jsos

college code for operating system fundamentals in js
queue.js

(943B)
      1 /* ------------
      2    Queue.js
      3    
      4    A simple Queue, which is really just a dressed-up Javascript Array.
      5    See the Javascript Array documentation at http://www.w3schools.com/jsref/jsref_obj_array.asp .
      6    Look at the push and shift methods, as they are the least obvious here.
      7    
      8    ------------ */
      9    
     10 function Queue() {
     11   this.q = new Array();
     12 
     13   this.getSize = function(){
     14     return this.q.length;    
     15   }
     16 
     17   this.isEmpty  = function() {
     18     return (this.q.length == 0);    
     19   }
     20 
     21   this.isNonEmpty  = function() {
     22     return (this.q.length > 0);    
     23   }
     24 
     25   this.enqueue  = function(element) {
     26     this.q.push(element);        
     27   }
     28     
     29   this.dequeue  = function() {
     30     var retVal = null;
     31     if (this.q.length > 0) {
     32       retVal = this.q.shift();
     33     }
     34     return retVal;        
     35   }
     36     
     37   this.toString = function() {
     38     retVal = "";
     39     for (i in this.q) {
     40       retVal += "[" + this.q[i] + "] ";
     41     }
     42     return retVal;
     43   }    
     44 }