Snippet Double-Ended Queue

Romek

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Double-Ended Queue
By Romek
Version 2.0
Introduction:
Inspired by this thread. I thought a double-ended queue data structure may actually have a few uses; mainly for well.. Queuing. :p
Click here to find out more.

Wikipedia (edited a little) said:
An appropriate metaphor often used to represent queues is the idea of a checkout line. Other examples of queues are people traveling up an escalator, machine parts on an assembly line, or cars in line at a petrol station. The recurring theme is clear: queues are essentially the same as a queue you would get in a shop waiting to pay.

In each of the cases, the customer or object at the front of the line was the first one to enter, while at the end of the line is the last to have entered. Every time a customer finishes paying for their items (or a person steps off the escalator, or the machine part is removed from the assembly line, etc.) that object leaves the queue from the front. This represents the queue “pop” function. Every time another object or customer enters the line to wait, they join the end of the line and represent the “push” function. The queue “size” would be the length of the line, and the “empty” function would return true only if there was nothing in the line.

Each queue instance and value in the queue uses up an instance. There is a maximum of 8191 instances. Destroy removes the queue instance and all the values.​


Methods and Members:
  • [ljass]local Queue q = queue.create()[/ljass]
    • Creates a new Queue object for you to use.

  • [ljass]call q.pushBack(/*value*/)[/ljass]
  • [ljass]call q.push(/*value*/)[/ljass]
    • Adds the given value to the back of the queue.

  • [ljass]local integer i = q.popFront()[/ljass]
  • [ljass]local integer i = q.pop()[/ljass]
    • Returns and removes the value at the front of the queue. Returns 0 if the queue is empty.

  • [ljass]call q.pushFront(/*value*/)[/ljass]
  • [ljass]call q.unshift(/*value*/)[/ljass]
    • Adds the given value to the front of the queue.

  • [ljass]local integer i = q.popBack()[/ljass]
  • [ljass]local integer i = q.shift()[/ljass]
    • Returns and removes the value at the back of the queue. Returns 0 if the queue is empty.

  • [ljass]local integer i = q.first()[/ljass]
  • [ljass]local integer i = q.front()[/ljass]
    • Returns (but doesn't remove) the value at the front of the queue. Returns 0 if the queue is empty.

  • [ljass]local integer i = q.last()[/ljass]
  • [ljass]local integer i = q.back()[/ljass]
    • Returns (but doesn't remove) the value at the back of the queue. Returns 0 if the queue is empty.

  • [ljass]local boolean b = q.contains(/*value*/)[/ljass]
  • [ljass]local boolean b = q.exists(/*value*/)[/ljass]
    • Returns true if the value is within the queue.

  • [ljass]local integer i = q.countValue(/*value*/)[/ljass]
    • Returns the number of times the given value is in the queue.

  • [ljass]call q.remove(/*value*/)[/ljass]
  • [ljass]call q.removeFirst(/*value*/)[/ljass]
  • [ljass]call q.delete(/*value*/)[/ljass]
  • [ljass]call q.deleteFirst(/*value*/)[/ljass]
    • Removes the first instance of the given value from within the queue.

  • [ljass]call q.removeLast(/*value*/)[/ljass]
  • [ljass]call q.deleteLast(/*value*/)[/ljass]
    • Removes the last instance of the given value from within the queue.

  • [ljass]call q.removeAll(/*value*/)[/ljass]
  • [ljass]call q.deleteAll(/*value*/)[/ljass]
  • [ljass]call q.purge(/*value*/)[/ljass]
    • Removes all instances of the given value from within the queue.

  • [ljass]local queue anotherQueue = q.copy()[/ljass]
    • Creates a copy of the queue, including the values within it.

  • [ljass]call q.combineBack(/*another queue*/)[/ljass]
  • [ljass]call q.combine(/*another queue*/)[/ljass]
    • Adds all values from the given queue to the back of the queue. Removes the given queue.

  • [ljass]call q.combineFront(/*another queue*/)[/ljass]
    • Adds all values from the given queue to the front of the queue. Removes the given queue.

  • [ljass]local boolean b = q.empty()[/ljass]
    • Returns true if the queue is empty, and false otherwise.

  • [ljass]local integer i = q.size[/ljass]
    • The amount of values in the queue.

  • [ljass]call q.destroy()[/ljass]
    • Destroys the queue to free up memory!


Example:
JASS:
function Example takes nothing returns nothing
    local Queue q = Queue.create()

    call q.push(-1) // Adds this value to the back of the queue
    call q.push(50)
    call q.push(100)
    call q.push(27)

    call BJDebugMsg(I2S(q.size)) // Displays "4"

    call BJDebugMsg(I2S(q.front())) // Displays "-1" (Doesn't remove value)

    call BJDebugMsg(I2S(q.size)) // Displays "4" (The value wasn't removed)

    call BJDebugMsg(I2S(q.pop())) // Displays "-1" (And removes the value)
    call BJDebugMsg(I2S(q.pop())) // Displays "50"
    call BJDebugMsg(I2S(q.pop())) // Displays "100"

    call BJDebugMsg(I2S(q.size)) // Displays "1"  (we removed 3 of the 4 values)
    call BJDebugMsg(I2S(q.pop())) // Displays "27"
    
    call q.destroy() // Destroys the queue
endfunction


The Code:
JASS:
library Queue
//   _____________________________________________________
//  +-----------------------------------------------------+
//  ||            ___                        Version 2.0 ||
//  ||           / _ \ _   _  ___ _   _  ___             ||
//  ||          | | | | | | |/ _ \ | | |/ _ \            ||
//  ||          | |_| | |_| |  __/ |_| |  __/            ||
//  ||           \__\_\\__,_|\___|\__,_|\___|            ||
//  ||                            By Romek               ||
//  ||___________________________________________________||
//  ||¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯||
//  ||  Queue implements the queue data structure into   ||
//  ||  vJass. Visit the wikipedia article for more      ||
//  ||  information:                                     ||
//  ||   <a href="http://en.wikipedia.org/wiki/Double-ended_queue" target="_blank" class="link link--external" rel="noopener">http://en.wikipedia.org/wiki/Double-ended_queue</a> ||
//  ||___________________________________________________||
//  ||¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯||
//  ||  See the following Thehelper.net thread for more  ||
//  ||  information regarding the functions:             ||
//  ||  <a href="http://www.thehelper.net/forums/showthread.php?t=137226" class="link link--internal">www.thehelper.net/forums/showthread.php?t=137226</a> ||
//  |+---------------------------------------------------+|
//   ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

    struct Queue
    
        private thistype next = 0 // first
        private thistype prev = 0 // last
        private integer  data = 0 // size
        
        // How many values are there?
        method operator size takes nothing returns integer
            return .data
        endmethod
        
        // Is the queue empty?
        method empty takes nothing returns boolean
            return .size == 0
        endmethod
        
        // Peek at the first value in the queue
        method front takes nothing returns integer
            if .empty() then
                debug call BJDebugMsg(&quot;Queue: Attempt to peek at an empty queue!&quot;)
                return 0
            endif
            return .next.data
        endmethod
        
        // Peek at the last value in the queue
        method back takes nothing returns integer
            if .empty() then
                debug call BJDebugMsg(&quot;Queue: Attempt to peek at an empty queue!&quot;)
                return 0
            endif
            return .prev.data
        endmethod
        
        // Return true if the selected value is in the queue.
        method contains takes integer in returns boolean
            local thistype node = .next
            loop
                if node.data == in then
                    return true
                endif
                set node = node.next
                exitwhen node == 0
            endloop
            return false
        endmethod
        
        // Return the amount of times &#039;in&#039; is in the queue.
        method countValue takes integer in returns integer
            local thistype node = .next
            local integer count = 0
            loop
                if node.data == in then
                    set count = count + 1
                endif
                set node = node.next
                exitwhen node == 0
            endloop
            return count
        endmethod
        
        // Remove the first value &#039;in&#039; in the queue.
        method remove takes integer in returns nothing
            local thistype node = .next
            loop
                if node.data == in then
                    set node.next.prev = node.prev
                    set node.prev.next = node.next
                    set node.prev = -2
                    call node.destroy()
                    return
                endif
                set node = node.next
                exitwhen node == 0
            endloop
        endmethod
        
        // Remove the last value &#039;in&#039; in the queue.
        method removeLast takes integer in returns nothing
            local thistype node = .prev
            loop
                if node.data == in then
                    set node.next.prev = node.prev
                    set node.prev.next = node.next
                    set node.prev = -2
                    call node.destroy()
                    return
                endif
                set node = node.prev
                exitwhen node == 0
            endloop
        endmethod
        
        // Remove all values &#039;in&#039; in the queue.
        method removeAll takes integer in returns nothing
            local thistype node = .next
            loop
                if node.data == in then
                    set node.next.prev = node.prev
                    set node.prev.next = node.next
                    set node.prev = -2
                    call node.destroy()
                endif
                set node = node.next
                exitwhen node == 0
            endloop
        endmethod
        
        // Add a value to the back of the queue.
        method pushBack takes integer in returns nothing
            local thistype node = .allocate()
            set node.data = in
            if .empty() then
                set .next = node
                set .prev = node
            else
                set .prev.next = node
                set node.prev = .prev
                set .prev = node
            endif
            set .data = .data + 1
        endmethod
        
        // Add a value to the back of the queue.
        method pushFront takes integer in returns nothing
            local thistype node = .allocate()
            set node.data = in
            if .empty() then
                set .next = node
                set .prev = node
            else
                set .next.prev = node
                set node.next = .next
                set .next = node
            endif
            set .data = .data + 1
        endmethod
        
        // Get a value from the front of the queue.
        method popFront takes nothing returns integer
            local integer toreturn
            if .empty() then
                debug call BJDebugMsg(&quot;Queue: Attempt to pop a value from an empty queue&quot;)
                return 0
            endif
            set toreturn = .next.data
            set .data = .data - 1
            if .empty() then
                set .next.prev = -2
                call .next.destroy()
            else
                set .next = .next.next
                set .next.prev.prev = -2
                call .next.prev.destroy()
                set .next.prev = 0
            endif
            return toreturn
        endmethod
        
        // Get a value from the back of the queue.
        method popBack takes nothing returns integer
            local integer toreturn
            if .empty() then
                debug call BJDebugMsg(&quot;Queue: Attempt to pop a value from an empty queue&quot;)
                return 0
            endif
            set toreturn = .prev.data
            set .data = .data - 1
            if .empty() then
                set .prev.prev = -2
                call .prev.destroy()
            else
                set .prev = .prev.prev
                set .prev.next.prev = -2
                call .prev.next.destroy()
                set .prev.next = 0
            endif
            return toreturn
        endmethod
        
        // Copy the queue
        method copy takes nothing returns thistype
            local thistype new = .allocate()
            local thistype node = .next
            loop
                call new.pushBack(node.data)
                set node = node.next
                exitwhen node == 0
            endloop
            return new
        endmethod   
        
        // Add another queue to the back of this one
        method combineBack takes thistype other returns nothing
            loop
                call .pushBack(other.popFront())
                exitwhen other.empty()
            endloop
            call other.destroy()
        endmethod
        
        // Add another queue to the back of this one
        method combineFront takes thistype other returns nothing
            loop
                call .pushFront(other.popBack())
                exitwhen other.empty()
            endloop
            call other.destroy()
        endmethod
        
        // Destroy node/queue
        method onDestroy takes nothing returns nothing
            if .prev != -2 and .next.prev != -2 and .next != 0 then
                set .next.prev = -1
                set .prev = -2
                call .next.destroy()
            endif
        endmethod
        
        // Alternative method names:
        method push takes integer in returns nothing
            call .pushBack(in)
        endmethod
        method pop takes nothing returns integer
            return .popFront()
        endmethod
         method unshift takes integer in returns nothing
            call .pushFront(in)
        endmethod
        method shift takes nothing returns integer
            return .popBack()
        endmethod
        method last takes nothing returns integer
            return .back()
        endmethod
        method first takes nothing returns integer
            return .front()
        endmethod
        method exists takes integer in returns boolean
            return .contains(in)
        endmethod
        method delete takes integer in returns nothing
            call .remove(in)
        endmethod
        method deleteFirst takes integer in returns nothing
            call .remove(in)
        endmethod
        method removeFirst takes integer in returns nothing
            call .remove(in)
        endmethod
        method deleteLast takes integer in returns nothing
            call .removeLast(in)
        endmethod
        method deleteAll takes integer in returns nothing
            call .removeAll(in)
        endmethod
        method purge takes integer in returns nothing
            call .removeAll(in)
        endmethod
        method combine takes thistype other returns nothing
            call .combineBack(other)
        endmethod
    
    endstruct

endlibrary


A demo map for something like this is pointless.
 

Romek

Super Moderator
Reaction score
964
> how can this work if you have more than 1 queue?
Normally; it works. :p

I use the same struct class for both the queue instance and the values within the queue, so some of the members are used in two different ways. 'next' is the size with the queue instance, and 'last' is the value on the 'node'.

Phyrex was also doubting whether or not this works in the chat; so for future reference:
JASS:
function InitTrig_Untitled_Trigger_001 takes nothing returns nothing
    local queue a = queue.create()
    local queue b = queue.create()
    
    call a.push(2)
    call b.push(2)
    call a.push(3)
    call a.push(3)
    
    call BJDebugMsg(I2S(a.size))
    call BJDebugMsg(I2S(b.size))
    
    call BJDebugMsg(I2S(a.pop()))
    call BJDebugMsg(I2S(b.pop()))
    call BJDebugMsg(I2S(a.pop()))
    call b.push(524)
    call b.destroy()
    call BJDebugMsg(I2S(a.pop()))
    
    set b = queue.create()
    call BJDebugMsg(I2S(b.pop()))
    call b.push(4)
    call BJDebugMsg(I2S(b.pop()))
    
    call a.destroy()
    call b.destroy()
endfunction

Displays: 3, 1, 2, 2, 3, 3, 0, 4.
 

Lyerae

I keep popping up on this site from time to time.
Reaction score
105
So.... What's the purpose of this?
I'm not seeing it... But then again, I'm a complete JASS noob, so yeah...
 

Renendaru

(Evol)ution is nothing without love.
Reaction score
309
Isn't this essentially Linked lists? In purpose at least.
 

Romek

Super Moderator
Reaction score
964
> So.... What's the purpose of this?
To queue integers. o_O

> Isn't this essentially Linked lists? In purpose at least.
> Its more primitive than linked list. it inserts at the end and takes from the front.
Yeah, this does function in a very similar way to a linked list.
Though it has less functions, and it's easier to use (as a result). I haven't got anything more to say about that, to be honest. :p
 

Renendaru

(Evol)ution is nothing without love.
Reaction score
309
Well, I have a self-made snippet like this. I call it IntegerPool, but it can be used in many ways, even to function as this one. I haven't found any downsides as of yet, nor bugs. Yet, I can't really submit it, too many people have used the idea, and probably did a better job than I did.
 

Nestharus

o-o
Reaction score
84
Pretty nice, but wouldn't this be a stack?

The method names are the same names that would be in a stack too : P.
 

Romek

Super Moderator
Reaction score
964
> Pretty nice, but wouldn't this be a stack?
No, this wouldn't be a stack.

> The method names are the same names that would be in a stack too : P.
That doesn't make it a stack.
 

Troll-Brain

You can change this now in User CP.
Reaction score
85
JASS:
local integer toreturn
inside the method pop is useless.

Also can't it be done with a simple linked list, not a double one, since it's a queue ?
(I mean keep the O(1) for all things)
I may be wrong though, linked lists are something really new for me.
 

Trollvottel

never aging title
Reaction score
262
JASS:
local integer toreturn
inside the method pop is useless.
Also can't it be done with a simple linked list, not a double one, since it's a queue ?
I may be wrong though, linked lists are something really new for me.


oh, stack and queue implementations can be done very easily using a linked list (may not be the best way). example (freehand not using the standart names):

JASS:
struct Queue
   private LinkedList list = LinkedList.create()

   method add....thing
       list.toLast()
       list.insertBehind(thing)
   endmethod

   method get...
       list.toFirst()
       return list.getItem() // you should make sure that the list is not empty here...
   endmethod
   
   method remove
        list.toFirst()
        list.remove()
   endmethod
   
   method isEmpty
         return list.isEmpty
   endmethod
endstruct

these are O(1) if you use for example my implementation.
 

Romek

Super Moderator
Reaction score
964
> inside the method pop is useless.
Why?

> Also can't it be done with a simple linked list, not a double one, since it's a queue ?
..This isn't a a doubly linked list. If it was, I'd make this a double-ended queue without much hassle (that'd be a pretty easy change though, I think).

> (I mean keep the O(1) for all things)
All method except .destroy have O(1) complexity.
 

Troll-Brain

You can change this now in User CP.
Reaction score
85
Nevermind, i didn't saw the .destroy line ...

..This isn't a a doubly linked list. If it was, I'd make this a double-ended queue without much hassle (that'd be a pretty easy change though, I think).
Aha, i said linked list are really new for me, to much i guess, go learning them ...

All method except .destroy have O(1) complexity.
I know.
 

Azlier

Old World Ghost
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461
I do believe that a stack is LIFO and a queue is FIFO, Vestras. The description says that this is FIFO.

The GIGO rule applies to both data structures.
 

Vestras

Retired
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249
I do believe that a stack is LIFO and a queue is FIFO, Vestras. The description says that this is FIFO.

The GIGO rule applies to both data structures.

Lol, you're right, fail.
Also, Queues normally don't use Push and Pop, they use Enqueue and Dequeue. (AFAIK)
 
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