/*
  OS Scheduler Simulator

  ** 連絡先： 琉球大学情報工学科 河野 真治  
  ** （E-Mail Address: kono@ie.u-ryukyu.ac.jp）
  **
  **    このソースのいかなる複写，改変，修正も許諾します。ただし、
  **    その際には、誰が貢献したを示すこの部分を残すこと。
  **    再配布や雑誌の付録などの問い合わせも必要ありません。
  **    営利利用も上記に反しない範囲で許可します。
  **    バイナリの配布の際にはversion messageを保存することを条件とします。
  **    このプログラムについては特に何の保証もしない、悪しからず。
  **
  **    Everyone is permitted to do anything on this program 
  **    including copying, modifying, improving,
  **    as long as you don't try to pretend that you wrote it.
  **    i.e., the above copyright notice has to appear in all copies.  
  **    Binary distribution requires original version messages.
  **    You don't have to ask before copying, redistribution or publishing.
  **    THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE.

  Task Queue Manager

  ** modify: Atsuki Shimoji(atsuki@cr.ie.u-ryukyu.ac.jp)

  */
#include "queue.h"

code create_queue(int count, PhilsPtr self, TaskPtr list, TaskPtr last,
				  code (*dest)(
					  int count,PhilsPtr self, TaskPtr list,TaskPtr last, TaskPtr q
					  ))
{
	TaskPtr q;
	q = (TaskPtr)malloc(sizeof(Task));
	if (q) {
	    q->next = NULL;
	    q->phils = self;
	}
	goto dest(count, self, list, last, q);    /* dest(TaskPtr new_queue) */
}

void
free_queue(TaskPtr q)
{
	free(q);
}

code lastSearch(code (*dest)(), TaskPtr list, TaskPtr p, TaskPtr q)
{
	if (p->next) {
		p = p->next;
		goto lastSearch(dest, list, p, q);
	} else {
		p->next = q;
		goto dest(list);    /* dest(TaskPtr appended_queue) */
	}
}

code enqueue(int count, PhilsPtr self, TaskPtr list, TaskPtr last, TaskPtr q,
			 code (*dest)(
				 int count, PhilsPtr self, TaskPtr list, TaskPtr last
				 ))
{
	q->next = list;
	goto dest(count,self,q, last);
}

//code dequeue(code (*dest)(), TaskPtr list)
code dequeue(code (*dest)(), TaskPtr list, TaskPtr *q)
{
	TaskPtr p = list;
	if (p) {
		list = list->next;
		p->next = 0;
		goto dest(p, list);    /* dest(TaskPtr out, TaskPtr queue) */
	}
	goto dest(p, list);    /* dest(TaskPtr out, TaskPtr queue) */
}

TaskIteratorPtr
create_task_iterator(TaskPtr list,StateDB s,TaskIteratorPtr prev)
{
    TaskIteratorPtr new = (TaskIteratorPtr)malloc(sizeof(TaskIterator));
    if (!new) die_exit("can't allocate task iterlator");

    new->prev = prev;
    new->state = s;
    new->list = list;
    new->last = list;
    return new;
}

TaskPtr
next_task_iterator(TaskIteratorPtr self)
{
    TaskPtr next;
    if (!self->list) {
		die_exit("task iterator inconsistency");
    }
    next = self->list->next;
    if (!next) {
		die_exit("task iterator next inconsistency");
    }
    if (next == self->last) {
		return 0;
    }
    self->list = next;
    return next;
}

void
free_task_iterator(TaskIteratorPtr iter)
{
    free(iter);
}

/* end */