Initial import of libucore
This commit is contained in:
Nils O. Selåsdal
@@ -0,0 +1,336 @@
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#include <stddef.h>
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#include "ucore_rbtree.h"
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//modified from generated code of tree.h
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static void
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rotateleft(RBTree *root, RBNode *node)
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{
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RBNode *right = node->right;
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node->right = right->left;
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if (right->left)
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right->left->parent = node;
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right->left = node;
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right->parent = node->parent;
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if (node->parent) {
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if (node == node->parent->left)
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node->parent->left = right;
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else
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node->parent->right = right;
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} else
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root->node = right;
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node->parent = right;
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}
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static void
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rotateright(RBTree *root, RBNode *node)
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{
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RBNode *left = node->left;
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node->left = left->right;
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if (left->right)
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left->right->parent = node;
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left->right = node;
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left->parent = node->parent;
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if (node->parent) {
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if (node == node->parent->right)
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node->parent->right = left;
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else
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node->parent->left = left;
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} else
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root->node = left;
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node->parent = left;
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}
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static void
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rb_insertcolor(RBTree *root, RBNode *node)
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{
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RBNode *parent, *gparent;
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while ((parent = node->parent) && parent->color == Red) {
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gparent = parent->parent;
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if (parent == gparent->left) {
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RBNode *uncle = gparent->right;
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if (uncle && uncle->color == Red) {
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uncle->color = Black;
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parent->color = Black;
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gparent->color = Red;
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node = gparent;
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continue;
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}
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if (parent->right == node) {
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RBNode *tmp;
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rotateleft(root, parent);
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tmp = parent;
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parent = node;
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node = tmp;
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}
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parent->color = Black;
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gparent->color = Red;
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rotateright(root, gparent);
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}
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else {
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RBNode *uncle = gparent->left;
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if (uncle && uncle->color == Red) {
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uncle->color = Black;
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parent->color = Black;
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gparent->color = Red;
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node = gparent;
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continue;
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}
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if (parent->left == node) {
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RBNode *tmp;
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rotateright(root, parent);
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tmp = parent;
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parent = node;
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node = tmp;
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}
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parent->color = Black;
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gparent->color = Red;
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rotateleft(root, gparent);
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}
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}
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root->node->color = Black;
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}
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static void
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removecolor(RBTree *root, RBNode *node, RBNode *parent)
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{
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RBNode *other;
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while ((!node || node->color == Black) && node != root->node) {
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if (parent->left == node) {
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other = parent->right;
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if (other->color == Red) {
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other->color = Black;
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parent->color = Red;
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rotateleft(root, parent);
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other = parent->right;
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}
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if ((!other->left || other->left->color == Black)
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&& (!other->right
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|| other->right->color == Black)) {
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other->color = Red;
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node = parent;
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parent = node->parent;
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} else {
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if (!other->right
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|| other->right->color == Black) {
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RBNode *o_left;
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if ((o_left = other->left))
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o_left->color = Black;
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other->color = Red;
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rotateright(root, other);
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other = parent->right;
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}
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other->color = parent->color;
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parent->color = Black;
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if (other->right)
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other->right->color = Black;
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rotateleft(root, parent);
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node = root->node;
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break;
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}
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}
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else {
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other = parent->left;
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if (other->color == Red) {
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other->color = Black;
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parent->color = Red;
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rotateright(root, parent);
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other = parent->left;
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}
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if ((!other->left || other->left->color == Black)
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&& (!other->right
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|| other->right->color == Black)) {
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other->color = Red;
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node = parent;
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parent = node->parent;
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} else {
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if (!other->left
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|| other->left->color == Black) {
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RBNode *o_right;
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if ((o_right = other->right))
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o_right->color = Black;
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other->color = Red;
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rotateleft(root, other);
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other = parent->left;
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}
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other->color = parent->color;
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parent->color = Black;
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if (other->left)
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other->left->color = Black;
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rotateright(root, parent);
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node = root->node;
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break;
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}
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}
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}
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if (node)
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node->color = Black;
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}
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void
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uc_rb_remove(RBTree *root, RBNode *node)
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{
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RBNode *child, *parent;
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int color;
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if (!node->left)
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child = node->right;
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else if (!node->right)
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child = node->left;
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else {
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RBNode *old = node, *left;
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node = node->right;
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while ((left = node->left))
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node = left;
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child = node->right;
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parent = node->parent;
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color = node->color;
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if (child)
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child->parent = parent;
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if (parent) {
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if (parent->left == node)
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parent->left = child;
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else
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parent->right = child;
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} else
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root->node = child;
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if (node->parent == old)
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parent = node;
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node->parent = old->parent;
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node->color = old->color;
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node->right = old->right;
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node->left = old->left;
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if (old->parent) {
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if (old->parent->left == old)
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old->parent->left = node;
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else
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old->parent->right = node;
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} else
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root->node = node;
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old->left->parent = node;
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if (old->right)
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old->right->parent = node;
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goto finish;
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}
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parent = node->parent;
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color = node->color;
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if (child)
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child->parent = parent;
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if (parent) {
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if (parent->left == node)
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parent->left = child;
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else
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parent->right = child;
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} else
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root->node = child;
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finish:
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if (color == Black)
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removecolor(root, child, parent);
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}
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RBNode*
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uc_rb_find(RBTree *root, const void *val)
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{
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RBNode *n = root->node;
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while (n) {
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int d = root->compare(val,n->data);
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if (d < 0)
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n = n->left;
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else if (d > 0)
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n = n->right;
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else
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return n;
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}
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return NULL;
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}
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RBNode*
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uc_rb_insert(RBTree *root, RBNode *child)
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{
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RBNode **p = &root->node;
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RBNode *parent = NULL;
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int d;
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while (*p) {
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parent = *p;
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d = root->compare(child->data, parent->data);
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if (d < 0)
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p = &(*p)->left;
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else if (d > 0)
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p = &(*p)->right;
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else
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return parent;
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}
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child->parent = parent;
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child->color = Red;
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child->left = child->right = NULL;
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*p = child;
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rb_insertcolor(root, child);
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return NULL;
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}
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RBNode *uc_rb_first(const RBTree *root)
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{
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RBNode *n = root->node;
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if(n == NULL)
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return NULL;
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while(n->left)
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n = n->left;
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return n;
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}
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RBNode *uc_rb_next(RBNode *node)
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{
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if(node->right) { //down and left of the right branch
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node = node->right;
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while(node->left)
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node = node->left;
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} else { //up until we are not the right node
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while(node->parent && node == node->parent->right)
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node = node->parent;
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node = node->parent;
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}
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return node;
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}
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RBNode *uc_rb_last(const RBTree *root)
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{
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RBNode *n = root->node;
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if(n == NULL)
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return NULL;
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while(n->right)
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n = n->right;
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return n;
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}
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