libtopo/common/topo_list.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <unistd.h>
#include <assert.h>

#include <topo_list.h>
#include <topo_tree.h>

/*
 * Embedded Linked Lists
 *
 * Simple doubly-linked list implementation.  This implementation assumes that
 * each list element contains an embedded topo_list_t (previous and next
 * pointers), which is typically the first member of the element struct.
 * An additional topo_list_t is used to store the head (l_next) and tail
 * (l_prev) pointers.  The current head and tail list elements have their
 * previous and next pointers set to NULL, respectively.
 *
 * NOTE: The embeddable list code in this file intentionally provides no
 * locking of any kind.  The implementation of any list in topo must provide
 * an appropriate locking strategy to protect the list or to protect access
 * to the embedded topo_list_t inside of each list element to avoid corruption.
 * Refer to comments in the source files that use topo_list_t for lock details.
 */


void
topo_list_append(topo_list_t *lp, void *new)
{
    topo_list_t *p = lp->l_prev;    /* p = tail list element */
    topo_list_t *q = new;       /* q = new list element */

    lp->l_prev = q;
    q->l_prev = p;
    q->l_next = NULL;

    if (p != NULL) {
        assert(p->l_next == NULL);
        p->l_next = q;
    } else {
        assert(lp->l_next == NULL);
        lp->l_next = q;
    }
}

void
topo_list_prepend(topo_list_t *lp, void *new)
{
    topo_list_t *p = new;       /* p = new list element */
    topo_list_t *q = lp->l_next;    /* q = head list element */

    lp->l_next = p;
    p->l_prev = NULL;
    p->l_next = q;

    if (q != NULL) {
        assert(q->l_prev == NULL);
        q->l_prev = p;
    } else {
        assert(lp->l_prev == NULL);
        lp->l_prev = p;
    }
}

void
topo_list_insert_before(topo_list_t *lp, void *before_me, void *new)
{
    topo_list_t *p = before_me;
    topo_list_t *q = new;

    if (p == NULL || p->l_prev == NULL) {
        topo_list_prepend(lp, new);
        return;
    }

    q->l_prev = p->l_prev;
    q->l_next = p;
    p->l_prev = q;
    q->l_prev->l_next = q;
}

void
topo_list_insert_after(topo_list_t *lp, void *after_me, void *new)
{
    topo_list_t *p = after_me;
    topo_list_t *q = new;

    if (p == NULL || p->l_next == NULL) {
        topo_list_append(lp, new);
        return;
    }

    q->l_next = p->l_next;
    q->l_prev = p;
    p->l_next = q;
    q->l_next->l_prev = q;
}

void
topo_list_delete(topo_list_t *lp, void *existing)
{
    topo_list_t *p = existing;

    if (p->l_prev != NULL)
        p->l_prev->l_next = p->l_next;
    else
        lp->l_next = p->l_next;

    if (p->l_next != NULL)
        p->l_next->l_prev = p->l_prev;
    else
        lp->l_prev = p->l_prev;
}

tnode_t *
topo_child_first(tnode_t *pnode)
{
    int i;
    topo_nodehash_t *nhp;

    for (nhp = topo_list_next(&pnode->tn_children); nhp != NULL;
        nhp = topo_list_next(nhp)) {
        for (i = 0; i < nhp->th_arrlen; ++i) {
            if (nhp->th_nodearr[i] != NULL)
                return (nhp->th_nodearr[i]);
        }
    }

    return (NULL);
}

tnode_t *
topo_child_next(tnode_t *pnode, tnode_t *node)
{
    int i;
    int index;
    topo_nodehash_t *nhp;

    if (node == NULL) {
        return (topo_child_first(pnode));
    }

    /*
     * Begin search for next child in the current hash array
     * If none found or we are at the end of the array, move
     * on to the next array
     */
    index = topo_node_hash(node->tn_phash, node->tn_instance) + 1;
    for (nhp = node->tn_phash; nhp != NULL; nhp = topo_list_next(nhp)) {
        for (i = index; i < nhp->th_arrlen; ++i) {
            if (nhp->th_nodearr[i] != NULL) {
                return (nhp->th_nodearr[i]);
            }
        }
        index = 0;
    }

    return (NULL);
}