score/src/rbtreepostorder.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  *
0006  * @ingroup RTEMSScoreRBTree
0007  *
0008  * @brief This source file contains the implementation of
0009  *   _RBTree_Postorder_next() and _RBTree_Postorder_first().
0010  */
0011
0012 /*
0013  * Copyright (c) 2018 embedded brains GmbH & Co. KG
0014  *
0015  * Redistribution and use in source and binary forms, with or without
0016  * modification, are permitted provided that the following conditions
0017  * are met:
0018  * 1. Redistributions of source code must retain the above copyright
0019  *    notice, this list of conditions and the following disclaimer.
0020  * 2. Redistributions in binary form must reproduce the above copyright
0021  *    notice, this list of conditions and the following disclaimer in the
0022  *    documentation and/or other materials provided with the distribution.
0023  *
0024  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0025  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0026  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0027  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0028  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0029  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0030  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0031  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0032  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0033  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0034  * POSSIBILITY OF SUCH DAMAGE.
0035  */
0036
0037 #ifdef HAVE_CONFIG_H
0038 #include "config.h"
0039 #endif
0040
0041 #include <rtems/score/rbtree.h>
0042
0043 static void *_RBTree_Postorder_dive_left(
0044   const RBTree_Node *the_node,
0045   size_t             offset
0046 )
0047 {
0048   while ( true ) {
0049     if ( _RBTree_Left( the_node ) != NULL ) {
0050       the_node = _RBTree_Left( the_node );
0051     } else if ( _RBTree_Right( the_node ) != NULL ) {
0052       the_node = _RBTree_Right( the_node );
0053     } else {
0054       return (void *) ( (uintptr_t) the_node - offset );
0055     }
0056   }
0057 }
0058
0059 void *_RBTree_Postorder_next(
0060   const RBTree_Node *the_node,
0061   size_t             offset
0062 )
0063 {
0064   const RBTree_Node *parent;
0065
0066   parent = _RBTree_Parent( the_node );
0067   if ( parent == NULL ) {
0068     return NULL;
0069   }
0070
0071   if (
0072     the_node == _RBTree_Left( parent )
0073       && _RBTree_Right( parent ) != NULL
0074   ) {
0075     return _RBTree_Postorder_dive_left( _RBTree_Right( parent ), offset );
0076   }
0077
0078   return (void *) ( (uintptr_t) parent - offset );
0079 }
0080
0081 void *_RBTree_Postorder_first(
0082   const RBTree_Control *the_rbtree,
0083   size_t                offset
0084 )
0085 {
0086   const RBTree_Node *the_node;
0087
0088   the_node = _RBTree_Root( the_rbtree );
0089   if ( the_node == NULL ) {
0090     return NULL;
0091   }
0092
0093   return _RBTree_Postorder_dive_left( the_node, offset );
0094 }