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
|
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
/*============================================================
**
**
**
**
** Purpose: For writing text to a string
**
**
===========================================================*/
using System;
using System.Runtime;
using System.Text;
using System.Globalization;
using System.Diagnostics.Contracts;
using System.Runtime.InteropServices;
using System.Security.Permissions;
using System.Threading.Tasks;
namespace System.IO {
// This class implements a text writer that writes to a string buffer and allows
// the resulting sequence of characters to be presented as a string.
//
[Serializable]
[ComVisible(true)]
public class StringWriter : TextWriter
{
private static volatile UnicodeEncoding m_encoding=null;
private StringBuilder _sb;
private bool _isOpen;
// Constructs a new StringWriter. A new StringBuilder is automatically
// created and associated with the new StringWriter.
public StringWriter()
: this(new StringBuilder(), CultureInfo.CurrentCulture)
{
}
public StringWriter(IFormatProvider formatProvider)
: this(new StringBuilder(), formatProvider) {
}
// Constructs a new StringWriter that writes to the given StringBuilder.
//
public StringWriter(StringBuilder sb) : this(sb, CultureInfo.CurrentCulture) {
}
public StringWriter(StringBuilder sb, IFormatProvider formatProvider) : base(formatProvider) {
if (sb==null)
throw new ArgumentNullException("sb", Environment.GetResourceString("ArgumentNull_Buffer"));
Contract.EndContractBlock();
_sb = sb;
_isOpen = true;
}
public override void Close()
{
Dispose(true);
}
protected override void Dispose(bool disposing)
{
// Do not destroy _sb, so that we can extract this after we are
// done writing (similar to MemoryStream's GetBuffer & ToArray methods)
_isOpen = false;
base.Dispose(disposing);
}
public override Encoding Encoding {
get {
if (m_encoding==null) {
m_encoding = new UnicodeEncoding(false, false);
}
return m_encoding;
}
}
// Returns the underlying StringBuilder. This is either the StringBuilder
// that was passed to the constructor, or the StringBuilder that was
// automatically created.
//
public virtual StringBuilder GetStringBuilder() {
return _sb;
}
// Writes a character to the underlying string buffer.
//
public override void Write(char value) {
if (!_isOpen)
__Error.WriterClosed();
_sb.Append(value);
}
// Writes a range of a character array to the underlying string buffer.
// This method will write count characters of data into this
// StringWriter from the buffer character array starting at position
// index.
//
public override void Write(char[] buffer, int index, int count) {
if (buffer==null)
throw new ArgumentNullException("buffer", Environment.GetResourceString("ArgumentNull_Buffer"));
if (index < 0)
throw new ArgumentOutOfRangeException("index", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
if (count < 0)
throw new ArgumentOutOfRangeException("count", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
if (buffer.Length - index < count)
throw new ArgumentException(Environment.GetResourceString("Argument_InvalidOffLen"));
Contract.EndContractBlock();
if (!_isOpen)
__Error.WriterClosed();
_sb.Append(buffer, index, count);
}
// Writes a string to the underlying string buffer. If the given string is
// null, nothing is written.
//
public override void Write(String value) {
if (!_isOpen)
__Error.WriterClosed();
if (value != null) _sb.Append(value);
}
#region Task based Async APIs
[HostProtection(ExternalThreading = true)]
[ComVisible(false)]
public override Task WriteAsync(char value)
{
Write(value);
return Task.CompletedTask;
}
[HostProtection(ExternalThreading = true)]
[ComVisible(false)]
public override Task WriteAsync(String value)
{
Write(value);
return Task.CompletedTask;
}
[HostProtection(ExternalThreading = true)]
[ComVisible(false)]
public override Task WriteAsync(char[] buffer, int index, int count)
{
Write(buffer, index, count);
return Task.CompletedTask;
}
[HostProtection(ExternalThreading = true)]
[ComVisible(false)]
public override Task WriteLineAsync(char value)
{
WriteLine(value);
return Task.CompletedTask;
}
[HostProtection(ExternalThreading = true)]
[ComVisible(false)]
public override Task WriteLineAsync(String value)
{
WriteLine(value);
return Task.CompletedTask;
}
[HostProtection(ExternalThreading = true)]
[ComVisible(false)]
public override Task WriteLineAsync(char[] buffer, int index, int count)
{
WriteLine(buffer, index, count);
return Task.CompletedTask;
}
[HostProtection(ExternalThreading = true)]
[ComVisible(false)]
public override Task FlushAsync()
{
return Task.CompletedTask;
}
#endregion
// Returns a string containing the characters written to this TextWriter
// so far.
//
public override String ToString() {
return _sb.ToString();
}
}
}
|
