探索一下 Enum 优化

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探索一下 Enum 优化

SV.Enums主要是探索如何让 enum 更高效

其中涉及的优化手段并非完全自创

很多内容参考于以下项目

主要优化手段

其实主要全是空间换时间，大量缓存

封装入口方法以及 source-generators 生成

不过本项目尝试了封装入口方法、ModuleInitializer、source-generators 来避免对使用影响（其实更主要是尝试如何避免使用interceptors）

    public static class Enums<T> where T : struct, Enum     {         public static bool IsFlags => CheckInfo().IsFlags;         public static bool IsEmpty => CheckInfo().IsEmpty;          internal static IEnumInfo<T> Info;          [MethodImpl(Enums.Optimization)]         internal static IEnumInfo<T> CheckInfo()         {             if (Info == null)             {                 Info = new EnumInfo<T>();             }             return Info;         }          public static T Parse(string name, bool ignoreCase)         {             if (CheckInfo().TryParse(name, ignoreCase, out var result))                 return result;             throw new ArgumentException($"Specified value '{name}' is not defined.", nameof(name));         }

这样做主要就可以利用 source-generators 生成enum 处理代码，

并通过 ModuleInitializer 在运行时启用生成的enum代码

如下为生成enum 代码示例

internal class EnumInfoAD125120120540FC9AA056E2DD394A7C : EnumBase<global::Benchmark.Fruits2>     {         public override bool IsDefined(string name)         {             return name switch             {                 nameof(global::Benchmark.Fruits2.Apple) => true, nameof(global::Benchmark.Fruits2.Lemon) => true, nameof(global::Benchmark.Fruits2.Melon) => true, nameof(global::Benchmark.Fruits2.Banana) => true,                 _ => false,             };         }          public override string? GetName(global::Benchmark.Fruits2 t)         {             switch (t)             {                 case global::Benchmark.Fruits2.Apple: return nameof(global::Benchmark.Fruits2.Apple); case global::Benchmark.Fruits2.Lemon: return nameof(global::Benchmark.Fruits2.Lemon); case global::Benchmark.Fruits2.Melon: return nameof(global::Benchmark.Fruits2.Melon); case global::Benchmark.Fruits2.Banana: return nameof(global::Benchmark.Fruits2.Banana);                 default:                     return null;             }         }          protected override bool TryParseCase(in ReadOnlySpan<char> name, out global::Benchmark.Fruits2 result)         {             switch (name)             {                 case ReadOnlySpan<char> current when current.Equals(nameof(global::Benchmark.Fruits2.Apple).AsSpan(), global::System.StringComparison.Ordinal):                     result = global::Benchmark.Fruits2.Apple;                     return true;                 case ReadOnlySpan<char> current when current.Equals(nameof(global::Benchmark.Fruits2.Lemon).AsSpan(), global::System.StringComparison.Ordinal):                     result = global::Benchmark.Fruits2.Lemon;                     return true;                 case ReadOnlySpan<char> current when current.Equals(nameof(global::Benchmark.Fruits2.Melon).AsSpan(), global::System.StringComparison.Ordinal):                     result = global::Benchmark.Fruits2.Melon;                     return true;                 case ReadOnlySpan<char> current when current.Equals(nameof(global::Benchmark.Fruits2.Banana).AsSpan(), global::System.StringComparison.Ordinal):                     result = global::Benchmark.Fruits2.Banana;                     return true;                 default:                     result = default;                     return false;             }         }          protected override bool TryParseIgnoreCase(in ReadOnlySpan<char> name, out global::Benchmark.Fruits2 result)         {             switch (name)             {                 case ReadOnlySpan<char> current when current.Equals(nameof(global::Benchmark.Fruits2.Apple).AsSpan(), global::System.StringComparison.OrdinalIgnoreCase):                     result = global::Benchmark.Fruits2.Apple;                     return true;                 case ReadOnlySpan<char> current when current.Equals(nameof(global::Benchmark.Fruits2.Lemon).AsSpan(), global::System.StringComparison.OrdinalIgnoreCase):                     result = global::Benchmark.Fruits2.Lemon;                     return true;                 case ReadOnlySpan<char> current when current.Equals(nameof(global::Benchmark.Fruits2.Melon).AsSpan(), global::System.StringComparison.OrdinalIgnoreCase):                     result = global::Benchmark.Fruits2.Melon;                     return true;                 case ReadOnlySpan<char> current when current.Equals(nameof(global::Benchmark.Fruits2.Banana).AsSpan(), global::System.StringComparison.OrdinalIgnoreCase):                     result = global::Benchmark.Fruits2.Banana;                     return true;                 default:                     result = default;                     return false;             }         }     }          internal static partial class EnumsF1029F0E5915401BBDD8559E2B5289B1     {         [ModuleInitializer]         internal static void Init4771B8A4BD2E4761973279D81E61089C()         {             global::SV.Enums.SetEnumInfo<global::Benchmark.Fruits2>(new EnumInfoAD125120120540FC9AA056E2DD394A7C());         }     }

不过这样封装入口，存在一定性能损失

空间换时间

当然如果不使用 source-generators，对应功能也有默认实现

部分代码如下，大部分东西都内存缓存了

    public class EnumInfo<T> : IEnumInfo<T> where T : struct, Enum     {         private readonly string[] names;         private readonly T[] values;         private readonly (string Name, T Value)[] members;         private readonly FastReadOnlyDictionary<string, T> membersByName;         private readonly FastReadOnlyDictionary<T, (string Name, EnumMemberAttribute Member, FastReadOnlyDictionary<int, string> Labels)> namesByMember;         private readonly Type underlyingType;         private readonly TypeCode underlyingTypeCode;          public bool IsFlags { get; private set; }         public bool IsEmpty => values.Length == 0;          public EnumInfo() : base()         {             var t = typeof(T);             names = Enum.GetNames(t);             members = names.Select(i => (i, (T)Enum.Parse(t, i))).ToArray();             values = members.Select(i => i.Value).ToArray();             membersByName = members.ToFastReadOnlyDictionary(i => i.Name, i => i.Value);             namesByMember = membersByName.AsEnumerable().DistinctBy(i => i.Value).ToFastReadOnlyDictionary(i => i.Value, i =>             {                 var fieldInfo = t.GetField(i.Key)!;                 return (i.Key, fieldInfo.GetCustomAttribute<EnumMemberAttribute>(), fieldInfo.GetCustomAttributes<LabelAttribute>().DistinctBy(i => i.Index).ToFastReadOnlyDictionary(x => x.Index, x => x.Value));             });             underlyingType = Enum.GetUnderlyingType(t);             underlyingTypeCode = Type.GetTypeCode(underlyingType);             IsFlags = t.IsDefined(typeof(FlagsAttribute), true);         }          [MethodImpl(Enums.Optimization)]         public bool TryParseIgnoreCase(in ReadOnlySpan<char> name, out T result)         {             foreach (var member in members.AsSpan())             {                 if (name.Equals(member.Name.AsSpan(), StringComparison.OrdinalIgnoreCase))                 {                     result = member.Value;                     return true;                 }             }             result = default;             return false;         }

enum 转换方法

同时提供一些不用拆箱装箱的 enum 转换方法，里面移除了类型检查的逻辑，所以理论只能保证正常使用不会有问题

public static T ToEnum(int value)  public static T ToEnum(byte value)  public static T ToEnum(Int16 value)  public static T ToEnum(Int64 value)  ...

性能测试

简单做下性能测试，部分代码如下

public enum Fruits     {         Apple,         Lemon,         Melon,         Banana,         Lemon1,         Melon2,         Banana3,         Lemon11,         Melon21,         Banana31,         Lemon12,         Melon22,         Banana32,         Lemon13,         Melon23,         Banana33,         Lemon131,         Melon231,         Banana331,         Lemon14,         Melon24,         Banana34,     }      [MemoryDiagnoser, Orderer(summaryOrderPolicy: SummaryOrderPolicy.FastestToSlowest), GroupBenchmarksBy(BenchmarkLogicalGroupRule.ByCategory), CategoriesColumn]     public class EnumBenchmarks     {         private readonly EnumInfo<Fruits> test;          public EnumBenchmarks()         {             test = new EnumInfo<Fruits>();         }          [Benchmark(Baseline = true), BenchmarkCategory("IgnoreCase")]         public Fruits ParseIgnoreCase()         {             return Enum.Parse<Fruits>("melon", true);         }          [Benchmark, BenchmarkCategory("IgnoreCase")]         public Fruits FastEnumParseIgnoreCase()         {             return FastEnum.Parse<Fruits>("melon", true);         }          [Benchmark, BenchmarkCategory("IgnoreCase")]         public Fruits SVEnumsParseIgnoreCase()         {             Enums<Fruits>.TryParse("melon", true, out var v);             return v;         }          [Benchmark, BenchmarkCategory("IgnoreCase")]         public Fruits EnumInfoParseIgnoreCase()         {             test.TryParse("melon", true, out var v);             return v;         }          [Benchmark(Baseline = true)]         public Fruits Parse()         {             return Enum.Parse<Fruits>("Melon", false);         }          [Benchmark]         public Fruits FastEnumParse()         {             return FastEnum.Parse<Fruits>("Melon", false);         }          [Benchmark]         public Fruits SVEnumsParse()         {             Enums<Fruits>.TryParse("Melon", out var v);             return v;         }          [Benchmark]         public Fruits EnumInfoParse()         {             test.TryParse("Melon", false, out var v);             return v;         }          ...      [MemoryDiagnoser, Orderer(summaryOrderPolicy: SummaryOrderPolicy.FastestToSlowest), GroupBenchmarksBy(BenchmarkLogicalGroupRule.ByCategory), CategoriesColumn]     public class ToEnumBenchmarks     {         private readonly EnumInfo<Fruits> test;          public ToEnumBenchmarks()         {             test = new EnumInfo<Fruits>();             //Enums.SetEnumInfo<Fruits>(new TestIEnumInfo());         }          [Benchmark(Baseline = true), BenchmarkCategory("ToEnumInt")]         public Fruits ToEnumInt()         {             return (Fruits)Enum.ToObject(typeof(Fruits), 11);         }          [Benchmark, BenchmarkCategory("ToEnumInt")]         public Fruits SVEnumsToEnumInt()         {             return Enums<Fruits>.ToEnum(11);         }          [Benchmark, BenchmarkCategory("ToEnumInt")]         public Fruits ToEnumIntByte()         {             return (Fruits)Enum.ToObject(typeof(Fruits), (byte)11);         }          [Benchmark, BenchmarkCategory("ToEnumInt")]         public Fruits SVEnumsToEnumIntByte()         {             return Enums<Fruits>.ToEnum((byte)11);         }          [Benchmark, BenchmarkCategory("ToEnumInt")]         public Fruits ToEnumIntObject()         {             return (Fruits)Enum.ToObject(typeof(Fruits), (object)11);         }          [Benchmark, BenchmarkCategory("ToEnumInt")]         public Fruits SVEnumsToEnumIntObject()         {             return Enums<Fruits>.ToEnum((object)11);         }     }

结果如下

 BenchmarkDotNet v0.14.0, Windows 10 (10.0.19045.4651/22H2/2022Update) Intel Core i7-10700 CPU 2.90GHz, 1 CPU, 16 logical and 8 physical cores .NET SDK 9.0.100-preview.5.24307.3   [Host]     : .NET 8.0.6 (8.0.624.26715), X64 RyuJIT AVX2   DefaultJob : .NET 8.0.6 (8.0.624.26715), X64 RyuJIT AVX2

Method	Mean	Error	StdDev	Median	Ratio	RatioSD	Gen0	Allocated	Alloc Ratio
SVEnumsToEnumInt	0.9796 ns	0.0062 ns	0.0055 ns	0.9781 ns	0.02	0.00	-	-	0.00
SVEnumsToEnumIntByte	1.0990 ns	0.0089 ns	0.0074 ns	1.0966 ns	0.03	0.00	-	-	0.00
SVEnumsToEnumIntObject	5.1211 ns	0.0842 ns	0.0746 ns	5.1295 ns	0.12	0.00	0.0029	24 B	1.00
ToEnumIntByte	40.9720 ns	0.2100 ns	0.1861 ns	40.9065 ns	1.00	0.03	0.0029	24 B	1.00
ToEnumInt	41.1962 ns	0.8452 ns	1.4122 ns	40.4985 ns	1.00	0.05	0.0029	24 B	1.00
ToEnumIntObject	48.2590 ns	0.4380 ns	0.3882 ns	48.0802 ns	1.17	0.04	0.0057	48 B	2.00

Method	Categories	Mean	Error	StdDev	Ratio	RatioSD	Gen0	Gen1	Allocated	Alloc Ratio
SVEnumsParse		2.8382 ns	0.0508 ns	0.0450 ns	0.12	0.00	-	-	-	NA
FastEnumParse		6.9671 ns	0.0437 ns	0.0388 ns	0.28	0.00	-	-	-	NA
EnumInfoParse		7.1513 ns	0.1049 ns	0.0930 ns	0.29	0.00	-	-	-	NA
Parse		24.5338 ns	0.0548 ns	0.0485 ns	1.00	0.00	-	-	-	NA

FastEnumGetName	GetName	0.8608 ns	0.0175 ns	0.0155 ns	0.32	0.01	-	-	-	NA
EnumInfoGetName	GetName	1.4291 ns	0.0147 ns	0.0130 ns	0.54	0.01	-	-	-	NA
SVEnumsGetName	GetName	1.6210 ns	0.0148 ns	0.0131 ns	0.61	0.01	-	-	-	NA
GetName	GetName	2.6512 ns	0.0150 ns	0.0125 ns	1.00	0.01	-	-	-	NA

SVEnumsGetNames	GetNames	0.2539 ns	0.0061 ns	0.0051 ns	0.01	0.00	-	-	-	0.00
FastEnumGetNames	GetNames	0.6874 ns	0.0195 ns	0.0163 ns	0.03	0.00	-	-	-	0.00
GetNames	GetNames	21.0463 ns	0.4645 ns	0.5162 ns	1.00	0.03	0.0239	0.0001	200 B	1.00

SVEnumsGetValues	GetValues	0.3022 ns	0.0296 ns	0.0277 ns	0.009	0.00	-	-	-	0.00
FastEnumGetValues	GetValues	0.6683 ns	0.0098 ns	0.0082 ns	0.021	0.00	-	-	-	0.00
GetValues	GetValues	32.5145 ns	0.6732 ns	0.5968 ns	1.000	0.03	0.0134	-	112 B	1.00

SVEnumsParseIgnoreCase	IgnoreCase	3.0465 ns	0.0680 ns	0.0727 ns	0.12	0.00	-	-	-	NA
EnumInfoParseIgnoreCase	IgnoreCase	10.1299 ns	0.1660 ns	0.1472 ns	0.42	0.01	-	-	-	NA
FastEnumParseIgnoreCase	IgnoreCase	10.3531 ns	0.0807 ns	0.0674 ns	0.42	0.00	-	-	-	NA
ParseIgnoreCase	IgnoreCase	24.3767 ns	0.1270 ns	0.1060 ns	1.00	0.01	-	-	-	NA

SVEnumsIsDefinedName	IsDefinedName	2.7188 ns	0.0111 ns	0.0098 ns	0.11	0.00	-	-	-	NA
EnumInfoIsDefinedName	IsDefinedName	6.6075 ns	0.0190 ns	0.0148 ns	0.26	0.00	-	-	-	NA
FastEnumIsDefinedName	IsDefinedName	6.7011 ns	0.0388 ns	0.0303 ns	0.26	0.00	-	-	-	NA
IsDefinedName	IsDefinedName	25.3131 ns	0.2064 ns	0.1829 ns	1.00	0.01	-	-	-	NA