[linux-block.git] / tools / include / linux / rbtree_augmented.h

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
  Red Black Trees
  (C) 1999  Andrea Arcangeli <andrea@suse.de>
  (C) 2002  David Woodhouse <dwmw2@infradead.org>
  (C) 2012  Michel Lespinasse <walken@google.com>


  tools/linux/include/linux/rbtree_augmented.h

  Copied from:
  linux/include/linux/rbtree_augmented.h
*/

#ifndef _TOOLS_LINUX_RBTREE_AUGMENTED_H
#define _TOOLS_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,
				  bool newleft, struct rb_node **leftmost,
	void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
/*
 * Fixup the rbtree and update the augmented information when rebalancing.
 *
 * On insertion, the user must update the augmented information on the path
 * leading to the inserted node, then call rb_link_node() as usual and
 * rb_augment_inserted() instead of the usual rb_insert_color() call.
 * If rb_augment_inserted() rebalances the rbtree, it will callback into
 * a user provided function to update the augmented information on the
 * affected subtrees.
 */
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, false, NULL, augment->rotate);
}

static inline void
rb_insert_augmented_cached(struct rb_node *node,
			   struct rb_root_cached *root, bool newleft,
			   const struct rb_augment_callbacks *augment)
{
	__rb_insert_augmented(node, &root->rb_root,
			      newleft, &root->rb_leftmost, 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 = {			\
	.propagate = rbname ## _propagate,				\
	.copy = rbname ## _copy,					\
	.rotate = 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)
			WRITE_ONCE(parent->rb_left, new);
		else
			WRITE_ONCE(parent->rb_right, new);
	} else
		WRITE_ONCE(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,
		     struct rb_node **leftmost,
		     const struct rb_augment_callbacks *augment)
{
	struct rb_node *child = node->rb_right;
	struct rb_node *tmp = node->rb_left;
	struct rb_node *parent, *rebalance;
	unsigned long pc;

	if (leftmost && node == *leftmost)
		*leftmost = rb_next(node);

	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);
			child2 = successor->rb_right;
			WRITE_ONCE(parent->rb_left, child2);
			WRITE_ONCE(successor->rb_right, child);
			rb_set_parent(child, successor);

			augment->copy(node, successor);
			augment->propagate(parent, successor);
		}

		tmp = node->rb_left;
		WRITE_ONCE(successor->rb_left, tmp);
		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,
							 NULL, augment);
	if (rebalance)
		__rb_erase_color(rebalance, root, augment->rotate);
}

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

#endif /* _TOOLS_LINUX_RBTREE_AUGMENTED_H */
Commit	Line	Data
1a59d1b8	1	/* SPDX-License-Identifier: GPL-2.0-or-later */
307bc971 ACM	2	/*
	3	Red Black Trees
	4	(C) 1999 Andrea Arcangeli <andrea@suse.de>
	5	(C) 2002 David Woodhouse <dwmw2@infradead.org>
	6	(C) 2012 Michel Lespinasse <walken@google.com>
	7
307bc971 ACM	8
	9	tools/linux/include/linux/rbtree_augmented.h
	10
	11	Copied from:
	12	linux/include/linux/rbtree_augmented.h
	13	*/
	14
	15	#ifndef _TOOLS_LINUX_RBTREE_AUGMENTED_H
	16	#define _TOOLS_LINUX_RBTREE_AUGMENTED_H
	17
	18	#include <linux/compiler.h>
	19	#include <linux/rbtree.h>
	20
	21	/*
	22	* Please note - only struct rb_augment_callbacks and the prototypes for
	23	* rb_insert_augmented() and rb_erase_augmented() are intended to be public.
	24	* The rest are implementation details you are not expected to depend on.
	25	*
	26	* See Documentation/rbtree.txt for documentation and samples.
	27	*/
	28
	29	struct rb_augment_callbacks {
	30	void (propagate)(struct rb_node node, struct rb_node *stop);
	31	void (copy)(struct rb_node old, struct rb_node *new);
	32	void (rotate)(struct rb_node old, struct rb_node *new);
	33	};
	34
3aef2cad DB	35	extern void __rb_insert_augmented(struct rb_node *node,
	36	struct rb_root *root,
	37	bool newleft, struct rb_node **leftmost,
307bc971 ACM	38	void (augment_rotate)(struct rb_node old, struct rb_node *new));
	39	/*
	40	* Fixup the rbtree and update the augmented information when rebalancing.
	41	*
	42	* On insertion, the user must update the augmented information on the path
	43	* leading to the inserted node, then call rb_link_node() as usual and
	44	* rb_augment_inserted() instead of the usual rb_insert_color() call.
	45	* If rb_augment_inserted() rebalances the rbtree, it will callback into
	46	* a user provided function to update the augmented information on the
	47	* affected subtrees.
	48	*/
	49	static inline void
	50	rb_insert_augmented(struct rb_node node, struct rb_root root,
	51	const struct rb_augment_callbacks *augment)
	52	{
3aef2cad DB	53	__rb_insert_augmented(node, root, false, NULL, augment->rotate);
	54	}
	55
	56	static inline void
	57	rb_insert_augmented_cached(struct rb_node *node,
	58	struct rb_root_cached *root, bool newleft,
	59	const struct rb_augment_callbacks *augment)
	60	{
	61	__rb_insert_augmented(node, &root->rb_root,
	62	newleft, &root->rb_leftmost, augment->rotate);
307bc971 ACM	63	}
	64
	65	#define RB_DECLARE_CALLBACKS(rbstatic, rbname, rbstruct, rbfield, \
	66	rbtype, rbaugmented, rbcompute) \
	67	static inline void \
	68	rbname ## _propagate(struct rb_node rb, struct rb_node stop) \
	69	{ \
	70	while (rb != stop) { \
	71	rbstruct *node = rb_entry(rb, rbstruct, rbfield); \
	72	rbtype augmented = rbcompute(node); \
	73	if (node->rbaugmented == augmented) \
	74	break; \
	75	node->rbaugmented = augmented; \
	76	rb = rb_parent(&node->rbfield); \
	77	} \
	78	} \
	79	static inline void \
	80	rbname ## _copy(struct rb_node rb_old, struct rb_node rb_new) \
	81	{ \
	82	rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \
	83	rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \
	84	new->rbaugmented = old->rbaugmented; \
	85	} \
	86	static void \
	87	rbname ## _rotate(struct rb_node rb_old, struct rb_node rb_new) \
	88	{ \
	89	rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \
	90	rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \
	91	new->rbaugmented = old->rbaugmented; \
	92	old->rbaugmented = rbcompute(old); \
	93	} \
	94	rbstatic const struct rb_augment_callbacks rbname = { \
3aef2cad DB	95	.propagate = rbname ## _propagate, \
	96	.copy = rbname ## _copy, \
	97	.rotate = rbname ## _rotate \
307bc971 ACM	98	};
	99
	100
	101	#define RB_RED 0
	102	#define RB_BLACK 1
	103
	104	#define __rb_parent(pc) ((struct rb_node *)(pc & ~3))
	105
	106	#define __rb_color(pc) ((pc) & 1)
	107	#define __rb_is_black(pc) __rb_color(pc)
	108	#define __rb_is_red(pc) (!__rb_color(pc))
	109	#define rb_color(rb) __rb_color((rb)->__rb_parent_color)
	110	#define rb_is_red(rb) __rb_is_red((rb)->__rb_parent_color)
	111	#define rb_is_black(rb) __rb_is_black((rb)->__rb_parent_color)
	112
	113	static inline void rb_set_parent(struct rb_node rb, struct rb_node p)
	114	{
	115	rb->__rb_parent_color = rb_color(rb) \| (unsigned long)p;
	116	}
	117
	118	static inline void rb_set_parent_color(struct rb_node *rb,
	119	struct rb_node *p, int color)
	120	{
	121	rb->__rb_parent_color = (unsigned long)p \| color;
	122	}
	123
	124	static inline void
	125	__rb_change_child(struct rb_node old, struct rb_node new,
	126	struct rb_node parent, struct rb_root root)
	127	{
	128	if (parent) {
	129	if (parent->rb_left == old)
3aef2cad	130	WRITE_ONCE(parent->rb_left, new);
307bc971	131	else
3aef2cad	132	WRITE_ONCE(parent->rb_right, new);
307bc971	133	} else
3aef2cad	134	WRITE_ONCE(root->rb_node, new);
307bc971 ACM	135	}
	136
	137	extern void __rb_erase_color(struct rb_node parent, struct rb_root root,
	138	void (augment_rotate)(struct rb_node old, struct rb_node *new));
	139
	140	static __always_inline struct rb_node *
	141	__rb_erase_augmented(struct rb_node node, struct rb_root root,
3aef2cad	142	struct rb_node **leftmost,
307bc971 ACM	143	const struct rb_augment_callbacks *augment)
307bc971 ACM	144	{
3aef2cad DB	145	struct rb_node *child = node->rb_right;
3aef2cad DB	146	struct rb_node *tmp = node->rb_left;
307bc971 ACM	147	struct rb_node parent, rebalance;
	148	unsigned long pc;
	149
3aef2cad DB	150	if (leftmost && node == *leftmost)
	151	*leftmost = rb_next(node);
	152
307bc971 ACM	153	if (!tmp) {
	154	/*
	155	* Case 1: node to erase has no more than 1 child (easy!)
	156	*
	157	* Note that if there is one child it must be red due to 5)
	158	* and node must be black due to 4). We adjust colors locally
	159	* so as to bypass __rb_erase_color() later on.
	160	*/
	161	pc = node->__rb_parent_color;
	162	parent = __rb_parent(pc);
	163	__rb_change_child(node, child, parent, root);
	164	if (child) {
	165	child->__rb_parent_color = pc;
	166	rebalance = NULL;
	167	} else
	168	rebalance = __rb_is_black(pc) ? parent : NULL;
	169	tmp = parent;
	170	} else if (!child) {
	171	/* Still case 1, but this time the child is node->rb_left */
	172	tmp->__rb_parent_color = pc = node->__rb_parent_color;
	173	parent = __rb_parent(pc);
	174	__rb_change_child(node, tmp, parent, root);
	175	rebalance = NULL;
	176	tmp = parent;
	177	} else {
	178	struct rb_node successor = child, child2;
3aef2cad	179
307bc971 ACM	180	tmp = child->rb_left;
	181	if (!tmp) {
	182	/*
	183	* Case 2: node's successor is its right child
	184	*
	185	* (n) (s)
	186	* / \ / \
	187	* (x) (s) -> (x) (c)
	188	* \
	189	* (c)
	190	*/
	191	parent = successor;
	192	child2 = successor->rb_right;
3aef2cad	193
307bc971 ACM	194	augment->copy(node, successor);
	195	} else {
	196	/*
	197	* Case 3: node's successor is leftmost under
	198	* node's right child subtree
	199	*
	200	* (n) (s)
	201	* / \ / \
	202	* (x) (y) -> (x) (y)
	203	* / /
	204	* (p) (p)
	205	* / /
	206	* (s) (c)
	207	* \
	208	* (c)
	209	*/
	210	do {
	211	parent = successor;
	212	successor = tmp;
	213	tmp = tmp->rb_left;
	214	} while (tmp);
3aef2cad DB	215	child2 = successor->rb_right;
	216	WRITE_ONCE(parent->rb_left, child2);
	217	WRITE_ONCE(successor->rb_right, child);
307bc971	218	rb_set_parent(child, successor);
3aef2cad	219
307bc971 ACM	220	augment->copy(node, successor);
	221	augment->propagate(parent, successor);
	222	}
	223
3aef2cad DB	224	tmp = node->rb_left;
3aef2cad DB	225	WRITE_ONCE(successor->rb_left, tmp);
307bc971 ACM	226	rb_set_parent(tmp, successor);
	227
	228	pc = node->__rb_parent_color;
	229	tmp = __rb_parent(pc);
	230	__rb_change_child(node, successor, tmp, root);
3aef2cad	231
307bc971 ACM	232	if (child2) {
	233	successor->__rb_parent_color = pc;
	234	rb_set_parent_color(child2, parent, RB_BLACK);
	235	rebalance = NULL;
	236	} else {
	237	unsigned long pc2 = successor->__rb_parent_color;
	238	successor->__rb_parent_color = pc;
	239	rebalance = __rb_is_black(pc2) ? parent : NULL;
	240	}
	241	tmp = successor;
	242	}
	243
	244	augment->propagate(tmp, NULL);
	245	return rebalance;
	246	}
	247
	248	static __always_inline void
	249	rb_erase_augmented(struct rb_node node, struct rb_root root,
	250	const struct rb_augment_callbacks *augment)
	251	{
3aef2cad DB	252	struct rb_node *rebalance = __rb_erase_augmented(node, root,
3aef2cad DB	253	NULL, augment);
307bc971 ACM	254	if (rebalance)
	255	__rb_erase_color(rebalance, root, augment->rotate);
	256	}
	257
3aef2cad DB	258	static __always_inline void
	259	rb_erase_augmented_cached(struct rb_node node, struct rb_root_cached root,
	260	const struct rb_augment_callbacks *augment)
	261	{
	262	struct rb_node *rebalance = __rb_erase_augmented(node, &root->rb_root,
	263	&root->rb_leftmost,
	264	augment);
	265	if (rebalance)
	266	__rb_erase_color(rebalance, &root->rb_root, augment->rotate);
	267	}
	268
	269	#endif /* _TOOLS_LINUX_RBTREE_AUGMENTED_H */