diff options
| -rw-r--r-- | include/rbtree.h | 23 | ||||
| -rw-r--r-- | nasmlib/rbtree.c | 36 |
2 files changed, 48 insertions, 11 deletions
diff --git a/include/rbtree.h b/include/rbtree.h index 8ccd129c..332f6f85 100644 --- a/include/rbtree.h +++ b/include/rbtree.h @@ -74,9 +74,30 @@ struct rbtree *rb_search(const struct rbtree *, uint64_t); /* * Return the immediately previous or next node in key order. - * Returns NULL if this node is the end of the + * Returns NULL if this node is the end of the tree. + * These operations are safe for complee (but not partial!) + * tree walk-with-destruction in key order. */ struct rbtree *rb_prev(const struct rbtree *); struct rbtree *rb_next(const struct rbtree *); +/* + * Return the very first or very last node in key order. + */ +struct rbtree *rb_first(const struct rbtree *); +struct rbtree *rb_last(const struct rbtree *); + +/* + * Left and right nodes, if real. These operations are + * safe for tree destruction, but not for splitting a tree. + */ +static inline struct rbtree *rb_left(const struct rbtree *rb) +{ + return (rb->m.flags & RBTREE_NODE_PRED) ? NULL : rb->m.left; +} +static inline struct rbtree *rb_right(const struct rbtree *rb) +{ + return (rb->m.flags & RBTREE_NODE_SUCC) ? NULL : rb->m.right; +} + #endif /* NASM_RBTREE_H */ diff --git a/nasmlib/rbtree.c b/nasmlib/rbtree.c index 8b74c0c4..510f34b1 100644 --- a/nasmlib/rbtree.c +++ b/nasmlib/rbtree.c @@ -208,17 +208,36 @@ _rb_insert(struct rbtree *tree, struct rbtree *node) return tree; } +struct rbtree *rb_first(const struct rbtree *tree) +{ + if (unlikely(!tree)) + return NULL; + + while (!(tree->m.flags & RBTREE_NODE_PRED)) + tree = tree->m.left; + + return (struct rbtree *)tree; +} + +struct rbtree *rb_last(const struct rbtree *tree) +{ + if (unlikely(!tree)) + return NULL; + + while (!(tree->m.flags & RBTREE_NODE_SUCC)) + tree = tree->m.right; + + return (struct rbtree *)tree; +} + struct rbtree *rb_prev(const struct rbtree *node) { struct rbtree *np = node->m.left; if (node->m.flags & RBTREE_NODE_PRED) return np; - - while (!(np->m.flags & RBTREE_NODE_SUCC)) - np = np->m.right; - - return np; + else + return rb_last(np); } struct rbtree *rb_next(const struct rbtree *node) @@ -227,9 +246,6 @@ struct rbtree *rb_next(const struct rbtree *node) if (node->m.flags & RBTREE_NODE_SUCC) return np; - - while (!(np->m.flags & RBTREE_NODE_PRED)) - np = np->m.left; - - return np; + else + return rb_first(np); } |