68e3802b23
Sometimes we want to search for an exact key only, and reject the case when tree->key < key. Add rb_search_exact() for this purpose, rather than forcing the caller to perform the comparison in open code. Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
108 lines
3.8 KiB
C
108 lines
3.8 KiB
C
/* ----------------------------------------------------------------------- *
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*
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* Copyright 1996-2020 The NASM Authors - All Rights Reserved
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* See the file AUTHORS included with the NASM distribution for
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* the specific copyright holders.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following
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* conditions are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials provided
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* with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* ----------------------------------------------------------------------- */
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#ifndef NASM_RBTREE_H
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#define NASM_RBTREE_H
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#include "compiler.h"
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/*
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* This structure should be embedded in a larger data structure;
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* the final output from rb_search() can then be converted back
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* to the larger data structure via container_of().
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*
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* An empty tree is simply represented by a NULL pointer.
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*/
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/* Note: the values of these flags is significant */
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enum rbtree_node_flags {
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RBTREE_NODE_BLACK = 1, /* Node color is black */
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RBTREE_NODE_PRED = 2, /* Left pointer is an uplink */
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RBTREE_NODE_SUCC = 4 /* Right pointer is an uplink */
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};
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struct rbtree {
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uint64_t key;
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struct rbtree_metadata {
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struct rbtree *left, *right;
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enum rbtree_node_flags flags;
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} m;
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};
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/*
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* Add a node to a tree. Returns the new root pointer.
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* The key value in the structure needs to be preinitialized;
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* the rest of the structure should be zero.
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*/
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struct rbtree *rb_insert(struct rbtree *, struct rbtree *);
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/*
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* Find a node in the tree corresponding to the key immediately
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* <= the passed-in key value.
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*/
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struct rbtree *rb_search(const struct rbtree *, uint64_t);
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/*
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* Find a node in the tree exactly matching the key value.
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*/
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struct rbtree *rb_search_exact(const struct rbtree *, uint64_t);
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/*
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* Return the immediately previous or next node in key order.
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* Returns NULL if this node is the end of the tree.
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* These operations are safe for complee (but not partial!)
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* tree walk-with-destruction in key order.
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*/
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struct rbtree *rb_prev(const struct rbtree *);
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struct rbtree *rb_next(const struct rbtree *);
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/*
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* Return the very first or very last node in key order.
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*/
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struct rbtree *rb_first(const struct rbtree *);
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struct rbtree *rb_last(const struct rbtree *);
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/*
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* Left and right nodes, if real. These operations are
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* safe for tree destruction, but not for splitting a tree.
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*/
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static inline struct rbtree *rb_left(const struct rbtree *rb)
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{
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return (rb->m.flags & RBTREE_NODE_PRED) ? NULL : rb->m.left;
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}
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static inline struct rbtree *rb_right(const struct rbtree *rb)
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{
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return (rb->m.flags & RBTREE_NODE_SUCC) ? NULL : rb->m.right;
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}
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#endif /* NASM_RBTREE_H */
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