usr/src/lib/libipmi/common/ipmi_list.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #pragma ident   "%Z%%M% %I%     %E% SMI"
  27
  28 /*
  29  * Embedded Linked Lists
  30  *
  31  * Simple doubly-linked list implementation.  This implementation assumes that
  32  * each list element contains an embedded ipmi_list_t (previous and next
  33  * pointers), which is typically the first member of the element struct.
  34  * An additional ipmi_list_t is used to store the head (l_next) and tail
  35  * (l_prev) pointers.  The current head and tail list elements have their
  36  * previous and next pointers set to NULL, respectively.
  37  */
  38
  39 #include <assert.h>
  40 #include <ipmi_impl.h>
  41
  42 void
  43 ipmi_list_append(ipmi_list_t *lp, void *new)
  44 {
  45         ipmi_list_t *p = lp->l_prev;    /* p = tail list element */
  46         ipmi_list_t *q = new;           /* q = new list element */
  47
  48         lp->l_prev = q;
  49         q->l_prev = p;
  50         q->l_next = NULL;
  51
  52         if (p != NULL) {
  53                 assert(p->l_next == NULL);
  54                 p->l_next = q;
  55         } else {
  56                 assert(lp->l_next == NULL);
  57                 lp->l_next = q;
  58         }
  59 }
  60
  61 void
  62 ipmi_list_prepend(ipmi_list_t *lp, void *new)
  63 {
  64         ipmi_list_t *p = new;           /* p = new list element */
  65         ipmi_list_t *q = lp->l_next;    /* q = head list element */
  66
  67         lp->l_next = p;
  68         p->l_prev = NULL;
  69         p->l_next = q;
  70
  71         if (q != NULL) {
  72                 assert(q->l_prev == NULL);
  73                 q->l_prev = p;
  74         } else {
  75                 assert(lp->l_prev == NULL);
  76                 lp->l_prev = p;
  77         }
  78 }
  79
  80 void
  81 ipmi_list_insert_before(ipmi_list_t *lp, void *before_me, void *new)
  82 {
  83         ipmi_list_t *p = before_me;
  84         ipmi_list_t *q = new;
  85
  86         if (p == NULL || p->l_prev == NULL) {
  87                 ipmi_list_prepend(lp, new);
  88                 return;
  89         }
  90
  91         q->l_prev = p->l_prev;
  92         q->l_next = p;
  93         p->l_prev = q;
  94         q->l_prev->l_next = q;
  95 }
  96
  97 void
  98 ipmi_list_insert_after(ipmi_list_t *lp, void *after_me, void *new)
  99 {
 100         ipmi_list_t *p = after_me;
 101         ipmi_list_t *q = new;
 102
 103         if (p == NULL || p->l_next == NULL) {
 104                 ipmi_list_append(lp, new);
 105                 return;
 106         }
 107
 108         q->l_next = p->l_next;
 109         q->l_prev = p;
 110         p->l_next = q;
 111         q->l_next->l_prev = q;
 112 }
 113
 114 void
 115 ipmi_list_delete(ipmi_list_t *lp, void *existing)
 116 {
 117         ipmi_list_t *p = existing;
 118
 119         if (p->l_prev != NULL)
 120                 p->l_prev->l_next = p->l_next;
 121         else
 122                 lp->l_next = p->l_next;
 123
 124         if (p->l_next != NULL)
 125                 p->l_next->l_prev = p->l_prev;
 126         else
 127                 lp->l_prev = p->l_prev;
 128 }