using System.Threading; using System.Diagnostics.CodeAnalysis; namespace System.Text { internal sealed class InternalEncoderBestFitFallback : EncoderFallback { internal BaseCodePageEncoding encoding = _encoding; internal char[] arrayBestFit; public override int MaxCharCount => 1; internal InternalEncoderBestFitFallback(BaseCodePageEncoding _encoding) { } public override EncoderFallbackBuffer CreateFallbackBuffer() { return new InternalEncoderBestFitFallbackBuffer(this); } public override bool Equals([System.Diagnostics.CodeAnalysis.NotNullWhen(true)] object value) { InternalEncoderBestFitFallback internalEncoderBestFitFallback = value as InternalEncoderBestFitFallback; InternalEncoderBestFitFallback internalEncoderBestFitFallback; if (internalEncoderBestFitFallback != null) return encoding.CodePage == internalEncoderBestFitFallback.encoding.CodePage; return false; } public override int GetHashCode() { return encoding.CodePage; } } } namespace System.Text { internal sealed class InternalEncoderBestFitFallbackBuffer : EncoderFallbackBuffer { private char _cBestFit; private readonly InternalEncoderBestFitFallback _oFallback; private int _iCount = -1; private int _iSize; private static object s_InternalSyncObject; private static object InternalSyncObject { get { if (s_InternalSyncObject == null) { object value = new object(); Interlocked.CompareExchange<object>(ref s_InternalSyncObject, value, (object)null); } return s_InternalSyncObject; } } public override int Remaining { get { if (_iCount <= 0) return 0; return _iCount; } } public InternalEncoderBestFitFallbackBuffer(InternalEncoderBestFitFallback fallback) { _oFallback = fallback; if (_oFallback.arrayBestFit == null) { lock (InternalSyncObject) { InternalEncoderBestFitFallback oFallback = _oFallback; if (oFallback.arrayBestFit == null) oFallback.arrayBestFit = fallback.encoding.GetBestFitUnicodeToBytesData(); } } } public override bool Fallback(char charUnknown, int index) { _iCount = (_iSize = 1); _cBestFit = TryBestFit(charUnknown); if (_cBestFit == '') _cBestFit = '?'; return true; } public override bool Fallback(char charUnknownHigh, char charUnknownLow, int index) { if (!char.IsHighSurrogate(charUnknownHigh)) throw new ArgumentOutOfRangeException("charUnknownHigh", System.SR.Format(System.SR.ArgumentOutOfRange_Range, 55296, 56319)); if (!char.IsLowSurrogate(charUnknownLow)) throw new ArgumentOutOfRangeException("charUnknownLow", System.SR.Format(System.SR.ArgumentOutOfRange_Range, 56320, 57343)); _cBestFit = '?'; _iCount = (_iSize = 2); return true; } public override char GetNextChar() { _iCount--; if (_iCount < 0) return ''; if (_iCount == 2147483647) { _iCount = -1; return ''; } return _cBestFit; } public override bool MovePrevious() { if (_iCount >= 0) _iCount++; if (_iCount >= 0) return _iCount <= _iSize; return false; } public override void Reset() { _iCount = -1; } private char TryBestFit(char cUnknown) { int num = 0; int num2 = _oFallback.arrayBestFit.Length; int num3; while ((num3 = num2 - num) > 6) { int num4 = (num3 / 2 + num) & 65534; char c = _oFallback.arrayBestFit[num4]; if (c == cUnknown) return _oFallback.arrayBestFit[num4 + 1]; if (c < cUnknown) num = num4; else num2 = num4; } for (int num4 = num; num4 < num2; num4 += 2) { if (_oFallback.arrayBestFit[num4] == cUnknown) return _oFallback.arrayBestFit[num4 + 1]; } return ''; } } }