/*      $NetBSD: tree.h,v 1.8 2004/03/28 19:38:30 provos Exp $  */
/*      $OpenBSD: tree.h,v 1.7 2002/10/17 21:51:54 art Exp $    */
/*
 * Copyright 2002 Niels Provos <provos@citi.umich.edu>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef _SYS_TREE_H_
#define _SYS_TREE_H_

#ifndef _SYS_SPINLOCK_H_
#include <sys/spinlock.h>
#endif

void rb_spin_lock(struct spinlock *spin);
void rb_spin_unlock(struct spinlock *spin);

/*
 * This file defines data structures for different types of trees:
 * splay trees and red-black trees.
 *
 * A splay tree is a self-organizing data structure.  Every operation
 * on the tree causes a splay to happen.  The splay moves the requested
 * node to the root of the tree and partly rebalances it.
 *
 * This has the benefit that request locality causes faster lookups as
 * the requested nodes move to the top of the tree.  On the other hand,
 * every lookup causes memory writes.
 *
 * The Balance Theorem bounds the total access time for m operations
 * and n inserts on an initially empty tree as O((m + n)lg n).  The
 * amortized cost for a sequence of m accesses to a splay tree is O(lg n);
 *
 * A red-black tree is a binary search tree with the node color as an
 * extra attribute.  It fulfills a set of conditions:
 *      - every search path from the root to a leaf consists of the
 *        same number of black nodes,
 *      - each red node (except for the root) has a black parent,
 *      - each leaf node is black.
 *
 * Every operation on a red-black tree is bounded as O(lg n).
 * The maximum height of a red-black tree is 2lg (n+1).
 */

#define SPLAY_HEAD(name, type)                                          \
struct name {                                                           \
        struct type *sph_root; /* root of the tree */                   \
}

#define SPLAY_INITIALIZER(root)                                         \
        { NULL }

#define SPLAY_INIT(root) do {                                           \
        (root)->sph_root = NULL;                                        \
} while (/*CONSTCOND*/ 0)

#define SPLAY_ENTRY(type)                                               \
struct {                                                                \
        struct type *spe_left; /* left element */                       \
        struct type *spe_right; /* right element */                     \
}

#define SPLAY_LEFT(elm, field)          (elm)->field.spe_left
#define SPLAY_RIGHT(elm, field)         (elm)->field.spe_right
#define SPLAY_ROOT(head)                (head)->sph_root
#define SPLAY_EMPTY(head)               (SPLAY_ROOT(head) == NULL)

/* SPLAY_ROTATE_{LEFT,RIGHT} expect that tmp hold SPLAY_{RIGHT,LEFT} */
#define SPLAY_ROTATE_RIGHT(head, tmp, field) do {                       \
        SPLAY_LEFT((head)->sph_root, field) = SPLAY_RIGHT(tmp, field);  \
        SPLAY_RIGHT(tmp, field) = (head)->sph_root;                     \
        (head)->sph_root = tmp;                                         \
} while (/*CONSTCOND*/ 0)
        
#define SPLAY_ROTATE_LEFT(head, tmp, field) do {                        \
        SPLAY_RIGHT((head)->sph_root, field) = SPLAY_LEFT(tmp, field);  \
        SPLAY_LEFT(tmp, field) = (head)->sph_root;                      \
        (head)->sph_root = tmp;                                         \
} while (/*CONSTCOND*/ 0)

#define SPLAY_LINKLEFT(head, tmp, field) do {                           \
        SPLAY_LEFT(tmp, field) = (head)->sph_root;                      \
        tmp = (head)->sph_root;                                         \
        (head)->sph_root = SPLAY_LEFT((head)->sph_root, field);         \
} while (/*CONSTCOND*/ 0)

#define SPLAY_LINKRIGHT(head, tmp, field) do {                          \
        SPLAY_RIGHT(tmp, field) = (head)->sph_root;                     \
        tmp = (head)->sph_root;                                         \
        (head)->sph_root = SPLAY_RIGHT((head)->sph_root, field);        \
} while (/*CONSTCOND*/ 0)

#define SPLAY_ASSEMBLE(head, node, left, right, field) do {             \
        SPLAY_RIGHT(left, field) = SPLAY_LEFT((head)->sph_root, field); \
        SPLAY_LEFT(right, field) = SPLAY_RIGHT((head)->sph_root, field);\
        SPLAY_LEFT((head)->sph_root, field) = SPLAY_RIGHT(node, field); \
        SPLAY_RIGHT((head)->sph_root, field) = SPLAY_LEFT(node, field); \
} while (/*CONSTCOND*/ 0)

/* Generates prototypes and inline functions */

#define SPLAY_PROTOTYPE(name, type, field, cmp)                         \
void name##_SPLAY(struct name *, struct type *);                        \
void name##_SPLAY_MINMAX(struct name *, int);                           \
struct type *name##_SPLAY_INSERT(struct name *, struct type *);         \
struct type *name##_SPLAY_REMOVE(struct name *, struct type *);         \
                                                                        \
/* Finds the node with the same key as elm */                           \
static __inline struct type *                                           \
name##_SPLAY_FIND(struct name *head, struct type *elm)                  \
{                                                                       \
        if (SPLAY_EMPTY(head))                                          \
                return(NULL);                                           \
        name##_SPLAY(head, elm);                                        \
        if ((cmp)(elm, (head)->sph_root) == 0)                          \
                return (head->sph_root);                                \
        return (NULL);                                                  \
}                                                                       \
                                                                        \
static __inline struct type *                                           \
name##_SPLAY_NEXT(struct name *head, struct type *elm)                  \
{                                                                       \
        name##_SPLAY(head, elm);                                        \
        if (SPLAY_RIGHT(elm, field) != NULL) {                          \
                elm = SPLAY_RIGHT(elm, field);                          \
                while (SPLAY_LEFT(elm, field) != NULL) {                \
                        elm = SPLAY_LEFT(elm, field);                   \
                }                                                       \
        } else                                                          \
                elm = NULL;                                             \
        return (elm);                                                   \
}                                                                       \
                                                                        \
static __inline struct type *                                           \
name##_SPLAY_MIN_MAX(struct name *head, int val)                        \
{                                                                       \
        name##_SPLAY_MINMAX(head, val);                                 \
        return (SPLAY_ROOT(head));                                      \
}

/* Main splay operation.
 * Moves node close to the key of elm to top
 */
#define SPLAY_GENERATE(name, type, field, cmp)                          \
struct type *                                                           \
name##_SPLAY_INSERT(struct name *head, struct type *elm)                \
{                                                                       \
    if (SPLAY_EMPTY(head)) {                                            \
            SPLAY_LEFT(elm, field) = SPLAY_RIGHT(elm, field) = NULL;    \
    } else {                                                            \
            int __comp;                                                 \
            name##_SPLAY(head, elm);                                    \
            __comp = (cmp)(elm, (head)->sph_root);                      \
            if(__comp < 0) {                                            \
                    SPLAY_LEFT(elm, field) = SPLAY_LEFT((head)->sph_root, field);\
                    SPLAY_RIGHT(elm, field) = (head)->sph_root;         \
                    SPLAY_LEFT((head)->sph_root, field) = NULL;         \
            } else if (__comp > 0) {                                    \
                    SPLAY_RIGHT(elm, field) = SPLAY_RIGHT((head)->sph_root, field);\
                    SPLAY_LEFT(elm, field) = (head)->sph_root;          \
                    SPLAY_RIGHT((head)->sph_root, field) = NULL;        \
            } else                                                      \
                    return ((head)->sph_root);                          \
    }                                                                   \
    (head)->sph_root = (elm);                                           \
    return (NULL);                                                      \
}                                                                       \
                                                                        \
struct type *                                                           \
name##_SPLAY_REMOVE(struct name *head, struct type *elm)                \
{                                                                       \
        struct type *__tmp;                                             \
        if (SPLAY_EMPTY(head))                                          \
                return (NULL);                                          \
        name##_SPLAY(head, elm);                                        \
        if ((cmp)(elm, (head)->sph_root) == 0) {                        \
                if (SPLAY_LEFT((head)->sph_root, field) == NULL) {      \
                        (head)->sph_root = SPLAY_RIGHT((head)->sph_root, field);\
                } else {                                                \
                        __tmp = SPLAY_RIGHT((head)->sph_root, field);   \
                        (head)->sph_root = SPLAY_LEFT((head)->sph_root, field);\
                        name##_SPLAY(head, elm);                        \
                        SPLAY_RIGHT((head)->sph_root, field) = __tmp;   \
                }                                                       \
                return (elm);                                           \
        }                                                               \
        return (NULL);                                                  \
}                                                                       \
                                                                        \
void                                                                    \
name##_SPLAY(struct name *head, struct type *elm)                       \
{                                                                       \
        struct type __node, *__left, *__right, *__tmp;                  \
        int __comp;                                                     \
\
        SPLAY_LEFT(&__node, field) = SPLAY_RIGHT(&__node, field) = NULL;\
        __left = __right = &__node;                                     \
\
        while ((__comp = (cmp)(elm, (head)->sph_root)) != 0) {          \
                if (__comp < 0) {                                       \
                        __tmp = SPLAY_LEFT((head)->sph_root, field);    \
                        if (__tmp == NULL)                              \
                                break;                                  \
                        if ((cmp)(elm, __tmp) < 0){                     \
                                SPLAY_ROTATE_RIGHT(head, __tmp, field); \
                                if (SPLAY_LEFT((head)->sph_root, field) == NULL)\
                                        break;                          \
                        }                                               \
                        SPLAY_LINKLEFT(head, __right, field);           \
                } else if (__comp > 0) {                                \
                        __tmp = SPLAY_RIGHT((head)->sph_root, field);   \
                        if (__tmp == NULL)                              \
                                break;                                  \
                        if ((cmp)(elm, __tmp) > 0){                     \
                                SPLAY_ROTATE_LEFT(head, __tmp, field);  \
                                if (SPLAY_RIGHT((head)->sph_root, field) == NULL)\
                                        break;                          \
                        }                                               \
                        SPLAY_LINKRIGHT(head, __left, field);           \
                }                                                       \
        }                                                               \
        SPLAY_ASSEMBLE(head, &__node, __left, __right, field);          \
}                                                                       \
                                                                        \
/* Splay with either the minimum or the maximum element                 \
 * Used to find minimum or maximum element in tree.                     \
 */                                                                     \
void name##_SPLAY_MINMAX(struct name *head, int __comp)                 \
{                                                                       \
        struct type __node, *__left, *__right, *__tmp;                  \
                                                                        \
        SPLAY_LEFT(&__node, field) = SPLAY_RIGHT(&__node, field) = NULL;\
        __left = __right = &__node;                                     \
                                                                        \
        while (1) {                                                     \
                if (__comp < 0) {                                       \
                        __tmp = SPLAY_LEFT((head)->sph_root, field);    \
                        if (__tmp == NULL)                              \
                                break;                                  \
                        if (__comp < 0){                                \
                                SPLAY_ROTATE_RIGHT(head, __tmp, field); \
                                if (SPLAY_LEFT((head)->sph_root, field) == NULL)\
                                        break;                          \
                        }                                               \
                        SPLAY_LINKLEFT(head, __right, field);           \
                } else if (__comp > 0) {                                \
                        __tmp = SPLAY_RIGHT((head)->sph_root, field);   \
                        if (__tmp == NULL)                              \
                                break;                                  \
                        if (__comp > 0) {                               \
                                SPLAY_ROTATE_LEFT(head, __tmp, field);  \
                                if (SPLAY_RIGHT((head)->sph_root, field) == NULL)\
                                        break;                          \
                        }                                               \
                        SPLAY_LINKRIGHT(head, __left, field);           \
                }                                                       \
        }                                                               \
        SPLAY_ASSEMBLE(head, &__node, __left, __right, field);          \
}

#define SPLAY_NEGINF    -1
#define SPLAY_INF       1

#define SPLAY_INSERT(name, x, y)        name##_SPLAY_INSERT(x, y)
#define SPLAY_REMOVE(name, x, y)        name##_SPLAY_REMOVE(x, y)
#define SPLAY_FIND(name, x, y)          name##_SPLAY_FIND(x, y)
#define SPLAY_NEXT(name, x, y)          name##_SPLAY_NEXT(x, y)
#define SPLAY_MIN(name, x)              (SPLAY_EMPTY(x) ? NULL  \
                                        : name##_SPLAY_MIN_MAX(x, SPLAY_NEGINF))
#define SPLAY_MAX(name, x)              (SPLAY_EMPTY(x) ? NULL  \
                                        : name##_SPLAY_MIN_MAX(x, SPLAY_INF))

#define SPLAY_FOREACH(x, name, head)                                    \
        for ((x) = SPLAY_MIN(name, head);                               \
             (x) != NULL;                                               \
             (x) = SPLAY_NEXT(name, head, x))

/*
 * Macros that define a red-black tree
 */

#define RB_SCAN_INFO(name, type)                                        \
struct name##_scan_info {                                               \
        struct name##_scan_info *link;                                  \
        struct type     *node;                                          \
}

#define RB_HEAD(name, type)                                             \
struct name {                                                           \
        struct type *rbh_root;               /* root of the tree */     \
        struct name##_scan_info *rbh_inprog; /* scans in progress */    \
        struct spinlock rbh_spin;                                       \
}

#define RB_INITIALIZER(root)                                            \
        { NULL, NULL, SPINLOCK_INITIALIZER(root.spin, "root.spin") }

#define RB_INIT(root) do {                                              \
        (root)->rbh_root = NULL;                                        \
        (root)->rbh_inprog = NULL;                                      \
} while (/*CONSTCOND*/ 0)

#ifdef _KERNEL
#define RB_SCAN_LOCK(spin)      rb_spin_lock(spin)
#define RB_SCAN_UNLOCK(spin)    rb_spin_unlock(spin)
#else
#define RB_SCAN_LOCK(spin)
#define RB_SCAN_UNLOCK(spin)
#endif

#define RB_BLACK        0
#define RB_RED          1
#define RB_ENTRY(type)                                                  \
struct {                                                                \
        struct type *rbe_left;          /* left element */              \
        struct type *rbe_right;         /* right element */             \
        struct type *rbe_parent;        /* parent element */            \
        int rbe_color;                  /* node color */                \
}

#define RB_LEFT(elm, field)             (elm)->field.rbe_left
#define RB_RIGHT(elm, field)            (elm)->field.rbe_right
#define RB_PARENT(elm, field)           (elm)->field.rbe_parent
#define RB_COLOR(elm, field)            (elm)->field.rbe_color
#define RB_ROOT(head)                   (head)->rbh_root
#define RB_INPROG(head)                 (head)->rbh_inprog
#define RB_EMPTY(head)                  (RB_ROOT(head) == NULL)

#define RB_SET(elm, parent, field) do {                                 \
        RB_PARENT(elm, field) = parent;                                 \
        RB_LEFT(elm, field) = RB_RIGHT(elm, field) = NULL;              \
        RB_COLOR(elm, field) = RB_RED;                                  \
} while (/*CONSTCOND*/ 0)

#define RB_SET_BLACKRED(black, red, field) do {                         \
        RB_COLOR(black, field) = RB_BLACK;                              \
        RB_COLOR(red, field) = RB_RED;                                  \
} while (/*CONSTCOND*/ 0)

#ifndef RB_AUGMENT
#define RB_AUGMENT(x)   do {} while (0)
#endif

#define RB_ROTATE_LEFT(head, elm, tmp, field) do {                      \
        (tmp) = RB_RIGHT(elm, field);                                   \
        if ((RB_RIGHT(elm, field) = RB_LEFT(tmp, field)) != NULL) {     \
                RB_PARENT(RB_LEFT(tmp, field), field) = (elm);          \
        }                                                               \
        RB_AUGMENT(elm);                                                \
        if ((RB_PARENT(tmp, field) = RB_PARENT(elm, field)) != NULL) {  \
                if ((elm) == RB_LEFT(RB_PARENT(elm, field), field))     \
                        RB_LEFT(RB_PARENT(elm, field), field) = (tmp);  \
                else                                                    \
                        RB_RIGHT(RB_PARENT(elm, field), field) = (tmp); \
        } else                                                          \
                (head)->rbh_root = (tmp);                               \
        RB_LEFT(tmp, field) = (elm);                                    \
        RB_PARENT(elm, field) = (tmp);                                  \
        RB_AUGMENT(tmp);                                                \
        if ((RB_PARENT(tmp, field)))                                    \
                RB_AUGMENT(RB_PARENT(tmp, field));                      \
} while (/*CONSTCOND*/ 0)

#define RB_ROTATE_RIGHT(head, elm, tmp, field) do {                     \
        (tmp) = RB_LEFT(elm, field);                                    \
        if ((RB_LEFT(elm, field) = RB_RIGHT(tmp, field)) != NULL) {     \
                RB_PARENT(RB_RIGHT(tmp, field), field) = (elm);         \
        }                                                               \
        RB_AUGMENT(elm);                                                \
        if ((RB_PARENT(tmp, field) = RB_PARENT(elm, field)) != NULL) {  \
                if ((elm) == RB_LEFT(RB_PARENT(elm, field), field))     \
                        RB_LEFT(RB_PARENT(elm, field), field) = (tmp);  \
                else                                                    \
                        RB_RIGHT(RB_PARENT(elm, field), field) = (tmp); \
        } else                                                          \
                (head)->rbh_root = (tmp);                               \
        RB_RIGHT(tmp, field) = (elm);                                   \
        RB_PARENT(elm, field) = (tmp);                                  \
        RB_AUGMENT(tmp);                                                \
        if ((RB_PARENT(tmp, field)))                                    \
                RB_AUGMENT(RB_PARENT(tmp, field));                      \
} while (/*CONSTCOND*/ 0)

/* Generates prototypes and inline functions */
#define RB_PROTOTYPE(name, type, field, cmp)                            \
        _RB_PROTOTYPE(name, type, field, cmp,)
#define RB_PROTOTYPE_STATIC(name, type, field, cmp)                     \
        _RB_PROTOTYPE(name, type, field, cmp, __unused static)

#define _RB_PROTOTYPE(name, type, field, cmp, STORQUAL)                 \
STORQUAL void name##_RB_INSERT_COLOR(struct name *, struct type *);     \
STORQUAL void name##_RB_REMOVE_COLOR(struct name *, struct type *, struct type *);\
STORQUAL struct type *name##_RB_REMOVE(struct name *, struct type *);   \
STORQUAL struct type *name##_RB_INSERT(struct name *, struct type *);   \
STORQUAL struct type *name##_RB_FIND(struct name *, struct type *);     \
STORQUAL int name##_RB_SCAN(struct name *, int (*)(struct type *, void *),\
                        int (*)(struct type *, void *), void *);        \
STORQUAL int name##_RB_SCAN_NOLK(struct name *, int (*)(struct type *, void *),\
                        int (*)(struct type *, void *), void *);        \
STORQUAL struct type *name##_RB_NEXT(struct type *);                    \
STORQUAL struct type *name##_RB_PREV(struct type *);                    \
STORQUAL struct type *name##_RB_MINMAX(struct name *, int);             \
RB_SCAN_INFO(name, type)                                                \

/*
 * A version which supplies a fast lookup routine for an exact match
 * on a numeric field.
 */
#define RB_PROTOTYPE2(name, type, field, cmp, datatype)                 \
RB_PROTOTYPE(name, type, field, cmp);                                   \
struct type *name##_RB_LOOKUP(struct name *, datatype);                 \
struct type *name##_RB_LOOKUP_REL(struct name *, datatype, struct type *) \

/*
 * A version which supplies a fast lookup routine for a numeric
 * field which resides within a ranged object, either using (begin,end),
 * or using (begin,size).
 */
#define RB_PROTOTYPE3(name, type, field, cmp, datatype)                 \
RB_PROTOTYPE2(name, type, field, cmp, datatype);                        \
struct type *name##_RB_RLOOKUP(struct name *, datatype)                 \

#define RB_PROTOTYPE4(name, type, field, cmp, datatype)                 \
RB_PROTOTYPE2(name, type, field, cmp, datatype);                        \
struct type *name##_RB_RLOOKUP(struct name *, datatype)                 \

#define RB_PROTOTYPEX(name, ext, type, field, cmp, datatype)            \
RB_PROTOTYPE(name, type, field, cmp);                                   \
struct type *name##_RB_LOOKUP_##ext (struct name *, datatype)           \

/* Main rb operation.
 * Moves node close to the key of elm to top
 */
#define RB_GENERATE(name, type, field, cmp)                             \
        _RB_GENERATE(name, type, field, cmp,)

#define RB_GENERATE_STATIC(name, type, field, cmp)                      \
        _RB_GENERATE(name, type, field, cmp, __unused static)

#define _RB_GENERATE(name, type, field, cmp, STORQUAL)                  \
STORQUAL void                                                           \
name##_RB_INSERT_COLOR(struct name *head, struct type *elm)             \
{                                                                       \
        struct type *parent, *gparent, *tmp;                            \
        while ((parent = RB_PARENT(elm, field)) != NULL &&              \
            RB_COLOR(parent, field) == RB_RED) {                        \
                gparent = RB_PARENT(parent, field);                     \
                if (parent == RB_LEFT(gparent, field)) {                \
                        tmp = RB_RIGHT(gparent, field);                 \
                        if (tmp && RB_COLOR(tmp, field) == RB_RED) {    \
                                RB_COLOR(tmp, field) = RB_BLACK;        \
                                RB_SET_BLACKRED(parent, gparent, field);\
                                elm = gparent;                          \
                                continue;                               \
                        }                                               \
                        if (RB_RIGHT(parent, field) == elm) {           \
                                RB_ROTATE_LEFT(head, parent, tmp, field);\
                                tmp = parent;                           \
                                parent = elm;                           \
                                elm = tmp;                              \
                        }                                               \
                        RB_SET_BLACKRED(parent, gparent, field);        \
                        RB_ROTATE_RIGHT(head, gparent, tmp, field);     \
                } else {                                                \
                        tmp = RB_LEFT(gparent, field);                  \
                        if (tmp && RB_COLOR(tmp, field) == RB_RED) {    \
                                RB_COLOR(tmp, field) = RB_BLACK;        \
                                RB_SET_BLACKRED(parent, gparent, field);\
                                elm = gparent;                          \
                                continue;                               \
                        }                                               \
                        if (RB_LEFT(parent, field) == elm) {            \
                                RB_ROTATE_RIGHT(head, parent, tmp, field);\
                                tmp = parent;                           \
                                parent = elm;                           \
                                elm = tmp;                              \
                        }                                               \
                        RB_SET_BLACKRED(parent, gparent, field);        \
                        RB_ROTATE_LEFT(head, gparent, tmp, field);      \
                }                                                       \
        }                                                               \
        RB_COLOR(head->rbh_root, field) = RB_BLACK;                     \
}                                                                       \
                                                                        \
STORQUAL void                                                           \
name##_RB_REMOVE_COLOR(struct name *head, struct type *parent,          \
                        struct type *elm)                               \
{                                                                       \
        struct type *tmp;                                               \
        while ((elm == NULL || RB_COLOR(elm, field) == RB_BLACK) &&     \
            elm != RB_ROOT(head)) {                                     \
                if (RB_LEFT(parent, field) == elm) {                    \
                        tmp = RB_RIGHT(parent, field);                  \
                        if (RB_COLOR(tmp, field) == RB_RED) {           \
                                RB_SET_BLACKRED(tmp, parent, field);    \
                                RB_ROTATE_LEFT(head, parent, tmp, field);\
                                tmp = RB_RIGHT(parent, field);          \
                        }                                               \
                        if ((RB_LEFT(tmp, field) == NULL ||             \
                            RB_COLOR(RB_LEFT(tmp, field), field) == RB_BLACK) &&\
                            (RB_RIGHT(tmp, field) == NULL ||            \
                            RB_COLOR(RB_RIGHT(tmp, field), field) == RB_BLACK)) {\
                                RB_COLOR(tmp, field) = RB_RED;          \
                                elm = parent;                           \
                                parent = RB_PARENT(elm, field);         \
                        } else {                                        \
                                if (RB_RIGHT(tmp, field) == NULL ||     \
                                    RB_COLOR(RB_RIGHT(tmp, field), field) == RB_BLACK) {\
                                        struct type *oleft;             \
                                        if ((oleft = RB_LEFT(tmp, field)) \
                                            != NULL)                    \
                                                RB_COLOR(oleft, field) = RB_BLACK;\
                                        RB_COLOR(tmp, field) = RB_RED;  \
                                        RB_ROTATE_RIGHT(head, tmp, oleft, field);\
                                        tmp = RB_RIGHT(parent, field);  \
                                }                                       \
                                RB_COLOR(tmp, field) = RB_COLOR(parent, field);\
                                RB_COLOR(parent, field) = RB_BLACK;     \
                                if (RB_RIGHT(tmp, field))               \
                                        RB_COLOR(RB_RIGHT(tmp, field), field) = RB_BLACK;\
                                RB_ROTATE_LEFT(head, parent, tmp, field);\
                                elm = RB_ROOT(head);                    \
                                break;                                  \
                        }                                               \
                } else {                                                \
                        tmp = RB_LEFT(parent, field);                   \
                        if (RB_COLOR(tmp, field) == RB_RED) {           \
                                RB_SET_BLACKRED(tmp, parent, field);    \
                                RB_ROTATE_RIGHT(head, parent, tmp, field);\
                                tmp = RB_LEFT(parent, field);           \
                        }                                               \
                        if ((RB_LEFT(tmp, field) == NULL ||             \
                            RB_COLOR(RB_LEFT(tmp, field), field) == RB_BLACK) &&\
                            (RB_RIGHT(tmp, field) == NULL ||            \
                            RB_COLOR(RB_RIGHT(tmp, field), field) == RB_BLACK)) {\
                                RB_COLOR(tmp, field) = RB_RED;          \
                                elm = parent;                           \
                                parent = RB_PARENT(elm, field);         \
                        } else {                                        \
                                if (RB_LEFT(tmp, field) == NULL ||      \
                                    RB_COLOR(RB_LEFT(tmp, field), field) == RB_BLACK) {\
                                        struct type *oright;            \
                                        if ((oright = RB_RIGHT(tmp, field)) \
                                            != NULL)                    \
                                                RB_COLOR(oright, field) = RB_BLACK;\
                                        RB_COLOR(tmp, field) = RB_RED;  \
                                        RB_ROTATE_LEFT(head, tmp, oright, field);\
                                        tmp = RB_LEFT(parent, field);   \
                                }                                       \
                                RB_COLOR(tmp, field) = RB_COLOR(parent, field);\
                                RB_COLOR(parent, field) = RB_BLACK;     \
                                if (RB_LEFT(tmp, field))                \
                                        RB_COLOR(RB_LEFT(tmp, field), field) = RB_BLACK;\
                                RB_ROTATE_RIGHT(head, parent, tmp, field);\
                                elm = RB_ROOT(head);                    \
                                break;                                  \
                        }                                               \
                }                                                       \
        }                                                               \
        if (elm)                                                        \
                RB_COLOR(elm, field) = RB_BLACK;                        \
}                                                                       \
                                                                        \
STORQUAL struct type *                                                  \
name##_RB_REMOVE(struct name *head, struct type *elm)                   \
{                                                                       \
        struct type *child, *parent, *old;                              \
        struct name##_scan_info *inprog;                                \
        int color;                                                      \
                                                                        \
        for (inprog = RB_INPROG(head); inprog; inprog = inprog->link) { \
                if (inprog->node == elm)                                \
                        inprog->node = RB_NEXT(name, head, elm);        \
        }                                                               \
                                                                        \
        old = elm;                                                      \
        if (RB_LEFT(elm, field) == NULL)                                \
                child = RB_RIGHT(elm, field);                           \
        else if (RB_RIGHT(elm, field) == NULL)                          \
                child = RB_LEFT(elm, field);                            \
        else {                                                          \
                struct type *left;                                      \
                elm = RB_RIGHT(elm, field);                             \
                while ((left = RB_LEFT(elm, field)) != NULL)            \
                        elm = left;                                     \
                child = RB_RIGHT(elm, field);                           \
                parent = RB_PARENT(elm, field);                         \
                color = RB_COLOR(elm, field);                           \
                if (child)                                              \
                        RB_PARENT(child, field) = parent;               \
                if (parent) {                                           \
                        if (RB_LEFT(parent, field) == elm)              \
                                RB_LEFT(parent, field) = child;         \
                        else                                            \
                                RB_RIGHT(parent, field) = child;        \
                        RB_AUGMENT(parent);                             \
                } else                                                  \
                        RB_ROOT(head) = child;                          \
                if (RB_PARENT(elm, field) == old)                       \
                        parent = elm;                                   \
                (elm)->field = (old)->field;                            \
                if (RB_PARENT(old, field)) {                            \
                        if (RB_LEFT(RB_PARENT(old, field), field) == old)\
                                RB_LEFT(RB_PARENT(old, field), field) = elm;\
                        else                                            \
                                RB_RIGHT(RB_PARENT(old, field), field) = elm;\
                        RB_AUGMENT(RB_PARENT(old, field));              \
                } else                                                  \
                        RB_ROOT(head) = elm;                            \
                RB_PARENT(RB_LEFT(old, field), field) = elm;            \
                if (RB_RIGHT(old, field))                               \
                        RB_PARENT(RB_RIGHT(old, field), field) = elm;   \
                if (parent) {                                           \
                        left = parent;                                  \
                        do {                                            \
                                RB_AUGMENT(left);                       \
                        } while ((left = RB_PARENT(left, field)) != NULL); \
                }                                                       \
                goto color;                                             \
        }                                                               \
        parent = RB_PARENT(elm, field);                                 \
        color = RB_COLOR(elm, field);                                   \
        if (child)                                                      \
                RB_PARENT(child, field) = parent;                       \
        if (parent) {                                                   \
                if (RB_LEFT(parent, field) == elm)                      \
                        RB_LEFT(parent, field) = child;                 \
                else                                                    \
                        RB_RIGHT(parent, field) = child;                \
                RB_AUGMENT(parent);                                     \
        } else                                                          \
                RB_ROOT(head) = child;                                  \
color:                                                                  \
        if (color == RB_BLACK)                                          \
                name##_RB_REMOVE_COLOR(head, parent, child);            \
        return (old);                                                   \
}                                                                       \
                                                                        \
/* Inserts a node into the RB tree */                                   \
STORQUAL struct type *                                                  \
name##_RB_INSERT(struct name *head, struct type *elm)                   \
{                                                                       \
        struct type *tmp;                                               \
        struct type *parent = NULL;                                     \
        int comp = 0;                                                   \
        tmp = RB_ROOT(head);                                            \
        while (tmp) {                                                   \
                parent = tmp;                                           \
                comp = (cmp)(elm, parent);                              \
                if (comp < 0)                                           \
                        tmp = RB_LEFT(tmp, field);                      \
                else if (comp > 0)                                      \
                        tmp = RB_RIGHT(tmp, field);                     \
                else                                                    \
                        return(tmp);                                    \
        }                                                               \
        RB_SET(elm, parent, field);                                     \
        if (parent != NULL) {                                           \
                if (comp < 0)                                           \
                        RB_LEFT(parent, field) = elm;                   \
                else                                                    \
                        RB_RIGHT(parent, field) = elm;                  \
                RB_AUGMENT(parent);                                     \
        } else                                                          \
                RB_ROOT(head) = elm;                                    \
        name##_RB_INSERT_COLOR(head, elm);                              \
        return (NULL);                                                  \
}                                                                       \
                                                                        \
/* Finds the node with the same key as elm */                           \
STORQUAL struct type *                                                  \
name##_RB_FIND(struct name *head, struct type *elm)                     \
{                                                                       \
        struct type *tmp = RB_ROOT(head);                               \
        int comp;                                                       \
        while (tmp) {                                                   \
                comp = cmp(elm, tmp);                                   \
                if (comp < 0)                                           \
                        tmp = RB_LEFT(tmp, field);                      \
                else if (comp > 0)                                      \
                        tmp = RB_RIGHT(tmp, field);                     \
                else                                                    \
                        return (tmp);                                   \
        }                                                               \
        return (NULL);                                                  \
}                                                                       \
                                                                        \
/*                                                                      \
 * Issue a callback for all matching items.  The scan function must     \
 * return < 0 for items below the desired range, 0 for items within     \
 * the range, and > 0 for items beyond the range.   Any item may be     \
 * deleted while the scan is in progress.                               \
 */                                                                     \
static int                                                              \
name##_SCANCMP_ALL(struct type *type __unused, void *data __unused)     \
{                                                                       \
        return(0);                                                      \
}                                                                       \
                                                                        \
static __inline void                                                    \
name##_scan_info_link(struct name##_scan_info *scan, struct name *head) \
{                                                                       \
        RB_SCAN_LOCK(&head->rbh_spin);                                  \
        scan->link = RB_INPROG(head);                                   \
        RB_INPROG(head) = scan;                                         \
        RB_SCAN_UNLOCK(&head->rbh_spin);                                \
}                                                                       \
                                                                        \
static __inline void                                                    \
name##_scan_info_done(struct name##_scan_info *scan, struct name *head) \
{                                                                       \
        struct name##_scan_info **infopp;                               \
                                                                        \
        RB_SCAN_LOCK(&head->rbh_spin);                                  \
        infopp = &RB_INPROG(head);                                      \
        while (*infopp != scan)                                         \
                infopp = &(*infopp)->link;                              \
        *infopp = scan->link;                                           \
        RB_SCAN_UNLOCK(&head->rbh_spin);                                \
}                                                                       \
                                                                        \
static __inline int                                                     \
_##name##_RB_SCAN(struct name *head,                                    \
                int (*scancmp)(struct type *, void *),                  \
                int (*callback)(struct type *, void *),                 \
                void *data, int uselock)                                \
{                                                                       \
        struct name##_scan_info info;                                   \
        struct type *best;                                              \
        struct type *tmp;                                               \
        int count;                                                      \
        int comp;                                                       \
                                                                        \
        if (scancmp == NULL)                                            \
                scancmp = name##_SCANCMP_ALL;                           \
                                                                        \
        /*                                                              \
         * Locate the first element.                                    \
         */                                                             \
        tmp = RB_ROOT(head);                                            \
        best = NULL;                                                    \
        while (tmp) {                                                   \
                comp = scancmp(tmp, data);                              \
                if (comp < 0) {                                         \
                        tmp = RB_RIGHT(tmp, field);                     \
                } else if (comp > 0) {                                  \
                        tmp = RB_LEFT(tmp, field);                      \
                } else {                                                \
                        best = tmp;                                     \
                        if (RB_LEFT(tmp, field) == NULL)                \
                                break;                                  \
                        tmp = RB_LEFT(tmp, field);                      \
                }                                                       \
        }                                                               \
        count = 0;                                                      \
        if (best) {                                                     \
                info.node = RB_NEXT(name, head, best);                  \
                if (uselock)                                            \
                        name##_scan_info_link(&info, head);             \
                while ((comp = callback(best, data)) >= 0) {            \
                        count += comp;                                  \
                        best = info.node;                               \
                        if (best == NULL || scancmp(best, data) != 0)   \
                                break;                                  \
                        info.node = RB_NEXT(name, head, best);          \
                }                                                       \
                if (uselock)                                            \
                        name##_scan_info_done(&info, head);             \
                if (comp < 0)   /* error or termination */              \
                        count = comp;                                   \
        }                                                               \
        return(count);                                                  \
}                                                                       \
                                                                        \
STORQUAL int                                                            \
name##_RB_SCAN(struct name *head,                                       \
                int (*scancmp)(struct type *, void *),                  \
                int (*callback)(struct type *, void *),                 \
                void *data)                                             \
{                                                                       \
        return _##name##_RB_SCAN(head, scancmp, callback, data, 1);     \
}                                                                       \
                                                                        \
STORQUAL int                                                            \
name##_RB_SCAN_NOLK(struct name *head,                                  \
                int (*scancmp)(struct type *, void *),                  \
                int (*callback)(struct type *, void *),                 \
                void *data)                                             \
{                                                                       \
        return _##name##_RB_SCAN(head, scancmp, callback, data, 0);     \
}                                                                       \
                                                                        \
/* ARGSUSED */                                                          \
STORQUAL struct type *                                                  \
name##_RB_NEXT(struct type *elm)                                        \
{                                                                       \
        if (RB_RIGHT(elm, field)) {                                     \
                elm = RB_RIGHT(elm, field);                             \
                while (RB_LEFT(elm, field))                             \
                        elm = RB_LEFT(elm, field);                      \
        } else {                                                        \
                if (RB_PARENT(elm, field) &&                            \
                    (elm == RB_LEFT(RB_PARENT(elm, field), field)))     \
                        elm = RB_PARENT(elm, field);                    \
                else {                                                  \
                        while (RB_PARENT(elm, field) &&                 \
                            (elm == RB_RIGHT(RB_PARENT(elm, field), field)))\
                                elm = RB_PARENT(elm, field);            \
                        elm = RB_PARENT(elm, field);                    \
                }                                                       \
        }                                                               \
        return (elm);                                                   \
}                                                                       \
                                                                        \
/* ARGSUSED */                                                          \
STORQUAL struct type *                                                  \
name##_RB_PREV(struct type *elm)                                        \
{                                                                       \
        if (RB_LEFT(elm, field)) {                                      \
                elm = RB_LEFT(elm, field);                              \
                while (RB_RIGHT(elm, field))                            \
                        elm = RB_RIGHT(elm, field);                     \
        } else {                                                        \
                if (RB_PARENT(elm, field) &&                            \
                    (elm == RB_RIGHT(RB_PARENT(elm, field), field)))    \
                        elm = RB_PARENT(elm, field);                    \
                else {                                                  \
                        while (RB_PARENT(elm, field) &&                 \
                            (elm == RB_LEFT(RB_PARENT(elm, field), field)))\
                                elm = RB_PARENT(elm, field);            \
                        elm = RB_PARENT(elm, field);                    \
                }                                                       \
        }                                                               \
        return (elm);                                                   \
}                                                                       \
                                                                        \
STORQUAL struct type *                                                  \
name##_RB_MINMAX(struct name *head, int val)                            \
{                                                                       \
        struct type *tmp = RB_ROOT(head);                               \
        struct type *parent = NULL;                                     \
        while (tmp) {                                                   \
                parent = tmp;                                           \
                if (val < 0)                                            \
                        tmp = RB_LEFT(tmp, field);                      \
                else                                                    \
                        tmp = RB_RIGHT(tmp, field);                     \
        }                                                               \
        return (parent);                                                \
}

/*
 * This extended version implements a fast LOOKUP function given
 * a numeric data type.
 *
 * The element whos index/offset field is exactly the specified value
 * will be returned, or NULL.
 */
#define RB_GENERATE2(name, type, field, cmp, datatype, indexfield)      \
RB_GENERATE(name, type, field, cmp)                                     \
                                                                        \
struct type *                                                           \
name##_RB_LOOKUP(struct name *head, datatype value)                     \
{                                                                       \
        struct type *tmp;                                               \
                                                                        \
        tmp = RB_ROOT(head);                                            \
        while (tmp) {                                                   \
                if (value > tmp->indexfield)                            \
                        tmp = RB_RIGHT(tmp, field);                     \
                else if (value < tmp->indexfield)                       \
                        tmp = RB_LEFT(tmp, field);                      \
                else                                                    \
                        return(tmp);                                    \
        }                                                               \
        return(NULL);                                                   \
}                                                                       \
                                                                        \
struct type *                                                           \
name##_RB_LOOKUP_REL(struct name *head, datatype value, struct type *rel)\
{                                                                       \
        struct type *tmp;                                               \
                                                                        \
        if (value == rel->indexfield - 1) {                             \
                tmp = name##_RB_PREV(rel);                              \
                if (tmp && value != tmp->indexfield)                    \
                        tmp = NULL;                                     \
                return tmp;                                             \
        }                                                               \
        if (value == rel->indexfield + 1) {                             \
                tmp = name##_RB_NEXT(rel);                              \
                if (tmp && value != tmp->indexfield)                    \
                        tmp = NULL;                                     \
                return tmp;                                             \
        }                                                               \
                                                                        \
        tmp = RB_ROOT(head);                                            \
        while (tmp) {                                                   \
                if (value > tmp->indexfield)                            \
                        tmp = RB_RIGHT(tmp, field);                     \
                else if (value < tmp->indexfield)                       \
                        tmp = RB_LEFT(tmp, field);                      \
                else                                                    \
                        return(tmp);                                    \
        }                                                               \
        return(NULL);                                                   \
}                                                                       \

/*
 * This extended version implements a fast ranged-based LOOKUP function
 * given a numeric data type, for data types with a beginning and end
 * (end is inclusive).
 *
 * The element whos range contains the specified value is returned, or NULL
 */
#define RB_GENERATE3(name, type, field, cmp, datatype, begfield, endfield) \
RB_GENERATE2(name, type, field, cmp, datatype, begfield)                \
                                                                        \
struct type *                                                           \
name##_RB_RLOOKUP(struct name *head, datatype value)                    \
{                                                                       \
        struct type *tmp;                                               \
                                                                        \
        tmp = RB_ROOT(head);                                            \
        while (tmp) {                                                   \
                if (value >= tmp->begfield && value <= tmp->endfield)   \
                        return(tmp);                                    \
                if (value > tmp->begfield)                              \
                        tmp = RB_RIGHT(tmp, field);                     \
                else                                                    \
                        tmp = RB_LEFT(tmp, field);                      \
        }                                                               \
        return(NULL);                                                   \
}                                                                       \

/*
 * This extended version implements a fast ranged-based LOOKUP function
 * given a numeric data type, for data types with a beginning and size.
 *
 * WARNING: The full range of the data type is not supported due to a
 * boundary condition at the end, where (beginning + size) might overflow.
 *
 * The element whos range contains the specified value is returned, or NULL
 */
#define RB_GENERATE4(name, type, field, cmp, datatype, begfield, sizefield) \
RB_GENERATE2(name, type, field, cmp, datatype, begfield)                \
                                                                        \
struct type *                                                           \
name##_RB_RLOOKUP(struct name *head, datatype value)                    \
{                                                                       \
        struct type *tmp;                                               \
                                                                        \
        tmp = RB_ROOT(head);                                            \
        while (tmp) {                                                   \
                if (value >= tmp->begfield &&                           \
                    value < tmp->begfield + tmp->sizefield) {           \
                        return(tmp);                                    \
                }                                                       \
                if (value > tmp->begfield)                              \
                        tmp = RB_RIGHT(tmp, field);                     \
                else                                                    \
                        tmp = RB_LEFT(tmp, field);                      \
        }                                                               \
        return(NULL);                                                   \
}                                                                       \

/*
 * This generates a custom lookup function for a red-black tree.
 * Note that the macro may be used with a storage qualifier.
 */

#define RB_GENERATE_XLOOKUP(name, ext, type, field, xcmp, datatype)        \
        _RB_GENERATE_XLOOKUP(name, ext, type, field, xcmp, datatype,)
#define RB_GENERATE_XLOOKUP_STATIC(name, ext, type, field, xcmp, datatype) \
        _RB_GENERATE_XLOOKUP(name, ext, type, field, xcmp, datatype, __unused static)

#define _RB_GENERATE_XLOOKUP(name, ext, type, field, xcmp, datatype, STORQUAL)\
                                                                        \
STORQUAL struct type *                                                  \
name##_RB_LOOKUP_##ext (struct name *head, datatype value)              \
{                                                                       \
        struct type *tmp;                                               \
        int r;                                                          \
                                                                        \
        tmp = RB_ROOT(head);                                            \
        while (tmp) {                                                   \
                r = xcmp(value, tmp);                                   \
                if (r == 0)                                             \
                        return(tmp);                                    \
                if (r > 0)                                              \
                        tmp = RB_RIGHT(tmp, field);                     \
                else                                                    \
                        tmp = RB_LEFT(tmp, field);                      \
        }                                                               \
        return(NULL);                                                   \
}                                                                       \


#define RB_NEGINF       -1
#define RB_INF  1

#define RB_INSERT(name, root, elm)      name##_RB_INSERT(root, elm)
#define RB_REMOVE(name, root, elm)      name##_RB_REMOVE(root, elm)
#define RB_FIND(name, root, elm)        name##_RB_FIND(root, elm)
#define RB_LOOKUP(name, root, value)    name##_RB_LOOKUP(root, value)
#define RB_RLOOKUP(name, root, value)   name##_RB_RLOOKUP(root, value)
#define RB_SCAN(name, root, cmp, callback, data)                        \
                                name##_RB_SCAN(root, cmp, callback, data)
#define RB_SCAN_NOLK(name, root, cmp, callback, data)                   \
                                name##_RB_SCAN_NOLK(root, cmp, callback, data)
#define RB_FIRST(name, root)            name##_RB_MINMAX(root, RB_NEGINF)
#define RB_NEXT(name, root, elm)        name##_RB_NEXT(elm)
#define RB_PREV(name, root, elm)        name##_RB_PREV(elm)
#define RB_MIN(name, root)              name##_RB_MINMAX(root, RB_NEGINF)
#define RB_MAX(name, root)              name##_RB_MINMAX(root, RB_INF)

#define RB_FOREACH(x, name, head)                                       \
        for ((x) = RB_MIN(name, head);                                  \
             (x) != NULL;                                               \
             (x) = name##_RB_NEXT(x))

#define RB_FOREACH_FROM(x, name, y)                                     \
        for ((x) = (y);                                                 \
            ((x) != NULL) && ((y) = name##_RB_NEXT(x), (x) != NULL);    \
             (x) = (y))

#define RB_FOREACH_SAFE(x, name, head, y)                               \
        for ((x) = RB_MIN(name, head);                                  \
            ((x) != NULL) && ((y) = name##_RB_NEXT(x), (x) != NULL);    \
             (x) = (y))

#define RB_FOREACH_REVERSE(x, name, head)                               \
        for ((x) = RB_MAX(name, head);                                  \
             (x) != NULL;                                               \
             (x) = name##_RB_PREV(x))

#define RB_FOREACH_REVERSE_FROM(x, name, y)                             \
        for ((x) = (y);                                                 \
            ((x) != NULL) && ((y) = name##_RB_PREV(x), (x) != NULL);    \
             (x) = (y))

#define RB_FOREACH_REVERSE_SAFE(x, name, head, y)                       \
        for ((x) = RB_MAX(name, head);                                  \
            ((x) != NULL) && ((y) = name##_RB_PREV(x), (x) != NULL);    \
             (x) = (y))

#endif  /* _SYS_TREE_H_ */