96 lines
4 KiB
C#
96 lines
4 KiB
C#
/*************************************************************************
|
|
* ModernUO *
|
|
* Copyright 2019-2022 - ModernUO Development Team *
|
|
* Email: hi@modernuo.com *
|
|
* File: HashUtility.cs *
|
|
* *
|
|
* This program is free software: you can redistribute it and/or modify *
|
|
* it under the terms of the GNU General Public License as published by *
|
|
* the Free Software Foundation, either version 3 of the License, or *
|
|
* (at your option) any later version. *
|
|
* *
|
|
* You should have received a copy of the GNU General Public License *
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>. *
|
|
*************************************************************************/
|
|
|
|
using System;
|
|
using System.Numerics;
|
|
using System.Runtime.CompilerServices;
|
|
using Standart.Hash.xxHash;
|
|
|
|
namespace Server;
|
|
|
|
/// <summary>
|
|
/// Represents supported non-cryptographic fast hash algorithms.
|
|
/// </summary>
|
|
public enum FastHashAlgorithm
|
|
{
|
|
None, // Used for collisions where full-data is serialized instead
|
|
XxHash3_64, // xxHash3 64bit
|
|
XxHash_32, // xxHash 32bit
|
|
}
|
|
|
|
public static class HashUtility
|
|
{
|
|
// *************** DO NOT CHANGE THIS NUMBER ****************
|
|
// * Computed hashes might be serialized against this seed! *
|
|
// **********************************************************
|
|
private const ulong xxHash3Seed = 9609125370673258709ul; // Randomly generated 64-bit prime number
|
|
private const uint xxHash1Seed = 665738807u; // Randomly generated 32-bit prime number
|
|
|
|
[MethodImpl(MethodImplOptions.AggressiveInlining)]
|
|
public static ulong ComputeHash64(string? data, FastHashAlgorithm algorithm = FastHashAlgorithm.XxHash3_64) =>
|
|
algorithm switch
|
|
{
|
|
FastHashAlgorithm.XxHash3_64 => ComputeXXHash3_64(data),
|
|
_ => throw new NotSupportedException($"Hash {algorithm} is not supported.")
|
|
};
|
|
|
|
[MethodImpl(MethodImplOptions.AggressiveInlining)]
|
|
public static ulong ComputeXXHash3_64(string? data) => data == null ? 0 : xxHash3.ComputeHash(data, xxHash3Seed);
|
|
|
|
[MethodImpl(MethodImplOptions.AggressiveInlining)]
|
|
public static uint ComputeHash32(string? data, FastHashAlgorithm algorithm = FastHashAlgorithm.XxHash_32) =>
|
|
algorithm switch
|
|
{
|
|
FastHashAlgorithm.XxHash_32 => ComputeXXHash_32(data),
|
|
_ => throw new NotSupportedException($"Hash {algorithm} is not supported.")
|
|
};
|
|
|
|
[MethodImpl(MethodImplOptions.AggressiveInlining)]
|
|
public static uint ComputeXXHash_32(string? data) => data == null ? 0 : xxHash32.ComputeHash(data, xxHash1Seed);
|
|
|
|
public static unsafe int GetNetFrameworkHashCode(this string? str)
|
|
{
|
|
if (str == null)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
fixed (char* src = &str.GetPinnableReference())
|
|
{
|
|
uint hash1 = (5381 << 16) + 5381;
|
|
uint hash2 = hash1;
|
|
|
|
uint* ptr = (uint*)src;
|
|
int length = str.Length;
|
|
|
|
while (length > 2)
|
|
{
|
|
length -= 4;
|
|
// Where length is 4n-1 (e.g. 3,7,11,15,19) this additionally consumes the null terminator
|
|
hash1 = (BitOperations.RotateLeft(hash1, 5) + hash1) ^ ptr[0];
|
|
hash2 = (BitOperations.RotateLeft(hash2, 5) + hash2) ^ ptr[1];
|
|
ptr += 2;
|
|
}
|
|
|
|
if (length > 0)
|
|
{
|
|
// Where length is 4n-3 (e.g. 1,5,9,13,17) this additionally consumes the null terminator
|
|
hash2 = (BitOperations.RotateLeft(hash2, 5) + hash2) ^ ptr[0];
|
|
}
|
|
|
|
return (int)(hash1 + hash2 * 1566083941);
|
|
}
|
|
}
|
|
}
|