[C#] PHPでserialize()されたデータをC#で復元する

PHP
class Hoge
{
    public $id = 100;
    public $name = 'ほげ';
}

enum Piyo
{
    case Pi;
    case Pipi;
}

$data = [
    'null' => null,
    'int' => 123,
    'boolTrue' => true,
    'boolFalse' => false,
    'float' => 3.141592,
    'string' => 'ABC1230',
    'stringJp' => '日本語',
    'array'=> [10, 20, 30],
    'hashtable' => [
        'key1' => 'value1',
        'key2' => 'value2',
        3 => 123
    ],
    'enum' => Piyo::Pi,
    'hoge' => new Hoge()
];

echo serialize($data);

PHP
echo serialize('ABC"D:E;F');

C#
using System.Dynamic;
using System.Globalization;
using System.Text;
using System.Text.RegularExpressions;

using PHPArrayEntry = System.Collections.Generic.KeyValuePair<string, object?>;

namespace Tabiji.Code.Utility;

public static class PHP
{
    public static object? Deserialize(string text)
    {
        var deserializer = new PHPDeserializer(text);

        return deserializer.Execute();
    }

    private class PHPDeserializer
    {
        private static Regex NumberValuePattern = new(@"\G(?<value>[^;]+);");
        private static Regex LengthPattern = new(@"\G(?<value>[^:]+):");

        private static Regex NullPattern = new(@"\GN;");
        private static Regex IntPattern = new(@"\Gi:");
        private static Regex DoublePattern = new(@"\Gd:");
        private static Regex BoolPattern = new(@"\Gb:");
        private static Regex StringPattern = new(@"\Gs:");
        private static Regex ArrayPattern = new(@"\Ga:");

        private static Encoding UTF8 = new UTF8Encoding();

        private static NumberFormatInfo NumberFormat = new()
        {
            NumberGroupSeparator = "",
            NumberDecimalSeparator = "."
        };

        private string Text { get; set; }
        private int CurrentIndex { get; set; }

        public PHPDeserializer(string text)
        {
            this.Text = text;
        }

        public object? Execute()
        {
            if (this.Text == "")
                return "";

            this.CurrentIndex = 0;

            return this.Read();
        }

        private object? Read()
        {
            Match match;

            match = this.MatchTypeIdentifier(NullPattern);

            if (match.Success)
                return null;

            match = this.MatchTypeIdentifier(IntPattern);

            if (match.Success)
                return this.ReadIntValue();

            match = this.MatchTypeIdentifier(DoublePattern);

            if (match.Success)
                return this.ReadDoubleValue();

            match = this.MatchTypeIdentifier(BoolPattern);

            if (match.Success)
                return this.ReadBoolValue();

            match = this.MatchTypeIdentifier(StringPattern);

            if (match.Success)
                return this.ReadStringValue();

            match = this.MatchTypeIdentifier(ArrayPattern);

            if (match.Success)
                return this.ReadArrayValue();

            throw new InvalidDataException("invalid format");
        }

        private Match MatchTypeIdentifier(Regex pattern)
        {
            var match = pattern.Match(this.Text, this.CurrentIndex);

            if (match.Success)
                this.CurrentIndex += match.Length;

            return match;
        }

        private string ReadNumberString()
        {
            var match = NumberValuePattern.Match(this.Text, this.CurrentIndex);

            if (match.Success)
            {
                this.CurrentIndex += match.Length;

                return match.Groups["value"].Value;
            }

            throw new InvalidDataException("invalid number value format");
        }

        private string ReadLengthString()
        {
            var match = LengthPattern.Match(this.Text, this.CurrentIndex);

            if (match.Success)
            {
                this.CurrentIndex += match.Length;

                return match.Groups["value"].Value;
            }

            throw new InvalidDataException("invalid number value format");
        }

        private string ReadChar()
        {
            return this.Text.Substring(this.CurrentIndex++, 1);
        }

        private void Skip(string text)
        {
            var subText = this.Text.Substring(this.CurrentIndex, text.Length);

            if (text != subText)
                throw new InvalidDataException("invalid format");

            this.CurrentIndex += text.Length;
        }

        private object ReadIntValue()
        {
            var numberString = this.ReadNumberString();

            if (int.TryParse(numberString, out int intValue))
                return intValue;
            if (long.TryParse(numberString, out long longValue))
                return longValue;

            throw new InvalidDataException("invalid integer value format");
        }

        private object ReadDoubleValue()
        {
            var numberString = this.ReadNumberString();

            if (double.TryParse(numberString, NumberStyles.Number, NumberFormat, out double doubleValue))
                return doubleValue;

            throw new InvalidDataException("invalid double value format");
        }

        private object ReadBoolValue()
        {
            var value = this.ReadNumberString();

            if (value == "1")
                return true;
            if (value == "0")
                return false;

            throw new InvalidDataException("invalid bool value format");
        }

        private object ReadStringValue()
        {
            var lengthString = this.ReadLengthString();

            if (!int.TryParse(lengthString, out int length))
                throw new InvalidDataException("invalid string length format");

            this.Skip("\"");

            var value = new StringBuilder();
            var byteCount = 0;

            while (byteCount < length)
            {
                var c = this.ReadChar();

                byteCount += UTF8.GetByteCount(c);

                value.Append(c);
            }

            if (byteCount != length)
                throw new InvalidDataException("invalid string length format");

            this.Skip("\";");

            return value.ToString();
        }

        private object ReadArrayValue()
        {
            var lengthString = this.ReadLengthString();

            if (!int.TryParse(lengthString, out int length))
                throw new InvalidDataException("invalid string length format");

            var list = new List<PHPArrayEntry>();
            var isArray = true;

            this.Skip("{");

            for (int n = 0; n < length; n++)
            {
                var key = this.Read();
                var value = this.Read();

                if (key is not string && key is not int)
                    throw new InvalidDataException("invalid array key");

                if (key is not int || (int)key != n)
                    isArray = false;

                var keyString = key.ToString();

                if (keyString == null)
                    throw new InvalidDataException("invalid array key");

                var pair = new PHPArrayEntry(keyString, value);

                list.Add(pair);
            }

            this.Skip("}");

            if (isArray)
            {
                return Array.ConvertAll(list.ToArray(), item => item.Value);
            }
            else
            {
                var obj = new ExpandoObject();
                var dic = (IDictionary<string, object?>)obj;

                foreach (var item in list)
                    dic[item.Key] =item.Value;

                return obj;
            }
        }
    }
}

C#
var serializedText = @"a:2:{s:6:""SomeId"";i:123;s:8:""SomeName"";s:15:""何かの名前"";}";

dynamic? obj = PHP.Deserialize(serializedText) as ExpandoObject;

if (obj == null)
    return;

var id = obj.SomeId;
var name = obj.SomeName;