/*! Scroller 1.2.2
   * ©2011-2014 SpryMedia Ltd - datatables.net/license
   */
  
  /**
   * @summary     Scroller
   * @description Virtual rendering for DataTables
   * @version     1.2.2
   * @file        dataTables.scroller.js
   * @author      SpryMedia Ltd (www.sprymedia.co.uk)
   * @contact     www.sprymedia.co.uk/contact
   * @copyright   Copyright 2011-2014 SpryMedia Ltd.
   *
   * This source file is free software, available under the following license:
   *   MIT license - http://datatables.net/license/mit
   *
   * This source file is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   * or FITNESS FOR A PARTICULAR PURPOSE. See the license files for details.
   *
   * For details please refer to: http://www.datatables.net
   */
  
  (function(window, document, undefined){
  
  
  var factory = function( $, DataTable ) {
  "use strict";
  
  /**
   * Scroller is a virtual rendering plug-in for DataTables which allows large
   * datasets to be drawn on screen every quickly. What the virtual rendering means
   * is that only the visible portion of the table (and a bit to either side to make
   * the scrolling smooth) is drawn, while the scrolling container gives the
   * visual impression that the whole table is visible. This is done by making use
   * of the pagination abilities of DataTables and moving the table around in the
   * scrolling container DataTables adds to the page. The scrolling container is
   * forced to the height it would be for the full table display using an extra
   * element.
   *
   * Note that rows in the table MUST all be the same height. Information in a cell
   * which expands on to multiple lines will cause some odd behaviour in the scrolling.
   *
   * Scroller is initialised by simply including the letter 'S' in the sDom for the
   * table you want to have this feature enabled on. Note that the 'S' must come
   * AFTER the 't' parameter in `dom`.
   *
   * Key features include:
   *   <ul class="limit_length">
   *     <li>Speed! The aim of Scroller for DataTables is to make rendering large data sets fast</li>
   *     <li>Full compatibility with deferred rendering in DataTables 1.9 for maximum speed</li>
   *     <li>Display millions of rows</li>
   *     <li>Integration with state saving in DataTables (scrolling position is saved)</li>
   *     <li>Easy to use</li>
   *   </ul>
   *
   *  @class
   *  @constructor
   *  @global
   *  @param {object} oDT DataTables settings object
   *  @param {object} [oOpts={}] Configuration object for FixedColumns. Options 
   *    are defined by {@link Scroller.defaults}
   *
   *  @requires jQuery 1.7+
   *  @requires DataTables 1.9.0+
   *
   *  @example
   *    $(document).ready(function() {
   *        $('#example').dataTable( {
   *            "sScrollY": "200px",
   *            "sAjaxSource": "media/dataset/large.txt",
   *            "sDom": "frtiS",
   *            "bDeferRender": true
   *        } );
   *    } );
   */
  var Scroller = function ( oDTSettings, oOpts ) {
  	/* Sanity check - you just know it will happen */
  	if ( ! this instanceof Scroller )
  	{
  		alert( "Scroller warning: Scroller must be initialised with the 'new' keyword." );
  		return;
  	}
  
  	if ( typeof oOpts == 'undefined' )
  	{
  		oOpts = {};
  	}
  
  	/**
  	 * Settings object which contains customisable information for the Scroller instance
  	 * @namespace
  	 * @private
  	 * @extends Scroller.defaults
  	 */
  	this.s = {
  		/**
  		 * DataTables settings object
  		 *  @type     object
  		 *  @default  Passed in as first parameter to constructor
  		 */
  		"dt": oDTSettings,
  
  		/**
  		 * Pixel location of the top of the drawn table in the viewport
  		 *  @type     int
  		 *  @default  0
  		 */
  		"tableTop": 0,
  
  		/**
  		 * Pixel location of the bottom of the drawn table in the viewport
  		 *  @type     int
  		 *  @default  0
  		 */
  		"tableBottom": 0,
  
  		/**
  		 * Pixel location of the boundary for when the next data set should be loaded and drawn
  		 * when scrolling up the way.
  		 *  @type     int
  		 *  @default  0
  		 *  @private
  		 */
  		"redrawTop": 0,
  
  		/**
  		 * Pixel location of the boundary for when the next data set should be loaded and drawn
  		 * when scrolling down the way. Note that this is actually calculated as the offset from
  		 * the top.
  		 *  @type     int
  		 *  @default  0
  		 *  @private
  		 */
  		"redrawBottom": 0,
  
  		/**
  		 * Auto row height or not indicator
  		 *  @type     bool
  		 *  @default  0
  		 */
  		"autoHeight": true,
  
  		/**
  		 * Number of rows calculated as visible in the visible viewport
  		 *  @type     int
  		 *  @default  0
  		 */
  		"viewportRows": 0,
  
  		/**
  		 * setTimeout reference for state saving, used when state saving is enabled in the DataTable
  		 * and when the user scrolls the viewport in order to stop the cookie set taking too much
  		 * CPU!
  		 *  @type     int
  		 *  @default  0
  		 */
  		"stateTO": null,
  
  		/**
  		 * setTimeout reference for the redraw, used when server-side processing is enabled in the
  		 * DataTables in order to prevent DoSing the server
  		 *  @type     int
  		 *  @default  null
  		 */
  		"drawTO": null,
  
  		heights: {
  			jump: null,
  			page: null,
  			virtual: null,
  			scroll: null,
  
  			/**
  			 * Height of rows in the table
  			 *  @type     int
  			 *  @default  0
  			 */
  			row: null,
  
  			/**
  			 * Pixel height of the viewport
  			 *  @type     int
  			 *  @default  0
  			 */
  			viewport: null
  		},
  
  		topRowFloat: 0,
  		scrollDrawDiff: null,
  		loaderVisible: false
  	};
  
  	// @todo The defaults should extend a `c` property and the internal settings
  	// only held in the `s` property. At the moment they are mixed
  	this.s = $.extend( this.s, Scroller.oDefaults, oOpts );
  
  	// Workaround for row height being read from height object (see above comment)
  	this.s.heights.row = this.s.rowHeight;
  
  	/**
  	 * DOM elements used by the class instance
  	 * @private
  	 * @namespace
  	 *
  	 */
  	this.dom = {
  		"force":    document.createElement('div'),
  		"scroller": null,
  		"table":    null,
  		"loader":   null
  	};
  
  	/* Attach the instance to the DataTables instance so it can be accessed */
  	this.s.dt.oScroller = this;
  
  	/* Let's do it */
  	this._fnConstruct();
  };
  
  
  
  Scroller.prototype = /** @lends Scroller.prototype */{
  	/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
  	 * Public methods
  	 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
  
  	/**
  	 * Calculate the pixel position from the top of the scrolling container for
  	 * a given row
  	 *  @param {int} iRow Row number to calculate the position of
  	 *  @returns {int} Pixels
  	 *  @example
  	 *    $(document).ready(function() {
  	 *      $('#example').dataTable( {
  	 *        "sScrollY": "200px",
  	 *        "sAjaxSource": "media/dataset/large.txt",
  	 *        "sDom": "frtiS",
  	 *        "bDeferRender": true,
  	 *        "fnInitComplete": function (o) {
  	 *          // Find where row 25 is
  	 *          alert( o.oScroller.fnRowToPixels( 25 ) );
  	 *        }
  	 *      } );
  	 *    } );
  	 */
  	"fnRowToPixels": function ( rowIdx, intParse, virtual )
  	{
  		var pixels;
  
  		if ( virtual ) {
  			pixels = this._domain( 'virtualToPhysical', rowIdx * this.s.heights.row );
  		}
  		else {
  			var diff = rowIdx - this.s.baseRowTop;
  			pixels = this.s.baseScrollTop + (diff * this.s.heights.row);
  		}
  
  		return intParse || intParse === undefined ?
  			parseInt( pixels, 10 ) :
  			pixels;
  	},
  
  
  	/**
  	 * Calculate the row number that will be found at the given pixel position
  	 * (y-scroll).
  	 *
  	 * Please note that when the height of the full table exceeds 1 million
  	 * pixels, Scroller switches into a non-linear mode for the scrollbar to fit
  	 * all of the records into a finite area, but this function returns a linear
  	 * value (relative to the last non-linear positioning).
  	 *  @param {int} iPixels Offset from top to calculate the row number of
  	 *  @param {int} [intParse=true] If an integer value should be returned
  	 *  @param {int} [virtual=false] Perform the calculations in the virtual domain
  	 *  @returns {int} Row index
  	 *  @example
  	 *    $(document).ready(function() {
  	 *      $('#example').dataTable( {
  	 *        "sScrollY": "200px",
  	 *        "sAjaxSource": "media/dataset/large.txt",
  	 *        "sDom": "frtiS",
  	 *        "bDeferRender": true,
  	 *        "fnInitComplete": function (o) {
  	 *          // Find what row number is at 500px
  	 *          alert( o.oScroller.fnPixelsToRow( 500 ) );
  	 *        }
  	 *      } );
  	 *    } );
  	 */
  	"fnPixelsToRow": function ( pixels, intParse, virtual )
  	{
  		var diff = pixels - this.s.baseScrollTop;
  		var row = virtual ?
  			this._domain( 'physicalToVirtual', pixels ) / this.s.heights.row :
  			( diff / this.s.heights.row ) + this.s.baseRowTop;
  
  		return intParse || intParse === undefined ?
  			parseInt( row, 10 ) :
  			row;
  	},
  
  
  	/**
  	 * Calculate the row number that will be found at the given pixel position (y-scroll)
  	 *  @param {int} iRow Row index to scroll to
  	 *  @param {bool} [bAnimate=true] Animate the transition or not
  	 *  @returns {void}
  	 *  @example
  	 *    $(document).ready(function() {
  	 *      $('#example').dataTable( {
  	 *        "sScrollY": "200px",
  	 *        "sAjaxSource": "media/dataset/large.txt",
  	 *        "sDom": "frtiS",
  	 *        "bDeferRender": true,
  	 *        "fnInitComplete": function (o) {
  	 *          // Immediately scroll to row 1000
  	 *          o.oScroller.fnScrollToRow( 1000 );
  	 *        }
  	 *      } );
  	 *     
  	 *      // Sometime later on use the following to scroll to row 500...
  	 *          var oSettings = $('#example').dataTable().fnSettings();
  	 *      oSettings.oScroller.fnScrollToRow( 500 );
  	 *    } );
  	 */
  	"fnScrollToRow": function ( iRow, bAnimate )
  	{
  		var that = this;
  		var ani = false;
  		var px = this.fnRowToPixels( iRow );
  
  		// We need to know if the table will redraw or not before doing the
  		// scroll. If it will not redraw, then we need to use the currently
  		// displayed table, and scroll with the physical pixels. Otherwise, we
  		// need to calculate the table's new position from the virtual
  		// transform.
  		var preRows = ((this.s.displayBuffer-1)/2) * this.s.viewportRows;
  		var drawRow = iRow - preRows;
  		if ( drawRow < 0 ) {
  			drawRow = 0;
  		}
  
  		if ( (px > this.s.redrawBottom || px < this.s.redrawTop) && this.s.dt._iDisplayStart !== drawRow ) {
  			ani = true;
  			px = this.fnRowToPixels( iRow, false, true );
  		}
  
  		if ( typeof bAnimate == 'undefined' || bAnimate )
  		{
  			this.s.ani = ani;
  			$(this.dom.scroller).animate( {
  				"scrollTop": px
  			}, function () {
  				// This needs to happen after the animation has completed and
  				// the final scroll event fired
  				setTimeout( function () {
  					that.s.ani = false;
  				}, 25 );
  			} );
  		}
  		else
  		{
  			$(this.dom.scroller).scrollTop( px );
  		}
  	},
  
  
  	/**
  	 * Calculate and store information about how many rows are to be displayed
  	 * in the scrolling viewport, based on current dimensions in the browser's
  	 * rendering. This can be particularly useful if the table is initially
  	 * drawn in a hidden element - for example in a tab.
  	 *  @param {bool} [bRedraw=true] Redraw the table automatically after the recalculation, with
  	 *    the new dimensions forming the basis for the draw.
  	 *  @returns {void}
  	 *  @example
  	 *    $(document).ready(function() {
  	 *      // Make the example container hidden to throw off the browser's sizing
  	 *      document.getElementById('container').style.display = "none";
  	 *      var oTable = $('#example').dataTable( {
  	 *        "sScrollY": "200px",
  	 *        "sAjaxSource": "media/dataset/large.txt",
  	 *        "sDom": "frtiS",
  	 *        "bDeferRender": true,
  	 *        "fnInitComplete": function (o) {
  	 *          // Immediately scroll to row 1000
  	 *          o.oScroller.fnScrollToRow( 1000 );
  	 *        }
  	 *      } );
  	 *     
  	 *      setTimeout( function () {
  	 *        // Make the example container visible and recalculate the scroller sizes
  	 *        document.getElementById('container').style.display = "block";
  	 *        oTable.fnSettings().oScroller.fnMeasure();
  	 *      }, 3000 );
  	 */
  	"fnMeasure": function ( bRedraw )
  	{
  		if ( this.s.autoHeight )
  		{
  			this._fnCalcRowHeight();
  		}
  
  		var heights = this.s.heights;
  
  		heights.viewport = $(this.dom.scroller).height();
  		this.s.viewportRows = parseInt( heights.viewport / heights.row, 10 )+1;
  		this.s.dt._iDisplayLength = this.s.viewportRows * this.s.displayBuffer;
  
  		if ( bRedraw === undefined || bRedraw )
  		{
  			this.s.dt.oInstance.fnDraw();
  		}
  	},
  
  
  
  	/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
  	 * Private methods (they are of course public in JS, but recommended as private)
  	 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
  
  	/**
  	 * Initialisation for Scroller
  	 *  @returns {void}
  	 *  @private
  	 */
  	"_fnConstruct": function ()
  	{
  		var that = this;
  
  		/* Sanity check */
  		if ( !this.s.dt.oFeatures.bPaginate ) {
  			this.s.dt.oApi._fnLog( this.s.dt, 0, 'Pagination must be enabled for Scroller' );
  			return;
  		}
  
  		/* Insert a div element that we can use to force the DT scrolling container to
  		 * the height that would be required if the whole table was being displayed
  		 */
  		this.dom.force.style.position = "absolute";
  		this.dom.force.style.top = "0px";
  		this.dom.force.style.left = "0px";
  		this.dom.force.style.width = "1px";
  
  		this.dom.scroller = $('div.'+this.s.dt.oClasses.sScrollBody, this.s.dt.nTableWrapper)[0];
  		this.dom.scroller.appendChild( this.dom.force );
  		this.dom.scroller.style.position = "relative";
  
  		this.dom.table = $('>table', this.dom.scroller)[0];
  		this.dom.table.style.position = "absolute";
  		this.dom.table.style.top = "0px";
  		this.dom.table.style.left = "0px";
  
  		// Add class to 'announce' that we are a Scroller table
  		$(this.s.dt.nTableWrapper).addClass('DTS');
  
  		// Add a 'loading' indicator
  		if ( this.s.loadingIndicator )
  		{
  			this.dom.loader = $('<div class="DTS_Loading">'+this.s.dt.oLanguage.sLoadingRecords+'</div>')
  				.css('display', 'none');
  
  			$(this.dom.scroller.parentNode)
  				.css('position', 'relative')
  				.append( this.dom.loader );
  		}
  
  		/* Initial size calculations */
  		if ( this.s.heights.row && this.s.heights.row != 'auto' )
  		{
  			this.s.autoHeight = false;
  		}
  		this.fnMeasure( false );
  
  		/* Scrolling callback to see if a page change is needed - use a throttled
  		 * function for the save save callback so we aren't hitting it on every
  		 * scroll
  		 */
  		this.s.ingnoreScroll = true;
  		this.s.stateSaveThrottle = this.s.dt.oApi._fnThrottle( function () {
  			that.s.dt.oApi._fnSaveState( that.s.dt );
  		}, 500 );
  		$(this.dom.scroller).on( 'scroll.DTS', function (e) {
  			that._fnScroll.call( that );
  		} );
  
  		/* In iOS we catch the touchstart event in case the user tries to scroll
  		 * while the display is already scrolling
  		 */
  		$(this.dom.scroller).on('touchstart.DTS', function () {
  			that._fnScroll.call( that );
  		} );
  
  		/* Update the scroller when the DataTable is redrawn */
  		this.s.dt.aoDrawCallback.push( {
  			"fn": function () {
  				if ( that.s.dt.bInitialised ) {
  					that._fnDrawCallback.call( that );
  				}
  			},
  			"sName": "Scroller"
  		} );
  
  		/* On resize, update the information element, since the number of rows shown might change */
  		$(window).on( 'resize.DTS', function () {
  			that.fnMeasure( false );
  			that._fnInfo();
  		} );
  
  		/* Add a state saving parameter to the DT state saving so we can restore the exact
  		 * position of the scrolling
  		 */
  		var initialStateSave = true;
  		this.s.dt.oApi._fnCallbackReg( this.s.dt, 'aoStateSaveParams', function (oS, oData) {
  			/* Set iScroller to saved scroll position on initialization.
  			 */
  			if(initialStateSave && that.s.dt.oLoadedState){
  				oData.iScroller = that.s.dt.oLoadedState.iScroller;
  				oData.iScrollerTopRow = that.s.dt.oLoadedState.iScrollerTopRow;
  				initialStateSave = false;
  			} else {
  				oData.iScroller = that.dom.scroller.scrollTop;
  				oData.iScrollerTopRow = that.s.topRowFloat;
  			}
  		}, "Scroller_State" );
  
  		if ( this.s.dt.oLoadedState ) {
  			this.s.topRowFloat = this.s.dt.oLoadedState.iScrollerTopRow || 0;
  		}
  
  		/* Destructor */
  		this.s.dt.aoDestroyCallback.push( {
  			"sName": "Scroller",
  			"fn": function () {
  				$(window).off( 'resize.DTS' );
  				$(that.dom.scroller).off('touchstart.DTS scroll.DTS');
  				$(that.s.dt.nTableWrapper).removeClass('DTS');
  				$('div.DTS_Loading', that.dom.scroller.parentNode).remove();
  
  				that.dom.table.style.position = "";
  				that.dom.table.style.top = "";
  				that.dom.table.style.left = "";
  			}
  		} );
  	},
  
  
  	/**
  	 * Scrolling function - fired whenever the scrolling position is changed.
  	 * This method needs to use the stored values to see if the table should be
  	 * redrawn as we are moving towards the end of the information that is
  	 * currently drawn or not. If needed, then it will redraw the table based on
  	 * the new position.
  	 *  @returns {void}
  	 *  @private
  	 */
  	"_fnScroll": function ()
  	{
  		var
  			that = this,
  			heights = this.s.heights,
  			iScrollTop = this.dom.scroller.scrollTop,
  			iTopRow;
  
  		if ( this.s.skip ) {
  			return;
  		}
  
  		if ( this.s.ingnoreScroll ) {
  			return;
  		}
  
  		/* If the table has been sorted or filtered, then we use the redraw that
  		 * DataTables as done, rather than performing our own
  		 */
  		if ( this.s.dt.bFiltered || this.s.dt.bSorted ) {
  			this.s.lastScrollTop = 0;
  			return;
  		}
  
  		/* Update the table's information display for what is now in the viewport */
  		this._fnInfo();
  
  		/* We don't want to state save on every scroll event - that's heavy
  		 * handed, so use a timeout to update the state saving only when the
  		 * scrolling has finished
  		 */
  		clearTimeout( this.s.stateTO );
  		this.s.stateTO = setTimeout( function () {
  			that.s.dt.oApi._fnSaveState( that.s.dt );
  		}, 250 );
  
  		/* Check if the scroll point is outside the trigger boundary which would required
  		 * a DataTables redraw
  		 */
  		if ( iScrollTop < this.s.redrawTop || iScrollTop > this.s.redrawBottom ) {
  			var preRows = Math.ceil( ((this.s.displayBuffer-1)/2) * this.s.viewportRows );
  
  			if ( Math.abs( iScrollTop - this.s.lastScrollTop ) > heights.viewport || this.s.ani ) {
  				iTopRow = parseInt(this._domain( 'physicalToVirtual', iScrollTop ) / heights.row, 10) - preRows;
  				this.s.topRowFloat = (this._domain( 'physicalToVirtual', iScrollTop ) / heights.row);
  			}
  			else {
  				iTopRow = this.fnPixelsToRow( iScrollTop ) - preRows;
  				this.s.topRowFloat = this.fnPixelsToRow( iScrollTop, false );
  			}
  
  			if ( iTopRow <= 0 ) {
  				/* At the start of the table */
  				iTopRow = 0;
  			}
  			else if ( iTopRow + this.s.dt._iDisplayLength > this.s.dt.fnRecordsDisplay() ) {
  				/* At the end of the table */
  				iTopRow = this.s.dt.fnRecordsDisplay() - this.s.dt._iDisplayLength;
  				if ( iTopRow < 0 ) {
  					iTopRow = 0;
  				}
  			}
  			else if ( iTopRow % 2 !== 0 ) {
  				// For the row-striping classes (odd/even) we want only to start
  				// on evens otherwise the stripes will change between draws and
  				// look rubbish
  				iTopRow++;
  			}
  
  			if ( iTopRow != this.s.dt._iDisplayStart ) {
  				/* Cache the new table position for quick lookups */
  				this.s.tableTop = $(this.s.dt.nTable).offset().top;
  				this.s.tableBottom = $(this.s.dt.nTable).height() + this.s.tableTop;
  
  				var draw =  function () {
  					if ( that.s.scrollDrawReq === null ) {
  						that.s.scrollDrawReq = iScrollTop;
  					}
  
  					that.s.dt._iDisplayStart = iTopRow;
  					if ( that.s.dt.oApi._fnCalculateEnd ) { // Removed in 1.10
  						that.s.dt.oApi._fnCalculateEnd( that.s.dt );
  					}
  					that.s.dt.oApi._fnDraw( that.s.dt );
  				};
  
  				/* Do the DataTables redraw based on the calculated start point - note that when
  				 * using server-side processing we introduce a small delay to not DoS the server...
  				 */
  				if ( this.s.dt.oFeatures.bServerSide ) {
  					clearTimeout( this.s.drawTO );
  					this.s.drawTO = setTimeout( draw, this.s.serverWait );
  				}
  				else {
  					draw();
  				}
  
  				if ( this.dom.loader && ! this.s.loaderVisible ) {
  					this.dom.loader.css( 'display', 'block' );
  					this.s.loaderVisible = true;
  				}
  			}
  		}
  
  		this.s.lastScrollTop = iScrollTop;
  		this.s.stateSaveThrottle();
  	},
  
  
  	/**
  	 * Convert from one domain to another. The physical domain is the actual
  	 * pixel count on the screen, while the virtual is if we had browsers which
  	 * had scrolling containers of infinite height (i.e. the absolute value)
  	 *
  	 *  @param {string} dir Domain transform direction, `virtualToPhysical` or
  	 *    `physicalToVirtual` 
  	 *  @returns {number} Calculated transform
  	 *  @private
  	 */
  	_domain: function ( dir, val )
  	{
  		var heights = this.s.heights;
  		var coeff;
  
  		// If the virtual and physical height match, then we use a linear
  		// transform between the two, allowing the scrollbar to be linear
  		if ( heights.virtual === heights.scroll ) {
  			coeff = (heights.virtual-heights.viewport) / (heights.scroll-heights.viewport);
  
  			if ( dir === 'virtualToPhysical' ) {
  				return val / coeff;
  			}
  			else if ( dir === 'physicalToVirtual' ) {
  				return val * coeff;
  			}
  		}
  
  		// Otherwise, we want a non-linear scrollbar to take account of the
  		// redrawing regions at the start and end of the table, otherwise these
  		// can stutter badly - on large tables 30px (for example) scroll might
  		// be hundreds of rows, so the table would be redrawing every few px at
  		// the start and end. Use a simple quadratic to stop this. It does mean
  		// the scrollbar is non-linear, but with such massive data sets, the
  		// scrollbar is going to be a best guess anyway
  		var xMax = (heights.scroll - heights.viewport) / 2;
  		var yMax = (heights.virtual - heights.viewport) / 2;
  
  		coeff = yMax / ( xMax * xMax );
  
  		if ( dir === 'virtualToPhysical' ) {
  			if ( val < yMax ) {
  				return Math.pow(val / coeff, 0.5);
  			}
  			else {
  				val = (yMax*2) - val;
  				return val < 0 ?
  					heights.scroll :
  					(xMax*2) - Math.pow(val / coeff, 0.5);
  			}
  		}
  		else if ( dir === 'physicalToVirtual' ) {
  			if ( val < xMax ) {
  				return val * val * coeff;
  			}
  			else {
  				val = (xMax*2) - val;
  				return val < 0 ?
  					heights.virtual :
  					(yMax*2) - (val * val * coeff);
  			}
  		}
  	},
  
  
  	/**
  	 * Draw callback function which is fired when the DataTable is redrawn. The main function of
  	 * this method is to position the drawn table correctly the scrolling container for the rows
  	 * that is displays as a result of the scrolling position.
  	 *  @returns {void}
  	 *  @private
  	 */
  	"_fnDrawCallback": function ()
  	{
  		var
  			that = this,
  			heights = this.s.heights,
  			iScrollTop = this.dom.scroller.scrollTop,
  			iActualScrollTop = iScrollTop,
  			iScrollBottom = iScrollTop + heights.viewport,
  			iTableHeight = $(this.s.dt.nTable).height(),
  			displayStart = this.s.dt._iDisplayStart,
  			displayLen = this.s.dt._iDisplayLength,
  			displayEnd = this.s.dt.fnRecordsDisplay();
  
  		// Disable the scroll event listener while we are updating the DOM
  		this.s.skip = true;
  
  		// Resize the scroll forcing element
  		this._fnScrollForce();
  
  		// Reposition the scrolling for the updated virtual position if needed
  		if ( displayStart === 0 ) {
  			// Linear calculation at the top of the table
  			iScrollTop = this.s.topRowFloat * heights.row;
  		}
  		else if ( displayStart + displayLen >= displayEnd ) {
  			// Linear calculation that the bottom as well
  			iScrollTop = heights.scroll - ((displayEnd - this.s.topRowFloat) * heights.row);
  		}
  		else {
  			// Domain scaled in the middle
  			iScrollTop = this._domain( 'virtualToPhysical', this.s.topRowFloat * heights.row );
  		}
  
  		this.dom.scroller.scrollTop = iScrollTop;
  
  		// Store positional information so positional calculations can be based
  		// upon the current table draw position
  		this.s.baseScrollTop = iScrollTop;
  		this.s.baseRowTop = this.s.topRowFloat;
  
  		// Position the table in the virtual scroller
  		var tableTop = iScrollTop - ((this.s.topRowFloat - displayStart) * heights.row);
  		if ( displayStart === 0 ) {
  			tableTop = 0;
  		}
  		else if ( displayStart + displayLen >= displayEnd ) {
  			tableTop = heights.scroll - iTableHeight;
  		}
  
  		this.dom.table.style.top = tableTop+'px';
  
  		/* Cache some information for the scroller */
  		this.s.tableTop = tableTop;
  		this.s.tableBottom = iTableHeight + this.s.tableTop;
  
  		// Calculate the boundaries for where a redraw will be triggered by the
  		// scroll event listener
  		var boundaryPx = (iScrollTop - this.s.tableTop) * this.s.boundaryScale;
  		this.s.redrawTop = iScrollTop - boundaryPx;
  		this.s.redrawBottom = iScrollTop + boundaryPx;
  
  		this.s.skip = false;
  
  		// Restore the scrolling position that was saved by DataTable's state
  		// saving Note that this is done on the second draw when data is Ajax
  		// sourced, and the first draw when DOM soured
  		if ( this.s.dt.oFeatures.bStateSave && this.s.dt.oLoadedState !== null &&
  			 typeof this.s.dt.oLoadedState.iScroller != 'undefined' )
  		{
  			// A quirk of DataTables is that the draw callback will occur on an
  			// empty set if Ajax sourced, but not if server-side processing.
  			var ajaxSourced = (this.s.dt.sAjaxSource || that.s.dt.ajax) && ! this.s.dt.oFeatures.bServerSide ?
  				true :
  				false;
  
  			if ( ( ajaxSourced && this.s.dt.iDraw == 2) ||
  			     (!ajaxSourced && this.s.dt.iDraw == 1) )
  			{
  				setTimeout( function () {
  					$(that.dom.scroller).scrollTop( that.s.dt.oLoadedState.iScroller );
  					that.s.redrawTop = that.s.dt.oLoadedState.iScroller - (heights.viewport/2);
  
  					// In order to prevent layout thrashing we need another
  					// small delay
  					setTimeout( function () {
  						that.s.ingnoreScroll = false;
  					}, 0 );
  				}, 0 );
  			}
  		}
  		else {
  			that.s.ingnoreScroll = false;
  		}
  
  		// Because of the order of the DT callbacks, the info update will
  		// take precedence over the one we want here. So a 'thread' break is
  		// needed
  		setTimeout( function () {
  			that._fnInfo.call( that );
  		}, 0 );
  
  		// Hide the loading indicator
  		if ( this.dom.loader && this.s.loaderVisible ) {
  			this.dom.loader.css( 'display', 'none' );
  			this.s.loaderVisible = false;
  		}
  	},
  
  
  	/**
  	 * Force the scrolling container to have height beyond that of just the
  	 * table that has been drawn so the user can scroll the whole data set.
  	 *
  	 * Note that if the calculated required scrolling height exceeds a maximum
  	 * value (1 million pixels - hard-coded) the forcing element will be set
  	 * only to that maximum value and virtual / physical domain transforms will
  	 * be used to allow Scroller to display tables of any number of records.
  	 *  @returns {void}
  	 *  @private
  	 */
  	_fnScrollForce: function ()
  	{
  		var heights = this.s.heights;
  		var max = 1000000;
  
  		heights.virtual = heights.row * this.s.dt.fnRecordsDisplay();
  		heights.scroll = heights.virtual;
  
  		if ( heights.scroll > max ) {
  			heights.scroll = max;
  		}
  
  		this.dom.force.style.height = heights.scroll+"px";
  	},
  
  
  	/**
  	 * Automatic calculation of table row height. This is just a little tricky here as using
  	 * initialisation DataTables has tale the table out of the document, so we need to create
  	 * a new table and insert it into the document, calculate the row height and then whip the
  	 * table out.
  	 *  @returns {void}
  	 *  @private
  	 */
  	"_fnCalcRowHeight": function ()
  	{
  		var dt = this.s.dt;
  		var origTable = dt.nTable;
  		var nTable = origTable.cloneNode( false );
  		var tbody = $('<tbody/>').appendTo( nTable );
  		var container = $(
  			'<div class="'+dt.oClasses.sWrapper+' DTS">'+
  				'<div class="'+dt.oClasses.sScrollWrapper+'">'+
  					'<div class="'+dt.oClasses.sScrollBody+'"></div>'+
  				'</div>'+
  			'</div>'
  		);
  
  		// Want 3 rows in the sizing table so :first-child and :last-child
  		// CSS styles don't come into play - take the size of the middle row
  		$('tbody tr:lt(4)', origTable).clone().appendTo( tbody );
  		while( $('tr', tbody).length < 3 ) {
  			tbody.append( '<tr><td>&nbsp;</td></tr>' );
  		}
  
  		$('div.'+dt.oClasses.sScrollBody, container).append( nTable );
  
  		var appendTo;
  		if (dt._bInitComplete) {
  			appendTo = origTable.parentNode;
  		} else {
  			if (!this.s.dt.nHolding) {
  				this.s.dt.nHolding = $( '<div></div>' ).insertBefore( this.s.dt.nTable );
  			}
  			appendTo = this.s.dt.nHolding;
  		}
  
  		container.appendTo( appendTo );
  		this.s.heights.row = $('tr', tbody).eq(1).outerHeight();
  		container.remove();
  	},
  
  
  	/**
  	 * Update any information elements that are controlled by the DataTable based on the scrolling
  	 * viewport and what rows are visible in it. This function basically acts in the same way as
  	 * _fnUpdateInfo in DataTables, and effectively replaces that function.
  	 *  @returns {void}
  	 *  @private
  	 */
  	"_fnInfo": function ()
  	{
  		if ( !this.s.dt.oFeatures.bInfo )
  		{
  			return;
  		}
  
  		var
  			dt = this.s.dt,
  			language = dt.oLanguage,
  			iScrollTop = this.dom.scroller.scrollTop,
  			iStart = Math.floor( this.fnPixelsToRow(iScrollTop, false, this.s.ani)+1 ),
  			iMax = dt.fnRecordsTotal(),
  			iTotal = dt.fnRecordsDisplay(),
  			iPossibleEnd = Math.ceil( this.fnPixelsToRow(iScrollTop+this.s.heights.viewport, false, this.s.ani) ),
  			iEnd = iTotal < iPossibleEnd ? iTotal : iPossibleEnd,
  			sStart = dt.fnFormatNumber( iStart ),
  			sEnd = dt.fnFormatNumber( iEnd ),
  			sMax = dt.fnFormatNumber( iMax ),
  			sTotal = dt.fnFormatNumber( iTotal ),
  			sOut;
  
  		if ( dt.fnRecordsDisplay() === 0 &&
  			   dt.fnRecordsDisplay() == dt.fnRecordsTotal() )
  		{
  			/* Empty record set */
  			sOut = language.sInfoEmpty+ language.sInfoPostFix;
  		}
  		else if ( dt.fnRecordsDisplay() === 0 )
  		{
  			/* Empty record set after filtering */
  			sOut = language.sInfoEmpty +' '+
  				language.sInfoFiltered.replace('_MAX_', sMax)+
  					language.sInfoPostFix;
  		}
  		else if ( dt.fnRecordsDisplay() == dt.fnRecordsTotal() )
  		{
  			/* Normal record set */
  			sOut = language.sInfo.
  					replace('_START_', sStart).
  					replace('_END_',   sEnd).
  					replace('_MAX_',   sMax).
  					replace('_TOTAL_', sTotal)+
  				language.sInfoPostFix;
  		}
  		else
  		{
  			/* Record set after filtering */
  			sOut = language.sInfo.
  					replace('_START_', sStart).
  					replace('_END_',   sEnd).
  					replace('_MAX_',   sMax).
  					replace('_TOTAL_', sTotal) +' '+
  				language.sInfoFiltered.replace(
  					'_MAX_',
  					dt.fnFormatNumber(dt.fnRecordsTotal())
  				)+
  				language.sInfoPostFix;
  		}
  
  		var callback = language.fnInfoCallback;
  		if ( callback ) {
  			sOut = callback.call( dt.oInstance,
  				dt, iStart, iEnd, iMax, iTotal, sOut
  			);
  		}
  
  		var n = dt.aanFeatures.i;
  		if ( typeof n != 'undefined' )
  		{
  			for ( var i=0, iLen=n.length ; i<iLen ; i++ )
  			{
  				$(n[i]).html( sOut );
  			}
  		}
  	}
  };
  
  
  
  /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
   * Statics
   * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
  
  
  /**
   * Scroller default settings for initialisation
   *  @namespace
   *  @name Scroller.defaults
   *  @static
   */
  Scroller.defaults = /** @lends Scroller.defaults */{
  	/**
  	 * Indicate if Scroller show show trace information on the console or not. This can be
  	 * useful when debugging Scroller or if just curious as to what it is doing, but should
  	 * be turned off for production.
  	 *  @type     bool
  	 *  @default  false
  	 *  @static
  	 *  @example
  	 *    var oTable = $('#example').dataTable( {
  	 *        "sScrollY": "200px",
  	 *        "sDom": "frtiS",
  	 *        "bDeferRender": true,
  	 *        "oScroller": {
  	 *          "trace": true
  	 *        }
  	 *    } );
  	 */
  	"trace": false,
  
  	/**
  	 * Scroller will attempt to automatically calculate the height of rows for it's internal
  	 * calculations. However the height that is used can be overridden using this parameter.
  	 *  @type     int|string
  	 *  @default  auto
  	 *  @static
  	 *  @example
  	 *    var oTable = $('#example').dataTable( {
  	 *        "sScrollY": "200px",
  	 *        "sDom": "frtiS",
  	 *        "bDeferRender": true,
  	 *        "oScroller": {
  	 *          "rowHeight": 30
  	 *        }
  	 *    } );
  	 */
  	"rowHeight": "auto",
  
  	/**
  	 * When using server-side processing, Scroller will wait a small amount of time to allow
  	 * the scrolling to finish before requesting more data from the server. This prevents
  	 * you from DoSing your own server! The wait time can be configured by this parameter.
  	 *  @type     int
  	 *  @default  200
  	 *  @static
  	 *  @example
  	 *    var oTable = $('#example').dataTable( {
  	 *        "sScrollY": "200px",
  	 *        "sDom": "frtiS",
  	 *        "bDeferRender": true,
  	 *        "oScroller": {
  	 *          "serverWait": 100
  	 *        }
  	 *    } );
  	 */
  	"serverWait": 200,
  
  	/**
  	 * The display buffer is what Scroller uses to calculate how many rows it should pre-fetch
  	 * for scrolling. Scroller automatically adjusts DataTables' display length to pre-fetch
  	 * rows that will be shown in "near scrolling" (i.e. just beyond the current display area).
  	 * The value is based upon the number of rows that can be displayed in the viewport (i.e.
  	 * a value of 1), and will apply the display range to records before before and after the
  	 * current viewport - i.e. a factor of 3 will allow Scroller to pre-fetch 1 viewport's worth
  	 * of rows before the current viewport, the current viewport's rows and 1 viewport's worth
  	 * of rows after the current viewport. Adjusting this value can be useful for ensuring
  	 * smooth scrolling based on your data set.
  	 *  @type     int
  	 *  @default  7
  	 *  @static
  	 *  @example
  	 *    var oTable = $('#example').dataTable( {
  	 *        "sScrollY": "200px",
  	 *        "sDom": "frtiS",
  	 *        "bDeferRender": true,
  	 *        "oScroller": {
  	 *          "displayBuffer": 10
  	 *        }
  	 *    } );
  	 */
  	"displayBuffer": 9,
  
  	/**
  	 * Scroller uses the boundary scaling factor to decide when to redraw the table - which it
  	 * typically does before you reach the end of the currently loaded data set (in order to
  	 * allow the data to look continuous to a user scrolling through the data). If given as 0
  	 * then the table will be redrawn whenever the viewport is scrolled, while 1 would not
  	 * redraw the table until the currently loaded data has all been shown. You will want
  	 * something in the middle - the default factor of 0.5 is usually suitable.
  	 *  @type     float
  	 *  @default  0.5
  	 *  @static
  	 *  @example
  	 *    var oTable = $('#example').dataTable( {
  	 *        "sScrollY": "200px",
  	 *        "sDom": "frtiS",
  	 *        "bDeferRender": true,
  	 *        "oScroller": {
  	 *          "boundaryScale": 0.75
  	 *        }
  	 *    } );
  	 */
  	"boundaryScale": 0.5,
  
  	/**
  	 * Show (or not) the loading element in the background of the table. Note that you should
  	 * include the dataTables.scroller.css file for this to be displayed correctly.
  	 *  @type     boolean
  	 *  @default  false
  	 *  @static
  	 *  @example
  	 *    var oTable = $('#example').dataTable( {
  	 *        "sScrollY": "200px",
  	 *        "sDom": "frtiS",
  	 *        "bDeferRender": true,
  	 *        "oScroller": {
  	 *          "loadingIndicator": true
  	 *        }
  	 *    } );
  	 */
  	"loadingIndicator": false
  };
  
  Scroller.oDefaults = Scroller.defaults;
  
  
  
  /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
   * Constants
   * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
  
  /**
   * Scroller version
   *  @type      String
   *  @default   See code
   *  @name      Scroller.version
   *  @static
   */
  Scroller.version = "1.2.2";
  
  
  
  /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
   * Initialisation
   * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
  
  /*
   * Register a new feature with DataTables
   */
  if ( typeof $.fn.dataTable == "function" &&
       typeof $.fn.dataTableExt.fnVersionCheck == "function" &&
       $.fn.dataTableExt.fnVersionCheck('1.9.0') )
  {
  	$.fn.dataTableExt.aoFeatures.push( {
  		"fnInit": function( oDTSettings ) {
  			var init = oDTSettings.oInit;
  			var opts = init.scroller || init.oScroller || {};
  			var oScroller = new Scroller( oDTSettings, opts );
  			return oScroller.dom.wrapper;
  		},
  		"cFeature": "S",
  		"sFeature": "Scroller"
  	} );
  }
  else
  {
  	alert( "Warning: Scroller requires DataTables 1.9.0 or greater - www.datatables.net/download");
  }
  
  
  // Attach Scroller to DataTables so it can be accessed as an 'extra'
  $.fn.dataTable.Scroller = Scroller;
  $.fn.DataTable.Scroller = Scroller;
  
  
  // DataTables 1.10 API method aliases
  if ( $.fn.dataTable.Api ) {
  	var Api = $.fn.dataTable.Api;
  
  	Api.register( 'scroller()', function () {
  		return this;
  	} );
  
  	Api.register( 'scroller().rowToPixels()', function ( rowIdx, intParse, virtual ) {
  		var ctx = this.context;
  
  		if ( ctx.length && ctx[0].oScroller ) {
  			return ctx[0].oScroller.fnRowToPixels( rowIdx, intParse, virtual );
  		}
  		// undefined
  	} );
  
  	Api.register( 'scroller().pixelsToRow()', function ( pixels, intParse, virtual ) {
  		var ctx = this.context;
  
  		if ( ctx.length && ctx[0].oScroller ) {
  			return ctx[0].oScroller.fnPixelsToRow( pixels, intParse, virtual );
  		}
  		// undefined
  	} );
  
  	Api.register( 'scroller().scrollToRow()', function ( row, ani ) {
  		this.iterator( 'table', function ( ctx ) {
  			if ( ctx.oScroller ) {
  				ctx.oScroller.fnScrollToRow( row, ani );
  			}
  		} );
  
  		return this;
  	} );
  
  	Api.register( 'scroller().measure()', function ( redraw ) {
  		this.iterator( 'table', function ( ctx ) {
  			if ( ctx.oScroller ) {
  				ctx.oScroller.fnMeasure( redraw );
  			}
  		} );
  
  		return this;
  	} );
  }
  
  
  return Scroller;
  }; // /factory
  
  
  // Define as an AMD module if possible
  if ( typeof define === 'function' && define.amd ) {
  	define( ['jquery', 'datatables'], factory );
  }
  else if ( typeof exports === 'object' ) {
      // Node/CommonJS
      factory( require('jquery'), require('datatables') );
  }
  else if ( jQuery && !jQuery.fn.dataTable.Scroller ) {
  	// Otherwise simply initialise as normal, stopping multiple evaluation
  	factory( jQuery, jQuery.fn.dataTable );
  }
  
  
  })(window, document);