1178479Sjb/* 2178479Sjb * CDDL HEADER START 3178479Sjb * 4178479Sjb * The contents of this file are subject to the terms of the 5178479Sjb * Common Development and Distribution License, Version 1.0 only 6178479Sjb * (the "License"). You may not use this file except in compliance 7178479Sjb * with the License. 8178479Sjb * 9178479Sjb * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10178479Sjb * or http://www.opensolaris.org/os/licensing. 11178479Sjb * See the License for the specific language governing permissions 12178479Sjb * and limitations under the License. 13178479Sjb * 14178479Sjb * When distributing Covered Code, include this CDDL HEADER in each 15178479Sjb * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16178479Sjb * If applicable, add the following below this CDDL HEADER, with the 17178479Sjb * fields enclosed by brackets "[]" replaced with your own identifying 18178479Sjb * information: Portions Copyright [yyyy] [name of copyright owner] 19178479Sjb * 20178479Sjb * CDDL HEADER END 21178479Sjb */ 22178479Sjb/* 23178479Sjb * Copyright 2003 Sun Microsystems, Inc. All rights reserved. 24178479Sjb * Use is subject to license terms. 25178479Sjb */ 26178479Sjb 27178479Sjb#pragma ident "%Z%%M% %I% %E% SMI" 28178479Sjb 29178479Sjb/* 30178479Sjb * Simple doubly-linked list implementation. This implementation assumes that 31178479Sjb * each list element contains an embedded dt_list_t (previous and next 32178479Sjb * pointers), which is typically the first member of the element struct. 33178479Sjb * An additional dt_list_t is used to store the head (dl_next) and tail 34178479Sjb * (dl_prev) pointers. The current head and tail list elements have their 35178479Sjb * previous and next pointers set to NULL, respectively. 36178479Sjb */ 37178479Sjb 38178479Sjb#include <unistd.h> 39178479Sjb#include <assert.h> 40178479Sjb#include <dt_list.h> 41178479Sjb 42178479Sjbvoid 43178479Sjbdt_list_append(dt_list_t *dlp, void *new) 44178479Sjb{ 45178479Sjb dt_list_t *p = dlp->dl_prev; /* p = tail list element */ 46178479Sjb dt_list_t *q = new; /* q = new list element */ 47178479Sjb 48178479Sjb dlp->dl_prev = q; 49178479Sjb q->dl_prev = p; 50178479Sjb q->dl_next = NULL; 51178479Sjb 52178479Sjb if (p != NULL) { 53178479Sjb assert(p->dl_next == NULL); 54178479Sjb p->dl_next = q; 55178479Sjb } else { 56178479Sjb assert(dlp->dl_next == NULL); 57178479Sjb dlp->dl_next = q; 58178479Sjb } 59178479Sjb} 60178479Sjb 61178479Sjbvoid 62178479Sjbdt_list_prepend(dt_list_t *dlp, void *new) 63178479Sjb{ 64178479Sjb dt_list_t *p = new; /* p = new list element */ 65178479Sjb dt_list_t *q = dlp->dl_next; /* q = head list element */ 66178479Sjb 67178479Sjb dlp->dl_next = p; 68178479Sjb p->dl_prev = NULL; 69178479Sjb p->dl_next = q; 70178479Sjb 71178479Sjb if (q != NULL) { 72178479Sjb assert(q->dl_prev == NULL); 73178479Sjb q->dl_prev = p; 74178479Sjb } else { 75178479Sjb assert(dlp->dl_prev == NULL); 76178479Sjb dlp->dl_prev = p; 77178479Sjb } 78178479Sjb} 79178479Sjb 80178479Sjbvoid 81178479Sjbdt_list_insert(dt_list_t *dlp, void *after_me, void *new) 82178479Sjb{ 83178479Sjb dt_list_t *p = after_me; 84178479Sjb dt_list_t *q = new; 85178479Sjb 86178479Sjb if (p == NULL || p->dl_next == NULL) { 87178479Sjb dt_list_append(dlp, new); 88178479Sjb return; 89178479Sjb } 90178479Sjb 91178479Sjb q->dl_next = p->dl_next; 92178479Sjb q->dl_prev = p; 93178479Sjb p->dl_next = q; 94178479Sjb q->dl_next->dl_prev = q; 95178479Sjb} 96178479Sjb 97178479Sjbvoid 98178479Sjbdt_list_delete(dt_list_t *dlp, void *existing) 99178479Sjb{ 100178479Sjb dt_list_t *p = existing; 101178479Sjb 102178479Sjb if (p->dl_prev != NULL) 103178479Sjb p->dl_prev->dl_next = p->dl_next; 104178479Sjb else 105178479Sjb dlp->dl_next = p->dl_next; 106178479Sjb 107178479Sjb if (p->dl_next != NULL) 108178479Sjb p->dl_next->dl_prev = p->dl_prev; 109178479Sjb else 110178479Sjb dlp->dl_prev = p->dl_prev; 111178479Sjb} 112