[people/ms/u-boot.git] / include / linux / rbtree_augmented.h

/*
  Red Black Trees
  (C) 1999  Andrea Arcangeli <andrea@suse.de>
  (C) 2002  David Woodhouse <dwmw2@infradead.org>
  (C) 2012  Michel Lespinasse <walken@google.com>

 * SPDX-License-Identifier:	GPL-2.0+

  linux/include/linux/rbtree_augmented.h
*/

#ifndef _LINUX_RBTREE_AUGMENTED_H
#define _LINUX_RBTREE_AUGMENTED_H

#include <linux/compiler.h>
#include <linux/rbtree.h>

/*
 * Please note - only struct rb_augment_callbacks and the prototypes for
 * rb_insert_augmented() and rb_erase_augmented() are intended to be public.
 * The rest are implementation details you are not expected to depend on.
 *
 * See Documentation/rbtree.txt for documentation and samples.
 */

struct rb_augment_callbacks {
	void (*propagate)(struct rb_node *node, struct rb_node *stop);
	void (*copy)(struct rb_node *old, struct rb_node *new);
	void (*rotate)(struct rb_node *old, struct rb_node *new);
};

extern void __rb_insert_augmented(struct rb_node *node, struct rb_root *root,
	void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
static inline void
rb_insert_augmented(struct rb_node *node, struct rb_root *root,
		    const struct rb_augment_callbacks *augment)
{
	__rb_insert_augmented(node, root, augment->rotate);
}

#define RB_DECLARE_CALLBACKS(rbstatic, rbname, rbstruct, rbfield,	\
			     rbtype, rbaugmented, rbcompute)		\
static inline void							\
rbname ## _propagate(struct rb_node *rb, struct rb_node *stop)		\
{									\
	while (rb != stop) {						\
		rbstruct *node = rb_entry(rb, rbstruct, rbfield);	\
		rbtype augmented = rbcompute(node);			\
		if (node->rbaugmented == augmented)			\
			break;						\
		node->rbaugmented = augmented;				\
		rb = rb_parent(&node->rbfield);				\
	}								\
}									\
static inline void							\
rbname ## _copy(struct rb_node *rb_old, struct rb_node *rb_new)		\
{									\
	rbstruct *old = rb_entry(rb_old, rbstruct, rbfield);		\
	rbstruct *new = rb_entry(rb_new, rbstruct, rbfield);		\
	new->rbaugmented = old->rbaugmented;				\
}									\
static void								\
rbname ## _rotate(struct rb_node *rb_old, struct rb_node *rb_new)	\
{									\
	rbstruct *old = rb_entry(rb_old, rbstruct, rbfield);		\
	rbstruct *new = rb_entry(rb_new, rbstruct, rbfield);		\
	new->rbaugmented = old->rbaugmented;				\
	old->rbaugmented = rbcompute(old);				\
}									\
rbstatic const struct rb_augment_callbacks rbname = {			\
	rbname ## _propagate, rbname ## _copy, rbname ## _rotate	\
};


#define	RB_RED		0
#define	RB_BLACK	1

#define __rb_parent(pc)    ((struct rb_node *)(pc & ~3))

#define __rb_color(pc)     ((pc) & 1)
#define __rb_is_black(pc)  __rb_color(pc)
#define __rb_is_red(pc)    (!__rb_color(pc))
#define rb_color(rb)       __rb_color((rb)->__rb_parent_color)
#define rb_is_red(rb)      __rb_is_red((rb)->__rb_parent_color)
#define rb_is_black(rb)    __rb_is_black((rb)->__rb_parent_color)

static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
{
	rb->__rb_parent_color = rb_color(rb) | (unsigned long)p;
}

static inline void rb_set_parent_color(struct rb_node *rb,
				       struct rb_node *p, int color)
{
	rb->__rb_parent_color = (unsigned long)p | color;
}

static inline void
__rb_change_child(struct rb_node *old, struct rb_node *new,
		  struct rb_node *parent, struct rb_root *root)
{
	if (parent) {
		if (parent->rb_left == old)
			parent->rb_left = new;
		else
			parent->rb_right = new;
	} else
		root->rb_node = new;
}

extern void __rb_erase_color(struct rb_node *parent, struct rb_root *root,
	void (*augment_rotate)(struct rb_node *old, struct rb_node *new));

static __always_inline struct rb_node *
__rb_erase_augmented(struct rb_node *node, struct rb_root *root,
		     const struct rb_augment_callbacks *augment)
{
	struct rb_node *child = node->rb_right, *tmp = node->rb_left;
	struct rb_node *parent, *rebalance;
	unsigned long pc;

	if (!tmp) {
		/*
		 * Case 1: node to erase has no more than 1 child (easy!)
		 *
		 * Note that if there is one child it must be red due to 5)
		 * and node must be black due to 4). We adjust colors locally
		 * so as to bypass __rb_erase_color() later on.
		 */
		pc = node->__rb_parent_color;
		parent = __rb_parent(pc);
		__rb_change_child(node, child, parent, root);
		if (child) {
			child->__rb_parent_color = pc;
			rebalance = NULL;
		} else
			rebalance = __rb_is_black(pc) ? parent : NULL;
		tmp = parent;
	} else if (!child) {
		/* Still case 1, but this time the child is node->rb_left */
		tmp->__rb_parent_color = pc = node->__rb_parent_color;
		parent = __rb_parent(pc);
		__rb_change_child(node, tmp, parent, root);
		rebalance = NULL;
		tmp = parent;
	} else {
		struct rb_node *successor = child, *child2;
		tmp = child->rb_left;
		if (!tmp) {
			/*
			 * Case 2: node's successor is its right child
			 *
			 *    (n)          (s)
			 *    / \          / \
			 *  (x) (s)  ->  (x) (c)
			 *        \
			 *        (c)
			 */
			parent = successor;
			child2 = successor->rb_right;
			augment->copy(node, successor);
		} else {
			/*
			 * Case 3: node's successor is leftmost under
			 * node's right child subtree
			 *
			 *    (n)          (s)
			 *    / \          / \
			 *  (x) (y)  ->  (x) (y)
			 *      /            /
			 *    (p)          (p)
			 *    /            /
			 *  (s)          (c)
			 *    \
			 *    (c)
			 */
			do {
				parent = successor;
				successor = tmp;
				tmp = tmp->rb_left;
			} while (tmp);
			parent->rb_left = child2 = successor->rb_right;
			successor->rb_right = child;
			rb_set_parent(child, successor);
			augment->copy(node, successor);
			augment->propagate(parent, successor);
		}

		successor->rb_left = tmp = node->rb_left;
		rb_set_parent(tmp, successor);

		pc = node->__rb_parent_color;
		tmp = __rb_parent(pc);
		__rb_change_child(node, successor, tmp, root);
		if (child2) {
			successor->__rb_parent_color = pc;
			rb_set_parent_color(child2, parent, RB_BLACK);
			rebalance = NULL;
		} else {
			unsigned long pc2 = successor->__rb_parent_color;
			successor->__rb_parent_color = pc;
			rebalance = __rb_is_black(pc2) ? parent : NULL;
		}
		tmp = successor;
	}

	augment->propagate(tmp, NULL);
	return rebalance;
}

static __always_inline void
rb_erase_augmented(struct rb_node *node, struct rb_root *root,
		   const struct rb_augment_callbacks *augment)
{
	struct rb_node *rebalance = __rb_erase_augmented(node, root, augment);
	if (rebalance)
		__rb_erase_color(rebalance, root, augment->rotate);
}

#endif	/* _LINUX_RBTREE_AUGMENTED_H */
Commit	Line	Data
9dd228b5 HS	1	/*
	2	Red Black Trees
	3	(C) 1999 Andrea Arcangeli <andrea@suse.de>
	4	(C) 2002 David Woodhouse <dwmw2@infradead.org>
	5	(C) 2012 Michel Lespinasse <walken@google.com>
	6
	7	* SPDX-License-Identifier: GPL-2.0+
	8
	9	linux/include/linux/rbtree_augmented.h
	10	*/
	11
	12	#ifndef _LINUX_RBTREE_AUGMENTED_H
	13	#define _LINUX_RBTREE_AUGMENTED_H
	14
	15	#include <linux/compiler.h>
	16	#include <linux/rbtree.h>
	17
	18	/*
	19	* Please note - only struct rb_augment_callbacks and the prototypes for
	20	* rb_insert_augmented() and rb_erase_augmented() are intended to be public.
	21	* The rest are implementation details you are not expected to depend on.
	22	*
	23	* See Documentation/rbtree.txt for documentation and samples.
	24	*/
	25
	26	struct rb_augment_callbacks {
	27	void (propagate)(struct rb_node node, struct rb_node *stop);
	28	void (copy)(struct rb_node old, struct rb_node *new);
	29	void (rotate)(struct rb_node old, struct rb_node *new);
	30	};
	31
	32	extern void __rb_insert_augmented(struct rb_node node, struct rb_root root,
	33	void (augment_rotate)(struct rb_node old, struct rb_node *new));
	34	static inline void
	35	rb_insert_augmented(struct rb_node node, struct rb_root root,
	36	const struct rb_augment_callbacks *augment)
	37	{
	38	__rb_insert_augmented(node, root, augment->rotate);
	39	}
	40
	41	#define RB_DECLARE_CALLBACKS(rbstatic, rbname, rbstruct, rbfield, \
	42	rbtype, rbaugmented, rbcompute) \
	43	static inline void \
	44	rbname ## _propagate(struct rb_node rb, struct rb_node stop) \
	45	{ \
	46	while (rb != stop) { \
	47	rbstruct *node = rb_entry(rb, rbstruct, rbfield); \
	48	rbtype augmented = rbcompute(node); \
	49	if (node->rbaugmented == augmented) \
	50	break; \
	51	node->rbaugmented = augmented; \
	52	rb = rb_parent(&node->rbfield); \
	53	} \
	54	} \
	55	static inline void \
	56	rbname ## _copy(struct rb_node rb_old, struct rb_node rb_new) \
	57	{ \
	58	rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \
	59	rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \
	60	new->rbaugmented = old->rbaugmented; \
	61	} \
	62	static void \
	63	rbname ## _rotate(struct rb_node rb_old, struct rb_node rb_new) \
	64	{ \
65	rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \
66	rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \
67	new->rbaugmented = old->rbaugmented; \
68	old->rbaugmented = rbcompute(old); \
69	} \
70	rbstatic const struct rb_augment_callbacks rbname = { \
71	rbname ## _propagate, rbname ## _copy, rbname ## _rotate \
72	};
73
74
75	#define RB_RED 0
76	#define RB_BLACK 1
77
78	#define __rb_parent(pc) ((struct rb_node *)(pc & ~3))
79
80	#define __rb_color(pc) ((pc) & 1)
81	#define __rb_is_black(pc) __rb_color(pc)
82	#define __rb_is_red(pc) (!__rb_color(pc))
83	#define rb_color(rb) __rb_color((rb)->__rb_parent_color)
84	#define rb_is_red(rb) __rb_is_red((rb)->__rb_parent_color)
85	#define rb_is_black(rb) __rb_is_black((rb)->__rb_parent_color)
86
87	static inline void rb_set_parent(struct rb_node rb, struct rb_node p)
88	{
89	rb->__rb_parent_color = rb_color(rb) \| (unsigned long)p;
90	}
91
92	static inline void rb_set_parent_color(struct rb_node *rb,
93	struct rb_node *p, int color)
94	{
95	rb->__rb_parent_color = (unsigned long)p \| color;
96	}
97
98	static inline void
99	__rb_change_child(struct rb_node old, struct rb_node new,
100	struct rb_node parent, struct rb_root root)
101	{
102	if (parent) {
103	if (parent->rb_left == old)
104	parent->rb_left = new;
105	else
106	parent->rb_right = new;
107	} else
108	root->rb_node = new;
109	}
110
111	extern void __rb_erase_color(struct rb_node parent, struct rb_root root,
112	void (augment_rotate)(struct rb_node old, struct rb_node *new));
113
114	static __always_inline struct rb_node *
115	__rb_erase_augmented(struct rb_node node, struct rb_root root,
116	const struct rb_augment_callbacks *augment)
117	{
118	struct rb_node child = node->rb_right, tmp = node->rb_left;
119	struct rb_node parent, rebalance;
120	unsigned long pc;
121
122	if (!tmp) {
123	/*
124	* Case 1: node to erase has no more than 1 child (easy!)
125	*
126	* Note that if there is one child it must be red due to 5)
127	* and node must be black due to 4). We adjust colors locally
128	* so as to bypass __rb_erase_color() later on.
129	*/
130	pc = node->__rb_parent_color;
131	parent = __rb_parent(pc);
132	__rb_change_child(node, child, parent, root);
133	if (child) {
134	child->__rb_parent_color = pc;
135	rebalance = NULL;
136	} else
137	rebalance = __rb_is_black(pc) ? parent : NULL;
138	tmp = parent;
139	} else if (!child) {
140	/* Still case 1, but this time the child is node->rb_left */
141	tmp->__rb_parent_color = pc = node->__rb_parent_color;
142	parent = __rb_parent(pc);
143	__rb_change_child(node, tmp, parent, root);
144	rebalance = NULL;
145	tmp = parent;
146	} else {
147	struct rb_node successor = child, child2;
148	tmp = child->rb_left;
149	if (!tmp) {
150	/*
151	* Case 2: node's successor is its right child
152	*
153	* (n) (s)
154	* / \ / \
155	* (x) (s) -> (x) (c)
156	* \
157	* (c)
158	*/
159	parent = successor;
160	child2 = successor->rb_right;
161	augment->copy(node, successor);
162	} else {
163	/*
164	* Case 3: node's successor is leftmost under
165	* node's right child subtree
166	*
167	* (n) (s)
168	* / \ / \
169	* (x) (y) -> (x) (y)
170	* / /
171	* (p) (p)
172	* / /
173	* (s) (c)
174	* \
175	* (c)
176	*/
177	do {
178	parent = successor;
179	successor = tmp;
180	tmp = tmp->rb_left;
181	} while (tmp);
182	parent->rb_left = child2 = successor->rb_right;
183	successor->rb_right = child;
184	rb_set_parent(child, successor);
185	augment->copy(node, successor);
186	augment->propagate(parent, successor);
187	}
188
189	successor->rb_left = tmp = node->rb_left;
190	rb_set_parent(tmp, successor);
191
192	pc = node->__rb_parent_color;
193	tmp = __rb_parent(pc);
194	__rb_change_child(node, successor, tmp, root);
195	if (child2) {
196	successor->__rb_parent_color = pc;
197	rb_set_parent_color(child2, parent, RB_BLACK);
198	rebalance = NULL;
199	} else {
200	unsigned long pc2 = successor->__rb_parent_color;
201	successor->__rb_parent_color = pc;
202	rebalance = __rb_is_black(pc2) ? parent : NULL;
203	}
204	tmp = successor;
205	}
206
207	augment->propagate(tmp, NULL);
208	return rebalance;
209	}
210
211	static __always_inline void
212	rb_erase_augmented(struct rb_node node, struct rb_root root,
213	const struct rb_augment_callbacks *augment)
214	{
215	struct rb_node *rebalance = __rb_erase_augmented(node, root, augment);
216	if (rebalance)
217	__rb_erase_color(rebalance, root, augment->rotate);
218	}
219
220	#endif /* _LINUX_RBTREE_AUGMENTED_H */