Fishery

2022-10-24 18:56:18 +02:00
parent 01ef055ff2
commit 9cdc8ccb4f
70 changed files with 19754 additions and 4 deletions
@@ -0,0 +1,86 @@
+// Copyright (c) 2022 bradson
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+namespace FisheryLib.FunctionPointers;
+public static class Convert<TFrom> where TFrom : IConvertible
+{
+	public static class To<TTo>
+	{
+		public static readonly unsafe delegate*<TFrom, IFormatProvider, TTo> Default = Convert.GetDefaultConverter<TFrom, TTo>();
+	}
+
+	/// <summary>
+	/// Used when TFrom isn't a known sealed type, i.e. with just the IConvertible interface
+	/// </summary>
+	internal static class Fallback<TTo>
+	{
+		internal static readonly Func<TFrom, IFormatProvider, TTo> Func = Convert.GetDefaultConverterFunc<TFrom, TTo>();
+		internal static TTo FallbackMethod(TFrom from, IFormatProvider provider) => Func(from, provider);
+	}
+}
+
+internal static class Convert
+{
+	private static MethodInfo GetConverterMethod<TFrom>(Type to) where TFrom : IConvertible
+	{
+		var info = typeof(TFrom).GetMethod(GetConvertMethodName(to));
+		if (info.GetParameters().Length > 1)
+		{
+			info = typeof(Convert)
+				.GetMethod(nameof(ConvertToType), AccessTools.allDeclared)
+				.MakeGenericMethod(new[] { typeof(TFrom), to });
+		}
+
+		return info;
+	}
+
+	internal static Func<TFrom, IFormatProvider, TTo> GetDefaultConverterFunc<TFrom, TTo>() where TFrom : IConvertible
+		=> (Func<TFrom, IFormatProvider, TTo>)GetConverterMethod<TFrom>(typeof(TTo))
+		.CreateDelegate(typeof(Func<TFrom, IFormatProvider, TTo>));
+
+	internal static unsafe delegate*<TFrom, IFormatProvider, TTo> GetDefaultConverter<TFrom, TTo>() where TFrom : IConvertible
+		=> !typeof(TFrom).IsValueType && (!typeof(TFrom).IsSealed || typeof(TFrom).IsInterface || typeof(TFrom).IsAbstract)
+		? &Convert<TFrom>.Fallback<TTo>.FallbackMethod
+		: (delegate*<TFrom, IFormatProvider, TTo>)GetConverterMethod<TFrom>(typeof(TTo))
+		.MethodHandle.GetFunctionPointer();
+
+	private static TTo ConvertToType<TFrom, TTo>(TFrom from, IFormatProvider provider) where TFrom : IConvertible
+		=> (TTo)from.ToType(typeof(TTo), provider);
+
+	private static string GetConvertMethodName(Type type)
+		=> type == typeof(bool)
+		? nameof(IConvertible.ToBoolean)
+		: type == typeof(char)
+		? nameof(IConvertible.ToChar)
+		: type == typeof(sbyte)
+		? nameof(IConvertible.ToSByte)
+		: type == typeof(byte)
+		? nameof(IConvertible.ToByte)
+		: type == typeof(short)
+		? nameof(IConvertible.ToInt16)
+		: type == typeof(ushort)
+		? nameof(IConvertible.ToUInt16)
+		: type == typeof(int)
+		? nameof(IConvertible.ToInt32)
+		: type == typeof(uint)
+		? nameof(IConvertible.ToUInt32)
+		: type == typeof(long)
+		? nameof(IConvertible.ToInt64)
+		: type == typeof(ulong)
+		? nameof(IConvertible.ToUInt64)
+		: type == typeof(float)
+		? nameof(IConvertible.ToSingle)
+		: type == typeof(double)
+		? nameof(IConvertible.ToDouble)
+		: type == typeof(decimal)
+		? nameof(IConvertible.ToDecimal)
+		: type == typeof(DateTime)
+		? nameof(IConvertible.ToDateTime)
+		: type == typeof(string)
+		? nameof(IConvertible.ToString)
+		//: type == typeof(object)
+		//? value
+		: nameof(IConvertible.ToType);
+}