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rbtree: Simplify _RBTree_Rotate()

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Add and use _RBTree_Direction().
This commit is contained in:
Sebastian Huber
2014-08-07 15:59:25 +02:00
parent d472d21780
commit 4752550f80
2 changed files with 61 additions and 18 deletions
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cpukit/score/include/rtems/score/rbtreeimpl.h
+61 -17
View File
@@ -76,6 +76,21 @@ RTEMS_INLINE_ROUTINE RBTree_Direction _RBTree_Opposite_direction(
return (RBTree_Direction) !((int) the_dir);
}
/**
* @brief Returns the direction of the node.
*
* @param[in] the_node The node of interest.
* @param[in] parent The parent of the node. The parent must exist, thus it is
* invalid to use this function for the root node.
*/
RTEMS_INLINE_ROUTINE RBTree_Direction _RBTree_Direction(
const RBTree_Node *the_node,
const RBTree_Node *parent
)
{
return (RBTree_Direction) ( the_node != parent->child[ 0 ] );
}
/**
* @brief Is this node red.
*
@@ -166,32 +181,61 @@ RTEMS_INLINE_ROUTINE bool _RBTree_Is_lesser(
}
/**
* @brief Rotate the_node in the direction passed as second argument.
* @brief Rotates the node in the specified direction.
*
* This routine rotates @a the_node to the direction @a dir, swapping
* @a the_node with its child\[@a dir\].
* The node is swapped with its child in the opposite direction if it exists.
*
* Sub-tree before rotation:
* @dot
* digraph state {
* parent -> the_node;
* the_node -> sibling [label="dir"];
* the_node -> child [label="opp_dir"];
* child -> grandchild [label="dir"];
* child -> grandchildsibling [label="opp_dir"];
* }
* @enddot
*
* Sub-tree after rotation:
* @dot
* digraph state {
* parent -> child;
* the_node -> sibling [label="dir"];
* the_node -> grandchild [label="opp_dir"];
* child -> the_node [label="dir"];
* child -> grandchildsibling [label="opp_dir"];
* }
* @enddot
*
* @param[in] the_node The node to rotate.
* @param[in] dir The rotation direction.
*/
RTEMS_INLINE_ROUTINE void _RBTree_Rotate(
RBTree_Node *the_node,
RBTree_Direction dir
)
RBTree_Node *the_node,
RBTree_Direction dir
)
{
RBTree_Node *c;
if (the_node == NULL) return;
if (the_node->child[_RBTree_Opposite_direction(dir)] == NULL) return;
RBTree_Direction opp_dir = _RBTree_Opposite_direction( dir );
RBTree_Node *child = the_node->child[ opp_dir ];
RBTree_Node *grandchild;
RBTree_Node *parent;
c = the_node->child[_RBTree_Opposite_direction(dir)];
the_node->child[_RBTree_Opposite_direction(dir)] = c->child[dir];
if ( child == NULL)
return;
if (c->child[dir])
c->child[dir]->parent = the_node;
grandchild = child->child[ dir ];
the_node->child[ opp_dir ] = grandchild;
c->child[dir] = the_node;
if ( grandchild != NULL )
grandchild->parent = the_node;
the_node->parent->child[the_node != the_node->parent->child[0]] = c;
child->child[ dir ] = the_node;
c->parent = the_node->parent;
the_node->parent = c;
parent = _RBTree_Parent( the_node );
parent->child[ _RBTree_Direction( the_node, parent ) ] = child;
child->parent = parent;
the_node->parent = child;
}
/** @} */
testsuites/sptests/sprbtree01/init.c
-1
View File
@@ -858,7 +858,6 @@ rtems_task Init( rtems_task_argument ignored )
rtems_test_assert( !rtems_rbtree_is_node_off_tree( &node1.Node ) );
_RBTree_Rotate(NULL, RBT_LEFT);
i = (node1.Node.parent == &node2.Node);
_RBTree_Rotate( &node1.Node,
!node1.Node.child[RBT_LEFT] ? RBT_RIGHT : RBT_LEFT