[linux-2.6-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,
	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_insert_augmented() instead of the usual rb_insert_color() call.
 * If rb_insert_augmented() 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, 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)
{
	if (newleft)
		root->rb_leftmost = node;
	rb_insert_augmented(node, &root->rb_root, augment);
}

/*
 * Template for declaring augmented rbtree callbacks
 *
 * RBSTATIC:    'static' or empty
 * RBNAME:      name of the rb_augment_callbacks structure
 * RBSTRUCT:    struct type of the tree nodes
 * RBFIELD:     name of struct rb_node field within RBSTRUCT
 * RBTYPE:      type of the RBAUGMENTED field
 * RBAUGMENTED: name of RBTYPE field within RBSTRUCT holding data for subtree
 * RBCOMPUTE:   name of function that recomputes the RBAUGMENTED data
 */

#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,
		     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 (!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, 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)
{
	if (root->rb_leftmost == node)
		root->rb_leftmost = rb_next(node);
	rb_erase_augmented(node, &root->rb_root, augment);
}

#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
c7d4f7ee	35	extern void __rb_insert_augmented(struct rb_node node, struct rb_root root,
307bc971	36	void (augment_rotate)(struct rb_node old, struct rb_node *new));
c7d4f7ee	37
307bc971 ACM	38	/*
	39	* Fixup the rbtree and update the augmented information when rebalancing.
	40	*
	41	* On insertion, the user must update the augmented information on the path
	42	* leading to the inserted node, then call rb_link_node() as usual and
c7d4f7ee ML	43	* rb_insert_augmented() instead of the usual rb_insert_color() call.
c7d4f7ee ML	44	* If rb_insert_augmented() rebalances the rbtree, it will callback into
307bc971 ACM	45	* a user provided function to update the augmented information on the
	46	* affected subtrees.
	47	*/
	48	static inline void
	49	rb_insert_augmented(struct rb_node node, struct rb_root root,
	50	const struct rb_augment_callbacks *augment)
	51	{
c7d4f7ee	52	__rb_insert_augmented(node, root, augment->rotate);
3aef2cad DB	53	}
	54
	55	static inline void
	56	rb_insert_augmented_cached(struct rb_node *node,
	57	struct rb_root_cached *root, bool newleft,
	58	const struct rb_augment_callbacks *augment)
	59	{
c7d4f7ee ML	60	if (newleft)
	61	root->rb_leftmost = node;
	62	rb_insert_augmented(node, &root->rb_root, augment);
307bc971 ACM	63	}
307bc971 ACM	64
444b8a83 ML	65	/*
	66	* Template for declaring augmented rbtree callbacks
	67	*
	68	* RBSTATIC: 'static' or empty
	69	* RBNAME: name of the rb_augment_callbacks structure
	70	* RBSTRUCT: struct type of the tree nodes
	71	* RBFIELD: name of struct rb_node field within RBSTRUCT
	72	* RBTYPE: type of the RBAUGMENTED field
	73	* RBAUGMENTED: name of RBTYPE field within RBSTRUCT holding data for subtree
	74	* RBCOMPUTE: name of function that recomputes the RBAUGMENTED data
	75	*/
	76
	77	#define RB_DECLARE_CALLBACKS(RBSTATIC, RBNAME, RBSTRUCT, RBFIELD, \
	78	RBTYPE, RBAUGMENTED, RBCOMPUTE) \
307bc971	79	static inline void \
444b8a83	80	RBNAME ## _propagate(struct rb_node rb, struct rb_node stop) \
307bc971 ACM	81	{ \
307bc971 ACM	82	while (rb != stop) { \
444b8a83 ML	83	RBSTRUCT *node = rb_entry(rb, RBSTRUCT, RBFIELD); \
	84	RBTYPE augmented = RBCOMPUTE(node); \
	85	if (node->RBAUGMENTED == augmented) \
307bc971	86	break; \
444b8a83 ML	87	node->RBAUGMENTED = augmented; \
444b8a83 ML	88	rb = rb_parent(&node->RBFIELD); \
307bc971 ACM	89	} \
	90	} \
	91	static inline void \
444b8a83	92	RBNAME ## _copy(struct rb_node rb_old, struct rb_node rb_new) \
307bc971	93	{ \
444b8a83 ML	94	RBSTRUCT *old = rb_entry(rb_old, RBSTRUCT, RBFIELD); \
	95	RBSTRUCT *new = rb_entry(rb_new, RBSTRUCT, RBFIELD); \
	96	new->RBAUGMENTED = old->RBAUGMENTED; \
307bc971 ACM	97	} \
307bc971 ACM	98	static void \
444b8a83	99	RBNAME ## _rotate(struct rb_node rb_old, struct rb_node rb_new) \
307bc971	100	{ \
444b8a83 ML	101	RBSTRUCT *old = rb_entry(rb_old, RBSTRUCT, RBFIELD); \
	102	RBSTRUCT *new = rb_entry(rb_new, RBSTRUCT, RBFIELD); \
	103	new->RBAUGMENTED = old->RBAUGMENTED; \
	104	old->RBAUGMENTED = RBCOMPUTE(old); \
307bc971	105	} \
444b8a83 ML	106	RBSTATIC const struct rb_augment_callbacks RBNAME = { \
	107	.propagate = RBNAME ## _propagate, \
	108	.copy = RBNAME ## _copy, \
	109	.rotate = RBNAME ## _rotate \
307bc971 ACM	110	};
	111
	112
	113	#define RB_RED 0
	114	#define RB_BLACK 1
	115
	116	#define __rb_parent(pc) ((struct rb_node *)(pc & ~3))
	117
	118	#define __rb_color(pc) ((pc) & 1)
	119	#define __rb_is_black(pc) __rb_color(pc)
	120	#define __rb_is_red(pc) (!__rb_color(pc))
	121	#define rb_color(rb) __rb_color((rb)->__rb_parent_color)
	122	#define rb_is_red(rb) __rb_is_red((rb)->__rb_parent_color)
	123	#define rb_is_black(rb) __rb_is_black((rb)->__rb_parent_color)
	124
	125	static inline void rb_set_parent(struct rb_node rb, struct rb_node p)
	126	{
	127	rb->__rb_parent_color = rb_color(rb) \| (unsigned long)p;
	128	}
	129
	130	static inline void rb_set_parent_color(struct rb_node *rb,
	131	struct rb_node *p, int color)
	132	{
	133	rb->__rb_parent_color = (unsigned long)p \| color;
	134	}
	135
	136	static inline void
	137	__rb_change_child(struct rb_node old, struct rb_node new,
	138	struct rb_node parent, struct rb_root root)
	139	{
	140	if (parent) {
	141	if (parent->rb_left == old)
3aef2cad	142	WRITE_ONCE(parent->rb_left, new);
307bc971	143	else
3aef2cad	144	WRITE_ONCE(parent->rb_right, new);
307bc971	145	} else
3aef2cad	146	WRITE_ONCE(root->rb_node, new);
307bc971 ACM	147	}
	148
	149	extern void __rb_erase_color(struct rb_node parent, struct rb_root root,
	150	void (augment_rotate)(struct rb_node old, struct rb_node *new));
	151
	152	static __always_inline struct rb_node *
	153	__rb_erase_augmented(struct rb_node node, struct rb_root root,
	154	const struct rb_augment_callbacks *augment)
	155	{
3aef2cad DB	156	struct rb_node *child = node->rb_right;
3aef2cad DB	157	struct rb_node *tmp = node->rb_left;
307bc971 ACM	158	struct rb_node parent, rebalance;
	159	unsigned long pc;
	160
	161	if (!tmp) {
	162	/*
	163	* Case 1: node to erase has no more than 1 child (easy!)
	164	*
	165	* Note that if there is one child it must be red due to 5)
	166	* and node must be black due to 4). We adjust colors locally
	167	* so as to bypass __rb_erase_color() later on.
	168	*/
	169	pc = node->__rb_parent_color;
	170	parent = __rb_parent(pc);
	171	__rb_change_child(node, child, parent, root);
	172	if (child) {
	173	child->__rb_parent_color = pc;
	174	rebalance = NULL;
	175	} else
	176	rebalance = __rb_is_black(pc) ? parent : NULL;
	177	tmp = parent;
	178	} else if (!child) {
	179	/* Still case 1, but this time the child is node->rb_left */
	180	tmp->__rb_parent_color = pc = node->__rb_parent_color;
	181	parent = __rb_parent(pc);
	182	__rb_change_child(node, tmp, parent, root);
	183	rebalance = NULL;
	184	tmp = parent;
	185	} else {
	186	struct rb_node successor = child, child2;
3aef2cad	187
307bc971 ACM	188	tmp = child->rb_left;
	189	if (!tmp) {
	190	/*
	191	* Case 2: node's successor is its right child
	192	*
	193	* (n) (s)
	194	* / \ / \
	195	* (x) (s) -> (x) (c)
	196	* \
	197	* (c)
	198	*/
	199	parent = successor;
	200	child2 = successor->rb_right;
3aef2cad	201
307bc971 ACM	202	augment->copy(node, successor);
	203	} else {
	204	/*
	205	* Case 3: node's successor is leftmost under
	206	* node's right child subtree
	207	*
	208	* (n) (s)
	209	* / \ / \
	210	* (x) (y) -> (x) (y)
	211	* / /
	212	* (p) (p)
	213	* / /
	214	* (s) (c)
	215	* \
	216	* (c)
	217	*/
	218	do {
	219	parent = successor;
	220	successor = tmp;
	221	tmp = tmp->rb_left;
	222	} while (tmp);
3aef2cad DB	223	child2 = successor->rb_right;
	224	WRITE_ONCE(parent->rb_left, child2);
	225	WRITE_ONCE(successor->rb_right, child);
307bc971	226	rb_set_parent(child, successor);
3aef2cad	227
307bc971 ACM	228	augment->copy(node, successor);
	229	augment->propagate(parent, successor);
	230	}
	231
3aef2cad DB	232	tmp = node->rb_left;
3aef2cad DB	233	WRITE_ONCE(successor->rb_left, tmp);
307bc971 ACM	234	rb_set_parent(tmp, successor);
	235
	236	pc = node->__rb_parent_color;
	237	tmp = __rb_parent(pc);
	238	__rb_change_child(node, successor, tmp, root);
3aef2cad	239
307bc971 ACM	240	if (child2) {
	241	successor->__rb_parent_color = pc;
	242	rb_set_parent_color(child2, parent, RB_BLACK);
	243	rebalance = NULL;
	244	} else {
	245	unsigned long pc2 = successor->__rb_parent_color;
	246	successor->__rb_parent_color = pc;
	247	rebalance = __rb_is_black(pc2) ? parent : NULL;
	248	}
	249	tmp = successor;
	250	}
	251
	252	augment->propagate(tmp, NULL);
	253	return rebalance;
	254	}
	255
	256	static __always_inline void
	257	rb_erase_augmented(struct rb_node node, struct rb_root root,
	258	const struct rb_augment_callbacks *augment)
	259	{
c7d4f7ee	260	struct rb_node *rebalance = __rb_erase_augmented(node, root, augment);
307bc971 ACM	261	if (rebalance)
	262	__rb_erase_color(rebalance, root, augment->rotate);
	263	}
	264
3aef2cad DB	265	static __always_inline void
	266	rb_erase_augmented_cached(struct rb_node node, struct rb_root_cached root,
	267	const struct rb_augment_callbacks *augment)
	268	{
c7d4f7ee ML	269	if (root->rb_leftmost == node)
	270	root->rb_leftmost = rb_next(node);
	271	rb_erase_augmented(node, &root->rb_root, augment);
3aef2cad DB	272	}
	273
	274	#endif /* _TOOLS_LINUX_RBTREE_AUGMENTED_H */