| | | 1 | | // Licensed to the .NET Foundation under one or more agreements. |
| | | 2 | | // The .NET Foundation licenses this file to you under the MIT license. |
| | | 3 | | |
| | | 4 | | using System.Diagnostics; |
| | | 5 | | using System.Diagnostics.CodeAnalysis; |
| | | 6 | | |
| | | 7 | | namespace System.Text |
| | | 8 | | { |
| | | 9 | | public sealed class DecoderReplacementFallback : DecoderFallback |
| | | 10 | | { |
| | | 11 | | internal static readonly DecoderReplacementFallback s_default = new DecoderReplacementFallback(); |
| | | 12 | | |
| | | 13 | | // Our variables |
| | | 14 | | private readonly string _strDefault; |
| | | 15 | | |
| | | 16 | | // Construction. Default replacement fallback uses no best fit and ? replacement string |
| | | 17 | | public DecoderReplacementFallback() : this("?") |
| | | 18 | | { |
| | | 19 | | } |
| | | 20 | | |
| | | 21 | | public DecoderReplacementFallback(string replacement) |
| | | 22 | | { |
| | | 23 | | ArgumentNullException.ThrowIfNull(replacement); |
| | | 24 | | |
| | | 25 | | // Make sure it doesn't have bad surrogate pairs |
| | | 26 | | bool bFoundHigh = false; |
| | | 27 | | foreach (char c in replacement) |
| | | 28 | | { |
| | | 29 | | // Found a surrogate? |
| | | 30 | | if (char.IsSurrogate(c)) |
| | | 31 | | { |
| | | 32 | | // High or Low? |
| | | 33 | | if (char.IsHighSurrogate(c)) |
| | | 34 | | { |
| | | 35 | | // if already had a high one, stop |
| | | 36 | | if (bFoundHigh) |
| | | 37 | | break; // break & throw at the bFoundHIgh below |
| | | 38 | | bFoundHigh = true; |
| | | 39 | | } |
| | | 40 | | else |
| | | 41 | | { |
| | | 42 | | // Low, did we have a high? |
| | | 43 | | if (!bFoundHigh) |
| | | 44 | | { |
| | | 45 | | // Didn't have one, make if fail when we stop |
| | | 46 | | bFoundHigh = true; |
| | | 47 | | break; |
| | | 48 | | } |
| | | 49 | | |
| | | 50 | | // Clear flag |
| | | 51 | | bFoundHigh = false; |
| | | 52 | | } |
| | | 53 | | } |
| | | 54 | | // If last was high we're in trouble (not surrogate so not low surrogate, so break) |
| | | 55 | | else if (bFoundHigh) |
| | | 56 | | break; |
| | | 57 | | } |
| | | 58 | | if (bFoundHigh) |
| | | 59 | | throw new ArgumentException(SR.Argument_InvalidCharSequenceNoIndex, nameof(replacement)); |
| | | 60 | | |
| | | 61 | | _strDefault = replacement; |
| | | 62 | | } |
| | | 63 | | |
| | | 64 | | public string DefaultString => _strDefault; |
| | | 65 | | |
| | | 66 | | public override DecoderFallbackBuffer CreateFallbackBuffer() => |
| | | 67 | | new DecoderReplacementFallbackBuffer(this); |
| | | 68 | | |
| | | 69 | | // Maximum number of characters that this instance of this fallback could return |
| | | 70 | | public override int MaxCharCount => _strDefault.Length; |
| | | 71 | | |
| | | 72 | | public override bool Equals([NotNullWhen(true)] object? value) => |
| | | 73 | | value is DecoderReplacementFallback that && |
| | | 74 | | _strDefault == that._strDefault; |
| | | 75 | | |
| | | 76 | | public override int GetHashCode() => _strDefault.GetHashCode(); |
| | | 77 | | } |
| | | 78 | | |
| | | 79 | | public sealed class DecoderReplacementFallbackBuffer : DecoderFallbackBuffer |
| | | 80 | | { |
| | | 81 | | // Store our default string |
| | | 82 | | private readonly string _strDefault; |
| | 14457 | 83 | | private int _fallbackCount = -1; |
| | 14457 | 84 | | private int _fallbackIndex = -1; |
| | | 85 | | |
| | | 86 | | // Construction |
| | 14457 | 87 | | public DecoderReplacementFallbackBuffer(DecoderReplacementFallback fallback) |
| | | 88 | | { |
| | 14457 | 89 | | _strDefault = fallback.DefaultString; |
| | 14457 | 90 | | } |
| | | 91 | | |
| | | 92 | | // Fallback Methods |
| | | 93 | | public override bool Fallback(byte[] bytesUnknown, int index) |
| | | 94 | | { |
| | | 95 | | // We expect no previous fallback in our buffer |
| | | 96 | | // We can't call recursively but others might (note, we don't test on last char!) |
| | 1000650 | 97 | | if (_fallbackCount >= 1) |
| | | 98 | | { |
| | 0 | 99 | | ThrowLastBytesRecursive(bytesUnknown); |
| | | 100 | | } |
| | | 101 | | |
| | | 102 | | // Go ahead and get our fallback |
| | 1000650 | 103 | | if (_strDefault.Length == 0) |
| | 0 | 104 | | return false; |
| | | 105 | | |
| | 1000650 | 106 | | _fallbackCount = _strDefault.Length; |
| | 1000650 | 107 | | _fallbackIndex = -1; |
| | | 108 | | |
| | 1000650 | 109 | | return true; |
| | | 110 | | } |
| | | 111 | | |
| | | 112 | | public override char GetNextChar() |
| | | 113 | | { |
| | | 114 | | // We want it to get < 0 because == 0 means that the current/last character is a fallback |
| | | 115 | | // and we need to detect recursion. We could have a flag but we already have this counter. |
| | 4669700 | 116 | | _fallbackCount--; |
| | 4669700 | 117 | | _fallbackIndex++; |
| | | 118 | | |
| | | 119 | | // Do we have anything left? 0 is now last fallback char, negative is nothing left |
| | 4669700 | 120 | | if (_fallbackCount < 0) |
| | 1000650 | 121 | | return '\0'; |
| | | 122 | | |
| | | 123 | | // Need to get it out of the buffer. |
| | | 124 | | // Make sure it didn't wrap from the fast count-- path |
| | 3669050 | 125 | | if (_fallbackCount == int.MaxValue) |
| | | 126 | | { |
| | 0 | 127 | | _fallbackCount = -1; |
| | 0 | 128 | | return '\0'; |
| | | 129 | | } |
| | | 130 | | |
| | | 131 | | // Now make sure its in the expected range |
| | 3669050 | 132 | | Debug.Assert(_fallbackIndex < _strDefault.Length && _fallbackIndex >= 0, |
| | 3669050 | 133 | | "Index exceeds buffer range"); |
| | | 134 | | |
| | 3669050 | 135 | | return _strDefault[_fallbackIndex]; |
| | | 136 | | } |
| | | 137 | | |
| | | 138 | | public override bool MovePrevious() |
| | | 139 | | { |
| | | 140 | | // Back up one, only if we just processed the last character (or earlier) |
| | 0 | 141 | | if (_fallbackCount >= -1 && _fallbackIndex >= 0) |
| | | 142 | | { |
| | 0 | 143 | | _fallbackIndex--; |
| | 0 | 144 | | _fallbackCount++; |
| | 0 | 145 | | return true; |
| | | 146 | | } |
| | | 147 | | |
| | | 148 | | // Return false 'cause we couldn't do it. |
| | 0 | 149 | | return false; |
| | | 150 | | } |
| | | 151 | | |
| | | 152 | | // How many characters left to output? |
| | | 153 | | public override int Remaining => |
| | | 154 | | // Our count is 0 for 1 character left. |
| | 14457 | 155 | | (_fallbackCount < 0) ? 0 : _fallbackCount; |
| | | 156 | | |
| | | 157 | | // Clear the buffer |
| | | 158 | | public override unsafe void Reset() |
| | | 159 | | { |
| | 0 | 160 | | _fallbackCount = -1; |
| | 0 | 161 | | _fallbackIndex = -1; |
| | 0 | 162 | | byteStart = null; |
| | 0 | 163 | | } |
| | | 164 | | |
| | | 165 | | // This version just counts the fallback and doesn't actually copy anything. |
| | | 166 | | internal override unsafe int InternalFallback(byte[] bytes, byte* pBytes) => |
| | | 167 | | // Right now this has both bytes and bytes[], since we might have extra bytes, |
| | | 168 | | // hence the array, and we might need the index, hence the byte*. |
| | | 169 | | // Return our replacement string Length |
| | 0 | 170 | | _strDefault.Length; |
| | | 171 | | } |
| | | 172 | | } |
| | | 173 | | |