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 #pragma ident   "%Z%%M% %I%     %E% SMI"
  27
  28 #include <pthread.h>
  29 #include <malloc.h>
  30 #include <memory.h>
  31 #include <assert.h>
  32 #include <poll.h>
  33 #include <stdio.h>
  34 #include "llt.h"
  35 void
  36 ll_init(llh_t *head)
  37 {
  38         head->back = &head->front;
  39         head->front = NULL;
  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  * apply the function func to every element of the ll in sequence.  Can
  50  * be used to free up the element, so "n" is computed before func is
  51  * called on it.
  52  */
  53 void
  54 ll_mapf(llh_t *head, void (*func)(void *))
  55 {
  56         ll_t *t = head->front;
  57         ll_t *n;
  58
  59         while (t) {
  60                 n = t->n;
  61                 func(t);
  62                 t = n;
  63         }
  64 }
  65 ll_t *
  66 ll_peek(llh_t *head)
  67 {
  68         return (head->front);
  69 }
  70 ll_t *
  71 ll_dequeue(llh_t *head)
  72 {
  73         ll_t *ptr;
  74         ptr = head->front;
  75         if (ptr && ((head->front = ptr->n) == NULL))
  76                 head->back = &head->front;
  77         return (ptr);
  78 }
  79 ll_t *
  80 ll_traverse(llh_t *ptr, int (*func)(void *, void *), void *user)
  81 {
  82         ll_t *t;
  83         ll_t **prev = &ptr->front;
  84
  85         t = ptr->front;
  86         while (t) {
  87                 switch (func(t, user)) {
  88                 case 1:
  89                         return (NULL);
  90                 case 0:
  91                         prev = &(t->n);
  92                         t = t->n;
  93                         break;
  94                 case -1:
  95                         if ((*prev = t->n) == NULL)
  96                                 ptr->back = prev;
  97                         return (t);
  98                 }
  99         }
 100         return (NULL);
 101 }
 102 /* Make sure the list isn't corrupt and returns number of list items */
 103 int
 104 ll_check(llh_t *head)
 105 {
 106         int i = 0;
 107         ll_t *ptr = head->front;
 108         ll_t **prev = &head->front;
 109
 110         while (ptr) {
 111                 i++;
 112                 prev = &ptr->n;
 113                 ptr = ptr->n;
 114         }
 115         assert(head->back == prev);
 116         return (i);
 117 }