Comments on: Base36 Encoder/Decoder in C#

By: mstum

mstum — Fri, 25 Nov 2011 23:56:31 +0000

I've just updated the Library on GitHub to add a BigInteger Version. This should ensure compatibility with large numbers in situations where a long overflows.

By: mstum

mstum — Fri, 25 Nov 2011 23:54:22 +0000

Yes, you will need to ensure Integer Division. In C#, the / operator is overloaded and performs integer division if both operands are integers, otherwise it does double division.

By: Mika Tähtinen

Mika Tähtinen — Fri, 25 Nov 2011 12:51:39 +0000

I ran into some problems converting this code to Visual Basic with .NET Framework 3.5. It seems that division with "/" uses double precision. The solution is to force integer division using "\=" instead of "/=".

By: kk

kk — Thu, 03 Nov 2011 20:41:50 +0000

nwisoft's syntax works fine and is C#, the problem is when he pasted it in the syntax got changed.
the syntax for List should be List followed by less then followed by "char" followed by greater then. If you change the syntax it works fine.

By: mstum

mstum — Fri, 22 Jul 2011 03:23:04 +0000

That's indeed true, input should have 12 characters or less. This is more intended for database IDs that should turn into URLs. If you are on .net 4, this method can be made a lot more robust through the use of System.Numerics.BigInteger.

By: Doug

Doug — Fri, 22 Jul 2011 03:05:10 +0000

Math.Pow(36, index) returns a double that may cause errors at very large numbers when its casted to the long.

By: Jeff O

Jeff O — Sun, 17 Jul 2011 11:31:26 +0000

@Jérémie:

Is there any (even slight) chance that this line on your computer may have some localized characters like those that appear in your name?

private const string CHARACTERS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

By: mstum

mstum — Tue, 29 Mar 2011 23:18:12 +0000

@Jérémie That's strange, it works for me on both .net 3.5 and 4.0:

long input = 5481594952936519619L;
var encoded = Base36.Encode(input);
Console.WriteLine(encoded);
var decoded = Base36.Decode(encoded);
Console.WriteLine(decoded);
Console.WriteLine(input == decoded);

Output is:
15n9z8l3au4eb
5481594952936519619
True

How are you using it? I have tried both the above code and the slightly revised version on GitHub with the same result.

By: Jérémie R

Jérémie R — Tue, 29 Mar 2011 16:07:27 +0000

I tried to use this code but it did not work fine.
Try to convert this number : 5481594952936519619
and when I revert I got : 5613318295101298955
as you see there is a problem there

By: Dani Rubio

Dani Rubio — Wed, 02 Mar 2011 03:03:02 +0000

@nwisoft
What languaje is that, not csharp guess.. i'm getting mad with your "List" utilization...
I'll better look for the publisher's one...

By: Not Rocket Science » Misc Utilities Library

Not Rocket Science » Misc Utilities Library — Mon, 27 Dec 2010 09:12:56 +0000

[...] Base36 Encoder/Decoder in C# [...]

By: synhershko

synhershko — Thu, 18 Mar 2010 19:00:53 +0000

Wikipedia had a C# sample, which wasn't working. I updated the code there to use your methods instead, which are working great.

By: Kofi Sarfo

Kofi Sarfo — Thu, 19 Mar 2009 16:20:08 +0000

Thanks so much for having posted this. It saved me however long I'd have been fooling around rolling my own implementation

Kofi

By: nwisoft

nwisoft — Thu, 06 Nov 2008 10:15:50 +0000

//Thank you for this good sample.
//You just need to Trim start zeros to avoid wrong result : "0H" must return 17.

private const string CHARACTERS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

static public long Decode(string value)
{
List database = new List(CHARACTERS);
List tmp = new List(value.ToUpper().TrimStart(new char[] { '0' }).ToCharArray());
tmp.Reverse();

long number = 0;
int index = 0;
foreach (char character in tmp)
{
number += database.IndexOf(character) * (long)Math.Pow(36, index);
index++;
}

return number;
}

static private string Encode(long number)
{
List database = new List(CHARACTERS);
List value = new List();
long tmp = number;

while (tmp != 0)
{
value.Add(database[Convert.ToInt32(tmp % 36)]);
tmp /= 36;
}

value.Reverse();
return new string(value.ToArray());
}