RSCG – System.Text.Json
| name | System.Text.Json |
| nuget | https://www.nuget.org/packages/System.Text.Json/ |
| link | https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json/source-generation |
| author | Microsoft |
Json Serialize without reflection
This is how you can use System.Text.Json .
The code that you start with is
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFramework>net7.0</TargetFramework>
<ImplicitUsings>enable</ImplicitUsings>
<Nullable>enable</Nullable>
</PropertyGroup>
<PropertyGroup>
<EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
<CompilerGeneratedFilesOutputPath>$(BaseIntermediateOutputPath)\GeneratedX</CompilerGeneratedFilesOutputPath>
</PropertyGroup>
</Project>
The code that you will use is
using JsonSerializerOptionsExample;
using System.Text.Json;
//for asp.net core
//services.AddControllers().AddJsonOptions(options => options.JsonSerializerOptions.AddContext<MyJsonContext>());
//https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/tokens/raw-string
string jsonString ="""
{
"date": "2019-08-01T00:00:00",
"temperatureCelsius": 25,
"summary": "Hot"
}
""";
WeatherForecast? weatherForecast= JsonSerializer.Deserialize(
jsonString,
typeof(WeatherForecast),
new OptionsExampleContext(
new JsonSerializerOptions(JsonSerializerDefaults.Web)))
as WeatherForecast;
Console.WriteLine($"Date={weatherForecast?.Date}");
// output:
//Date=8/1/2019 12:00:00 AM
jsonString = JsonSerializer.Serialize(
weatherForecast,
typeof(WeatherForecast),
new OptionsExampleContext(
new JsonSerializerOptions(JsonSerializerDefaults.Web)));
Console.WriteLine(jsonString);
jsonString = JsonSerializer.Serialize(
weatherForecast,
typeof(WeatherForecast),
new OptionsExampleContext(
new JsonSerializerOptions(JsonSerializerDefaults.General)));
Console.WriteLine(jsonString);
// output:
//{ "date":"2019-08-01T00:00:00","temperatureCelsius":25,"summary":"Hot"}
namespace JsonSerializerOptionsExample;
public class WeatherForecast
{
public DateTime Date { get; set; }
public int TemperatureCelsius { get; set; }
public string? Summary { get; set; }
}
using System.Text.Json.Serialization;
namespace JsonSerializerOptionsExample;
[JsonSerializable(typeof(WeatherForecast))]
internal partial class OptionsExampleContext : JsonSerializerContext
{
}
The code that is generated is
// <auto-generated/>
#nullable enable annotations
#nullable disable warnings
// Suppress warnings about [Obsolete] member usage in generated code.
#pragma warning disable CS0618
namespace JsonSerializerOptionsExample
{
internal partial class OptionsExampleContext
{
private global::System.Text.Json.Serialization.Metadata.JsonTypeInfo<global::System.DateTime>? _DateTime;
/// <summary>
/// Defines the source generated JSON serialization contract metadata for a given type.
/// </summary>
public global::System.Text.Json.Serialization.Metadata.JsonTypeInfo<global::System.DateTime> DateTime
{
get => _DateTime ??= Create_DateTime(Options, makeReadOnly: true);
}
private global::System.Text.Json.Serialization.Metadata.JsonTypeInfo<global::System.DateTime> Create_DateTime(global::System.Text.Json.JsonSerializerOptions options, bool makeReadOnly)
{
global::System.Text.Json.Serialization.Metadata.JsonTypeInfo<global::System.DateTime>? jsonTypeInfo = null;
global::System.Text.Json.Serialization.JsonConverter? customConverter;
if (options.Converters.Count > 0 && (customConverter = GetRuntimeProvidedCustomConverter(options, typeof(global::System.DateTime))) != null)
{
jsonTypeInfo = global::System.Text.Json.Serialization.Metadata.JsonMetadataServices.CreateValueInfo<global::System.DateTime>(options, customConverter);
}
else
{
jsonTypeInfo = global::System.Text.Json.Serialization.Metadata.JsonMetadataServices.CreateValueInfo<global::System.DateTime>(options, global::System.Text.Json.Serialization.Metadata.JsonMetadataServices.DateTimeConverter);
}
if (makeReadOnly)
{
jsonTypeInfo.MakeReadOnly();
}
return jsonTypeInfo;
}
}
}
// <auto-generated/>
#nullable enable annotations
#nullable disable warnings
// Suppress warnings about [Obsolete] member usage in generated code.
#pragma warning disable CS0618
namespace JsonSerializerOptionsExample
{
[global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Text.Json.SourceGeneration", "7.0.8.17405")]
internal partial class OptionsExampleContext
{
private static global::System.Text.Json.JsonSerializerOptions s_defaultOptions { get; } = new global::System.Text.Json.JsonSerializerOptions()
{
DefaultIgnoreCondition = global::System.Text.Json.Serialization.JsonIgnoreCondition.Never,
IgnoreReadOnlyFields = false,
IgnoreReadOnlyProperties = false,
IncludeFields = false,
WriteIndented = false,
};
private static global::JsonSerializerOptionsExample.OptionsExampleContext? s_defaultContext;
/// <summary>
/// The default <see cref="global::System.Text.Json.Serialization.JsonSerializerContext"/> associated with a default <see cref="global::System.Text.Json.JsonSerializerOptions"/> instance.
/// </summary>
public static global::JsonSerializerOptionsExample.OptionsExampleContext Default => s_defaultContext ??= new global::JsonSerializerOptionsExample.OptionsExampleContext(new global::System.Text.Json.JsonSerializerOptions(s_defaultOptions));
/// <summary>
/// The source-generated options associated with this context.
/// </summary>
protected override global::System.Text.Json.JsonSerializerOptions? GeneratedSerializerOptions { get; } = s_defaultOptions;
/// <inheritdoc/>
public OptionsExampleContext() : base(null)
{
}
/// <inheritdoc/>
public OptionsExampleContext(global::System.Text.Json.JsonSerializerOptions options) : base(options)
{
}
private static global::System.Text.Json.Serialization.JsonConverter? GetRuntimeProvidedCustomConverter(global::System.Text.Json.JsonSerializerOptions options, global::System.Type type)
{
global::System.Collections.Generic.IList<global::System.Text.Json.Serialization.JsonConverter> converters = options.Converters;
for (int i = 0; i < converters.Count; i++)
{
global::System.Text.Json.Serialization.JsonConverter? converter = converters[i];
if (converter.CanConvert(type))
{
if (converter is global::System.Text.Json.Serialization.JsonConverterFactory factory)
{
converter = factory.CreateConverter(type, options);
if (converter == null || converter is global::System.Text.Json.Serialization.JsonConverterFactory)
{
throw new global::System.InvalidOperationException(string.Format("The converter '{0}' cannot return null or a JsonConverterFactory instance.", factory.GetType()));
}
}
return converter;
}
}
return null;
}
}
}
// <auto-generated/>
#nullable enable annotations
#nullable disable warnings
// Suppress warnings about [Obsolete] member usage in generated code.
#pragma warning disable CS0618
namespace JsonSerializerOptionsExample
{
internal partial class OptionsExampleContext: global::System.Text.Json.Serialization.Metadata.IJsonTypeInfoResolver
{
/// <inheritdoc/>
public override global::System.Text.Json.Serialization.Metadata.JsonTypeInfo GetTypeInfo(global::System.Type type)
{
if (type == typeof(global::JsonSerializerOptionsExample.WeatherForecast))
{
return this.WeatherForecast;
}
if (type == typeof(global::System.DateTime))
{
return this.DateTime;
}
if (type == typeof(global::System.Int32))
{
return this.Int32;
}
if (type == typeof(global::System.String))
{
return this.String;
}
return null!;
}
global::System.Text.Json.Serialization.Metadata.JsonTypeInfo? global::System.Text.Json.Serialization.Metadata.IJsonTypeInfoResolver.GetTypeInfo(global::System.Type type, global::System.Text.Json.JsonSerializerOptions options)
{
if (type == typeof(global::JsonSerializerOptionsExample.WeatherForecast))
{
return Create_WeatherForecast(options, makeReadOnly: false);
}
if (type == typeof(global::System.DateTime))
{
return Create_DateTime(options, makeReadOnly: false);
}
if (type == typeof(global::System.Int32))
{
return Create_Int32(options, makeReadOnly: false);
}
if (type == typeof(global::System.String))
{
return Create_String(options, makeReadOnly: false);
}
return null;
}
}
}
// <auto-generated/>
#nullable enable annotations
#nullable disable warnings
// Suppress warnings about [Obsolete] member usage in generated code.
#pragma warning disable CS0618
namespace JsonSerializerOptionsExample
{
internal partial class OptionsExampleContext
{
private global::System.Text.Json.Serialization.Metadata.JsonTypeInfo<global::System.Int32>? _Int32;
/// <summary>
/// Defines the source generated JSON serialization contract metadata for a given type.
/// </summary>
public global::System.Text.Json.Serialization.Metadata.JsonTypeInfo<global::System.Int32> Int32
{
get => _Int32 ??= Create_Int32(Options, makeReadOnly: true);
}
private global::System.Text.Json.Serialization.Metadata.JsonTypeInfo<global::System.Int32> Create_Int32(global::System.Text.Json.JsonSerializerOptions options, bool makeReadOnly)
{
global::System.Text.Json.Serialization.Metadata.JsonTypeInfo<global::System.Int32>? jsonTypeInfo = null;
global::System.Text.Json.Serialization.JsonConverter? customConverter;
if (options.Converters.Count > 0 && (customConverter = GetRuntimeProvidedCustomConverter(options, typeof(global::System.Int32))) != null)
{
jsonTypeInfo = global::System.Text.Json.Serialization.Metadata.JsonMetadataServices.CreateValueInfo<global::System.Int32>(options, customConverter);
}
else
{
jsonTypeInfo = global::System.Text.Json.Serialization.Metadata.JsonMetadataServices.CreateValueInfo<global::System.Int32>(options, global::System.Text.Json.Serialization.Metadata.JsonMetadataServices.Int32Converter);
}
if (makeReadOnly)
{
jsonTypeInfo.MakeReadOnly();
}
return jsonTypeInfo;
}
}
}
// <auto-generated/>
#nullable enable annotations
#nullable disable warnings
// Suppress warnings about [Obsolete] member usage in generated code.
#pragma warning disable CS0618
namespace JsonSerializerOptionsExample
{
internal partial class OptionsExampleContext
{
private static readonly global::System.Text.Json.JsonEncodedText PropName_Date = global::System.Text.Json.JsonEncodedText.Encode("Date");
private static readonly global::System.Text.Json.JsonEncodedText PropName_TemperatureCelsius = global::System.Text.Json.JsonEncodedText.Encode("TemperatureCelsius");
private static readonly global::System.Text.Json.JsonEncodedText PropName_Summary = global::System.Text.Json.JsonEncodedText.Encode("Summary");
}
}
// <auto-generated/>
#nullable enable annotations
#nullable disable warnings
// Suppress warnings about [Obsolete] member usage in generated code.
#pragma warning disable CS0618
namespace JsonSerializerOptionsExample
{
internal partial class OptionsExampleContext
{
private global::System.Text.Json.Serialization.Metadata.JsonTypeInfo<global::System.String>? _String;
/// <summary>
/// Defines the source generated JSON serialization contract metadata for a given type.
/// </summary>
public global::System.Text.Json.Serialization.Metadata.JsonTypeInfo<global::System.String> String
{
get => _String ??= Create_String(Options, makeReadOnly: true);
}
private global::System.Text.Json.Serialization.Metadata.JsonTypeInfo<global::System.String> Create_String(global::System.Text.Json.JsonSerializerOptions options, bool makeReadOnly)
{
global::System.Text.Json.Serialization.Metadata.JsonTypeInfo<global::System.String>? jsonTypeInfo = null;
global::System.Text.Json.Serialization.JsonConverter? customConverter;
if (options.Converters.Count > 0 && (customConverter = GetRuntimeProvidedCustomConverter(options, typeof(global::System.String))) != null)
{
jsonTypeInfo = global::System.Text.Json.Serialization.Metadata.JsonMetadataServices.CreateValueInfo<global::System.String>(options, customConverter);
}
else
{
jsonTypeInfo = global::System.Text.Json.Serialization.Metadata.JsonMetadataServices.CreateValueInfo<global::System.String>(options, global::System.Text.Json.Serialization.Metadata.JsonMetadataServices.StringConverter);
}
if (makeReadOnly)
{
jsonTypeInfo.MakeReadOnly();
}
return jsonTypeInfo;
}
}
}
// <auto-generated/>
#nullable enable annotations
#nullable disable warnings
// Suppress warnings about [Obsolete] member usage in generated code.
#pragma warning disable CS0618
namespace JsonSerializerOptionsExample
{
internal partial class OptionsExampleContext
{
private global::System.Text.Json.Serialization.Metadata.JsonTypeInfo<global::JsonSerializerOptionsExample.WeatherForecast>? _WeatherForecast;
/// <summary>
/// Defines the source generated JSON serialization contract metadata for a given type.
/// </summary>
public global::System.Text.Json.Serialization.Metadata.JsonTypeInfo<global::JsonSerializerOptionsExample.WeatherForecast> WeatherForecast
{
get => _WeatherForecast ??= Create_WeatherForecast(Options, makeReadOnly: true);
}
private global::System.Text.Json.Serialization.Metadata.JsonTypeInfo<global::JsonSerializerOptionsExample.WeatherForecast> Create_WeatherForecast(global::System.Text.Json.JsonSerializerOptions options, bool makeReadOnly)
{
global::System.Text.Json.Serialization.Metadata.JsonTypeInfo<global::JsonSerializerOptionsExample.WeatherForecast>? jsonTypeInfo = null;
global::System.Text.Json.Serialization.JsonConverter? customConverter;
if (options.Converters.Count > 0 && (customConverter = GetRuntimeProvidedCustomConverter(options, typeof(global::JsonSerializerOptionsExample.WeatherForecast))) != null)
{
jsonTypeInfo = global::System.Text.Json.Serialization.Metadata.JsonMetadataServices.CreateValueInfo<global::JsonSerializerOptionsExample.WeatherForecast>(options, customConverter);
}
else
{
global::System.Text.Json.Serialization.Metadata.JsonObjectInfoValues<global::JsonSerializerOptionsExample.WeatherForecast> objectInfo = new global::System.Text.Json.Serialization.Metadata.JsonObjectInfoValues<global::JsonSerializerOptionsExample.WeatherForecast>()
{
ObjectCreator = static () => new global::JsonSerializerOptionsExample.WeatherForecast(),
ObjectWithParameterizedConstructorCreator = null,
PropertyMetadataInitializer = _ => WeatherForecastPropInit(options),
ConstructorParameterMetadataInitializer = null,
NumberHandling = default,
SerializeHandler = WeatherForecastSerializeHandler
};
jsonTypeInfo = global::System.Text.Json.Serialization.Metadata.JsonMetadataServices.CreateObjectInfo<global::JsonSerializerOptionsExample.WeatherForecast>(options, objectInfo);
}
if (makeReadOnly)
{
jsonTypeInfo.MakeReadOnly();
}
return jsonTypeInfo;
}
private static global::System.Text.Json.Serialization.Metadata.JsonPropertyInfo[] WeatherForecastPropInit(global::System.Text.Json.JsonSerializerOptions options)
{
global::System.Text.Json.Serialization.Metadata.JsonPropertyInfo[] properties = new global::System.Text.Json.Serialization.Metadata.JsonPropertyInfo[3];
global::System.Text.Json.Serialization.Metadata.JsonPropertyInfoValues<global::System.DateTime> info0 = new global::System.Text.Json.Serialization.Metadata.JsonPropertyInfoValues<global::System.DateTime>()
{
IsProperty = true,
IsPublic = true,
IsVirtual = false,
DeclaringType = typeof(global::JsonSerializerOptionsExample.WeatherForecast),
Converter = null,
Getter = static (obj) => ((global::JsonSerializerOptionsExample.WeatherForecast)obj).Date,
Setter = static (obj, value) => ((global::JsonSerializerOptionsExample.WeatherForecast)obj).Date = value!,
IgnoreCondition = null,
HasJsonInclude = false,
IsExtensionData = false,
NumberHandling = default,
PropertyName = "Date",
JsonPropertyName = null
};
global::System.Text.Json.Serialization.Metadata.JsonPropertyInfo propertyInfo0 = global::System.Text.Json.Serialization.Metadata.JsonMetadataServices.CreatePropertyInfo<global::System.DateTime>(options, info0);
properties[0] = propertyInfo0;
global::System.Text.Json.Serialization.Metadata.JsonPropertyInfoValues<global::System.Int32> info1 = new global::System.Text.Json.Serialization.Metadata.JsonPropertyInfoValues<global::System.Int32>()
{
IsProperty = true,
IsPublic = true,
IsVirtual = false,
DeclaringType = typeof(global::JsonSerializerOptionsExample.WeatherForecast),
Converter = null,
Getter = static (obj) => ((global::JsonSerializerOptionsExample.WeatherForecast)obj).TemperatureCelsius,
Setter = static (obj, value) => ((global::JsonSerializerOptionsExample.WeatherForecast)obj).TemperatureCelsius = value!,
IgnoreCondition = null,
HasJsonInclude = false,
IsExtensionData = false,
NumberHandling = default,
PropertyName = "TemperatureCelsius",
JsonPropertyName = null
};
global::System.Text.Json.Serialization.Metadata.JsonPropertyInfo propertyInfo1 = global::System.Text.Json.Serialization.Metadata.JsonMetadataServices.CreatePropertyInfo<global::System.Int32>(options, info1);
properties[1] = propertyInfo1;
global::System.Text.Json.Serialization.Metadata.JsonPropertyInfoValues<global::System.String> info2 = new global::System.Text.Json.Serialization.Metadata.JsonPropertyInfoValues<global::System.String>()
{
IsProperty = true,
IsPublic = true,
IsVirtual = false,
DeclaringType = typeof(global::JsonSerializerOptionsExample.WeatherForecast),
Converter = null,
Getter = static (obj) => ((global::JsonSerializerOptionsExample.WeatherForecast)obj).Summary!,
Setter = static (obj, value) => ((global::JsonSerializerOptionsExample.WeatherForecast)obj).Summary = value!,
IgnoreCondition = null,
HasJsonInclude = false,
IsExtensionData = false,
NumberHandling = default,
PropertyName = "Summary",
JsonPropertyName = null
};
global::System.Text.Json.Serialization.Metadata.JsonPropertyInfo propertyInfo2 = global::System.Text.Json.Serialization.Metadata.JsonMetadataServices.CreatePropertyInfo<global::System.String>(options, info2);
properties[2] = propertyInfo2;
return properties;
}
// Intentionally not a static method because we create a delegate to it. Invoking delegates to instance
// methods is almost as fast as virtual calls. Static methods need to go through a shuffle thunk.
private void WeatherForecastSerializeHandler(global::System.Text.Json.Utf8JsonWriter writer, global::JsonSerializerOptionsExample.WeatherForecast? value)
{
if (value == null)
{
writer.WriteNullValue();
return;
}
writer.WriteStartObject();
writer.WriteString(PropName_Date, value.Date);
writer.WriteNumber(PropName_TemperatureCelsius, value.TemperatureCelsius);
writer.WriteString(PropName_Summary, value.Summary);
writer.WriteEndObject();
}
}
}
// <auto-generated/>
#nullable enable annotations
#nullable disable warnings
// Suppress warnings about [Obsolete] member usage in generated code.
#pragma warning disable CS0618
namespace BothModesNoOptions
{
[global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Text.Json.SourceGeneration", "7.0.8.17405")]
internal partial class SourceGenerationContext
{
private static global::System.Text.Json.JsonSerializerOptions s_defaultOptions { get; } = new global::System.Text.Json.JsonSerializerOptions()
{
DefaultIgnoreCondition = global::System.Text.Json.Serialization.JsonIgnoreCondition.Never,
IgnoreReadOnlyFields = false,
IgnoreReadOnlyProperties = false,
IncludeFields = false,
WriteIndented = true,
};
private static global::BothModesNoOptions.SourceGenerationContext? s_defaultContext;
/// <summary>
/// The default <see cref="global::System.Text.Json.Serialization.JsonSerializerContext"/> associated with a default <see cref="global::System.Text.Json.JsonSerializerOptions"/> instance.
/// </summary>
public static global::BothModesNoOptions.SourceGenerationContext Default => s_defaultContext ??= new global::BothModesNoOptions.SourceGenerationContext(new global::System.Text.Json.JsonSerializerOptions(s_defaultOptions));
/// <summary>
/// The source-generated options associated with this context.
/// </summary>
protected override global::System.Text.Json.JsonSerializerOptions? GeneratedSerializerOptions { get; } = s_defaultOptions;
/// <inheritdoc/>
public SourceGenerationContext() : base(null)
{
}
/// <inheritdoc/>
public SourceGenerationContext(global::System.Text.Json.JsonSerializerOptions options) : base(options)
{
}
private static global::System.Text.Json.Serialization.JsonConverter? GetRuntimeProvidedCustomConverter(global::System.Text.Json.JsonSerializerOptions options, global::System.Type type)
{
global::System.Collections.Generic.IList<global::System.Text.Json.Serialization.JsonConverter> converters = options.Converters;
for (int i = 0; i < converters.Count; i++)
{
global::System.Text.Json.Serialization.JsonConverter? converter = converters[i];
if (converter.CanConvert(type))
{
if (converter is global::System.Text.Json.Serialization.JsonConverterFactory factory)
{
converter = factory.CreateConverter(type, options);
if (converter == null || converter is global::System.Text.Json.Serialization.JsonConverterFactory)
{
throw new global::System.InvalidOperationException(string.Format("The converter '{0}' cannot return null or a JsonConverterFactory instance.", factory.GetType()));
}
}
return converter;
}
}
return null;
}
}
}
// <auto-generated/>
#nullable enable
#pragma warning disable CS0162 // Unreachable code
#pragma warning disable CS0164 // Unreferenced label
#pragma warning disable CS0219 // Variable assigned but never used
namespace JsonSerializerOptionsExample
{
partial class WeatherForecast
{
/// <remarks>
/// Pattern explanation:<br/>
/// <code>
/// ○ Match with 2 alternative expressions, atomically.<br/>
/// ○ Match a sequence of expressions.<br/>
/// ○ Match a character in the set [Aa].<br/>
/// ○ Match a character in the set [Bb].<br/>
/// ○ Match a character in the set [Cc].<br/>
/// ○ Match a sequence of expressions.<br/>
/// ○ Match a character in the set [Dd].<br/>
/// ○ Match a character in the set [Ee].<br/>
/// ○ Match a character in the set [Ff].<br/>
/// </code>
/// </remarks>
[global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Text.RegularExpressions.Generator", "7.0.8.17405")]
private static partial global::System.Text.RegularExpressions.Regex AbcOrDefGeneratedRegex() => global::System.Text.RegularExpressions.Generated.AbcOrDefGeneratedRegex_0.Instance;
}
}
namespace System.Text.RegularExpressions.Generated
{
using System;
using System.CodeDom.Compiler;
using System.Collections;
using System.ComponentModel;
using System.Globalization;
using System.Runtime.CompilerServices;
using System.Text.RegularExpressions;
using System.Threading;
/// <summary>Custom <see cref="Regex"/>-derived type for the AbcOrDefGeneratedRegex method.</summary>
[GeneratedCodeAttribute("System.Text.RegularExpressions.Generator", "7.0.8.17405")]
file sealed class AbcOrDefGeneratedRegex_0 : Regex
{
/// <summary>Cached, thread-safe singleton instance.</summary>
internal static readonly AbcOrDefGeneratedRegex_0 Instance = new();
/// <summary>Initializes the instance.</summary>
private AbcOrDefGeneratedRegex_0()
{
base.pattern = "abc|def";
base.roptions = RegexOptions.IgnoreCase;
ValidateMatchTimeout(Utilities.s_defaultTimeout);
base.internalMatchTimeout = Utilities.s_defaultTimeout;
base.factory = new RunnerFactory();
base.capsize = 1;
}
/// <summary>Provides a factory for creating <see cref="RegexRunner"/> instances to be used by methods on <see cref="Regex"/>.</summary>
private sealed class RunnerFactory : RegexRunnerFactory
{
/// <summary>Creates an instance of a <see cref="RegexRunner"/> used by methods on <see cref="Regex"/>.</summary>
protected override RegexRunner CreateInstance() => new Runner();
/// <summary>Provides the runner that contains the custom logic implementing the specified regular expression.</summary>
private sealed class Runner : RegexRunner
{
/// <summary>Scan the <paramref name="inputSpan"/> starting from base.runtextstart for the next match.</summary>
/// <param name="inputSpan">The text being scanned by the regular expression.</param>
protected override void Scan(ReadOnlySpan<char> inputSpan)
{
// Search until we can't find a valid starting position, we find a match, or we reach the end of the input.
while (TryFindNextPossibleStartingPosition(inputSpan) &&
!TryMatchAtCurrentPosition(inputSpan) &&
base.runtextpos != inputSpan.Length)
{
base.runtextpos++;
if (Utilities.s_hasTimeout)
{
base.CheckTimeout();
}
}
}
/// <summary>Search <paramref name="inputSpan"/> starting from base.runtextpos for the next location a match could possibly start.</summary>
/// <param name="inputSpan">The text being scanned by the regular expression.</param>
/// <returns>true if a possible match was found; false if no more matches are possible.</returns>
private bool TryFindNextPossibleStartingPosition(ReadOnlySpan<char> inputSpan)
{
int pos = base.runtextpos;
ulong charMinusLow;
// Any possible match is at least 3 characters.
if (pos <= inputSpan.Length - 3)
{
// The pattern matches a character in the set [CFcf] at index 2.
// Find the next occurrence. If it can't be found, there's no match.
ReadOnlySpan<char> span = inputSpan.Slice(pos);
for (int i = 0; i < span.Length - 2; i++)
{
int indexOfPos = span.Slice(i + 2).IndexOfAny("CFcf");
if (indexOfPos < 0)
{
goto NoMatchFound;
}
i += indexOfPos;
if (((long)((0x9000000090000000UL << (int)(charMinusLow = (uint)span[i] - 'A')) & (charMinusLow - 64)) < 0) &&
((long)((0x9000000090000000UL << (int)(charMinusLow = (uint)span[i + 1] - 'B')) & (charMinusLow - 64)) < 0))
{
base.runtextpos = pos + i;
return true;
}
}
}
// No match found.
NoMatchFound:
base.runtextpos = inputSpan.Length;
return false;
}
/// <summary>Determine whether <paramref name="inputSpan"/> at base.runtextpos is a match for the regular expression.</summary>
/// <param name="inputSpan">The text being scanned by the regular expression.</param>
/// <returns>true if the regular expression matches at the current position; otherwise, false.</returns>
private bool TryMatchAtCurrentPosition(ReadOnlySpan<char> inputSpan)
{
int pos = base.runtextpos;
int matchStart = pos;
ReadOnlySpan<char> slice = inputSpan.Slice(pos);
// Match with 2 alternative expressions, atomically.
{
if (slice.IsEmpty)
{
return false; // The input didn't match.
}
switch (slice[0])
{
case 'A' or 'a':
if ((uint)slice.Length < 3 ||
!slice.Slice(1).StartsWith("bc", StringComparison.OrdinalIgnoreCase)) // Match the string "bc" (ordinal case-insensitive)
{
return false; // The input didn't match.
}
pos += 3;
slice = inputSpan.Slice(pos);
break;
case 'D' or 'd':
if ((uint)slice.Length < 3 ||
!slice.Slice(1).StartsWith("ef", StringComparison.OrdinalIgnoreCase)) // Match the string "ef" (ordinal case-insensitive)
{
return false; // The input didn't match.
}
pos += 3;
slice = inputSpan.Slice(pos);
break;
default:
return false; // The input didn't match.
}
}
// The input matched.
base.runtextpos = pos;
base.Capture(0, matchStart, pos);
return true;
}
}
}
}
/// <summary>Helper methods used by generated <see cref="Regex"/>-derived implementations.</summary>
[GeneratedCodeAttribute("System.Text.RegularExpressions.Generator", "7.0.8.17405")]
file static class Utilities
{
/// <summary>Default timeout value set in <see cref="AppContext"/>, or <see cref="Regex.InfiniteMatchTimeout"/> if none was set.</summary>
internal static readonly TimeSpan s_defaultTimeout = AppContext.GetData("REGEX_DEFAULT_MATCH_TIMEOUT") is TimeSpan timeout ? timeout : Regex.InfiniteMatchTimeout;
/// <summary>Whether <see cref="s_defaultTimeout"/> is non-infinite.</summary>
internal static readonly bool s_hasTimeout = s_defaultTimeout != Timeout.InfiniteTimeSpan;
}
}
Code and pdf at
https://ignatandrei.github.io/RSCG_Examples/v2/docs/System.Text.Json
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