zfs/lib/libzcommon/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 2007 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26
  27
  28 /*
  29  * Generic doubly-linked list implementation
  30  */
  31
  32 #include <sys/list.h>
  33 #include <sys/list_impl.h>
  34 #include <sys/types.h>
  35 #include <sys/sysmacros.h>
  36 #include <sys/debug.h>
  37
  38 #define list_d2l(a, obj) ((list_node_t *)(((char *)obj) + (a)->list_offset))
  39 #define list_object(a, node) ((void *)(((char *)node) - (a)->list_offset))
  40 #define list_empty(a) ((a)->list_head.list_next == &(a)->list_head)
  41
  42 #define list_insert_after_node(list, node, object) {    \
  43         list_node_t *lnew = list_d2l(list, object);     \
  44         lnew->list_prev = node;                         \
  45         lnew->list_next = node->list_next;              \
  46         node->list_next->list_prev = lnew;              \
  47         node->list_next = lnew;                         \
  48 }
  49
  50 #define list_insert_before_node(list, node, object) {   \
  51         list_node_t *lnew = list_d2l(list, object);     \
  52         lnew->list_next = node;                         \
  53         lnew->list_prev = node->list_prev;              \
  54         node->list_prev->list_next = lnew;              \
  55         node->list_prev = lnew;                         \
  56 }
  57
  58 void
  59 list_create(list_t *list, size_t size, size_t offset)
  60 {
  61         ASSERT(list);
  62         ASSERT(size > 0);
  63         ASSERT(size >= offset + sizeof (list_node_t));
  64
  65         list->list_size = size;
  66         list->list_offset = offset;
  67         list->list_head.list_next = list->list_head.list_prev =
  68             &list->list_head;
  69 }
  70
  71 void
  72 list_destroy(list_t *list)
  73 {
  74         list_node_t *node = &list->list_head;
  75
  76         ASSERT(list);
  77         ASSERT(list->list_head.list_next == node);
  78         ASSERT(list->list_head.list_prev == node);
  79
  80         node->list_next = node->list_prev = NULL;
  81 }
  82
  83 void
  84 list_insert_after(list_t *list, void *object, void *nobject)
  85 {
  86         list_node_t *lold = list_d2l(list, object);
  87         list_insert_after_node(list, lold, nobject);
  88 }
  89
  90 void
  91 list_insert_before(list_t *list, void *object, void *nobject)
  92 {
  93         list_node_t *lold = list_d2l(list, object);
  94         list_insert_before_node(list, lold, nobject)
  95 }
  96
  97 void
  98 list_insert_head(list_t *list, void *object)
  99 {
 100         list_node_t *lold = &list->list_head;
 101         list_insert_after_node(list, lold, object);
 102 }
 103
 104 void
 105 list_insert_tail(list_t *list, void *object)
 106 {
 107         list_node_t *lold = &list->list_head;
 108         list_insert_before_node(list, lold, object);
 109 }
 110
 111 void
 112 list_remove(list_t *list, void *object)
 113 {
 114         list_node_t *lold = list_d2l(list, object);
 115         ASSERT(!list_empty(list));
 116         ASSERT(lold->list_next != NULL);
 117         lold->list_prev->list_next = lold->list_next;
 118         lold->list_next->list_prev = lold->list_prev;
 119         lold->list_next = lold->list_prev = NULL;
 120 }
 121
 122 void *
 123 list_head(list_t *list)
 124 {
 125         if (list_empty(list))
 126                 return (NULL);
 127         return (list_object(list, list->list_head.list_next));
 128 }
 129
 130 void *
 131 list_tail(list_t *list)
 132 {
 133         if (list_empty(list))
 134                 return (NULL);
 135         return (list_object(list, list->list_head.list_prev));
 136 }
 137
 138 void *
 139 list_next(list_t *list, void *object)
 140 {
 141         list_node_t *node = list_d2l(list, object);
 142
 143         if (node->list_next != &list->list_head)
 144                 return (list_object(list, node->list_next));
 145
 146         return (NULL);
 147 }
 148
 149 void *
 150 list_prev(list_t *list, void *object)
 151 {
 152         list_node_t *node = list_d2l(list, object);
 153
 154         if (node->list_prev != &list->list_head)
 155                 return (list_object(list, node->list_prev));
 156
 157         return (NULL);
 158 }
 159
 160 /*
 161  *  Insert src list after dst list. Empty src list thereafter.
 162  */
 163 void
 164 list_move_tail(list_t *dst, list_t *src)
 165 {
 166         list_node_t *dstnode = &dst->list_head;
 167         list_node_t *srcnode = &src->list_head;
 168
 169         ASSERT(dst->list_size == src->list_size);
 170         ASSERT(dst->list_offset == src->list_offset);
 171
 172         if (list_empty(src))
 173                 return;
 174
 175         dstnode->list_prev->list_next = srcnode->list_next;
 176         srcnode->list_next->list_prev = dstnode->list_prev;
 177         dstnode->list_prev = srcnode->list_prev;
 178         srcnode->list_prev->list_next = dstnode;
 179
 180         /* empty src list */
 181         srcnode->list_next = srcnode->list_prev = srcnode;
 182 }
 183
 184 int
 185 list_link_active(list_node_t *link)
 186 {
 187         return (link->list_next != NULL);
 188 }
 189
 190 int
 191 list_is_empty(list_t *list)
 192 {
 193         return (list_empty(list));
 194 }