What's the best way to create a short hash, similar to what tiny Url does?

0

Issue

I’m currently using MD5 hashes but I would like to find something that will create a shorter hash that uses just [a-z][A-Z][0-9]. It only needs to be around 5-10 characters long.

Is there something out there that already does this?

Update 1:

I like the CRC32 hash. Is there a clean way of calculating it in .NET?

Update 2:

I’m using the CRC32 function from the link Joe provided. How can I convert the uInt into the characters defined above?

Solution

.NET string object has a GetHashCode() function. It returns an integer.
Convert it into a hex and then to an 8 characters long string.

Like so:

string hashCode = String.Format("{0:X}", sourceString.GetHashCode());

More on that: http://msdn.microsoft.com/en-us/library/system.string.gethashcode.aspx

UPDATE: Added the remarks from the link above to this answer:

The behavior of GetHashCode is dependent on its implementation, which
might change from one version of the common language runtime to
another. A reason why this might happen is to improve the performance
of GetHashCode.

If two string objects are equal, the GetHashCode method returns
identical values. However, there is not a unique hash code value for
each unique string value. Different strings can return the same hash
code.

Notes to Callers

The value returned by GetHashCode is platform-dependent. It differs on
the 32-bit and 64-bit versions of the .NET Framework.

Answered By – Vlad

This Answer collected from stackoverflow, is licensed under cc by-sa 2.5 , cc by-sa 3.0 and cc by-sa 4.0

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