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A small rbtree insert fixup optimization.

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Thanks to 洪志道 (Hong Zhi Dao).
This commit is contained in:
Igor Sysoev
2017-05-26 19:12:47 +03:00
parent 48155f3a49
commit 4f9f463799
1 changed files with 9 additions and 4 deletions
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13
src/nxt_rbtree.c
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@@ -126,11 +126,15 @@ nxt_rbtree_insert_fixup(nxt_rbtree_node_t *node)
nxt_rbtree_left_rotate(node); nxt_rbtree_left_rotate(node);
} }
/*
* nxt_rbtree_left_rotate() swaps parent and
* child whilst keeps grandparent the same.
*/
parent = node->parent; parent = node->parent;
parent->color = NXT_RBTREE_BLACK;
grandparent = parent->parent; parent->color = NXT_RBTREE_BLACK;
grandparent->color = NXT_RBTREE_RED; grandparent->color = NXT_RBTREE_RED;
nxt_rbtree_right_rotate(grandparent); nxt_rbtree_right_rotate(grandparent);
/* /*
* nxt_rbtree_right_rotate() does not change node->parent * nxt_rbtree_right_rotate() does not change node->parent
@@ -150,11 +154,12 @@ nxt_rbtree_insert_fixup(nxt_rbtree_node_t *node)
nxt_rbtree_right_rotate(node); nxt_rbtree_right_rotate(node);
} }
/* See the comment in the symmetric branch above. */
parent = node->parent; parent = node->parent;
parent->color = NXT_RBTREE_BLACK;
grandparent = parent->parent; parent->color = NXT_RBTREE_BLACK;
grandparent->color = NXT_RBTREE_RED; grandparent->color = NXT_RBTREE_RED;
nxt_rbtree_left_rotate(grandparent); nxt_rbtree_left_rotate(grandparent);
/* See the comment in the symmetric branch above. */ /* See the comment in the symmetric branch above. */