release/src/router/dropbear/queue.c

   1 /*
   2  * Dropbear - a SSH2 server
   3  *
   4  * Copyright (c) 2002,2003 Matt Johnston
   5  * All rights reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23  * SOFTWARE. */
  24
  25 #include "includes.h"
  26 #include "dbutil.h"
  27 #include "queue.h"
  28
  29 void initqueue(struct Queue* queue) {
  30
  31         queue->head = NULL;
  32         queue->tail = NULL;
  33         queue->count = 0;
  34 }
  35
  36 int isempty(struct Queue* queue) {
  37
  38         return (queue->head == NULL);
  39 }
  40
  41 void* dequeue(struct Queue* queue) {
  42
  43         void* ret;
  44         struct Link* oldhead;
  45         dropbear_assert(!isempty(queue));
  46
  47         ret = queue->head->item;
  48         oldhead = queue->head;
  49
  50         if (oldhead->link != NULL) {
  51                 queue->head = oldhead->link;
  52         } else {
  53                 queue->head = NULL;
  54                 queue->tail = NULL;
  55                 TRACE(("empty queue dequeing"))
  56         }
  57
  58         m_free(oldhead);
  59         queue->count--;
  60         return ret;
  61 }
  62
  63 void *examine(struct Queue* queue) {
  64
  65         dropbear_assert(!isempty(queue));
  66         return queue->head->item;
  67 }
  68
  69 void enqueue(struct Queue* queue, void* item) {
  70
  71         struct Link* newlink;
  72
  73         TRACE(("enter enqueue"))
  74         newlink = (struct Link*)m_malloc(sizeof(struct Link));
  75
  76         newlink->item = item;
  77         newlink->link = NULL;
  78
  79         if (queue->tail != NULL) {
  80                 queue->tail->link = newlink;
  81         }
  82         queue->tail = newlink;
  83
  84         if (queue->head == NULL) {
  85                 queue->head = newlink;
  86         }
  87         queue->count++;
  88         TRACE(("leave enqueue"))
  89 }