MultiArrayQueue.github.io/Simulator_MultiArrayQueue.html at main · MultiArrayQueue/MultiArrayQueue.github.io · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="description" content="Interactive Simulator of the Multi-Array Queue">
<title>Interactive Simulator of the Multi-Array Queue</title>
<style>
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
  color: #24292e;
  background-color: #fdfdfd;
  -webkit-text-size-adjust: 100%;
  -webkit-font-feature-settings: "kern" 1;
  -moz-font-feature-settings: "kern" 1;
  -o-font-feature-settings: "kern" 1;
  font-feature-settings: "kern" 1;
  font-kerning: normal;
  padding-right: 30px;
  padding-left: 30px;
}
h1 {
  margin-bottom: 10px;
}
h4 {
  margin-top: 0px;
  margin-bottom: 10px;
}
button {
  padding: 10px;
  margin-right: 20px;
  margin-bottom: 10px;
}
p.remark {
  margin-top: 10px;
  font-size: small;
  line-height: 1.5;
}
</style>
</head>

<body>

<h1>Interactive Simulator of the Multi-Array Queue</h1>
<h4 id="subcap"></h4>
<canvas id="canv" width="560" height="560"></canvas>
<br>
<button id="MAQ_0_4" onclick="start_again(0,4)">Start again MAQ(0,4)</button>
<button id="MAQ_1_3" onclick="start_again(1,3)">MAQ(1,3)</button>
<button id="MAQ_2_2" onclick="start_again(2,2)">MAQ(2,2)</button>
<button id="MAQ_3_2" onclick="start_again(3,2)">MAQ(3,2)</button>
<button id="MAQ_7_1" onclick="start_again(7,1)">MAQ(7,1)</button>
<button id="MAQ_15_0" onclick="start_again(15,0)">MAQ(15,0)</button>
<button id="MAQ_1_0" onclick="start_again(1,0)">MAQ(1,0)</button>
<button id="MAQ_0_0" onclick="start_again(0,0)">MAQ(0,0) corner case</button>
<br>
<button id="enqueue" onclick="remark(null); enqueue()"><b>Enqueue</b></button>
<button id="dequeue" onclick="remark(null); dequeue()"><b>Dequeue</b></button>
<button id="enqueue_dequeue" onclick="remark(null); enqueue(); dequeue()"><b>Enqueue + Dequeue</b></button>
<button id="play_scenario" onclick="play_scenario()"><b>Play a scenario with microbursts on the Enqueue side</b></button>
<div id="rem"></div>

<script>
  "use strict"
  const subcap = document.getElementById("subcap")
  const canv = document.getElementById("canv")
  const rem = document.getElementById("rem")
  const ctx = canv.getContext("2d")
  var remText
  // ----------------------
  function remark( t ) {
    if (!t) {
      remText = null
      rem.innerHTML = ''
    } else {
      if (remText) remText += " " + t
      else         remText = t
      rem.innerHTML = '<p class="remark">' + remText
    }
  }
  function assertionError( t ) {
    remark('<span style="color:#FF0000; font-weight:bold;">' + t + '</span>')
  }
  function resultAttention( t ) {
    remark('<span style="color:#0000FF; font-weight:bold;">' + t + '</span>')
  }
  function result( t ) {
    remark('<span style="font-weight:bold;">' + t + '</span>')
  }
  // ----------------------
  const leftOff = 50
  const objSize = 30
  const divDist = 12
  const bottOff = divDist * 5
  const arrDist = divDist * 7 + objSize

  function arrow_up(x, y) {
    ctx.lineTo( x, y )
    ctx.lineTo( x - 3, y + 5 )
    ctx.moveTo( x, y )
    ctx.lineTo( x + 3, y + 5 )
  }
  function arrow_left(x, y ) {
    ctx.lineTo( x, y )
    ctx.lineTo( x + 5, y - 3 )
    ctx.moveTo( x, y )
    ctx.lineTo( x + 5, y + 3 )
  }
  function draw_object( rix, ix, full, writer, reader ) {
    if ( full ) ctx.fillStyle = "#FF9999"
    else        ctx.fillStyle = "#FFFFFF"
    ctx.fillRect( leftOff + (rix * arrDist), canv.height - bottOff - objSize - (ix * objSize), objSize, objSize )
    ctx.lineWidth = 2
    ctx.strokeStyle = "#000000"
    ctx.strokeRect( leftOff + (rix * arrDist), canv.height - bottOff - objSize - (ix * objSize), objSize, objSize )
    let txt
    if (writer && reader) txt = "WR"
    else if (writer)      txt = "W"
    else if (reader)      txt = "R"
    if (txt) {
      ctx.font = "14px Arial"
      ctx.textAlign = "center"
      ctx.fillStyle = "#000000"
      ctx.fillText( txt, leftOff + (rix * arrDist) + (objSize / 2), canv.height - bottOff - objSize - (ix * objSize) + (objSize / 2) + 5)
    }
  }
  function draw_diversion(dix, rix, ix) {
    ctx.lineWidth = 1
    ctx.strokeStyle = "#000000"

    ctx.beginPath()
    ctx.moveTo( leftOff + (rix * arrDist) + objSize                         , canv.height - bottOff - (ix * objSize)                         )
    ctx.lineTo( leftOff + (rix * arrDist) + objSize + ((2 + dix) * divDist) , canv.height - bottOff - (ix * objSize)                         )
    ctx.lineTo( leftOff + (rix * arrDist) + objSize + ((2 + dix) * divDist) , canv.height - bottOff + ((1 + dix) * divDist)                  )
    ctx.lineTo( leftOff + ((1 + dix) * arrDist) + (objSize / 2)             , canv.height - bottOff + ((1 + dix) * divDist)                  )
    arrow_up  ( leftOff + ((1 + dix) * arrDist) + (objSize / 2)             , canv.height - bottOff                                          )
    ctx.stroke()

    ctx.beginPath()
    ctx.moveTo( leftOff + ((1 + dix) * arrDist) + (objSize / 2)             , canv.height - bottOff - ((firstArraySize << (1 + dix)) * objSize)           )
    ctx.lineTo( leftOff + ((1 + dix) * arrDist) + (objSize / 2)             , canv.height - bottOff - ((firstArraySize << (1 + dix)) * objSize) - divDist )
    ctx.lineTo( leftOff + (rix * arrDist) + objSize + ((2 + dix) * divDist) , canv.height - bottOff - ((firstArraySize << (1 + dix)) * objSize) - divDist )
    ctx.lineTo( leftOff + (rix * arrDist) + objSize + ((2 + dix) * divDist) , canv.height - bottOff - (ix * objSize) - (objSize / 2)                      )
    arrow_left( leftOff + (rix * arrDist) + objSize                         , canv.height - bottOff - (ix * objSize) - (objSize / 2)                      )
    ctx.stroke()
  }
  // ----------------------
  // private data of the Multi-Array Queue
  var firstArraySize
  var ringsMaxIndex
  var diversions
  var writerPositionRix
  var writerPositionIx
  var readerPositionRix
  var readerPositionIx

  function enqueue() {
    let isQueueExtensionPossible = (ringsMaxIndex < diversions.length)  // if there is room yet for the extension
    let extendQueue = false
    let writerRix = writerPositionRix  // writer prospective
    let writerIx  = writerPositionIx
    let tmpRix

    go_forward:
    for (;;)
    {
      writerIx ++  // prospective move forward

      // if the prospective move goes "beyond" the end of rings[writerRix]
      if ((firstArraySize << writerRix) == writerIx)
      {
        if (0 == writerRix)  // if in rings[0]
        {
          remark("Moved to rings[0][0].")
          writerRix = 0
          writerIx  = 0
          // do not break here because from rings[0][0] eventually diversion(s) shall be followed forward
        }
        else  // i.e. we are in a "higher" rings[N]
        {
          remark("Followed diversion[" + (writerRix - 1) + "] back.")
          tmpRix = writerRix
          writerRix = diversions[tmpRix - 1].rix  // follow diversion[N-1] back
          writerIx  = diversions[tmpRix - 1].ix

          // if the prospective move has hit the reader (that is in the previous round) "from behind"
          if ((readerPositionRix == writerRix) && (readerPositionIx == writerIx))
          {
            if (isQueueExtensionPossible)
            {
              assertionError("Hit reader on the return path of a diversion.")
              return
            }
            else
            {
              resultAttention("Queue is full.")
              return
            }
          }
          break go_forward  // the prospective move forward is done, we are on the return path of a diversion
        }
      }

      // if the prospective move reached (an entry side of) a diversion: follow it - to the beginning of respective rings[rix]
      // (another diversion may sit there, so then continue following)
      for (tmpRix = 1 + writerRix; tmpRix <= ringsMaxIndex; tmpRix ++)
      {
        if ((diversions[tmpRix - 1].rix == writerRix) && (diversions[tmpRix - 1].ix == writerIx))
        {
          remark("Followed diversion[" + (tmpRix - 1) + "] forward.")
          writerRix = tmpRix  // move to the first element of the array of Objects the diversion leads to
          writerIx  = 0
        }
      }

      // if the prospective move has hit the reader (that is in the previous round) "from behind"
      if ((readerPositionRix == writerRix) && (readerPositionIx == writerIx))
      {
        if (isQueueExtensionPossible)
        {
          remark("Extended the Queue.")
          extendQueue = true
        }
        else
        {
          resultAttention("Queue is full.")
          return
        }
      }

      // the forward-looking check to prevent the next writer from hitting the reader "from behind"
      // on the return path of a diversion (see Paper for explanation)
      else
      {
        let testNextWriterRix = writerRix
        let testNextWriterIx = writerIx

        test_next:
        for (; ((0 != testNextWriterRix) && ((firstArraySize << testNextWriterRix) == (1 + testNextWriterIx))) ;)
        {
          tmpRix = testNextWriterRix
          testNextWriterRix = diversions[tmpRix - 1].rix  // follow the diversion back
          testNextWriterIx  = diversions[tmpRix - 1].ix
          if ((readerPositionRix == testNextWriterRix) && (readerPositionIx == testNextWriterIx))  // if we would hit the reader
          {
            if (isQueueExtensionPossible)
            {
              remark("Created new diversion because next writer could hit reader on the return path of a diversion.")
              extendQueue = true
            }
            break test_next
          }
        }
      }
      break go_forward  // prospective move forward is now done
    }

    // preparations are done, start the actual work
    if (extendQueue)
    {
      let rixMaxNew = 1 + ringsMaxIndex

      // impossible for writerPos to be already in the diversions array, but better check ...
      for (tmpRix = 1; tmpRix <= ringsMaxIndex; tmpRix ++)
      {
        if ((diversions[tmpRix - 1].rix == writerRix) && (diversions[tmpRix - 1].ix == writerIx))
        {
          assertionError("Duplicity in the diversions array.")
          return
        }
      }

      diversions[rixMaxNew - 1] = new Object()  // write the new diversion = the prospective writer position
      diversions[rixMaxNew - 1].rix = writerRix
      diversions[rixMaxNew - 1].ix  = writerIx

      ringsMaxIndex = rixMaxNew  // increment ringsMaxIndex

      draw_object( rixMaxNew, 0, true, true, false )
      for (let tmpIx = 1; tmpIx < (firstArraySize << rixMaxNew); tmpIx ++)
      {
        draw_object( rixMaxNew, tmpIx, false, false, false )
      }
      draw_diversion( rixMaxNew - 1, writerRix, writerIx )
      redrawOldWriterPosition( writerPositionRix, writerPositionIx, readerPositionRix, readerPositionIx )

      writerPositionRix = rixMaxNew  // new writer position = first array element of the new array
      writerPositionIx = 0
    }
    else  // no extendQueue
    {
      draw_object( writerRix, writerIx, true, true, false )
      redrawOldWriterPosition( writerPositionRix, writerPositionIx, readerPositionRix, readerPositionIx )

      writerPositionRix = writerRix  // new writer position = prospective writer position
      writerPositionIx = writerIx
    }
    result("Enqueued.")
  }
  function redrawOldWriterPosition( oldWriterRix, oldWriterIx, currReaderRix, currReaderIx )
  {
    if ((currReaderRix == oldWriterRix) && (currReaderIx == oldWriterIx)) {
      draw_object( oldWriterRix, oldWriterIx, false, false, true )
    } else {
      draw_object( oldWriterRix, oldWriterIx, true, false, false )
    }
  }
  // ----------------------
  function dequeue() {
    let readerRix = readerPositionRix  // reader prospective
    let readerIx  = readerPositionIx
    let tmpRix

    // if the reader stands on the writer: the Queue is empty
    if ((writerPositionRix == readerRix) && (writerPositionIx == readerIx))
    {
      resultAttention("Queue is empty.")
      return
    }

    go_forward:
    for (;;)
    {
      readerIx ++  // prospective move forward

      // if the prospective move goes "beyond" the end of rings[readerRix]
      if ((firstArraySize << readerRix) == readerIx)
      {
        if (0 == readerRix)  // if in rings[0]
        {
          remark("Moved to rings[0][0].")
          readerRix = 0
          readerIx  = 0
          // do not break here because from rings[0][0] eventually diversion(s) shall be followed forward
        }
        else  // i.e. we are in a "higher" rings[N]
        {
          remark("Followed diversion[" + (readerRix - 1) + "] back.")
          tmpRix = readerRix
          readerRix = diversions[tmpRix - 1].rix  // follow diversion[N-1] back
          readerIx  = diversions[tmpRix - 1].ix
          break go_forward  // the prospective move forward is done, we are on the return path of a diversion
        }
      }

      // if the prospective move reached (an entry side of) a diversion: follow it - to the beginning of respective rings[rix]
      // (another diversion may sit there, so then continue following)
      for (tmpRix = 1 + readerRix; tmpRix <= ringsMaxIndex; tmpRix ++)
      {
        if ((diversions[tmpRix - 1].rix == readerRix) && (diversions[tmpRix - 1].ix == readerIx))
        {
          remark("Followed diversion[" + (tmpRix - 1) + "] forward.")
          readerRix = tmpRix  // move to the first element of the array of Objects the diversion leads to
          readerIx  = 0
        }
      }
      break go_forward  // prospective move forward is now done
    }

    if ((writerPositionRix == readerRix) && (writerPositionIx == readerIx)) {
      draw_object(readerRix, readerIx, false, true, true )
    } else {
      draw_object(readerRix, readerIx, false, false, true )
    }
    redrawOldReaderPosition( readerPositionRix, readerPositionIx, writerPositionRix, writerPositionIx )

    readerPositionRix = readerRix  // new reader position = prospective reader position
    readerPositionIx  = readerIx
    result("Dequeued.")
  }
  function redrawOldReaderPosition( oldReaderRix, oldReaderIx, currWriterRix, currWriterIx )
  {
    draw_object( oldReaderRix, oldReaderIx, false, false, false )
  }
  // ----------------------
  const scenario = [+300, +300, +300, +300, -300, +100, +100, +50,  +50,  +50,
                    +50,  +50,  +50,  +50,  +50,  +50,  +50,  +50,  +50,  +50,
                    +50,  +50,  +50,  +50,  -200, -200, -200, -200, -200, -200,
                    +50,  +50,  -100, -100, -100, -100, -100, -100, -100, -100,
                    +50,  +50,  -100, -100, -100, -100, -100, -100, -100, -100,
                    +50,  +50,  +50,  +50,  +50,  +50,  +50,  +50,  +50,  +50,
                    -100, -100, -100, -100, -100, -100, -100, -100, -100, -100,
                    -100, -100, -100, -100, +100, -100, +100, -100, +100, -100,
                    +100, -100, +50,  +50,  +50,  +50,  +50,  +50,  -100, -100,
                    -100, -100, -100, -100, +100, -100, +100, -100, +100, -100]
  var scenario_step

  function play_scenario() {
    disable_buttons(true)
    scenario_step = 0
    setTimeout(play_scenario_step, Math.abs(scenario[scenario_step]))
  }
  function play_scenario_step() {
    if (scenario[scenario_step] < 0) {remark(null); dequeue()}
    else {remark(null); enqueue()}
    scenario_step ++
    if (scenario_step < scenario.length) {
      setTimeout(play_scenario_step, Math.abs(scenario[scenario_step]))
    } else {
      disable_buttons(false)
    }
  }
  function disable_buttons(disabled) {
    document.getElementById("MAQ_0_4").disabled = disabled
    document.getElementById("MAQ_1_3").disabled = disabled
    document.getElementById("MAQ_2_2").disabled = disabled
    document.getElementById("MAQ_3_2").disabled = disabled
    document.getElementById("MAQ_7_1").disabled = disabled
    document.getElementById("MAQ_15_0").disabled = disabled
    document.getElementById("MAQ_1_0").disabled = disabled
    document.getElementById("MAQ_0_0").disabled = disabled
    document.getElementById("enqueue").disabled = disabled
    document.getElementById("dequeue").disabled = disabled
    document.getElementById("enqueue_dequeue").disabled = disabled
    document.getElementById("play_scenario").disabled = disabled
  }
  // ----------------------
  function start_again(initialCapacity, cntAllowedExtensions) {
    subcap.innerHTML = 'Contains simplified versions of the algorithms' +
      ' (Constructor parameters: initialCapacity = ' + initialCapacity +
      ', cntAllowedExtensions = ' + cntAllowedExtensions + ')'
    firstArraySize = 1 + initialCapacity
    ringsMaxIndex = 0
    diversions = new Array(cntAllowedExtensions)
    writerPositionRix = 0
    writerPositionIx = firstArraySize - 1
    readerPositionRix = 0
    readerPositionIx = firstArraySize - 1
    ctx.clearRect( 0, 0, canv.width, canv.height )
    remark(null)
    for (let tmpIx = 0; tmpIx < (firstArraySize - 1); tmpIx ++)
    {
      draw_object( 0, tmpIx, false, false, false )
    }
    draw_object( 0, (firstArraySize - 1), false, true, true )
  }
  start_again(0,4)  // MAQ(0,4) is default
</script>
<noscript>Sorry, your browser does not support JavaScript!</noscript>

</body>
</html>