1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
|
<Type Name="Decoder" FullName="System.Text.Decoder" FullNameSP="System_Text_Decoder" Maintainer="ecma">
<TypeSignature Language="ILASM" Value=".class public abstract serializable Decoder extends System.Object" />
<TypeSignature Language="C#" Value="public abstract class Decoder" />
<MemberOfLibrary>BCL</MemberOfLibrary>
<AssemblyInfo>
<AssemblyName>mscorlib</AssemblyName>
<AssemblyPublicKey>[00 00 00 00 00 00 00 00 04 00 00 00 00 00 00 00 ]</AssemblyPublicKey>
<AssemblyVersion>1.0.5000.0</AssemblyVersion>
</AssemblyInfo>
<ThreadingSafetyStatement>All public static members of this type are safe for multithreaded operations. No instance members are guaranteed to be thread safe.</ThreadingSafetyStatement>
<Docs>
<summary>
<para> Converts blocks of bytes into blocks of characters,
maintaining state across successive calls for reading from a <see cref="T:System.IO.Stream" />.
</para>
</summary>
<remarks>
<para>
<block subset="none" type="note">Following instantiation of a decoder,
sequential blocks of bytes are converted into blocks of characters through calls
to the <see cref="M:System.Text.Decoder.GetChars(System.Byte[],System.Int32,System.Int32,System.Char[],System.Int32)" /> method. The decoder maintains state between the
conversions, allowing it to correctly decode a character whose bytes span
multiple blocks. This greatly assists decoding streams of bytes into
characters. An instance of a specific implementation of the
<see cref="T:System.Text.Decoder" />
class is typically obtained through a call to the <see cref="M:System.Text.Encoding.GetDecoder" />
method of a <see cref="T:System.Text.Encoding" /> object.</block>
</para>
</remarks>
<example>
<para> The following example demonstrates using the <see cref="T:System.Text.UTF8Encoding" />
implementation of the <see cref="T:System.Text.Decoder" /> class to convert two byte arrays to a character
array, where one character's bytes span multiple byte arrays. This demonstrates
how to use a <see cref="T:System.Text.Decoder" />
in streaming-like situations.</para>
<code lang="C#">
using System;
using System.Text;
public class DecoderExample
{
public static void Main()
{
// These bytes in UTF-8 correspond to 3 different
// Unicode characters - A (U+0041), # (U+0023),
// and the biohazard symbol (U+2623). Note the
// biohazard symbol requires 3 bytes in UTF-8
// (in hex, e2, 98, a3). Decoders store state across
// multiple calls to GetChars, handling the case
// when one char spans multiple byte arrays.
byte[] bytes1 = { 0x41, 0x23, 0xe2 };
byte[] bytes2 = { 0x98, 0xa3 };
char[] chars = new char[3];
Decoder d = Encoding.UTF8.GetDecoder();
int charLen = d.GetChars(bytes1, 0, bytes1.Length,
chars, 0);
// charLen is 2.
charLen += d.GetChars(bytes2, 0, bytes2.Length,
chars, charLen);
// charLen is now 3.
foreach(char c in chars)
Console.Write("U+{0:x} ", (ushort)c);
}
}
</code>
<para>The output is </para>
<c>
<para>U+41 U+23 U+2623</para>
</c>
</example>
</Docs>
<Base>
<BaseTypeName>System.Object</BaseTypeName>
</Base>
<Interfaces />
<Members>
<Member MemberName="GetChars">
<MemberSignature Language="ILASM" Value=".method public hidebysig virtual abstract int32 GetChars(class System.Byte[] bytes, int32 byteIndex, int32 byteCount, class System.Char[] chars, int32 charIndex)" />
<MemberSignature Language="C#" Value="public abstract int GetChars (byte[] bytes, int byteIndex, int byteCount, char[] chars, int charIndex);" />
<MemberType>Method</MemberType>
<ReturnValue>
<ReturnType>System.Int32</ReturnType>
</ReturnValue>
<Parameters>
<Parameter Name="bytes" Type="System.Byte[]" />
<Parameter Name="byteIndex" Type="System.Int32" />
<Parameter Name="byteCount" Type="System.Int32" />
<Parameter Name="chars" Type="System.Char[]" />
<Parameter Name="charIndex" Type="System.Int32" />
</Parameters>
<Docs>
<summary>
<para> Decodes the specified range of the specified array of bytes into the specified range
of the specified array of characters for a particular encoding.
</para>
</summary>
<param name="bytes">A <see cref="T:System.Byte" /> array to decode. </param>
<param name="byteIndex">A <see cref="T:System.Int32" /> that specifies the first index of <paramref name="bytes" /> from which to decode. </param>
<param name="byteCount">A <see cref="T:System.Int32" /> that specifies the number elements in <paramref name="bytes" /> to decode. </param>
<param name="chars">A <see cref="T:System.Char" /> array of characters to decode into. </param>
<param name="charIndex">A <see cref="T:System.Int32" /> that specifies the first index of <paramref name="chars" /> to store the decoded bytes. </param>
<returns>
<para> A <see cref="T:System.Int32" /> containing
the number of characters decoded into <paramref name="chars" /> for a
particular encoding.
</para>
</returns>
<exception cref="T:System.ArgumentException">
<para>
<paramref name="chars" /> does not contain sufficient space to store the decoded characters.</para>
</exception>
<exception cref="T:System.ArgumentNullException">
<para>
<paramref name="bytes " />is <see langword="null" /> . </para>
<para>-or- </para>
<para>
<paramref name="chars " />is <see langword="null" /> . </para>
</exception>
<exception cref="T:System.ArgumentOutOfRangeException">
<para>
<paramref name="byteIndex" /> < 0. </para>
<para> -or- </para>
<para>
<paramref name="byteCount " /> < 0. </para>
<para> -or- </para>
<para>
<paramref name="charIndex " /> < 0. </para>
<para> -or- </para>
<para>
<paramref name="byteIndex" /> and <paramref name="byteCount" /> do not specify a valid range in <paramref name="bytes" /> (i.e. (<paramref name="byteIndex " />+ <paramref name="byteCount " /> ) > <paramref name="bytes" />.Length). </para>
<para>-or- </para>
<para>
<paramref name="charIndex" /> > <paramref name="chars" />.Length.</para>
</exception>
<remarks>
<para>
<block subset="none" type="note">
<see cref="M:System.Text.Decoder.GetCharCount(System.Byte[],System.Int32,System.Int32)" /> can be used to determine the exact number of
characters that will be produced for a specified range of bytes.
Alternatively, <see cref="M:System.Text.Encoding.GetMaxCharCount(System.Int32)" /> of the <see cref="T:System.Text.Encoding" /> object that produced the current instance can be used to
determine the maximum number of characters that may be produced for a specified
number of bytes, regardless of the actual byte values.</block>
</para>
<para>
<block subset="none" type="behaviors">As described above.</block>
</para>
<para>
<block subset="none" type="overrides">Override this method to decode the values of a <see cref="T:System.Byte" /> array for a
particular encoding.</block>
</para>
<para>
<block subset="none" type="usage">Use this method to
decode the elements of a byte array for a particular encoding.</block>
</para>
</remarks>
</Docs>
<Excluded>0</Excluded>
</Member>
<Member MemberName="GetCharCount">
<MemberSignature Language="ILASM" Value=".method public hidebysig virtual abstract int32 GetCharCount(class System.Byte[] bytes, int32 index, int32 count)" />
<MemberSignature Language="C#" Value="public abstract int GetCharCount (byte[] bytes, int index, int count);" />
<MemberType>Method</MemberType>
<ReturnValue>
<ReturnType>System.Int32</ReturnType>
</ReturnValue>
<Parameters>
<Parameter Name="bytes" Type="System.Byte[]" />
<Parameter Name="index" Type="System.Int32" />
<Parameter Name="count" Type="System.Int32" />
</Parameters>
<Docs>
<summary>
<para> Determines the exact number of characters that will be produced by
decoding the specified range of the specified array of
bytes.
</para>
</summary>
<param name="bytes">A <see cref="T:System.Byte" /> array to decode. </param>
<param name="index">A <see cref="T:System.Int32" /> that specifies the first index in <paramref name="bytes" /> to decode. </param>
<param name="count">A <see cref="T:System.Int32" /> that specifies the number elements in <paramref name="bytes" /> to decode. </param>
<returns>
<para> A <see cref="T:System.Int32" /> containing
the number of characters the next call to <see cref="M:System.Text.Decoder.GetChars(System.Byte[],System.Int32,System.Int32,System.Char[],System.Int32)" /> will produce if presented with the
specified range of <paramref name="bytes" />
.</para>
<para>
<block subset="none" type="note">This value takes into account the state in which the current instance was
left following the last call to <see cref="M:System.Text.Decoder.GetChars(System.Byte[],System.Int32,System.Int32,System.Char[],System.Int32)" qualify="true" />. This
contrasts with <see cref="M:System.Text.Encoding.GetChars(System.Byte[])" qualify="true" />, which does not maintain state information
across subsequent calls.</block>
</para>
</returns>
<exception cref="T:System.ArgumentNullException">
<paramref name="bytes" /> is <see langword="null" /> . </exception>
<exception cref="T:System.ArgumentOutOfRangeException">
<para>
<paramref name="index" /> < 0. </para>
<para> -or- </para>
<para>
<paramref name="count" /> < 0. </para>
<para> -or- </para>
<para>
<paramref name="index " />and <paramref name="count " />do not specify a valid range in <paramref name="bytes" /> (i.e. (<paramref name="index" /> + <paramref name="count" />) > <paramref name="bytes" />.Length).</para>
</exception>
<remarks>
<para>
<block subset="none" type="behaviors">As described
above.</block>
</para>
<para>
<block subset="none" type="overrides">Override this
method
to return the appropriate value for a
particular encoding.</block>
</para>
<para>
<block subset="none" type="usage">Use this method to
determine the appropriate size of a buffer to contain the
decoded values.</block>
</para>
</remarks>
</Docs>
<Excluded>0</Excluded>
</Member>
<Member MemberName=".ctor">
<MemberSignature Language="ILASM" Value="family rtspecialname specialname instance void .ctor()" />
<MemberSignature Language="C#" Value="protected Decoder ();" />
<MemberType>Constructor</MemberType>
<ReturnValue />
<Parameters />
<Docs>
<summary>
<para> Constructs a new instance of the <see cref="T:System.Text.Decoder" /> class.
</para>
</summary>
<remarks>
<para>This constructor is called only by classes that inherit from the <see cref="T:System.Text.Decoder" /> class.</para>
</remarks>
</Docs>
<Excluded>0</Excluded>
</Member>
</Members>
<TypeExcluded>0</TypeExcluded>
</Type>
|
