| /* A splay-tree datatype. |
| Copyright (C) 1998-2019 Free Software Foundation, Inc. |
| Contributed by Mark Mitchell (mark@markmitchell.com). |
| |
| This file is part of the GNU Offloading and Multi Processing Library |
| (libgomp). |
| |
| Libgomp 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 3, or (at your option) |
| any later version. |
| |
| Libgomp 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. |
| |
| Under Section 7 of GPL version 3, you are granted additional |
| permissions described in the GCC Runtime Library Exception, version |
| 3.1, as published by the Free Software Foundation. |
| |
| You should have received a copy of the GNU General Public License and |
| a copy of the GCC Runtime Library Exception along with this program; |
| see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* The splay tree code copied from include/splay-tree.h and adjusted, |
| so that all the data lives directly in splay_tree_node_s structure |
| and no extra allocations are needed. */ |
| |
| /* For an easily readable description of splay-trees, see: |
| |
| Lewis, Harry R. and Denenberg, Larry. Data Structures and Their |
| Algorithms. Harper-Collins, Inc. 1991. |
| |
| The major feature of splay trees is that all basic tree operations |
| are amortized O(log n) time for a tree with n nodes. */ |
| |
| #include "libgomp.h" |
| |
| /* Rotate the edge joining the left child N with its parent P. PP is the |
| grandparents' pointer to P. */ |
| |
| 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; |
| } |
| |
| /* Bottom up splay of KEY. */ |
| |
| static void |
| splay_tree_splay (splay_tree sp, splay_tree_key key) |
| { |
| if (sp->root == NULL) |
| return; |
| |
| do { |
| int cmp1, cmp2; |
| splay_tree_node n, c; |
| |
| n = sp->root; |
| cmp1 = splay_compare (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 = splay_compare (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); |
| } |
| |
| /* Insert a new NODE into SP. The NODE shouldn't exist in the tree. */ |
| |
| attribute_hidden void |
| splay_tree_insert (splay_tree sp, splay_tree_node node) |
| { |
| int comparison = 0; |
| |
| splay_tree_splay (sp, &node->key); |
| |
| if (sp->root) |
| comparison = splay_compare (&sp->root->key, &node->key); |
| |
| if (sp->root && comparison == 0) |
| gomp_fatal ("Duplicate node"); |
| else |
| { |
| /* Insert it at the root. */ |
| if (sp->root == NULL) |
| node->left = node->right = NULL; |
| else if (comparison < 0) |
| { |
| node->left = sp->root; |
| node->right = node->left->right; |
| node->left->right = NULL; |
| } |
| else |
| { |
| node->right = sp->root; |
| node->left = node->right->left; |
| node->right->left = NULL; |
| } |
| |
| sp->root = node; |
| } |
| } |
| |
| /* Remove node with KEY from SP. It is not an error if it did not exist. */ |
| |
| attribute_hidden void |
| splay_tree_remove (splay_tree sp, splay_tree_key key) |
| { |
| splay_tree_splay (sp, key); |
| |
| if (sp->root && splay_compare (&sp->root->key, key) == 0) |
| { |
| splay_tree_node left, right; |
| |
| left = sp->root->left; |
| right = sp->root->right; |
| |
| /* 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 NODE if present, and NULL |
| otherwise. */ |
| |
| attribute_hidden splay_tree_key |
| splay_tree_lookup (splay_tree sp, splay_tree_key key) |
| { |
| splay_tree_splay (sp, key); |
| |
| if (sp->root && splay_compare (&sp->root->key, key) == 0) |
| return &sp->root->key; |
| else |
| return NULL; |
| } |
| |
| /* Helper function for splay_tree_foreach. |
| |
| Run FUNC on every node in KEY. */ |
| |
| static void |
| splay_tree_foreach_internal (splay_tree_node node, splay_tree_callback func, |
| void *data) |
| { |
| if (!node) |
| return; |
| func (&node->key, data); |
| splay_tree_foreach_internal (node->left, func, data); |
| /* Yeah, whatever. GCC can fix my tail recursion. */ |
| splay_tree_foreach_internal (node->right, func, data); |
| } |
| |
| /* Run FUNC on each of the nodes in SP. */ |
| |
| attribute_hidden void |
| splay_tree_foreach (splay_tree sp, splay_tree_callback func, void *data) |
| { |
| splay_tree_foreach_internal (sp->root, func, data); |
| } |