Converting a users Steam ID from console to the 64bit version in C#

Question

I am creating an application where someone can paste a user's steam ID in a search box. In most cases it is going to be the steam ID from the in-game console which looks like: STEAM_1:0:12345678. I need to take this and convert it to the 64bit version in order to make requests to the Steam API for that user.

There is a lot of useful information here: https://developer.valvesoftware.com/wiki/SteamID

But I still can't figure out how to do the conversion to 64bit.

Use binary shift operators like `<<` and/or `>>` to shift the individual ID components to the correct bit positions, and the binary OR operator `|` to combine the shifted components. The documentation can tell you more about those operators. (https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/operators/) — , Mar 06 '19 at 18:00
@Rup, correct. You are so correct. Of course i meant the binary OR `|` (hastily editing my comment before anybody else spots this ludicrous mistake...) ;-) — , Mar 06 '19 at 18:02

Joel Coehoorn · Accepted Answer · 2019-03-06T20:33:31.367

5

It's your lucky day; I wrote the whole thing for you. Normally we expect to see some effort in your own implementation first, even if it's rough, and we help you fix issues with that code.

public static Int64 TranslateSteamID(string steamID)
{
    Int64 result = 0;

    var template = new Regex(@"STEAM_(\d):([0-1]):(\d+)");
    var matches = template.Matches(steamID);
    if (matches.Count <= 0) return 0;
    var parts = matches[0].Groups;
    if (parts.Count != 4) return 0;

    Int64 x = Int64.Parse(parts[1].Value) << 24;
    Int64 y = Int64.Parse(parts[2].Value);
    Int64 z = Int64.Parse(parts[3].Value) << 1;

    result =  ((1 + (1 << 20) + x) << 32) | (y + z);        
    return result;
}

It at least works for the sample value on the linked page. You can try it here:

https://dotnetfiddle.net/Ejrqcw

edited Mar 06 '19 at 20:33

answered Mar 06 '19 at 18:44

Joel Coehoorn

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Thank you so much for this. Is converting back the other direction complicated? – Blake Rivell Mar 06 '19 at 21:44
1

Do these things in reverse. – Joel Coehoorn Mar 06 '19 at 21:50
one last question. In the link I posted there is a section titled: Steam ID as a Steam Community ID. They say to simply do W=Z*2+V+Y. Does this mean anything? – Blake Rivell Mar 06 '19 at 22:43
It means some, but I'm not sure where "v" comes from. The z*2 part works because multiplying by two is the same as shifting bits one position. – Joel Coehoorn Mar 06 '19 at 23:05
Yeah they say you get V from the table above the section which means nothing I guess. It could be number 1-9 in most cases number 1 but that can't be right as far as the formula goes. – Blake Rivell Mar 06 '19 at 23:13
hey after further research I figured out what V is and posted my version of the answer. Take a look at it and tell me what you think. – Blake Rivell Mar 07 '19 at 21:26

Blake Rivell · Answer 2 · 2019-03-07T21:35:44.533

After further research and trying to follow the exact Steam Id documentation here is the solution I came up with:

STEAM_X:Y:Z

The formula from the documentation: W=Z*2+V+Y

Using STEAM_1:1:66138017 as an example:

var steamId = "STEAM_1:1:66138017";
var match = Regex.Match(steamId, @"^STEAM_[0-5]:[01]:\d+$", RegexOptions.IgnoreCase);

if (!match.Success)
{
    return null;
}

// Split it into 3 parts using ":"
var split = steamId.Split(":");

var v = 76561197960265728;
var y = long.Parse(split[1]);
var z = long.Parse(split[2]);

var w = (z * 2) + v + y;

return w;

Explanation on where V came from:

In the documentation there is a table that lists all of the Steam Account types. The most common account type is Individual. The table shows that the hex for this is 0x0110000100000000. Using a hex to decimal converter I ended up with 76561197960265728.

You can write 0x0110000100000000 in your code, and IMO that's clearer than the decimal number. — Rup, Mar 08 '19 at 09:50

Converting a users Steam ID from console to the 64bit version in C#

2 Answers2