409 lines
12 KiB
C
409 lines
12 KiB
C
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/*========================================================================
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//
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// rbtree.c
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//
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// Red Black tree implementation
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//
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//========================================================================
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// ####ECOSGPLCOPYRIGHTBEGIN####
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// -------------------------------------------
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// This file is part of eCos, the Embedded Configurable Operating System.
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// Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
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//
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// eCos is free software; you can redistribute it and/or modify it under
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// the terms of the GNU General Public License as published by the Free
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// Software Foundation; either version 2 or (at your option) any later
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// version.
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//
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// eCos is distributed in the hope that it will be useful, but WITHOUT
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// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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// for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with eCos; if not, write to the Free Software Foundation, Inc.,
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// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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//
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// As a special exception, if other files instantiate templates or use
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// macros or inline functions from this file, or you compile this file
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// and link it with other works to produce a work based on this file,
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// this file does not by itself cause the resulting work to be covered by
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// the GNU General Public License. However the source code for this file
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// must still be made available in accordance with section (3) of the GNU
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// General Public License v2.
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//
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// This exception does not invalidate any other reasons why a work based
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// on this file might be covered by the GNU General Public License.
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// -------------------------------------------
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// ####ECOSGPLCOPYRIGHTEND####
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//========================================================================
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//#####DESCRIPTIONBEGIN####
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//
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// Author(s): Niels Provos/OpenBSD
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// Contributors: dwmw2
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// Date: 2003-01-21
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// Purpose: This file provides an implementation of red-black trees.
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// Description: Derived from OpenBSD src/sys/sys/tree.h
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// Usage:
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//
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//####DESCRIPTIONEND####
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//
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//======================================================================
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*/
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/* $OpenBSD: tree.h,v 1.7 2002/10/17 21:51:54 art Exp $ */
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/*
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* Copyright 2002 Niels Provos <provos@citi.umich.edu>
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* All rights reserved.
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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 conditions
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* are met:
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* 1. 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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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/* Fields renamed to match Linux ones. */
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#include <linux/rbtree.h>
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#define RB_HEAD(head) (head)->rb_node
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#define RB_LEFT(elm) (elm)->rb_left
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#define RB_RIGHT(elm) (elm)->rb_right
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#define RB_PARENT(elm) (elm)->rb_parent
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#define RB_COLOR(elm) (elm)->rb_color
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#define RB_SET(elm, parent) do { \
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RB_PARENT(elm) = parent; \
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RB_LEFT(elm) = RB_RIGHT(elm) = NULL; \
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RB_COLOR(elm) = RB_RED; \
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} while (0)
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#define RB_SET_BLACKRED(black, red) do { \
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RB_COLOR(black) = RB_BLACK; \
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RB_COLOR(red) = RB_RED; \
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} while (0)
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#ifndef RB_AUGMENT
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#define RB_AUGMENT(x)
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#endif
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#define RB_ROTATE_LEFT(head, elm, tmp) do { \
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(tmp) = RB_RIGHT(elm); \
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if ((RB_RIGHT(elm) = RB_LEFT(tmp))) { \
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RB_PARENT(RB_LEFT(tmp)) = (elm); \
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} \
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RB_AUGMENT(elm); \
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if ((RB_PARENT(tmp) = RB_PARENT(elm))) { \
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if ((elm) == RB_LEFT(RB_PARENT(elm))) \
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RB_LEFT(RB_PARENT(elm)) = (tmp); \
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else \
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RB_RIGHT(RB_PARENT(elm)) = (tmp); \
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} else \
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(head)->rb_node = (tmp); \
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RB_LEFT(tmp) = (elm); \
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RB_PARENT(elm) = (tmp); \
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RB_AUGMENT(tmp); \
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if ((RB_PARENT(tmp))) \
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RB_AUGMENT(RB_PARENT(tmp)); \
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} while (0)
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#define RB_ROTATE_RIGHT(head, elm, tmp) do { \
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(tmp) = RB_LEFT(elm); \
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if ((RB_LEFT(elm) = RB_RIGHT(tmp))) { \
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RB_PARENT(RB_RIGHT(tmp)) = (elm); \
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} \
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RB_AUGMENT(elm); \
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if ((RB_PARENT(tmp) = RB_PARENT(elm))) { \
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if ((elm) == RB_LEFT(RB_PARENT(elm))) \
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RB_LEFT(RB_PARENT(elm)) = (tmp); \
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else \
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RB_RIGHT(RB_PARENT(elm)) = (tmp); \
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} else \
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(head)->rb_node = (tmp); \
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RB_RIGHT(tmp) = (elm); \
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RB_PARENT(elm) = (tmp); \
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RB_AUGMENT(tmp); \
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if ((RB_PARENT(tmp))) \
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RB_AUGMENT(RB_PARENT(tmp)); \
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} while(0)
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/* Note args swapped to match Linux */
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void rb_insert_color(struct rb_node *elm, struct rb_root *head)
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{
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struct rb_node *parent, *gparent, *tmp;
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while ((parent = RB_PARENT(elm)) &&
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RB_COLOR(parent) == RB_RED) {
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gparent = RB_PARENT(parent);
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if (parent == RB_LEFT(gparent)) {
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tmp = RB_RIGHT(gparent);
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if (tmp && RB_COLOR(tmp) == RB_RED) {
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RB_COLOR(tmp) = RB_BLACK;
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RB_SET_BLACKRED(parent, gparent);
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elm = gparent;
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continue;
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}
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if (RB_RIGHT(parent) == elm) {
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RB_ROTATE_LEFT(head, parent, tmp);
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tmp = parent;
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parent = elm;
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elm = tmp;
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}
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RB_SET_BLACKRED(parent, gparent);
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RB_ROTATE_RIGHT(head, gparent, tmp);
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} else {
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tmp = RB_LEFT(gparent);
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if (tmp && RB_COLOR(tmp) == RB_RED) {
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RB_COLOR(tmp) = RB_BLACK;
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RB_SET_BLACKRED(parent, gparent);
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elm = gparent;
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continue;
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}
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if (RB_LEFT(parent) == elm) {
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RB_ROTATE_RIGHT(head, parent, tmp);
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tmp = parent;
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parent = elm;
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elm = tmp;
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}
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RB_SET_BLACKRED(parent, gparent);
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RB_ROTATE_LEFT(head, gparent, tmp);
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}
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}
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RB_COLOR(head->rb_node) = RB_BLACK;
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}
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static void rb_remove_color(struct rb_root *head, struct rb_node *parent,
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struct rb_node *elm)
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{
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struct rb_node *tmp;
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while ((elm == NULL || RB_COLOR(elm) == RB_BLACK) &&
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elm != RB_HEAD(head)) {
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if (RB_LEFT(parent) == elm) {
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tmp = RB_RIGHT(parent);
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if (RB_COLOR(tmp) == RB_RED) {
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RB_SET_BLACKRED(tmp, parent);
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RB_ROTATE_LEFT(head, parent, tmp);
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tmp = RB_RIGHT(parent);
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}
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if ((RB_LEFT(tmp) == NULL ||
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RB_COLOR(RB_LEFT(tmp)) == RB_BLACK) &&
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(RB_RIGHT(tmp) == NULL ||
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RB_COLOR(RB_RIGHT(tmp)) == RB_BLACK)) {
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RB_COLOR(tmp) = RB_RED;
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elm = parent;
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parent = RB_PARENT(elm);
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} else {
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if (RB_RIGHT(tmp) == NULL ||
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RB_COLOR(RB_RIGHT(tmp)) == RB_BLACK) {
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struct rb_node *oleft;
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if ((oleft = RB_LEFT(tmp)))
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RB_COLOR(oleft) = RB_BLACK;
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RB_COLOR(tmp) = RB_RED;
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RB_ROTATE_RIGHT(head, tmp, oleft);
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tmp = RB_RIGHT(parent);
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}
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RB_COLOR(tmp) = RB_COLOR(parent);
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RB_COLOR(parent) = RB_BLACK;
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if (RB_RIGHT(tmp))
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RB_COLOR(RB_RIGHT(tmp)) = RB_BLACK;
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RB_ROTATE_LEFT(head, parent, tmp);
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elm = RB_HEAD(head);
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break;
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}
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} else {
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tmp = RB_LEFT(parent);
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if (RB_COLOR(tmp) == RB_RED) {
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RB_SET_BLACKRED(tmp, parent);
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RB_ROTATE_RIGHT(head, parent, tmp);
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tmp = RB_LEFT(parent);
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}
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if ((RB_LEFT(tmp) == NULL ||
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RB_COLOR(RB_LEFT(tmp)) == RB_BLACK) &&
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(RB_RIGHT(tmp) == NULL ||
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RB_COLOR(RB_RIGHT(tmp)) == RB_BLACK)) {
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RB_COLOR(tmp) = RB_RED;
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elm = parent;
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parent = RB_PARENT(elm);
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} else {
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if (RB_LEFT(tmp) == NULL ||
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RB_COLOR(RB_LEFT(tmp)) == RB_BLACK) {
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struct rb_node *oright;
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if ((oright = RB_RIGHT(tmp)))
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RB_COLOR(oright) = RB_BLACK;
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RB_COLOR(tmp) = RB_RED;
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RB_ROTATE_LEFT(head, tmp, oright);
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tmp = RB_LEFT(parent);
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}
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RB_COLOR(tmp) = RB_COLOR(parent);
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RB_COLOR(parent) = RB_BLACK;
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if (RB_LEFT(tmp))
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RB_COLOR(RB_LEFT(tmp)) = RB_BLACK;
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RB_ROTATE_RIGHT(head, parent, tmp);
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elm = RB_HEAD(head);
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break;
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}
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}
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}
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if (elm)
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RB_COLOR(elm) = RB_BLACK;
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}
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/* Note name changed. Guess why :) */
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void rb_erase(struct rb_node *elm, struct rb_root *head)
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{
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struct rb_node *child, *parent, *old = elm;
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int color;
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if (RB_LEFT(elm) == NULL)
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child = RB_RIGHT(elm);
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else if (RB_RIGHT(elm) == NULL)
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child = RB_LEFT(elm);
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else {
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struct rb_node *left;
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elm = RB_RIGHT(elm);
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while ((left = RB_LEFT(elm)))
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elm = left;
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child = RB_RIGHT(elm);
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parent = RB_PARENT(elm);
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color = RB_COLOR(elm);
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if (child)
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RB_PARENT(child) = parent;
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if (parent) {
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if (RB_LEFT(parent) == elm)
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RB_LEFT(parent) = child;
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else
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RB_RIGHT(parent) = child;
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RB_AUGMENT(parent);
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} else
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RB_HEAD(head) = child;
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if (RB_PARENT(elm) == old)
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parent = elm;
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*(elm) = *(old);
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if (RB_PARENT(old)) {
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if (RB_LEFT(RB_PARENT(old)) == old)
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RB_LEFT(RB_PARENT(old)) = elm;
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else
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RB_RIGHT(RB_PARENT(old)) = elm;
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RB_AUGMENT(RB_PARENT(old));
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} else
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RB_HEAD(head) = elm;
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RB_PARENT(RB_LEFT(old)) = elm;
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if (RB_RIGHT(old))
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RB_PARENT(RB_RIGHT(old)) = elm;
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if (parent) {
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left = parent;
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do {
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RB_AUGMENT(left);
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} while ((left = RB_PARENT(left)));
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}
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goto color;
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}
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parent = RB_PARENT(elm);
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color = RB_COLOR(elm);
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if (child)
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RB_PARENT(child) = parent;
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if (parent) {
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if (RB_LEFT(parent) == elm)
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RB_LEFT(parent) = child;
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else
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RB_RIGHT(parent) = child;
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RB_AUGMENT(parent);
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} else
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RB_HEAD(head) = child;
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color:
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if (color == RB_BLACK)
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rb_remove_color(head, parent, child);
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}
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struct rb_node *rb_next(struct rb_node *elm)
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{
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if (RB_RIGHT(elm)) {
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elm = RB_RIGHT(elm);
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while (RB_LEFT(elm))
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elm = RB_LEFT(elm);
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} else {
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if (RB_PARENT(elm) &&
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(elm == RB_LEFT(RB_PARENT(elm))))
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elm = RB_PARENT(elm);
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else {
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while (RB_PARENT(elm) &&
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(elm == RB_RIGHT(RB_PARENT(elm))))
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elm = RB_PARENT(elm);
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elm = RB_PARENT(elm);
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}
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}
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return (elm);
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}
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struct rb_node *rb_prev(struct rb_node *elm)
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{
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if (RB_LEFT(elm)) {
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elm = RB_LEFT(elm);
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while (RB_RIGHT(elm))
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elm = RB_RIGHT(elm);
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} else {
|
||
|
|
if (RB_PARENT(elm) &&
|
||
|
|
(elm == RB_RIGHT(RB_PARENT(elm))))
|
||
|
|
elm = RB_PARENT(elm);
|
||
|
|
else {
|
||
|
|
while (RB_PARENT(elm) &&
|
||
|
|
(elm == RB_LEFT(RB_PARENT(elm))))
|
||
|
|
elm = RB_PARENT(elm);
|
||
|
|
elm = RB_PARENT(elm);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return (elm);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* These ones are lifted from Linux -- but that's OK because I
|
||
|
|
wrote them. dwmw2. */
|
||
|
|
struct rb_node *rb_first(struct rb_root *root)
|
||
|
|
{
|
||
|
|
struct rb_node *n;
|
||
|
|
|
||
|
|
n = root->rb_node;
|
||
|
|
if (!n)
|
||
|
|
return 0;
|
||
|
|
while (n->rb_left)
|
||
|
|
n = n->rb_left;
|
||
|
|
return n;
|
||
|
|
}
|
||
|
|
|
||
|
|
void rb_replace_node(struct rb_node *victim, struct rb_node *new,
|
||
|
|
struct rb_root *root)
|
||
|
|
{
|
||
|
|
struct rb_node *parent = victim->rb_parent;
|
||
|
|
|
||
|
|
/* Set the surrounding nodes to point to the replacement */
|
||
|
|
if (parent) {
|
||
|
|
if (victim == parent->rb_left)
|
||
|
|
parent->rb_left = new;
|
||
|
|
else
|
||
|
|
parent->rb_right = new;
|
||
|
|
} else {
|
||
|
|
root->rb_node = new;
|
||
|
|
}
|
||
|
|
if (victim->rb_left)
|
||
|
|
victim->rb_left->rb_parent = new;
|
||
|
|
if (victim->rb_right)
|
||
|
|
victim->rb_right->rb_parent = new;
|
||
|
|
|
||
|
|
/* Copy the pointers/colour from the victim to the replacement */
|
||
|
|
*new = *victim;
|
||
|
|
}
|