/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2019 The FreeBSD Foundation
 *
 * This software was developed by Konstantin Belousov <kib@FreeBSD.org>
 * under sponsorship from the FreeBSD Foundation.
 *
 * 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
 */

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/pctrie.h>
#include <sys/rangeset.h>
#include <vm/uma.h>

#ifdef DIAGNOSTIC
static void rangeset_check(struct rangeset *rs);
#else
#define rangeset_check(rs)
#endif

static uma_zone_t rs_node_zone;

static void
rs_rangeset_init(void *arg __unused)
{

        rs_node_zone = uma_zcreate("rangeset pctrie nodes",
            pctrie_node_size(), NULL, NULL, pctrie_zone_init, NULL,
            UMA_ALIGN_PTR, 0);
}
SYSINIT(rs, SI_SUB_LOCK, SI_ORDER_ANY, rs_rangeset_init, NULL);

static void *
rs_node_alloc(struct pctrie *ptree)
{
        struct rangeset *rs;

        rs = __containerof(ptree, struct rangeset, rs_trie);
        return (uma_zalloc(rs_node_zone, rs->rs_alloc_flags));
}

static void
rs_node_free(struct pctrie *ptree __unused, void *node)
{

        uma_zfree(rs_node_zone, node);
}

PCTRIE_DEFINE(RANGESET, rs_el, re_start, rs_node_alloc, rs_node_free);

void
rangeset_init(struct rangeset *rs, rs_dup_data_t dup_data,
    rs_free_data_t free_data, void *data_ctx, u_int alloc_flags)
{

        pctrie_init(&rs->rs_trie);
        rs->rs_dup_data = dup_data;
        rs->rs_free_data = free_data;
        rs->rs_data_ctx = data_ctx;
        rs->rs_alloc_flags = alloc_flags;
}

void
rangeset_fini(struct rangeset *rs)
{

        rangeset_check(rs);
        rangeset_remove_all(rs);
}

bool
rangeset_check_empty(struct rangeset *rs, uint64_t start, uint64_t end)
{
        struct rs_el *r;

        rangeset_check(rs);
        r = RANGESET_PCTRIE_LOOKUP_LE(&rs->rs_trie, end);
        return (r == NULL || r->re_end <= start);
}

int
rangeset_insert(struct rangeset *rs, uint64_t start, uint64_t end,
    void *data)
{
        struct rs_el *r;
        int error;

        rangeset_check(rs);
        error = rangeset_remove(rs, start, end);
        if (error != 0)
                return (error);
        r = data;
        r->re_start = start;
        r->re_end = end;
        error = RANGESET_PCTRIE_INSERT(&rs->rs_trie, r);
        rangeset_check(rs);
        return (error);
}

int
rangeset_remove_pred(struct rangeset *rs, uint64_t start, uint64_t end,
    rs_pred_t pred)
{
        struct rs_el *r, *rn;
        int error;

        rangeset_check(rs);
        error = 0;
        for (; end > 0 && start < end;) {
                r = RANGESET_PCTRIE_LOOKUP_LE(&rs->rs_trie, end - 1);
                if (r == NULL)
                        break;

                /*
                 * ------============================--|-------|----
                 *       rs                        re  s       e
                 */
                if (r->re_end <= start)
                        break;

                if (r->re_end <= end) {
                        if (r->re_start < start) {
                                /*
                                 * ------========|==============-------|----
                                 *       rs      s            re       e
                                 */
                                if (pred(rs->rs_data_ctx, r))
                                        r->re_end = start;
                                break;
                        }

                        /*
                         * ------|--------===================----------|----
                         *       s        rs               re          e
                         */
                        end = r->re_start;
                        if (pred(rs->rs_data_ctx, r)) {
                                RANGESET_PCTRIE_REMOVE(&rs->rs_trie,
                                    r->re_start);
                                rs->rs_free_data(rs->rs_data_ctx, r);
                        }
                        continue;
                }

                /*
                 * ------|--------====================|==========----
                 *       s        rs                  e         re
                 */
                if (r->re_start >= start) {
                        if (pred(rs->rs_data_ctx, r)) {
                                RANGESET_PCTRIE_REMOVE(&rs->rs_trie,
                                    r->re_start);
                                r->re_start = end;
                                error = RANGESET_PCTRIE_INSERT(&rs->rs_trie, r);
                                /*
                                 * The insert above must succeed
                                 * because rs_node zone is marked
                                 * nofree and we freed one element
                                 * just before.
                                 */
                                MPASS(error == 0);
                        } else {
                                end = r->re_start;
                        }
                        continue;
                }

                /*
                 * ------=========|===================|==========----
                 *       rs       s                   e         re
                 */
                if (pred(rs->rs_data_ctx, r)) {
                        /*
                         * Split.  Can only happen once, and then if
                         * any allocation fails, the rangeset is kept
                         * intact.
                         */
                        rn = rs->rs_dup_data(rs->rs_data_ctx, r);
                        if (rn == NULL) {
                                error = ENOMEM;
                                break;
                        }
                        rn->re_start = end;
                        rn->re_end = r->re_end;
                        error = RANGESET_PCTRIE_INSERT(&rs->rs_trie, rn);
                        if (error != 0) {
                                rs->rs_free_data(rs->rs_data_ctx, rn);
                                break;
                        }
                        r->re_end = start;
                }
                break;
        }
        rangeset_check(rs);
        return (error);
}

static bool
rangeset_true_pred(void *ctx __unused, void *r __unused)
{

        return (true);
}

int
rangeset_remove(struct rangeset *rs, uint64_t start, uint64_t end)
{

        return (rangeset_remove_pred(rs, start, end, rangeset_true_pred));
}

static void
rangeset_remove_leaf(struct rs_el *r, void *rsv)
{
        struct rangeset *rs = rsv;

        rs->rs_free_data(rs->rs_data_ctx, r);
}

void
rangeset_remove_all(struct rangeset *rs)
{
        RANGESET_PCTRIE_RECLAIM_CALLBACK(&rs->rs_trie,
            rangeset_remove_leaf, rs);
}

void *
rangeset_containing(struct rangeset *rs, uint64_t place)
{
        struct rs_el *r;

        rangeset_check(rs);
        r = RANGESET_PCTRIE_LOOKUP_LE(&rs->rs_trie, place);
        if (r != NULL && place < r->re_end)
                return (r);
        return (NULL);
}

bool
rangeset_empty(struct rangeset *rs, uint64_t start, uint64_t end)
{
        struct rs_el *r;

        r = RANGESET_PCTRIE_LOOKUP_GE(&rs->rs_trie, start + 1);
        return (r == NULL || r->re_start >= end);
}

void *
rangeset_beginning(struct rangeset *rs, uint64_t place)
{

        rangeset_check(rs);
        return (RANGESET_PCTRIE_LOOKUP(&rs->rs_trie, place));
}

int
rangeset_copy(struct rangeset *dst_rs, struct rangeset *src_rs)
{
        struct rs_el *src_r, *dst_r;
        uint64_t cursor;
        int error;

        MPASS(pctrie_is_empty(&dst_rs->rs_trie));
        rangeset_check(src_rs);
        MPASS(dst_rs->rs_dup_data == src_rs->rs_dup_data);

        error = 0;
        for (cursor = 0;; cursor = src_r->re_start + 1) {
                src_r = RANGESET_PCTRIE_LOOKUP_GE(&src_rs->rs_trie, cursor);
                if (src_r == NULL)
                        break;
                dst_r = dst_rs->rs_dup_data(dst_rs->rs_data_ctx, src_r);
                if (dst_r == NULL) {
                        error = ENOMEM;
                        break;
                }
                error = RANGESET_PCTRIE_INSERT(&dst_rs->rs_trie, dst_r);
                if (error != 0)
                        break;
        }
        if (error != 0)
                rangeset_remove_all(dst_rs);
        return (error);
}

#ifdef DIAGNOSTIC
static void
rangeset_check(struct rangeset *rs)
{
        struct rs_el *r, *rp;
        uint64_t cursor;

        for (cursor = 0, rp = NULL;; cursor = r->re_start + 1, rp = r) {
                r = RANGESET_PCTRIE_LOOKUP_GE(&rs->rs_trie, cursor);
                if (r == NULL)
                        break;
                KASSERT(r->re_start < r->re_end,
                    ("invalid interval rs %p elem %p (%#jx, %#jx)",
                    rs, r, (uintmax_t)r->re_start,  (uintmax_t)r->re_end));
                if (rp != NULL) {
                        KASSERT(rp->re_end <= r->re_start,
                            ("non-ascending neighbors rs %p "
                            "prev elem %p (%#jx, %#jx) elem %p (%#jx, %#jx)",
                            rs, rp,  (uintmax_t)rp->re_start,
                            (uintmax_t)rp->re_end, r,  (uintmax_t)r->re_start,
                            (uintmax_t)r->re_end));
                }
        }
}
#endif

#include "opt_ddb.h"
#ifdef DDB
#include <sys/kernel.h>
#include <ddb/ddb.h>

DB_SHOW_COMMAND(rangeset, rangeset_show_fn)
{
        struct rangeset *rs;
        struct rs_el *r;
        uint64_t cursor;

        if (!have_addr) {
                db_printf("show rangeset addr\n");
                return;
        }

        rs = (struct rangeset *)addr;
        db_printf("rangeset %p\n", rs);
        for (cursor = 0;; cursor = r->re_start + 1) {
                r = RANGESET_PCTRIE_LOOKUP_GE(&rs->rs_trie, cursor);
                if (r == NULL)
                        break;
                db_printf("  el %p start %#jx end %#jx\n",
                    r, r->re_start, r->re_end);
        }
}
#endif