/*

 * Dropbear - a SSH2 server

 * 

 * Copyright (c) 2002,2003 Matt Johnston

 * All rights reserved.

 * 

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 * 

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 * 

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

 * SOFTWARE. */

#include "includes.h"

#include "dbutil.h"

#include "queue.h"

void initqueue(struct Queue* queue) {

  queue->head = NULL;

  queue->tail = NULL;

  queue->count = 0;

}

int isempty(const struct Queue* queue) {

  return (queue->head == NULL);

}

void* dequeue(struct Queue* queue) {

  void* ret;

  struct Link* oldhead;

  dropbear_assert(!isempty(queue));

  ret = queue->head->item;

  oldhead = queue->head;

  if (oldhead->link != NULL) {

    queue->head = oldhead->link;

  } else {

    queue->head = NULL;

    queue->tail = NULL;

    TRACE(("empty queue dequeing"))

  }

  m_free(oldhead);

  queue->count--;

  return ret;

}

void *examine(const struct Queue* queue) {

  dropbear_assert(!isempty(queue));

  return queue->head->item;

}

void enqueue(struct Queue* queue, void* item) {

  struct Link* newlink;

  newlink = (struct Link*)m_malloc(sizeof(struct Link));

  newlink->item = item;

  newlink->link = NULL;

  if (queue->tail != NULL) {

    queue->tail->link = newlink;

  }

  queue->tail = newlink;

  if (queue->head == NULL) {

    queue->head = newlink;

  }

  queue->count++;

}