Question

I want to get 64 bit hash code of given string. How can i do that with fastest way ?
There is a ready method for get 32 bit hash code but i need 64 bit.

I am looking for only integer hashing. Not md5.

Thank you very much.

C# 4.0

Answer 1

This code is from Code Project Article – Convert String to 64bit Integer

 static Int64 GetInt64HashCode(string strText)
{
    Int64 hashCode = 0;
    if (!string.IsNullOrEmpty(strText))
    {
        //Unicode Encode Covering all characterset
          byte[] byteContents = Encoding.Unicode.GetBytes(strText);
        System.Security.Cryptography.SHA256 hash = 
        new System.Security.Cryptography.SHA256CryptoServiceProvider();
        byte[] hashText = hash.ComputeHash(byteContents);
        //32Byte hashText separate
        //hashCodeStart = 0~7  8Byte
        //hashCodeMedium = 8~23  8Byte
        //hashCodeEnd = 24~31  8Byte
        //and Fold
        Int64 hashCodeStart = BitConverter.ToInt64(hashText, 0);
        Int64 hashCodeMedium = BitConverter.ToInt64(hashText, 8);
        Int64 hashCodeEnd = BitConverter.ToInt64(hashText, 24);
        hashCode = hashCodeStart ^ hashCodeMedium ^ hashCodeEnd;
    }
    return (hashCode);
}