usr/src/cmd/syslogd/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 2006 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #include <pthread.h>
  27 #include <malloc.h>
  28 #include <memory.h>
  29 #include <assert.h>
  30 #include <poll.h>
  31 #include <stdio.h>
  32 #include "llt.h"
  33
  34 void
  35 ll_init(llh_t *head)
  36 {
  37         head->back = &head->front;
  38         head->front = NULL;
  39 }
  40
  41 void
  42 ll_enqueue(llh_t *head, ll_t *data)
  43 {
  44         data->n = NULL;
  45         *head->back = data;
  46         head->back = &data->n;
  47 }
  48
  49 /*
  50  * apply the function func to every element of the ll in sequence.  Can
  51  * be used to free up the element, so "n" is computed before func is
  52  * called on it.
  53  */
  54 void
  55 ll_mapf(llh_t *head, void (*func)(void *))
  56 {
  57         ll_t *t = head->front;
  58         ll_t *n;
  59
  60         while (t) {
  61                 n = t->n;
  62                 func(t);
  63                 t = n;
  64         }
  65 }
  66
  67 ll_t *
  68 ll_peek(llh_t *head)
  69 {
  70         return (head->front);
  71 }
  72
  73 ll_t *
  74 ll_dequeue(llh_t *head)
  75 {
  76         ll_t *ptr;
  77         ptr = head->front;
  78         if (ptr && ((head->front = ptr->n) == NULL))
  79                 head->back = &head->front;
  80         return (ptr);
  81 }
  82
  83 ll_t *
  84 ll_traverse(llh_t *ptr, int (*func)(void *, void *), void *user)
  85 {
  86         ll_t *t;
  87         ll_t **prev = &ptr->front;
  88
  89         t = ptr->front;
  90         while (t) {
  91                 switch (func(t, user)) {
  92                 case 1:
  93                         return (NULL);
  94                 case 0:
  95                         prev = &(t->n);
  96                         t = t->n;
  97                         break;
  98                 case -1:
  99                         if ((*prev = t->n) == NULL)
 100                                 ptr->back = prev;
 101                         return (t);
 102                 }
 103         }
 104         return (NULL);
 105 }
 106
 107 /* Make sure the list isn't corrupt and returns number of list items */
 108 int
 109 ll_check(llh_t *head)
 110 {
 111         int i = 0;
 112         ll_t *ptr = head->front;
 113 #ifndef NDEBUG
 114         ll_t **prev = &head->front;
 115 #endif
 116
 117         while (ptr) {
 118                 i++;
 119 #ifndef NDEBUG
 120                 prev = &ptr->n;
 121 #endif
 122                 ptr = ptr->n;
 123         }
 124         assert(head->back == prev);
 125         return (i);
 126 }