[411] | 1 | /*!
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| 2 | @file Classes/System/Text/UTF8Encoding.ab
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| 3 | @brief UTF8Encodingクラスとそれに関係するクラスなどの宣言・定義
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| 4 | */
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| 5 |
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| 6 | Namespace System
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| 7 | Namespace Text
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| 8 |
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| 9 | Namespace Detail
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| 10 |
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| 11 | Class UTF8Encoder
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| 12 | Inherits Encoder
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| 13 | Protected
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[676] | 14 | Override Sub EncodeImpl(src As *WCHAR, size As SIZE_T, s As IO.Stream, last As Boolean)
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| 15 | Dim i As Long
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| 16 | For i = 0 To ELM(size)
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| 17 | If buffer <> 0 Then
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| 18 | If _System_IsLowSurrogate(src[i]) Then
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| 19 | 'UTF-16列からUnicodeコードポイントを復元
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| 20 | Dim c = (((buffer And &h3FF) As DWord << 10) Or (src[i] And &h3FF)) + &h10000
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| 21 | '4バイト変換
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| 22 | s.WriteByte(((c >> 18) Or &hf0) As Byte)
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| 23 | s.WriteByte(((c >> 12) And &h3F Or &h80) As Byte)
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| 24 | s.WriteByte(((c >> 6) And &h3F Or &h80) As Byte)
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| 25 | s.WriteByte((c And &h3F Or &h80) As Byte)
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| 26 | Else
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| 27 | writeReplacementChar(s)
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| 28 | End If
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| 29 | buffer = 0
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| 30 | ElseIf src[i] < &h80 Then
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[411] | 31 | '1バイト変換
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[676] | 32 | s.WriteByte(src[i] As Byte)
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| 33 | ElseIf src[i] < &h800 Then
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[411] | 34 | '2バイト変換
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[676] | 35 | s.WriteByte(((src[i] >> 6) Or &hC0) As Byte)
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| 36 | s.WriteByte((src[i] And &h3F Or &h80) As Byte)
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| 37 | ElseIf _System_IsHighSurrogate(src[i]) Then
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| 38 | 'バッファに貯め込む
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| 39 | buffer = src[i]
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| 40 | ElseIf _System_IsLowSurrogate(src[i]) Then
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| 41 | writeReplacementChar(s)
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[411] | 42 | Else
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| 43 | '3バイト変換
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[676] | 44 | s.WriteByte(((src[i] >> 12) Or &hE0) As Byte)
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| 45 | s.WriteByte(((src[i] >> 6) And &h3F Or &h80) As Byte)
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| 46 | s.WriteByte((src[i] And &h3F Or &h80) As Byte)
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[411] | 47 | End If
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| 48 | Next
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[676] | 49 | End Sub
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[411] | 50 |
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[676] | 51 | Private
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| 52 | ' U+FFFD Replacement CharacterのUTF-8表現、EF BF BDを書き込む。
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| 53 | Sub writeReplacementChar(s As IO.Stream)
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| 54 | Dim rc[2] = [&hef, &hbf, &hbd] As Byte
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| 55 | s.Write(rc, 0, Len(rc))
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[411] | 56 | End Sub
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| 57 |
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| 58 | buffer As WCHAR
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| 59 | End Class
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| 60 |
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| 61 | Class UTF8Decoder
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| 62 | Inherits Decoder
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| 63 | Protected
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[676] | 64 | Override Function DecodeImpl(dst As Collections.Generic.List<WCHAR>, s As IO.Stream) As Boolean
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| 65 | Dim i As Long
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| 66 | For i = 0 To DefalultDecodingBufferSize - 1 'ELM
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| 67 | Dim b = s.ReadByte()
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| 68 | If b = -1 Then
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| 69 | DecodeImpl = False
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| 70 | Exit Function
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| 71 | ElseIf state = 0 Then
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| 72 | If b <= &h80 Then
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[411] | 73 | '1バイト変換
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[676] | 74 | dst.Add(b As WCHAR)
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| 75 | ElseIf b < &hC0 Then
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| 76 | '先頭バイトがなく、いきなりマルチバイトの2バイト目以降
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| 77 | dst.Add(&hFFFD As WCHAR)
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| 78 | ElseIf b < &hD0 Then
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[411] | 79 | '2バイト文字の始まり
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| 80 | last = 2
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[676] | 81 | buffer = b And &h3F
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[411] | 82 | state++
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[676] | 83 | ElseIf b < &hF0 Then
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[411] | 84 | '3バイト文字の始まり
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| 85 | last = 3
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[676] | 86 | buffer = b And &h1F
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[411] | 87 | state++
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[676] | 88 | ElseIf b < &hF8 Then
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[411] | 89 | '4バイト文字の始まり
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| 90 | last = 4
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[676] | 91 | buffer = b And &h0F
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[411] | 92 | state++
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[676] | 93 | Else
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| 94 | '現在のUTF-8は4バイトを超える表現を認めていない。
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| 95 | dst.Add(&hFFFD As WCHAR)
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[411] | 96 | End If
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| 97 | Else
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[676] | 98 | If &h80 <= b And b < &hC0 Then
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[411] | 99 | 'マルチバイト文字の2バイト目以降
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[676] | 100 | buffer <<= 6
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| 101 | buffer Or= b And &h3F
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[411] | 102 | state++
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| 103 | If state = last Then '最終バイトに到達
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[676] | 104 | If state = 2 And buffer >= &h80 Then
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| 105 | dst.Add(buffer As WCHAR)
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| 106 | ElseIf state = 3 And buffer >= &h800 And buffer < &hD800 And &hE0000 >= buffer Then
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| 107 | dst.Add(buffer As WCHAR)
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| 108 | ElseIf state = 4 And buffer <= &h10FFFF Then
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| 109 | buffer -= &h10000
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| 110 | dst.Add((&hD800 Or (buffer >> 10)) As WCHAR)
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| 111 | dst.Add((&hDC00 Or (buffer And &h3FF)) As WCHAR)
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[411] | 112 | Else
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[682] | 113 | '最短形式でないもの、または4バイト形式で10FFFFを超えるコードポイントのもの
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[676] | 114 | dst.Add(&hfffd As WCHAR)
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[411] | 115 | End If
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| 116 | state = 0
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| 117 | End If
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| 118 | Else
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[676] | 119 | 'マルチバイト文字の途中なのに、それ以外のバイトが現れた場合
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| 120 | dst.Add(&hFFFD As WCHAR)
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| 121 | state = 0
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[411] | 122 | End If
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| 123 | End If
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| 124 | Next
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[676] | 125 | DecodeImpl = True
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| 126 | End Function
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[411] | 127 |
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| 128 | Private
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[676] | 129 | buffer As DWord
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[411] | 130 | state As Long
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| 131 | last As Long
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| 132 | End Class
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| 133 |
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| 134 | End Namespace 'Detail
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| 135 |
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| 136 |
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| 137 | /*!
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| 138 | @brief UTF-8用のEncoding
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| 139 | @date 2007/12/21
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| 140 | @auther Egtra
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| 141 | */
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| 142 | Class UTF8Encoding
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| 143 | Inherits Encoding
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| 144 | Public
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| 145 | Override Function Clone() As Object
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[676] | 146 | Clone = New UTF8Encoding
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[411] | 147 | End Function
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| 148 |
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| 149 | Override Function GetDecoder() As Decoder
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| 150 | GetDecoder = New Detail.UTF8Decoder
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| 151 | End Function
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| 152 |
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| 153 | Override Function GetEncoder() As Encoder
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| 154 | GetEncoder = New Detail.UTF8Encoder
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| 155 | End Function
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| 156 |
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| 157 | Override Function GetMaxByteCount(charCount As Long) As Long
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[676] | 158 | GetMaxByteCount = charCount * 3
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[411] | 159 | '全てがUTF-8で3バイトになる文字の場合が最大。
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| 160 |
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[676] | 161 | 'なお、UTF-8で4バイトになる列は、UTF-16だとサロゲートペアで表現するので、
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| 162 | '1単位あたりでは2バイトしか食わないことになり、最大ではない。
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[411] | 163 | End Function
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| 164 |
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| 165 | Override Function GetMaxCharCount(byteCount As Long) As Long
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| 166 | '全てU+7F以下の文字だけだった場合
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[676] | 167 | GetMaxCharCount = byteCount
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[411] | 168 | End Function
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| 169 |
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| 170 | Override Function GetPreamble() As *Byte
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| 171 | Return bom
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| 172 | End Function
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| 173 |
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| 174 | Override Function GetPreambleLength() As Long
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| 175 | Return Len(bom)
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| 176 | End Function
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[676] | 177 | /*
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[411] | 178 | Override Function BodyName() As String
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| 179 | Return "utf-8"
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| 180 | End Function
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| 181 |
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| 182 | Override Function HeaderName() As String
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| 183 | Return "utf-8"
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| 184 | End Function
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| 185 |
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| 186 | Override Function EncodingName() As String
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| 187 | Return "UTF-8"
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| 188 | End Function
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| 189 |
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| 190 | Override Function WebName() As String
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| 191 | Return "utf-8"
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| 192 | End Function
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| 193 |
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| 194 | Override Function IsSingleByte() As Boolean
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| 195 | Return False
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| 196 | End Function
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[676] | 197 | */
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| 198 |
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[411] | 199 | Private
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| 200 | Static bom[2] = [&hEF, &hBB, &hBF] As Byte
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| 201 | End Class
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| 202 |
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| 203 | End Namespace 'Text
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| 204 | End Namespace 'System
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