initial commit

2026-08-27 10:56:38 -06:00
commit 2e2fbbdb3c
4538 changed files with 820183 additions and 0 deletions
@@ -0,0 +1,205 @@
+using System.Collections.Generic;
+using System.Threading;
+
+namespace System.Text;
+
+public sealed class CodePagesEncodingProvider : EncodingProvider
+{
+	private static readonly EncodingProvider s_singleton = new CodePagesEncodingProvider();
+
+	private readonly Dictionary<int, Encoding> _encodings = new Dictionary<int, Encoding>();
+
+	private readonly ReaderWriterLockSlim _cacheLock = new ReaderWriterLockSlim();
+
+	private const int ISCIIAssemese = 57006;
+
+	private const int ISCIIBengali = 57003;
+
+	private const int ISCIIDevanagari = 57002;
+
+	private const int ISCIIGujarathi = 57010;
+
+	private const int ISCIIKannada = 57008;
+
+	private const int ISCIIMalayalam = 57009;
+
+	private const int ISCIIOriya = 57007;
+
+	private const int ISCIIPanjabi = 57011;
+
+	private const int ISCIITamil = 57004;
+
+	private const int ISCIITelugu = 57005;
+
+	private const int ISOKorean = 50225;
+
+	private const int ChineseHZ = 52936;
+
+	private const int ISO2022JP = 50220;
+
+	private const int ISO2022JPESC = 50221;
+
+	private const int ISO2022JPSISO = 50222;
+
+	private const int ISOSimplifiedCN = 50227;
+
+	private const int EUCJP = 51932;
+
+	private const int CodePageMacGB2312 = 10008;
+
+	private const int CodePageMacKorean = 10003;
+
+	private const int CodePageGB2312 = 20936;
+
+	private const int CodePageDLLKorean = 20949;
+
+	private const int GB18030 = 54936;
+
+	private const int DuplicateEUCCN = 51936;
+
+	private const int EUCKR = 51949;
+
+	private const int EUCCN = 936;
+
+	private const int ISO_8859_8I = 38598;
+
+	private const int ISO_8859_8_Visual = 28598;
+
+	public static EncodingProvider Instance => s_singleton;
+
+	private static int SystemDefaultCodePage
+	{
+		get
+		{
+			if (!global::Interop.Kernel32.TryGetACPCodePage(out var codePage))
+			{
+				return 0;
+			}
+			return codePage;
+		}
+	}
+
+	internal CodePagesEncodingProvider()
+	{
+	}
+
+	public override Encoding? GetEncoding(int codepage)
+	{
+		if (codepage < 0 || codepage > 65535)
+		{
+			return null;
+		}
+		if (codepage == 0)
+		{
+			int systemDefaultCodePage = SystemDefaultCodePage;
+			if (systemDefaultCodePage == 0)
+			{
+				return null;
+			}
+			return GetEncoding(systemDefaultCodePage);
+		}
+		Encoding value = null;
+		_cacheLock.EnterUpgradeableReadLock();
+		try
+		{
+			if (_encodings.TryGetValue(codepage, out value))
+			{
+				return value;
+			}
+			switch (BaseCodePageEncoding.GetCodePageByteSize(codepage))
+			{
+			case 1:
+				value = new SBCSCodePageEncoding(codepage);
+				break;
+			case 2:
+				value = new DBCSCodePageEncoding(codepage);
+				break;
+			default:
+				value = GetEncodingRare(codepage);
+				if (value == null)
+				{
+					return null;
+				}
+				break;
+			}
+			_cacheLock.EnterWriteLock();
+			try
+			{
+				if (_encodings.TryGetValue(codepage, out var value2))
+				{
+					return value2;
+				}
+				_encodings.Add(codepage, value);
+				return value;
+			}
+			finally
+			{
+				_cacheLock.ExitWriteLock();
+			}
+		}
+		finally
+		{
+			_cacheLock.ExitUpgradeableReadLock();
+		}
+	}
+
+	public override Encoding? GetEncoding(string name)
+	{
+		int codePageFromName = System.Text.EncodingTable.GetCodePageFromName(name);
+		if (codePageFromName == 0)
+		{
+			return null;
+		}
+		return GetEncoding(codePageFromName);
+	}
+
+	private static Encoding GetEncodingRare(int codepage)
+	{
+		Encoding result = null;
+		switch (codepage)
+		{
+		case 57002:
+		case 57003:
+		case 57004:
+		case 57005:
+		case 57006:
+		case 57007:
+		case 57008:
+		case 57009:
+		case 57010:
+		case 57011:
+			result = new ISCIIEncoding(codepage);
+			break;
+		case 10008:
+			result = new DBCSCodePageEncoding(10008, 20936);
+			break;
+		case 10003:
+			result = new DBCSCodePageEncoding(10003, 20949);
+			break;
+		case 54936:
+			result = new GB18030Encoding();
+			break;
+		case 50220:
+		case 50221:
+		case 50222:
+		case 50225:
+		case 52936:
+			result = new ISO2022Encoding(codepage);
+			break;
+		case 50227:
+		case 51936:
+			result = new DBCSCodePageEncoding(codepage, 936);
+			break;
+		case 51932:
+			result = new EUCJPEncoding();
+			break;
+		case 51949:
+			result = new DBCSCodePageEncoding(codepage, 20949);
+			break;
+		case 38598:
+			result = new SBCSCodePageEncoding(codepage, 28598);
+			break;
+		}
+		return result;
+	}
+}