WwiseHash.cs

//This code is released into the public domain.

using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;
using System.Globalization;

class WwiseHash
{
	///<summary>Generates ShortID values for objects such as Actions and Sounds.</summary>
	public static uint HashGUID(string ID)
	{
		Regex alphanum = new Regex("[^0-9A-Za-z]");
		string filtered = alphanum.Replace(ID, "");
		List<byte> guidBytes = new List<byte>();
		int[] byteOrder = { 3, 2, 1, 0, 5, 4, 7, 6, 8, 9, 10, 11, 12, 13, 14, 15 }; //Mixed-endian order
		for (int i = 0; i < byteOrder.Length; i++) {
			guidBytes.Add(
				byte.Parse(
					filtered.Substring(byteOrder[i] * 2, 2), 
					NumberStyles.HexNumber,
					CultureInfo.InvariantCulture
			));
		}
		return FnvHash(guidBytes.ToArray(), false);
	}

	///<summary>Generates ShortID values for Events, SoundBanks and GameSyncs.
	///<para>Note: This should NOT be explicitly declared in XML files.</para></summary>
	public static uint HashString(string Name)
	{
		return FnvHash(Encoding.ASCII.GetBytes(Name.ToLowerInvariant()), true);
	}

	static uint FnvHash(byte[] input, bool use32bits)
	{
		uint prime = 16777619;
		uint offset = 2166136261;
		uint mask = 1073741823; //Bitmask for first 30 bits

		uint hash = offset;
		for (int i = 0; i < input.Length; i++) {
			hash *= prime;
			hash ^= input[i];
		}

		if (use32bits) {
			return hash;
		} else { 
			return (hash >> 30) ^ (hash & mask); //XOR folding
		}
	}
}