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this.packageSize            = 4096;
this.timerHandle            = 0;
this.receivedPackageSize    = 0; 
this.inbound                = [];
this.sendDataCnt            = 0;
this.parallelRequests       = 2;

/* Request:  uint32 (number of requested bytes ); */
/* Response: uint32 (number of send bytes); uint8[] data; */

var webSocket = new WebSocket('ws://10.1.0.92:6325', ['istest']);
webSocket.binaryType = 'arraybuffer';

function sendDataRequest()
{
    var buf  = new ArrayBuffer(4);
    var view = new DataView(buf, 0);
    view.setUint32(0, this.packageSize, true);
    for (var i = 0; i < this.parallelRequests; i++)
        webSocket.send(buf);
    $('#sendDataCnt')[0].innerHTML = this.sendDataCnt++;
}

webSocket.onopen = function()
{
    $('#log')[0].innerHTML += 'connected<br/>';
    this.timerHandle = setInterval(sendDataRequest, 100);
}.bind(this);

webSocket.onmessage = function(event)
{
    this.inbound.push.apply(this.inbound, new Uint8Array(event.data));
    if (this.receivedPackageSize == 0 && this.inbound.length >= 4)
    {
        var u8Arr = new Uint8Array(new ArrayBuffer(4));
        u8Arr.set(this.inbound.slice(0, 4));
        this.receivedPackageSize = new DataView(u8Arr.buffer).getUint32(0, true);
        this.inbound = this.inbound.slice(4);
        if (this.receivedPackageSize != this.packageSize)
        {
            clearInterval(this.timerHandle);
            $('#header')[0].innerHTML = 'ERROR: receivedPackageSize = ' + this.receivedPackageSize;
        }
        else
            $('#header')[0].innerHTML = 'receivedPackageSize = ' + this.receivedPackageSize;
        $('#data')[0].innerHTML = 'waiting for data...';
    }
    else if (this.inbound.length >= this.receivedPackageSize)
    {
        var u8Arr = new Uint8Array(new ArrayBuffer(this.receivedPackageSize));
        u8Arr.set(this.inbound.slice(0, this.receivedPackageSize));
        this.inbound = this.inbound.slice(this.receivedPackageSize);
        for (var i = 0; i < this.receivedPackageSize; i++)
        {
            if (u8Arr[i] != (i & 0xFF))
            {
                clearInterval(timerHandle);
                $('#data')[0].innerHTML = 'ERROR: invalid package data';
                break;
            }
        }
        $('#data')[0].innerHTML = 'data OK';
        this.receivedPackageSize = 0;
    }
}.bind(this);

webSocket.onerror = function(e)
{
    clearInterval(timerHandle);
    $('#log')[0].innerHTML += 'error<br/>';
    console.log(e);
}.bind(this);

webSocket.onclose = function()
{
    clearInterval(timerHandle);
    $('#log')[0].innerHTML += 'disconnected<br/>';
}.bind(this);