using System.Collections.Generic; namespace System.Formats.Asn1 { internal abstract class RestrictedAsciiStringEncoding : SpanBasedEncoding { private readonly bool[] _isAllowed; protected RestrictedAsciiStringEncoding(byte minCharAllowed, byte maxCharAllowed) { bool[] array = new bool[128]; for (byte b = minCharAllowed; b <= maxCharAllowed; b = (byte)(b + 1)) { array[b] = true; } _isAllowed = array; } protected RestrictedAsciiStringEncoding(IEnumerable<char> allowedChars) { bool[] array = new bool[127]; foreach (char allowedChar in allowedChars) { if (allowedChar >= array.Length) throw new ArgumentOutOfRangeException("allowedChars"); array[allowedChar] = true; } _isAllowed = array; } public override int GetMaxByteCount(int charCount) { return charCount; } public override int GetMaxCharCount(int byteCount) { return byteCount; } protected override int GetBytes(ReadOnlySpan<char> chars, Span<byte> bytes, bool write) { if (chars.IsEmpty) return 0; for (int i = 0; i < chars.Length; i++) { char c = chars[i]; if ((uint)c >= (uint)_isAllowed.Length || !_isAllowed[c]) { base.EncoderFallback.CreateFallbackBuffer().Fallback(c, i); throw new InvalidOperationException(); } if (write) bytes[i] = (byte)c; } return chars.Length; } protected override int GetChars(ReadOnlySpan<byte> bytes, Span<char> chars, bool write) { if (bytes.IsEmpty) return 0; for (int i = 0; i < bytes.Length; i++) { byte b = bytes[i]; if ((uint)b >= (uint)_isAllowed.Length || !_isAllowed[b]) { base.DecoderFallback.CreateFallbackBuffer().Fallback(new byte[1] { b }, i); throw new InvalidOperationException(); } if (write) chars[i] = (char)b; } return bytes.Length; } } }