tools/perf/util/rbtree.c

   1 /*
   2   Red Black Trees
   3   (C) 1999  Andrea Arcangeli <andrea@suse.de>
   4   (C) 2002  David Woodhouse <dwmw2@infradead.org>
   5
   6   This program is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU General Public License as published by
   8   the Free Software Foundation; either version 2 of the License, or
   9   (at your option) any later version.
  10
  11   This program is distributed in the hope that it will be useful,
  12   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14   GNU General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   along with this program; if not, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19
  20   linux/lib/rbtree.c
  21 */
  22
  23 #include "rbtree.h"
  24
  25 static void __rb_rotate_left(struct rb_node *node, struct rb_root *root)
  26 {
  27         struct rb_node *right = node->rb_right;
  28         struct rb_node *parent = rb_parent(node);
  29
  30         if ((node->rb_right = right->rb_left))
  31                 rb_set_parent(right->rb_left, node);
  32         right->rb_left = node;
  33
  34         rb_set_parent(right, parent);
  35
  36         if (parent)
  37         {
  38                 if (node == parent->rb_left)
  39                         parent->rb_left = right;
  40                 else
  41                         parent->rb_right = right;
  42         }
  43         else
  44                 root->rb_node = right;
  45         rb_set_parent(node, right);
  46 }
  47
  48 static void __rb_rotate_right(struct rb_node *node, struct rb_root *root)
  49 {
  50         struct rb_node *left = node->rb_left;
  51         struct rb_node *parent = rb_parent(node);
  52
  53         if ((node->rb_left = left->rb_right))
  54                 rb_set_parent(left->rb_right, node);
  55         left->rb_right = node;
  56
  57         rb_set_parent(left, parent);
  58
  59         if (parent)
  60         {
  61                 if (node == parent->rb_right)
  62                         parent->rb_right = left;
  63                 else
  64                         parent->rb_left = left;
  65         }
  66         else
  67                 root->rb_node = left;
  68         rb_set_parent(node, left);
  69 }
  70
  71 void rb_insert_color(struct rb_node *node, struct rb_root *root)
  72 {
  73         struct rb_node *parent, *gparent;
  74
  75         while ((parent = rb_parent(node)) && rb_is_red(parent))
  76         {
  77                 gparent = rb_parent(parent);
  78
  79                 if (parent == gparent->rb_left)
  80                 {
  81                         {
  82                                 register struct rb_node *uncle = gparent->rb_right;
  83                                 if (uncle && rb_is_red(uncle))
  84                                 {
  85                                         rb_set_black(uncle);
  86                                         rb_set_black(parent);
  87                                         rb_set_red(gparent);
  88                                         node = gparent;
  89                                         continue;
  90                                 }
  91                         }
  92
  93                         if (parent->rb_right == node)
  94                         {
  95                                 register struct rb_node *tmp;
  96                                 __rb_rotate_left(parent, root);
  97                                 tmp = parent;
  98                                 parent = node;
  99                                 node = tmp;
 100                         }
 101
 102                         rb_set_black(parent);
 103                         rb_set_red(gparent);
 104                         __rb_rotate_right(gparent, root);
 105                 } else {
 106                         {
 107                                 register struct rb_node *uncle = gparent->rb_left;
 108                                 if (uncle && rb_is_red(uncle))
 109                                 {
 110                                         rb_set_black(uncle);
 111                                         rb_set_black(parent);
 112                                         rb_set_red(gparent);
 113                                         node = gparent;
 114                                         continue;
 115                                 }
 116                         }
 117
 118                         if (parent->rb_left == node)
 119                         {
 120                                 register struct rb_node *tmp;
 121                                 __rb_rotate_right(parent, root);
 122                                 tmp = parent;
 123                                 parent = node;
 124                                 node = tmp;
 125                         }
 126
 127                         rb_set_black(parent);
 128                         rb_set_red(gparent);
 129                         __rb_rotate_left(gparent, root);
 130                 }
 131         }
 132
 133         rb_set_black(root->rb_node);
 134 }
 135
 136 static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
 137                              struct rb_root *root)
 138 {
 139         struct rb_node *other;
 140
 141         while ((!node || rb_is_black(node)) && node != root->rb_node)
 142         {
 143                 if (parent->rb_left == node)
 144                 {
 145                         other = parent->rb_right;
 146                         if (rb_is_red(other))
 147                         {
 148                                 rb_set_black(other);
 149                                 rb_set_red(parent);
 150                                 __rb_rotate_left(parent, root);
 151                                 other = parent->rb_right;
 152                         }
 153                         if ((!other->rb_left || rb_is_black(other->rb_left)) &&
 154                             (!other->rb_right || rb_is_black(other->rb_right)))
 155                         {
 156                                 rb_set_red(other);
 157                                 node = parent;
 158                                 parent = rb_parent(node);
 159                         }
 160                         else
 161                         {
 162                                 if (!other->rb_right || rb_is_black(other->rb_right))
 163                                 {
 164                                         rb_set_black(other->rb_left);
 165                                         rb_set_red(other);
 166                                         __rb_rotate_right(other, root);
 167                                         other = parent->rb_right;
 168                                 }
 169                                 rb_set_color(other, rb_color(parent));
 170                                 rb_set_black(parent);
 171                                 rb_set_black(other->rb_right);
 172                                 __rb_rotate_left(parent, root);
 173                                 node = root->rb_node;
 174                                 break;
 175                         }
 176                 }
 177                 else
 178                 {
 179                         other = parent->rb_left;
 180                         if (rb_is_red(other))
 181                         {
 182                                 rb_set_black(other);
 183                                 rb_set_red(parent);
 184                                 __rb_rotate_right(parent, root);
 185                                 other = parent->rb_left;
 186                         }
 187                         if ((!other->rb_left || rb_is_black(other->rb_left)) &&
 188                             (!other->rb_right || rb_is_black(other->rb_right)))
 189                         {
 190                                 rb_set_red(other);
 191                                 node = parent;
 192                                 parent = rb_parent(node);
 193                         }
 194                         else
 195                         {
 196                                 if (!other->rb_left || rb_is_black(other->rb_left))
 197                                 {
 198                                         rb_set_black(other->rb_right);
 199                                         rb_set_red(other);
 200                                         __rb_rotate_left(other, root);
 201                                         other = parent->rb_left;
 202                                 }
 203                                 rb_set_color(other, rb_color(parent));
 204                                 rb_set_black(parent);
 205                                 rb_set_black(other->rb_left);
 206                                 __rb_rotate_right(parent, root);
 207                                 node = root->rb_node;
 208                                 break;
 209                         }
 210                 }
 211         }
 212         if (node)
 213                 rb_set_black(node);
 214 }
 215
 216 void rb_erase(struct rb_node *node, struct rb_root *root)
 217 {
 218         struct rb_node *child, *parent;
 219         int color;
 220
 221         if (!node->rb_left)
 222                 child = node->rb_right;
 223         else if (!node->rb_right)
 224                 child = node->rb_left;
 225         else
 226         {
 227                 struct rb_node *old = node, *left;
 228
 229                 node = node->rb_right;
 230                 while ((left = node->rb_left) != NULL)
 231                         node = left;
 232                 child = node->rb_right;
 233                 parent = rb_parent(node);
 234                 color = rb_color(node);
 235
 236                 if (child)
 237                         rb_set_parent(child, parent);
 238                 if (parent == old) {
 239                         parent->rb_right = child;
 240                         parent = node;
 241                 } else
 242                         parent->rb_left = child;
 243
 244                 node->rb_parent_color = old->rb_parent_color;
 245                 node->rb_right = old->rb_right;
 246                 node->rb_left = old->rb_left;
 247
 248                 if (rb_parent(old))
 249                 {
 250                         if (rb_parent(old)->rb_left == old)
 251                                 rb_parent(old)->rb_left = node;
 252                         else
 253                                 rb_parent(old)->rb_right = node;
 254                 } else
 255                         root->rb_node = node;
 256
 257                 rb_set_parent(old->rb_left, node);
 258                 if (old->rb_right)
 259                         rb_set_parent(old->rb_right, node);
 260                 goto color;
 261         }
 262
 263         parent = rb_parent(node);
 264         color = rb_color(node);
 265
 266         if (child)
 267                 rb_set_parent(child, parent);
 268         if (parent)
 269         {
 270                 if (parent->rb_left == node)
 271                         parent->rb_left = child;
 272                 else
 273                         parent->rb_right = child;
 274         }
 275         else
 276                 root->rb_node = child;
 277
 278  color:
 279         if (color == RB_BLACK)
 280                 __rb_erase_color(child, parent, root);
 281 }
 282
 283 /*
 284  * This function returns the first node (in sort order) of the tree.
 285  */
 286 struct rb_node *rb_first(const struct rb_root *root)
 287 {
 288         struct rb_node  *n;
 289
 290         n = root->rb_node;
 291         if (!n)
 292                 return NULL;
 293         while (n->rb_left)
 294                 n = n->rb_left;
 295         return n;
 296 }
 297
 298 struct rb_node *rb_last(const struct rb_root *root)
 299 {
 300         struct rb_node  *n;
 301
 302         n = root->rb_node;
 303         if (!n)
 304                 return NULL;
 305         while (n->rb_right)
 306                 n = n->rb_right;
 307         return n;
 308 }
 309
 310 struct rb_node *rb_next(const struct rb_node *node)
 311 {
 312         struct rb_node *parent;
 313
 314         if (rb_parent(node) == node)
 315                 return NULL;
 316
 317         /* If we have a right-hand child, go down and then left as far
 318            as we can. */
 319         if (node->rb_right) {
 320                 node = node->rb_right;
 321                 while (node->rb_left)
 322                         node=node->rb_left;
 323                 return (struct rb_node *)node;
 324         }
 325
 326         /* No right-hand children.  Everything down and left is
 327            smaller than us, so any 'next' node must be in the general
 328            direction of our parent. Go up the tree; any time the
 329            ancestor is a right-hand child of its parent, keep going
 330            up. First time it's a left-hand child of its parent, said
 331            parent is our 'next' node. */
 332         while ((parent = rb_parent(node)) && node == parent->rb_right)
 333                 node = parent;
 334
 335         return parent;
 336 }
 337
 338 struct rb_node *rb_prev(const struct rb_node *node)
 339 {
 340         struct rb_node *parent;
 341
 342         if (rb_parent(node) == node)
 343                 return NULL;
 344
 345         /* If we have a left-hand child, go down and then right as far
 346            as we can. */
 347         if (node->rb_left) {
 348                 node = node->rb_left;
 349                 while (node->rb_right)
 350                         node=node->rb_right;
 351                 return (struct rb_node *)node;
 352         }
 353
 354         /* No left-hand children. Go up till we find an ancestor which
 355            is a right-hand child of its parent */
 356         while ((parent = rb_parent(node)) && node == parent->rb_left)
 357                 node = parent;
 358
 359         return parent;
 360 }
 361
 362 void rb_replace_node(struct rb_node *victim, struct rb_node *new,
 363                      struct rb_root *root)
 364 {
 365         struct rb_node *parent = rb_parent(victim);
 366
 367         /* Set the surrounding nodes to point to the replacement */
 368         if (parent) {
 369                 if (victim == parent->rb_left)
 370                         parent->rb_left = new;
 371                 else
 372                         parent->rb_right = new;
 373         } else {
 374                 root->rb_node = new;
 375         }
 376         if (victim->rb_left)
 377                 rb_set_parent(victim->rb_left, new);
 378         if (victim->rb_right)
 379                 rb_set_parent(victim->rb_right, new);
 380
 381         /* Copy the pointers/colour from the victim to the replacement */
 382         *new = *victim;
 383 }