Question

I am in the process of “re-developing” an application that was started in PHP sometime ago. The developer involved has left the company quite awhile ago and all efforts to contact him have fallen to the wayside.

I do not need help converting the whole site as its quite a simple application. However we are integrating with an API service (who’s documentation is rather poor) and I am having problems understanding their dateTime strings.

Here is the excerpt (the only bit) on how they use there datetimes.

”
The datetime is expressed as a number derived from an algorithm using the day month year hour minutes and seconds as follows:

date=year<<20; 
date|=month<<16; 
date|=day<<11; 
date|=hour<<6;
date|=minute; 

To unpack the date from a given number is as follows:

year=(date & 0xfff00000) >> 20;
month=(date & 0x000f0000) >> 16;
day=(date & 0x0000f800) >> 11; 
hour=(date & 0x000007c0) >> 6; 
minute=(date & 0x0000003f);

“

Now comes my question. The developer (and this is a working example) has created the following PHP Function that converts a timestamp to the required format. I am unsure if bitwise timestamp is a “generic algorithm”.

I have tried looking around and couldnt find anything.

/**
 * Converts a unixtime stamp to a bitwise timestamp
 * 
 * @access public
 * @param mixed $unixtime
 * @return void
 */
function convert_unixtime_to_bitwise($unixtime)
{
    /*$year = date('Y', $unixtime);
    $month = date('m', $unixtime);
    $day = date('j', $unixtime);
    $hour = date('G', $unixtime);
    $min = date('i', $unixtime);*/

        $year = date('Y', $unixtime);
    $month = date('m', $unixtime);
    $day = date('j', $unixtime);
    $hour = date('G', $unixtime);
    $min = date('i', $unixtime);

    $date = 0;
    $date = $year << 20;
    $date |= $month << 16;
    $date |= $day <<11;
    $date |= $hour <<6;
    $date |= $min;

    return $date;
}

/**
 * Converts a bitwise datestamp to a standard unixtime stamp
 * 
 * @access public
 * @param mixed $timestamp
 * @return void
 */
function convert_bitwise_to_unixtime($timestamp)
{
    $dateline = array();

    $dateline['year'] = ($timestamp & 0xfff00000) >> 20;
    $dateline['month'] =($timestamp & 0x000f0000) >> 16;
    $dateline['day'] = ($timestamp & 0x0000f800) >> 11;
    $dateline['hour'] = ($timestamp & 0x000007c0) >> 6;
    $dateline['min'] = ($timestamp & 0x0000003f);

    return mktime($dateline['hour'], $dateline['min'], 0, $dateline['month'], $dateline['day'], $dateline['year']);
}

Can anyone help me convert this to .Net in the simplest of fashions. Ideally i would write an extension method to the datetime object to return a “bitwise?” object and an extension methods to turn a bitwise timestamp into a datetime timestamp. I would ideally end up with something similar to bel..

public static class Extensions
{
    public static BitWiseDateStamp ToBitWiseDateStamp(this DateTime timeStamp)
    {
        return BitWiseDateStamp.New(timeStamp);
    }

}

public class BitWiseDateStamp
{
    private string _value;

    public string Value
    {
        get { return _value; }
        set { _value = value; }
    }


    public static BitWiseDateStamp New(DateTime date)
    {
        var b = new BitWiseDateStamp();

        var bitWiseStr = string.Empty; 

        //= Convert to bitwise string format...

        b.Value = bitWiseStr;
        return b;
    }

    public override string ToString()
    {
        return this._value;
    }

    public DateTime ToDateTime()
    {
        var date = DateTime.MinValue;
        var dateStr = string.Empty;

        //== Convert bitwise string to date string respresenation

        DateTime.TryParse(dateStr, out date);
        return date;
    }
}

I really appreciate any help anyone can provide.

Cheers,

Nico

Answer 1

Perhaps I’m missing something, but won’t this do?

public class BitwiseDateStamp
{
    private readonly int _value;

    public BitwiseDateStamp(DateTime dt)
    {
        this._value = dt.Year << 20;
        this._value |= dt.Month << 16;
        this._value |= dt.Day << 11;
        this._value |= dt.Hour << 6;
        this._value |= dt.Minute;
    }

    public BitwiseDateStamp() : this(DateTime.Now)
    {   
    }

    public DateTime ToDateTime()
    {
        int year = this._value >> 20;
        int month = (this._value & 0x000f0000) >> 16;
        int day = (this._value & 0x0000f800) >> 11;
        int hour = (this._value & 0x000007c0) >> 6;
        int minute = this._value & 0x0000003f;

        return new DateTime(year, month, day, hour, minute, 0);
    }

    public override string ToString()
    {
        return this._value.ToString();
    }
}

and

public static class DateTimeExtensions
{
    public static BitwiseDateStamp ToBitwiseDateStamp(this DateTime dt)
    {
        return new BitwiseDateStamp(dt);
    }
}