/*      $OpenBSD: subr_tree.c,v 1.10 2018/10/09 08:28:43 dlg 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.
 */

/*
 * Copyright (c) 2016 David Gwynne <dlg@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/tree.h>

static inline struct rb_entry *
rb_n2e(const struct rb_type *t, void *node)
{
        unsigned long addr = (unsigned long)node;

        return ((struct rb_entry *)(addr + t->t_offset));
}

static inline void *
rb_e2n(const struct rb_type *t, struct rb_entry *rbe)
{
        unsigned long addr = (unsigned long)rbe;

        return ((void *)(addr - t->t_offset));
}

#define RBE_LEFT(_rbe)          (_rbe)->rbt_left
#define RBE_RIGHT(_rbe)         (_rbe)->rbt_right
#define RBE_PARENT(_rbe)        (_rbe)->rbt_parent
#define RBE_COLOR(_rbe)         (_rbe)->rbt_color

#define RBH_ROOT(_rbt)          (_rbt)->rbt_root

static inline void
rbe_set(struct rb_entry *rbe, struct rb_entry *parent)
{
        RBE_PARENT(rbe) = parent;
        RBE_LEFT(rbe) = RBE_RIGHT(rbe) = NULL;
        RBE_COLOR(rbe) = RB_RED;
}

static inline void
rbe_set_blackred(struct rb_entry *black, struct rb_entry *red)
{
        RBE_COLOR(black) = RB_BLACK;
        RBE_COLOR(red) = RB_RED;
}

static inline void
rbe_augment(const struct rb_type *t, struct rb_entry *rbe)
{
        (*t->t_augment)(rb_e2n(t, rbe));
}

static inline void
rbe_if_augment(const struct rb_type *t, struct rb_entry *rbe)
{
        if (t->t_augment != NULL)
                rbe_augment(t, rbe);
}

static inline void
rbe_rotate_left(const struct rb_type *t, struct rb_tree *rbt,
    struct rb_entry *rbe)
{
        struct rb_entry *parent;
        struct rb_entry *tmp;

        tmp = RBE_RIGHT(rbe);
        RBE_RIGHT(rbe) = RBE_LEFT(tmp);
        if (RBE_RIGHT(rbe) != NULL)
                RBE_PARENT(RBE_LEFT(tmp)) = rbe;

        parent = RBE_PARENT(rbe);
        RBE_PARENT(tmp) = parent;
        if (parent != NULL) {
                if (rbe == RBE_LEFT(parent))
                        RBE_LEFT(parent) = tmp;
                else
                        RBE_RIGHT(parent) = tmp;
        } else
                RBH_ROOT(rbt) = tmp;

        RBE_LEFT(tmp) = rbe;
        RBE_PARENT(rbe) = tmp;

        if (t->t_augment != NULL) {
                rbe_augment(t, rbe);
                rbe_augment(t, tmp);
                parent = RBE_PARENT(tmp);
                if (parent != NULL)
                        rbe_augment(t, parent);
        }
}

static inline void
rbe_rotate_right(const struct rb_type *t, struct rb_tree *rbt,
    struct rb_entry *rbe)
{
        struct rb_entry *parent;
        struct rb_entry *tmp;

        tmp = RBE_LEFT(rbe);
        RBE_LEFT(rbe) = RBE_RIGHT(tmp);
        if (RBE_LEFT(rbe) != NULL)
                RBE_PARENT(RBE_RIGHT(tmp)) = rbe;

        parent = RBE_PARENT(rbe);
        RBE_PARENT(tmp) = parent;
        if (parent != NULL) {
                if (rbe == RBE_LEFT(parent))
                        RBE_LEFT(parent) = tmp;
                else
                        RBE_RIGHT(parent) = tmp;
        } else
                RBH_ROOT(rbt) = tmp;

        RBE_RIGHT(tmp) = rbe;
        RBE_PARENT(rbe) = tmp;

        if (t->t_augment != NULL) {
                rbe_augment(t, rbe);
                rbe_augment(t, tmp);
                parent = RBE_PARENT(tmp);
                if (parent != NULL)
                        rbe_augment(t, parent);
        }
}

static inline void
rbe_insert_color(const struct rb_type *t, struct rb_tree *rbt,
    struct rb_entry *rbe)
{
        struct rb_entry *parent, *gparent, *tmp;

        while ((parent = RBE_PARENT(rbe)) != NULL &&
            RBE_COLOR(parent) == RB_RED) {
                gparent = RBE_PARENT(parent);

                if (parent == RBE_LEFT(gparent)) {
                        tmp = RBE_RIGHT(gparent);
                        if (tmp != NULL && RBE_COLOR(tmp) == RB_RED) {
                                RBE_COLOR(tmp) = RB_BLACK;
                                rbe_set_blackred(parent, gparent);
                                rbe = gparent;
                                continue;
                        }

                        if (RBE_RIGHT(parent) == rbe) {
                                rbe_rotate_left(t, rbt, parent);
                                tmp = parent;
                                parent = rbe;
                                rbe = tmp;
                        }

                        rbe_set_blackred(parent, gparent);
                        rbe_rotate_right(t, rbt, gparent);
                } else {
                        tmp = RBE_LEFT(gparent);
                        if (tmp != NULL && RBE_COLOR(tmp) == RB_RED) {
                                RBE_COLOR(tmp) = RB_BLACK;
                                rbe_set_blackred(parent, gparent);
                                rbe = gparent;
                                continue;
                        }

                        if (RBE_LEFT(parent) == rbe) {
                                rbe_rotate_right(t, rbt, parent);
                                tmp = parent;
                                parent = rbe;
                                rbe = tmp;
                        }

                        rbe_set_blackred(parent, gparent);
                        rbe_rotate_left(t, rbt, gparent);
                }
        }

        RBE_COLOR(RBH_ROOT(rbt)) = RB_BLACK;
}

static inline void
rbe_remove_color(const struct rb_type *t, struct rb_tree *rbt,
    struct rb_entry *parent, struct rb_entry *rbe)
{
        struct rb_entry *tmp;

        while ((rbe == NULL || RBE_COLOR(rbe) == RB_BLACK) &&
            rbe != RBH_ROOT(rbt)) {
                if (RBE_LEFT(parent) == rbe) {
                        tmp = RBE_RIGHT(parent);
                        if (RBE_COLOR(tmp) == RB_RED) {
                                rbe_set_blackred(tmp, parent);
                                rbe_rotate_left(t, rbt, parent);
                                tmp = RBE_RIGHT(parent);
                        }
                        if ((RBE_LEFT(tmp) == NULL ||
                             RBE_COLOR(RBE_LEFT(tmp)) == RB_BLACK) &&
                            (RBE_RIGHT(tmp) == NULL ||
                             RBE_COLOR(RBE_RIGHT(tmp)) == RB_BLACK)) {
                                RBE_COLOR(tmp) = RB_RED;
                                rbe = parent;
                                parent = RBE_PARENT(rbe);
                        } else {
                                if (RBE_RIGHT(tmp) == NULL ||
                                    RBE_COLOR(RBE_RIGHT(tmp)) == RB_BLACK) {
                                        struct rb_entry *oleft;

                                        oleft = RBE_LEFT(tmp);
                                        if (oleft != NULL)
                                                RBE_COLOR(oleft) = RB_BLACK;

                                        RBE_COLOR(tmp) = RB_RED;
                                        rbe_rotate_right(t, rbt, tmp);
                                        tmp = RBE_RIGHT(parent);
                                }

                                RBE_COLOR(tmp) = RBE_COLOR(parent);
                                RBE_COLOR(parent) = RB_BLACK;
                                if (RBE_RIGHT(tmp))
                                        RBE_COLOR(RBE_RIGHT(tmp)) = RB_BLACK;

                                rbe_rotate_left(t, rbt, parent);
                                rbe = RBH_ROOT(rbt);
                                break;
                        }
                } else {
                        tmp = RBE_LEFT(parent);
                        if (RBE_COLOR(tmp) == RB_RED) {
                                rbe_set_blackred(tmp, parent);
                                rbe_rotate_right(t, rbt, parent);
                                tmp = RBE_LEFT(parent);
                        }

                        if ((RBE_LEFT(tmp) == NULL ||
                             RBE_COLOR(RBE_LEFT(tmp)) == RB_BLACK) &&
                            (RBE_RIGHT(tmp) == NULL ||
                             RBE_COLOR(RBE_RIGHT(tmp)) == RB_BLACK)) {
                                RBE_COLOR(tmp) = RB_RED;
                                rbe = parent;
                                parent = RBE_PARENT(rbe);
                        } else {
                                if (RBE_LEFT(tmp) == NULL ||
                                    RBE_COLOR(RBE_LEFT(tmp)) == RB_BLACK) {
                                        struct rb_entry *oright;

                                        oright = RBE_RIGHT(tmp);
                                        if (oright != NULL)
                                                RBE_COLOR(oright) = RB_BLACK;

                                        RBE_COLOR(tmp) = RB_RED;
                                        rbe_rotate_left(t, rbt, tmp);
                                        tmp = RBE_LEFT(parent);
                                }

                                RBE_COLOR(tmp) = RBE_COLOR(parent);
                                RBE_COLOR(parent) = RB_BLACK;
                                if (RBE_LEFT(tmp) != NULL)
                                        RBE_COLOR(RBE_LEFT(tmp)) = RB_BLACK;

                                rbe_rotate_right(t, rbt, parent);
                                rbe = RBH_ROOT(rbt);
                                break;
                        }
                }
        }

        if (rbe != NULL)
                RBE_COLOR(rbe) = RB_BLACK;
}

static inline struct rb_entry *
rbe_remove(const struct rb_type *t, struct rb_tree *rbt, struct rb_entry *rbe)
{
        struct rb_entry *child, *parent, *old = rbe;
        unsigned int color;

        if (RBE_LEFT(rbe) == NULL)
                child = RBE_RIGHT(rbe);
        else if (RBE_RIGHT(rbe) == NULL)
                child = RBE_LEFT(rbe);
        else {
                struct rb_entry *tmp;

                rbe = RBE_RIGHT(rbe);
                while ((tmp = RBE_LEFT(rbe)) != NULL)
                        rbe = tmp;

                child = RBE_RIGHT(rbe);
                parent = RBE_PARENT(rbe);
                color = RBE_COLOR(rbe);
                if (child != NULL)
                        RBE_PARENT(child) = parent;
                if (parent != NULL) {
                        if (RBE_LEFT(parent) == rbe)
                                RBE_LEFT(parent) = child;
                        else
                                RBE_RIGHT(parent) = child;

                        rbe_if_augment(t, parent);
                } else
                        RBH_ROOT(rbt) = child;
                if (RBE_PARENT(rbe) == old)
                        parent = rbe;
                *rbe = *old;

                tmp = RBE_PARENT(old);
                if (tmp != NULL) {
                        if (RBE_LEFT(tmp) == old)
                                RBE_LEFT(tmp) = rbe;
                        else
                                RBE_RIGHT(tmp) = rbe;

                        rbe_if_augment(t, tmp);
                } else
                        RBH_ROOT(rbt) = rbe;

                RBE_PARENT(RBE_LEFT(old)) = rbe;
                if (RBE_RIGHT(old))
                        RBE_PARENT(RBE_RIGHT(old)) = rbe;

                if (t->t_augment != NULL && parent != NULL) {
                        tmp = parent;
                        do {
                                rbe_augment(t, tmp);
                                tmp = RBE_PARENT(tmp);
                        } while (tmp != NULL);
                }

                goto color;
        }

        parent = RBE_PARENT(rbe);
        color = RBE_COLOR(rbe);

        if (child != NULL)
                RBE_PARENT(child) = parent;
        if (parent != NULL) {
                if (RBE_LEFT(parent) == rbe)
                        RBE_LEFT(parent) = child;
                else
                        RBE_RIGHT(parent) = child;

                rbe_if_augment(t, parent);
        } else
                RBH_ROOT(rbt) = child;
color:
        if (color == RB_BLACK)
                rbe_remove_color(t, rbt, parent, child);

        return (old);
}

void *
_rb_remove(const struct rb_type *t, struct rb_tree *rbt, void *elm)
{
        struct rb_entry *rbe = rb_n2e(t, elm);
        struct rb_entry *old;

        old = rbe_remove(t, rbt, rbe);

        return (old == NULL ? NULL : rb_e2n(t, old));
}

void *
_rb_insert(const struct rb_type *t, struct rb_tree *rbt, void *elm)
{
        struct rb_entry *rbe = rb_n2e(t, elm);
        struct rb_entry *tmp;
        struct rb_entry *parent = NULL;
        void *node;
        int comp = 0;

        tmp = RBH_ROOT(rbt);
        while (tmp != NULL) {
                parent = tmp;

                node = rb_e2n(t, tmp);
                comp = (*t->t_compare)(elm, node);
                if (comp < 0)
                        tmp = RBE_LEFT(tmp);
                else if (comp > 0)
                        tmp = RBE_RIGHT(tmp);
                else
                        return (node);
        }

        rbe_set(rbe, parent);

        if (parent != NULL) {
                if (comp < 0)
                        RBE_LEFT(parent) = rbe;
                else
                        RBE_RIGHT(parent) = rbe;

                rbe_if_augment(t, parent);
        } else
                RBH_ROOT(rbt) = rbe;

        rbe_insert_color(t, rbt, rbe);

        return (NULL);
}

/* Finds the node with the same key as elm */
void *
_rb_find(const struct rb_type *t, struct rb_tree *rbt, const void *key)
{
        struct rb_entry *tmp = RBH_ROOT(rbt);
        void *node;
        int comp;

        while (tmp != NULL) {
                node = rb_e2n(t, tmp);
                comp = (*t->t_compare)(key, node);
                if (comp < 0)
                        tmp = RBE_LEFT(tmp);
                else if (comp > 0)
                        tmp = RBE_RIGHT(tmp);
                else
                        return (node);
        }

        return (NULL);
}

/* Finds the first node greater than or equal to the search key */
void *
_rb_nfind(const struct rb_type *t, struct rb_tree *rbt, const void *key)
{
        struct rb_entry *tmp = RBH_ROOT(rbt);
        void *node;
        void *res = NULL;
        int comp;

        while (tmp != NULL) {
                node = rb_e2n(t, tmp);
                comp = (*t->t_compare)(key, node);
                if (comp < 0) {
                        res = node;
                        tmp = RBE_LEFT(tmp);
                } else if (comp > 0)
                        tmp = RBE_RIGHT(tmp);
                else
                        return (node);
        }

        return (res);
}

void *
_rb_next(const struct rb_type *t, void *elm)
{
        struct rb_entry *rbe = rb_n2e(t, elm);

        if (RBE_RIGHT(rbe) != NULL) {
                rbe = RBE_RIGHT(rbe);
                while (RBE_LEFT(rbe) != NULL)
                        rbe = RBE_LEFT(rbe);
        } else {
                if (RBE_PARENT(rbe) &&
                    (rbe == RBE_LEFT(RBE_PARENT(rbe))))
                        rbe = RBE_PARENT(rbe);
                else {
                        while (RBE_PARENT(rbe) &&
                            (rbe == RBE_RIGHT(RBE_PARENT(rbe))))
                                rbe = RBE_PARENT(rbe);
                        rbe = RBE_PARENT(rbe);
                }
        }

        return (rbe == NULL ? NULL : rb_e2n(t, rbe));
}

void *
_rb_prev(const struct rb_type *t, void *elm)
{
        struct rb_entry *rbe = rb_n2e(t, elm);

        if (RBE_LEFT(rbe)) {
                rbe = RBE_LEFT(rbe);
                while (RBE_RIGHT(rbe))
                        rbe = RBE_RIGHT(rbe);
        } else {
                if (RBE_PARENT(rbe) &&
                    (rbe == RBE_RIGHT(RBE_PARENT(rbe))))
                        rbe = RBE_PARENT(rbe);
                else {
                        while (RBE_PARENT(rbe) &&
                            (rbe == RBE_LEFT(RBE_PARENT(rbe))))
                                rbe = RBE_PARENT(rbe);
                        rbe = RBE_PARENT(rbe);
                }
        }

        return (rbe == NULL ? NULL : rb_e2n(t, rbe));
}

void *
_rb_root(const struct rb_type *t, struct rb_tree *rbt)
{
        struct rb_entry *rbe = RBH_ROOT(rbt);

        return (rbe == NULL ? rbe : rb_e2n(t, rbe));
}

void *
_rb_min(const struct rb_type *t, struct rb_tree *rbt)
{
        struct rb_entry *rbe = RBH_ROOT(rbt);
        struct rb_entry *parent = NULL;

        while (rbe != NULL) {
                parent = rbe;
                rbe = RBE_LEFT(rbe);
        }

        return (parent == NULL ? NULL : rb_e2n(t, parent));
}

void *
_rb_max(const struct rb_type *t, struct rb_tree *rbt)
{
        struct rb_entry *rbe = RBH_ROOT(rbt);
        struct rb_entry *parent = NULL;

        while (rbe != NULL) {
                parent = rbe;
                rbe = RBE_RIGHT(rbe);
        }

        return (parent == NULL ? NULL : rb_e2n(t, parent));
}

void *
_rb_left(const struct rb_type *t, void *node)
{
        struct rb_entry *rbe = rb_n2e(t, node);
        rbe = RBE_LEFT(rbe);
        return (rbe == NULL ? NULL : rb_e2n(t, rbe));
}

void *
_rb_right(const struct rb_type *t, void *node)
{
        struct rb_entry *rbe = rb_n2e(t, node);
        rbe = RBE_RIGHT(rbe);
        return (rbe == NULL ? NULL : rb_e2n(t, rbe));
}

void *
_rb_parent(const struct rb_type *t, void *node)
{
        struct rb_entry *rbe = rb_n2e(t, node);
        rbe = RBE_PARENT(rbe);
        return (rbe == NULL ? NULL : rb_e2n(t, rbe));
}

void
_rb_set_left(const struct rb_type *t, void *node, void *left)
{
        struct rb_entry *rbe = rb_n2e(t, node);
        struct rb_entry *rbl = (left == NULL) ? NULL : rb_n2e(t, left);

        RBE_LEFT(rbe) = rbl;
}

void
_rb_set_right(const struct rb_type *t, void *node, void *right)
{
        struct rb_entry *rbe = rb_n2e(t, node);
        struct rb_entry *rbr = (right == NULL) ? NULL : rb_n2e(t, right);

        RBE_RIGHT(rbe) = rbr;
}

void
_rb_set_parent(const struct rb_type *t, void *node, void *parent)
{
        struct rb_entry *rbe = rb_n2e(t, node);
        struct rb_entry *rbp = (parent == NULL) ? NULL : rb_n2e(t, parent);

        RBE_PARENT(rbe) = rbp;
}

void
_rb_poison(const struct rb_type *t, void *node, unsigned long poison)
{
        struct rb_entry *rbe = rb_n2e(t, node);

        RBE_PARENT(rbe) = RBE_LEFT(rbe) = RBE_RIGHT(rbe) =
            (struct rb_entry *)poison;
}

int
_rb_check(const struct rb_type *t, void *node, unsigned long poison)
{
        struct rb_entry *rbe = rb_n2e(t, node);

        return ((unsigned long)RBE_PARENT(rbe) == poison &&
            (unsigned long)RBE_LEFT(rbe) == poison &&
            (unsigned long)RBE_RIGHT(rbe) == poison);
}