9fa9459Szrj sp->deallocate = deallocate_fn;
343*a9fa9459Szrj sp->allocate_data = allocate_data;
344*a9fa9459Szrj
345*a9fa9459Szrj return sp;
346*a9fa9459Szrj }
347*a9fa9459Szrj
348*a9fa9459Szrj /* Deallocate SP. */
349*a9fa9459Szrj
350*a9fa9459Szrj void
splay_tree_delete(splay_tree sp)351*a9fa9459Szrj splay_tree_delete (splay_tree sp)
352*a9fa9459Szrj {
353*a9fa9459Szrj splay_tree_delete_helper (sp, sp->root);
354*a9fa9459Szrj (*sp->deallocate) ((char*) sp, sp->allocate_data);
355*a9fa9459Szrj }
356*a9fa9459Szrj
357*a9fa9459Szrj /* Insert a new node (associating KEY with DATA) into SP. If a
358*a9fa9459Szrj previous node with the indicated KEY exists, its data is replaced
359*a9fa9459Szrj with the new value. Returns the new node. */
360*a9fa9459Szrj
361*a9fa9459Szrj splay_tree_node
splay_tree_insert(splay_tree sp,splay_tree_key key,splay_tree_value value)362*a9fa9459Szrj splay_tree_insert (splay_tree sp, splay_tree_key key, splay_tree_value value)
363*a9fa9459Szrj {
364*a9fa9459Szrj int comparison = 0;
365*a9fa9459Szrj
366*a9fa9459Szrj splay_tree_splay (sp, key);
367*a9fa9459Szrj
368*a9fa9459Szrj if (sp->root)
369*a9fa9459Szrj comparison = (*sp->comp)(sp->root->key, key);
370*a9fa9459Szrj
371*a9fa9459Szrj if (sp->root && comparison == 0)
372*a9fa9459Szrj {
373*a9fa9459Szrj /* If the root of the tree already has the indicated KEY, just
374*a9fa9459Szrj replace the value with VALUE. */
375*a9fa9459Szrj if (sp->delete_value)
376*a9fa9459Szrj (*sp->delete_value)(sp->root->value);
377*a9fa9459Szrj sp->root->value = value;
378*a9fa9459Szrj }
379*a9fa9459Szrj else
380*a9fa9459Szrj {
381*a9fa9459Szrj /* Create a new node, and insert it at the root. */
382*a9fa9459Szrj splay_tree_node node;
383*a9fa9459Szrj
384*a9fa9459Szrj node = ((splay_tree_node)
385*a9fa9459Szrj (*sp->allocate) (sizeof (struct splay_tree_node_s),
386*a9fa9459Szrj sp->allocate_data));
387*a9fa9459Szrj node->key = key;
388*a9fa9459Szrj node->value = value;
389*a9fa9459Szrj
390*a9fa9459Szrj if (!sp->root)
391*a9fa9459Szrj node->left = node->right = 0;
392*a9fa9459Szrj else if (comparison < 0)
393*a9fa9459Szrj {
394*a9fa9459Szrj node->left = sp->root;
395*a9fa9459Szrj node->right = node->left->right;
396*a9fa9459Szrj node->left->right = 0;
397*a9fa9459Szrj }
398*a9fa9459Szrj else
399*a9fa9459Szrj {
400*a9fa9459Szrj node->right = sp->root;
401*a9fa9459Szrj node->left = node->right->left;
402*a9fa9459Szrj node->right->left = 0;
403*a9fa9459Szrj }
404*a9fa9459Szrj
405*a9fa9459Szrj sp->root = node;
406*a9fa9459Szrj }
407*a9fa9459Szrj
408*a9fa9459Szrj return sp->root;
409*a9fa9459Szrj }
410*a9fa9459Szrj
411*a9fa9459Szrj /* Remove KEY from SP. It is not an error if it did not exist. */
412*a9fa9459Szrj
413*a9fa9459Szrj void
splay_tree_remove(splay_tree sp,splay_tree_key key)414*a9fa9459Szrj splay_tree_remove (splay_tree sp, splay_tree_key key)
415*a9fa9459Szrj {
416*a9fa9459Szrj splay_tree_splay (sp, key);
417*a9fa9459Szrj
418*a9fa9459Szrj if (sp->root && (*sp->comp) (sp->root->key, key) == 0)
419*a9fa9459Szrj {
420*a9fa9459Szrj splay_tree_node left, right;
421*a9fa9459Szrj
422*a9fa9459Szrj left = sp->root->left;
423*a9fa9459Szrj right = sp->root->right;
424*a9fa9459Szrj
425*a9fa9459Szrj /* Delete the root node itself. */
426*a9fa9459Szrj if (sp->delete_value)
427*a9fa9459Szrj (*sp->delete_value) (sp->root->value);
428*a9fa9459Szrj (*sp->deallocate) (sp->root, sp->allocate_data);
429*a9fa9459Szrj
430*a9fa9459Szrj /* One of the children is now the root. Doesn't matter much
431*a9fa9459Szrj which, so long as we preserve the properties of the tree. */
432*a9fa9459Szrj if (left)
433*a9fa9459Szrj {
434*a9fa9459Szrj sp->root = left;
435*a9fa9459Szrj
436*a9fa9459Szrj /* If there was a right child as well, hang it off the
437*a9fa9459Szrj right-most leaf of the left child. */
438*a9fa9459Szrj if (right)
439*a9fa9459Szrj {
440*a9fa9459Szrj while (left->right)
441*a9fa9459Szrj left = left->right;
442*a9fa9459Szrj left->right = right;
443*a9fa9459Szrj }
444*a9fa9459Szrj }
445*a9fa9459Szrj else
446*a9fa9459Szrj sp->root = right;
447*a9fa9459Szrj }
448*a9fa9459Szrj }
449*a9fa9459Szrj
450*a9fa9459Szrj /* Lookup KEY in SP, returning VALUE if present, and NULL
451*a9fa9459Szrj otherwise. */
452*a9fa9459Szrj
453*a9fa9459Szrj splay_tree_node
splay_tree_lookup(splay_tree sp,splay_tree_key key)454*a9fa9459Szrj splay_tree_lookup (splay_tree sp, splay_tree_key key)
455*a9fa9459Szrj {
456*a9fa9459Szrj splay_tree_splay (sp, key);
457*a9fa9459Szrj
458*a9fa9459Szrj if (sp->root && (*sp->comp)(sp->root->key, key) == 0)
459*a9fa9459Szrj return sp->root;
460*a9fa9459Szrj else
461*a9fa9459Szrj return 0;
462*a9fa9459Szrj }
463*a9fa9459Szrj
464*a9fa9459Szrj /* Return the node in SP with the greatest key. */
465*a9fa9459Szrj
466*a9fa9459Szrj splay_tree_node
splay_tree_max(splay_tree sp)467*a9fa9459Szrj splay_tree_max (splay_tree sp)
468*a9fa9459Szrj {
469*a9fa9459Szrj splay_tree_node n = sp->root;
470*a9fa9459Szrj
471*a9fa9459Szrj if (!n)
472*a9fa9459Szrj return NULL;
473*a9fa9459Szrj
474*a9fa9459Szrj while (n->right)
475*a9fa9459Szrj n = n->right;
476*a9fa9459Szrj
477*a9fa9459Szrj return n;
478*a9fa9459Szrj }
479*a9fa9459Szrj
480*a9fa9459Szrj /* Return the node in SP with the smallest key. */
481*a9fa9459Szrj
482*a9fa9459Szrj splay_tree_node
splay_tree_min(splay_tree sp)483*a9fa9459Szrj splay_tree_min (splay_tree sp)
484*a9fa9459Szrj {
485*a9fa9459Szrj splay_tree_node n = sp->root;
486*a9fa9459Szrj
487*a9fa9459Szrj if (!n)
488*a9fa9459Szrj return NULL;
489*a9fa9459Szrj
490*a9fa9459Szrj while (n->left)
491*a9fa9459Szrj n = n->left;
492*a9fa9459Szrj
493*a9fa9459Szrj return n;
494*a9fa9459Szrj }
495*a9fa9459Szrj
496*a9fa9459Szrj /* Return the immediate predecessor KEY, or NULL if there is no
497*a9fa9459Szrj predecessor. KEY need not be present in the tree. */
498*a9fa9459Szrj
499*a9fa9459Szrj splay_tree_node
splay_tree_predecessor(splay_tree sp,splay_tree_key key)500*a9fa9459Szrj splay_tree_predecessor (splay_tree sp, splay_tree_key key)
501*a9fa9459Szrj {
502*a9fa9459Szrj int comparison;
503*a9fa9459Szrj splay_tree_node node;
504*a9fa9459Szrj
505*a9fa9459Szrj /* If the tree is empty, there is certainly no predecessor. */
506*a9fa9459Szrj if (!sp->root)
507*a9fa9459Szrj return NULL;
508*a9fa9459Szrj
509*a9fa9459Szrj /* Splay the tree around KEY. That will leave either the KEY
510*a9fa9459Szrj itself, its predecessor, or its successor at the root. */
511*a9fa9459Szrj splay_tree_splay (sp, key);
512*a9fa9459Szrj comparison = (*sp->comp)(sp->root->key, key);
513*a9fa9459Szrj
514*a9fa9459Szrj /* If the predecessor is at the root, just return it. */
515*a9fa9459Szrj if (comparison < 0)
516*a9fa9459Szrj return sp->root;
517*a9fa9459Szrj
518*a9fa9459Szrj /* Otherwise, find the rightmost element of the left subtree. */
519*a9fa9459Szrj node = sp->root->left;
520*a9fa9459Szrj if (node)
521*a9fa9459Szrj while (node->right)
522*a9fa9459Szrj node = node->right;
523*a9fa9459Szrj
524*a9fa9459Szrj return node;
525*a9fa9459Szrj }
526*a9fa9459Szrj
527*a9fa9459Szrj /* Return the immediate successor KEY, or NULL if there is no
528*a9fa9459Szrj successor. KEY need not be present in the tree. */
529*a9fa9459Szrj
530*a9fa9459Szrj splay_tree_node
splay_tree_successor(splay_tree sp,splay_tree_key key)531*a9fa9459Szrj splay_tree_successor (splay_tree sp, splay_tree_key key)
532*a9fa9459Szrj {
533*a9fa9459Szrj int comparison;
534*a9fa9459Szrj splay_tree_node node;
535*a9fa9459Szrj
536*a9fa9459Szrj /* If the tree is empty, there is certainly no successor. */
537*a9fa9459Szrj if (!sp->root)
538*a9fa9459Szrj return NULL;
539*a9fa9459Szrj
540*a9fa9459Szrj /* Splay the tree around KEY. That will leave either the KEY
541*a9fa9459Szrj itself, its predecessor, or its successor at the root. */
542*a9fa9459Szrj splay_tree_splay (sp, key);
543*a9fa9459Szrj comparison = (*sp->comp)(sp->root->key, key);
544*a9fa9459Szrj
545*a9fa9459Szrj /* If the successor is at the root, just return it. */
546*a9fa9459Szrj if (comparison > 0)
547*a9fa9459Szrj return sp->root;
548*a9fa9459Szrj
549*a9fa9459Szrj /* Otherwise, find the leftmost element of the right subtree. */
550*a9fa9459Szrj node = sp->root->right;
551*a9fa9459Szrj if (node)
552*a9fa9459Szrj while (node->left)
553*a9fa9459Szrj node = node->left;
554*a9fa9459Szrj
555*a9fa9459Szrj return node;
556*a9fa9459Szrj }
557*a9fa9459Szrj
558*a9fa9459Szrj /* Call FN, passing it the DATA, for every node in SP, following an
559*a9fa9459Szrj in-order traversal. If FN every returns a non-zero value, the
560*a9fa9459Szrj iteration ceases immediately, and the value is returned.
561*a9fa9459Szrj Otherwise, this function returns 0. */
562*a9fa9459Szrj
563*a9fa9459Szrj int
splay_tree_foreach(splay_tree sp,splay_tree_foreach_fn fn,void * data)564*a9fa9459Szrj splay_tree_foreach (splay_tree sp, splay_tree_foreach_fn fn, void *data)
565*a9fa9459Szrj {
566*a9fa9459Szrj return splay_tree_foreach_helper (sp->root, fn, data);
567*a9fa9459Szrj }
568*a9fa9459Szrj
569*a9fa9459Szrj /* Splay-tree comparison function, treating the keys as ints. */
570*a9fa9459Szrj
571*a9fa9459Szrj int
splay_tree_compare_ints(splay_tree_key k1,splay_tree_key k2)572*a9fa9459Szrj splay_tree_compare_ints (splay_tree_key k1, splay_tree_key k2)
573*a9fa9459Szrj {
574*a9fa9459Szrj if ((int) k1 < (int) k2)
575*a9fa9459Szrj return -1;
576*a9fa9459Szrj else if ((int) k1 > (int) k2)
577*a9fa9459Szrj return 1;
578*a9fa9459Szrj else
579*a9fa9459Szrj return 0;
580*a9fa9459Szrj }
581*a9fa9459Szrj
582*a9fa9459Szrj /* Splay-tree comparison function, treating the keys as pointers. */
583*a9fa9459Szrj
584*a9fa9459Szrj int
splay_tree_compare_pointers(splay_tree_key k1,splay_tree_key k2)585*a9fa9459Szrj splay_tree_compare_pointers (splay_tree_key k1, splay_tree_key k2)
586*a9fa9459Szrj {
587*a9fa9459Szrj if ((char*) k1 < (char*) k2)
588*a9fa9459Szrj return -1;
589*a9fa9459Szrj else if ((char*) k1 > (char*) k2)
590*a9fa9459Szrj return 1;
591*a9fa9459Szrj else
592*a9fa9459Szrj return 0;
593*a9fa9459Szrj }
594