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UTF8Encoding.ab@ 478

Last change on this file since 478 was 411, checked in by イグトランス (egtra), 17 years ago
UTF8Encoding（仮）の追加
File size: 6.6 KB

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1	/*!
2	@file Classes/System/Text/UTF8Encoding.ab
3	@brief UTF8Encodingクラスとそれに関係するクラスなどの宣言・定義
4	*/
5
6	Namespace System
7	Namespace Text
8
9	Namespace Detail
10
11	Class UTF8Encoder
12	Inherits Encoder
13	Protected
14	Override Sub ConvertCore(chars As WCHAR, charCount As Long, bytes As Byte, byteCount As Long, flush As Boolean,
15	ByRef bytesUsed As Long, ByRef charsUsed As Long, ByRef completed As Boolean)
16
17	Dim i As Long, j = 0 As Long
18	For i = 0 To ELM(charCount)
19	If chars[i] < &h80 Then
20	'1バイト変換
21	If j + 1 > byteCount Then
22	'バッファ不足
23	Goto *BufferOver
24	End If
25	bytes[j] = chars[i] As Byte
26	j++
27	ElseIf chars[i] < &h800 Then
28	'2バイト変換
29	If j + 2 > byteCount Then
30	Goto *BufferOver
31	End If
32	bytes[j] = ((chars[i] >> 6) Or &hC0) As Byte
33	j++
34	bytes[j] = (chars[i] And &h3F Or &h80) As Byte
35	j++
36	ElseIf _System_IsHighSurrogate(chars[i]) Then
37	If i + 1 >= charCount Then
38	'バッファに貯め込む
39	If flush = False Then
40	buffer = chars[i]
41	Exit Sub
42	End If
43	'ToDo: chars[i + 1]が範囲外になる場合が考慮されていない
44	ElseIf _System_IsLowSurrogate(chars[i + 1]) = False Then
45	'EncoderFallback
46	End If
47	If j + 4 > byteCount Then
48	Goto *BufferOver
49	End If
50	'UTF-16列からUnicodeコードポイントを復元
51	Dim c = (((chars[i] And &h3FF) As DWord << 10) Or (chars[i + 1] And &h3FF)) + &h10000
52	'4バイト変換
53	bytes[j] = ((c >> 18) Or &hf0) As Byte
54	j++
55	bytes[j] = ((c >> 12) And &h3F Or &h80) As Byte
56	j++
57	bytes[j] = ((c >> 6) And &h3F Or &h80) As Byte
58	j++
59	bytes[j] = (c And &h3F Or &h80) As Byte
60	j++
61	i++
62	ElseIf _System_IsLowSurrogate(chars[i]) Then
63	'EncoderFallback
64	Else
65	'3バイト変換
66	If j + 3 > byteCount Then
67	Goto *BufferOver
68	End If
69	bytes[j] = ((chars[i] >> 12) Or &hE0) As Byte
70	j++
71	bytes[j] = ((chars[i] >> 6) And &h3F Or &h80) As Byte
72	j++
73	bytes[j] = (chars[i] And &h3F Or &h80) As Byte
74	j++
75	End If
76	Next
77
78	Exit Sub
79	*BufferOver
80	'バッファ不足
81	Throw New ArgumentException("Buffer is not enough.", "bytes")
82	End Sub
83
84	Private
85	buffer As WCHAR
86	End Class
87
88	Class UTF8Decoder
89	Inherits Decoder
90	Protected
91	Override Sub ConvertCore(bytes As Byte, byteCount As Long, chars As WCHAR, charCount As Long, flush As Boolean,
92	ByRef bytesUsed As Long, ByRef charsUsed As Long, ByRef completed As Boolean)
93	Dim i As Long, j = 0 As Long
94	For i = 0 To ELM(byteCount)
95	If state = 0 Then
96	If bytes[i] <= &h80 Then
97	'1バイト変換
98	If j = charCount Then Goto *BufferOver
99	chars[j] = bytes[i]
100	j++
101	ElseIf bytes[i] < &hC0 Then
102	'マルチバイトの2バイト目以降
103	'DecoderFallback完成までの暫定
104	If j = charCount Then Goto *BufferOver
105	chars[j] = &hfffd
106	j++
107	ElseIf bytes[i] < &hD0 Then
108	'2バイト文字の始まり
109	last = 2
110	buf = bytes[i] And &h3f
111	state++
112	ElseIf bytes[i] < &hF0 Then
113	'3バイト文字の始まり
114	last = 3
115	buf = bytes[i] And &h1f
116	state++
117	Else
118	'4バイト文字の始まり
119	last = 4
120	buf = bytes[i] And &h0f
121	state++
122	End If
123	Else
124	If &h80 <= bytes[i] And bytes[i] < &hC0 Then
125	'マルチバイト文字の2バイト目以降
126	buf <<= 6
127	buf Or= bytes[i] And &h3F
128	state++
129	If state = last Then '最終バイトに到達
130	If state = 2 And buf >= &h80 Then
131	chars[j] = buf As WCHAR
132	j++
133	ElseIf state = 3 And buf >= &h800 And buf < &hD800 And &hE0000 >= buf Then
134	chars[j] = buf As WCHAR
135	j++
136	ElseIf state = 4 And buf <= &h10ffff Then
137	buf -= &h10000
138	chars[j] = (&hD800 Or (buf >> 10)) As WCHAR
139	j++
140	chars[j] = (&hDC00 Or (buf And &h3FF)) As WCHAR
141	j++
142	Else
143	'DecoderFallback
144	If j = charCount Then Goto *BufferOver
145	chars[j] = &hfffd
146	j++
147	End If
148	state = 0
149	End If
150	Else
151	'3, 4バイト文字の先頭
152	'DecoderFallback
153	If j = charCount Then Goto *BufferOver
154	chars[j] = &hfffd
155	j++
156	End If
157	End If
158	Next
159	Exit Sub
160	*BufferOver
161	'バッファ不足
162	Throw New ArgumentException("Buffer is not enough.", "bytes")
163	End Sub
164
165	Private
166	buf As DWord
167	state As Long
168	last As Long
169	End Class
170
171	End Namespace 'Detail
172
173
174	/*!
175	@brief UTF-8用のEncoding
176	@date 2007/12/21
177	@auther Egtra
178	*/
179	Class UTF8Encoding
180	Inherits Encoding
181	Public
182
183	Override Function Clone() As Object
184	Dim c = New UTF8Encoding
185	c.DecoderFallback = This.DecoderFallback
186	c.EncoderFallback = This.EncoderFallback
187	Return c
188	End Function
189
190	Override Function GetDecoder() As Decoder
191	GetDecoder = New Detail.UTF8Decoder
192	' GetDecoder.Fallback = DecoderFallback
193	End Function
194
195	Override Function GetEncoder() As Encoder
196	GetEncoder = New Detail.UTF8Encoder
197	' GetEncoder.Fallback = EncoderFallback
198	End Function
199
200	Override Function GetMaxByteCount(charCount As Long) As Long
201	Return charCount * 3
202	'全てがUTF-8で3バイトになる文字の場合が最大。
203
204	'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、
205	'1単位あたりでは2バイトしか食わないことになる。
206	End Function
207
208	Override Function GetMaxCharCount(byteCount As Long) As Long
209	'全てU+7F以下の文字だけだった場合
210	Return byteCount
211	End Function
212	Protected
213	Override Function GetBytesCountCore(s As *WCHAR, n As Long) As Long
214	End Function
215
216	Override Function GetBytesCore(chars As WCHAR, charCount As Long, bytes As Byte, byteCount As Long) As Long
217	End Function
218
219	Override Function GetCharsCountCore(s As *Byte, n As Long) As Long
220	End Function
221
222	Override Function GetCharsCore(bytes As Byte, byteCount As Long, chars As WCHAR, charCount As Long) As Long
223	End Function
224	Public
225	Override Function GetPreamble() As *Byte
226	Return bom
227	End Function
228
229	Override Function GetPreambleLength() As Long
230	Return Len(bom)
231	End Function
232
233	Override Function IsAlwaysNormalized() As Boolean
234	IsAlwaysNormalized = False
235	End Function
236
237	Override Function IsAlwaysNormalized(f As NormalizationForm) As Boolean
238	IsAlwaysNormalized = False
239	End Function
240
241	Override Function BodyName() As String
242	Return "utf-8"
243	End Function
244
245	Override Function HeaderName() As String
246	Return "utf-8"
247	End Function
248
249	Override Function EncodingName() As String
250	Return "UTF-8"
251	End Function
252
253	Override Function WebName() As String
254	Return "utf-8"
255	End Function
256
257	Override Function IsSingleByte() As Boolean
258	Return False
259	End Function
260	Private
261	Static bom[2] = [&hEF, &hBB, &hBF] As Byte
262	End Class
263
264	End Namespace 'Text
265	End Namespace 'System

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