bbradson
98 lines
3.0 KiB
C#
98 lines
3.0 KiB
C#
// Copyright (c) 2022 bradson
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, You can obtain one at https://mozilla.org/MPL/2.0/.
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using System.Linq;
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using System.Runtime.CompilerServices;
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namespace FisheryLib.FunctionPointers;
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public static class GetHashCodeByRef<T>
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{
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public static readonly unsafe delegate*<ref T, int> Default = (delegate*<ref T, int>)GetHashCodeByRef.MakeDelegate(typeof(T));
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}
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public static class GetHashCodeByRef
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{
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public static class Methods
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{
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public static int Byte(ref byte obj)
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=> obj;
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public static int Int(ref int obj)
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=> obj;
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public static int Uint(ref uint obj)
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=> (int)obj;
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public static int Ushort(ref ushort obj)
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=> obj;
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public static unsafe int VoidPtr(ref void* obj)
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=> (int)obj;
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public static int Enum<T>(ref T obj) where T : struct
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=> JitHelpers.UnsafeEnumCast(obj).GetHashCode();
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public static int SbyteEnum<T>(ref T obj) where T : struct
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=> ((sbyte)JitHelpers.UnsafeEnumCast(obj)).GetHashCode();
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public static int ShortEnum<T>(ref T obj) where T : struct
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=> ((short)JitHelpers.UnsafeEnumCast(obj)).GetHashCode();
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public static int LongEnum<T>(ref T obj) where T : struct
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=> JitHelpers.UnsafeEnumCastLong(obj).GetHashCode();
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public static int ValueType<T>(ref T obj) where T : struct
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=> obj.GetHashCode();
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public static int Nullable<T>(ref T? obj) where T : struct
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=> obj.GetHashCode();
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public static int Reference<T>(ref T obj) where T : class
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=> RuntimeHelpers.GetHashCode(obj);
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public static int Object<T>(ref T obj)
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=> obj?.GetHashCode() ?? 0;
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}
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internal static unsafe IntPtr MakeDelegate(Type type)
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=> _getHashCodeMethods.Where(m => !m.IsGenericMethod)
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.FirstOrDefault(m
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=> m.GetParameters().First().ParameterType.GetElementType() == type)
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is { } specializedMethod
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? specializedMethod.GetFunctionPointer()
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: type.IsNullable(out var genericArgument)
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&& genericArgument.IsAssignableTo(typeof(IEquatable<>), genericArgument)
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? GetMethod(nameof(Methods.Nullable)).MakeGenericMethod(genericArgument).GetFunctionPointer()
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: GetMethod(
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type.IsEnum
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? Type.GetTypeCode(Enum.GetUnderlyingType(type))
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switch
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{
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TypeCode.Int16 => nameof(Methods.ShortEnum),
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TypeCode.SByte => nameof(Methods.SbyteEnum),
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TypeCode.Byte
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or TypeCode.UInt16
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or TypeCode.Int32
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or TypeCode.UInt32 => nameof(Methods.Enum),
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TypeCode.Int64
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or TypeCode.UInt64 => nameof(Methods.LongEnum),
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_ => ThrowHelper.ThrowNotSupportedException<string>()
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}
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: type.IsValueType
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? nameof(Methods.ValueType)
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: nameof(Methods.Object)
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).MakeGenericMethod(type).GetFunctionPointer();
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private static MethodInfo GetMethod(string name)
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=> Array.Find(_getHashCodeMethods, m => m.Name == name);
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private static MethodInfo[] _getHashCodeMethods
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= typeof(Methods)
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.GetMethods(BindingFlags.Static | BindingFlags.Public | BindingFlags.DeclaredOnly)
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.Where(m
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=> m.ReturnType == typeof(int)
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&& m.GetParameters().Length == 1)
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.ToArray();
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} |