1 | /* |
---|
2 | * Copyright (c) 2010-2012 Gedare Bloom. |
---|
3 | * |
---|
4 | * The license and distribution terms for this file may be |
---|
5 | * found in the file LICENSE in this distribution or at |
---|
6 | * http://www.rtems.org/license/LICENSE. |
---|
7 | */ |
---|
8 | |
---|
9 | #if HAVE_CONFIG_H |
---|
10 | #include "config.h" |
---|
11 | #endif |
---|
12 | |
---|
13 | #include <rtems/score/rbtreeimpl.h> |
---|
14 | |
---|
15 | RTEMS_STATIC_ASSERT( |
---|
16 | sizeof( RBTree_Compare_result ) >= sizeof( intptr_t ), |
---|
17 | RBTree_Compare_result_intptr_t |
---|
18 | ); |
---|
19 | |
---|
20 | RTEMS_STATIC_ASSERT( |
---|
21 | sizeof( RBTree_Compare_result ) >= sizeof( int32_t ), |
---|
22 | RBTree_Compare_result_int32_t |
---|
23 | ); |
---|
24 | |
---|
25 | /** @brief Validate and fix-up tree properties for a new insert/colored node |
---|
26 | * |
---|
27 | * This routine checks and fixes the Red-Black Tree properties based on |
---|
28 | * @a the_node being just added to the tree. |
---|
29 | * |
---|
30 | * @note It does NOT disable interrupts to ensure the atomicity of the |
---|
31 | * append operation. |
---|
32 | */ |
---|
33 | static void _RBTree_Validate_insert( RBTree_Node *the_node ) |
---|
34 | { |
---|
35 | RBTree_Node *parent = _RBTree_Parent( the_node ); |
---|
36 | RBTree_Node *grandparent = _RBTree_Parent( parent ); |
---|
37 | |
---|
38 | /* note: the insert root case is handled already */ |
---|
39 | /* if the parent is black, nothing needs to be done |
---|
40 | * otherwise may need to loop a few times */ |
---|
41 | while ( parent->color == RBT_RED ) { |
---|
42 | /* The root is black, so the grandparent must exist */ |
---|
43 | RBTree_Node *uncle = _RBTree_Sibling( parent, grandparent ); |
---|
44 | |
---|
45 | /* |
---|
46 | * If uncle exists and is red, repaint uncle/parent black and grandparent |
---|
47 | * red. |
---|
48 | */ |
---|
49 | if ( uncle != NULL && uncle->color == RBT_RED ) { |
---|
50 | parent->color = RBT_BLACK; |
---|
51 | uncle->color = RBT_BLACK; |
---|
52 | grandparent->color = RBT_RED; |
---|
53 | the_node = grandparent; |
---|
54 | parent = _RBTree_Parent( the_node ); |
---|
55 | grandparent = _RBTree_Parent( parent ); |
---|
56 | |
---|
57 | if ( grandparent == NULL ) |
---|
58 | break; |
---|
59 | } else { /* If uncle does not exist or is black */ |
---|
60 | RBTree_Direction dir = _RBTree_Direction( the_node, parent ); |
---|
61 | RBTree_Direction parentdir = _RBTree_Direction( parent, grandparent ); |
---|
62 | |
---|
63 | /* ensure node is on the same branch direction as parent */ |
---|
64 | if ( dir != parentdir ) { |
---|
65 | RBTree_Node *oldparent = parent; |
---|
66 | |
---|
67 | parent = the_node; |
---|
68 | the_node = oldparent; |
---|
69 | _RBTree_Rotate( oldparent, parentdir ); |
---|
70 | } |
---|
71 | |
---|
72 | parent->color = RBT_BLACK; |
---|
73 | grandparent->color = RBT_RED; |
---|
74 | |
---|
75 | /* now rotate grandparent in the other branch direction (toward uncle) */ |
---|
76 | _RBTree_Rotate( grandparent, _RBTree_Opposite_direction( parentdir ) ); |
---|
77 | |
---|
78 | grandparent = _RBTree_Parent( parent ); |
---|
79 | break; |
---|
80 | } |
---|
81 | } |
---|
82 | |
---|
83 | if ( grandparent == NULL ) |
---|
84 | the_node->color = RBT_BLACK; |
---|
85 | } |
---|
86 | |
---|
87 | RBTree_Node *_RBTree_Insert( |
---|
88 | RBTree_Control *the_rbtree, |
---|
89 | RBTree_Node *the_node, |
---|
90 | RBTree_Compare compare, |
---|
91 | bool is_unique |
---|
92 | ) |
---|
93 | { |
---|
94 | RBTree_Node *iter_node = the_rbtree->root; |
---|
95 | |
---|
96 | if ( !iter_node ) { /* special case: first node inserted */ |
---|
97 | the_node->color = RBT_BLACK; |
---|
98 | the_rbtree->root = the_node; |
---|
99 | the_rbtree->first[ 0 ] = the_rbtree->first[ 1 ] = the_node; |
---|
100 | the_node->parent = (RBTree_Node *) the_rbtree; |
---|
101 | the_node->child[ RBT_LEFT ] = the_node->child[ RBT_RIGHT ] = NULL; |
---|
102 | } else { |
---|
103 | /* typical binary search tree insert, descend tree to leaf and insert */ |
---|
104 | while ( iter_node ) { |
---|
105 | RBTree_Compare_result compare_result = |
---|
106 | ( *compare )( the_node, iter_node ); |
---|
107 | |
---|
108 | if ( is_unique && _RBTree_Is_equal( compare_result ) ) |
---|
109 | return iter_node; |
---|
110 | |
---|
111 | RBTree_Direction dir = !_RBTree_Is_lesser( compare_result ); |
---|
112 | |
---|
113 | if ( !iter_node->child[ dir ] ) { |
---|
114 | the_node->child[ RBT_LEFT ] = the_node->child[ RBT_RIGHT ] = NULL; |
---|
115 | the_node->color = RBT_RED; |
---|
116 | iter_node->child[ dir ] = the_node; |
---|
117 | the_node->parent = iter_node; |
---|
118 | /* update min/max */ |
---|
119 | compare_result = ( *compare )( |
---|
120 | the_node, |
---|
121 | _RBTree_First( the_rbtree, dir ) |
---|
122 | ); |
---|
123 | |
---|
124 | if ( |
---|
125 | ( dir == RBT_LEFT && _RBTree_Is_lesser( compare_result ) ) |
---|
126 | || ( dir == RBT_RIGHT && !_RBTree_Is_lesser( compare_result ) ) |
---|
127 | ) { |
---|
128 | the_rbtree->first[ dir ] = the_node; |
---|
129 | } |
---|
130 | |
---|
131 | break; |
---|
132 | } else { |
---|
133 | iter_node = iter_node->child[ dir ]; |
---|
134 | } |
---|
135 | } /* while(iter_node) */ |
---|
136 | |
---|
137 | /* verify red-black properties */ |
---|
138 | _RBTree_Validate_insert( the_node ); |
---|
139 | } |
---|
140 | |
---|
141 | return (RBTree_Node *) 0; |
---|
142 | } |
---|