jimRound

//
// ------------MYSQL-STYLE FLOATING POINT CONVERTER-------
// Jim Reilly
// Use to convert a floating point value to the precision of another floating point value
//
// Usage: var ouput = jimRound(pattern[string], propval[float])
// return: float
//
// Examples
// ------------------------
//
// jimRound(1, 555.55) = 556
// jimRound(11, 555.55) = 556
// jimRound(111, 555.55) = 556
// jimRound(10, 555.55) = 560
// jimRound(10., 555.55) = 560
// jimRound(10.1, 555.55) = 555.6
// jimRound(10.11, 555.55) = 555.55
// jimRound(1000.11, 555.55) = 555.55
// jimRound(1000.1111, 555.55) = 555.5500
// jimRound(1000, 555.55) = 1000
// jimRound(10000, 555.55) = 0
// jimRound(10001, 555.55) = 556


var jimRound = function(pattern, propval)
{
    var dSplit = pattern.toString().split(".");
    var wNum = dSplit[0];
    var w = dSplit[0].toString().split("");

    if (typeof dSplit[1] === 'undefined')
    {
        var d = new Array();
    }
    else
    {
        var d = dSplit[1].toString().split("");

    }
    var wRound = 0;
    var foundPrec_N = false;
    for (var i = w.length - 1; i > -1; i--)
    {
        if ((w[i] == '0') && (!foundPrec_N))
        {
            wRound++;
        }
        else
        {
            foundPrec_N = true;
        }
    }

    var wAll = w.length;

    if (d.length > 0)
    {
        var wSigs = wAll;
    }
    else
    {
        var wSigs = wAll - wRound;
    }

    var dPrec = d.length;

    if (d.length > 0)
    {
        var propvalArray = propval.toString().split(".");
        if (typeof propvalArray[1] === 'undefined')
        {
            var pPrec = "0";
        }
        else
        {
            var pPrec = propvalArray[1].length;
            var propDec = propvalArray[1];
        }
        var trailZeros = 0;
        var foundNonZero = false;
        var trailZeroString = '';

        var propDecArray = propDec.split("");
        for (var z = 0; z < propDecArray.length; z++)
        {

            if ((propDecArray[z] == '0') && (!foundNonZero))
            {

                trailZeros++;
                trailZeroString += '0';
            }
            else
            {
                foundNonZero = true;
            }
        }
        var roundDecLength = propDecArray.length - trailZeros;
        var trimmedDec = propDec.substr(trailZeros, roundDecLength);
        var numTemplateDecs = d.length;

        var decCorrect = Math.pow(10, propDecArray.length - numTemplateDecs)

        if (pPrec >= dPrec)
        {
            var reduce = Math.pow(10, (pPrec - dPrec));
            var reducedValue = parseFloat(propDec) / reduce;
            var roundDec = Math.round(reducedValue);
            var roundDecString = '.' + roundDec;
        }
        else
        {
            var extraZeros = dPrec - pPrec;
            var extraZeroString = '';
            for (var e = 0; e < extraZeros; e++)
            {
                extraZeroString += '0';
            }

            var roundDecString = '.' + propDec + extraZeroString.toString();

        }

        if (trailZeroString == '')
        {

            var output = propvalArray[0] + roundDecString;

        }
        else
        {

            if (d.length > 1)
            {
                var output = propvalArray[0] + '.' + trailZeroString.toString() + roundDec;
            }
            else
            {
                var output = propvalArray[0] + '.' + roundDec;
            }
        }

    }
    else
    {
        var DigitRound = wAll - wSigs;
        var totalDivide = Math.pow(10, DigitRound);
        var output = Math.round(propval / totalDivide) * Math.pow(10, (wAll - wSigs));
    }
    return (output);
}