/
XmlReaderExtensions.cs
113 lines (90 loc) · 4.28 KB
/
XmlReaderExtensions.cs
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
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using System.Xml;
namespace BlueChappie
{
public static class XmlReaderExtensions
{
private const long DefaultStreamReaderBufferSize = 1024;
public static long GetPosition(this XmlReader xr, StreamReader underlyingStreamReader)
{
// Get the position of the FileStream
long fileStreamPos = underlyingStreamReader.BaseStream.Position;
// Get current XmlReader state
long xmlReaderBufferLength = GetXmlReaderBufferLength(xr);
long xmlReaderBufferPos = GetXmlReaderBufferPosition(xr);
// Get current StreamReader state
long streamReaderBufferLength = GetStreamReaderBufferLength(underlyingStreamReader);
int streamReaderBufferPos = GetStreamReaderBufferPos(underlyingStreamReader);
long preambleSize = GetStreamReaderPreambleSize(underlyingStreamReader);
// Calculate the actual file position
long pos = fileStreamPos
- (streamReaderBufferLength == DefaultStreamReaderBufferSize ? DefaultStreamReaderBufferSize : 0)
- xmlReaderBufferLength
+ xmlReaderBufferPos + streamReaderBufferPos - preambleSize;
return pos;
}
#region Supporting methods
private static PropertyInfo _xmlReaderBufferSizeProperty;
private static long GetXmlReaderBufferLength(XmlReader xr)
{
if (_xmlReaderBufferSizeProperty == null)
{
_xmlReaderBufferSizeProperty = xr.GetType()
.GetProperty("DtdParserProxy_ParsingBufferLength",
BindingFlags.Instance | BindingFlags.NonPublic);
}
return (int)_xmlReaderBufferSizeProperty.GetValue(xr);
}
private static PropertyInfo _xmlReaderBufferPositionProperty;
private static int GetXmlReaderBufferPosition(XmlReader xr)
{
if (_xmlReaderBufferPositionProperty == null)
{
_xmlReaderBufferPositionProperty = xr.GetType()
.GetProperty("DtdParserProxy_CurrentPosition",
BindingFlags.Instance | BindingFlags.NonPublic);
}
return (int)_xmlReaderBufferPositionProperty.GetValue(xr);
}
private static PropertyInfo _streamReaderPreambleProperty;
private static long GetStreamReaderPreambleSize(StreamReader sr)
{
if (_streamReaderPreambleProperty == null)
{
_streamReaderPreambleProperty = sr.GetType()
.GetProperty("Preamble_Prop",
BindingFlags.Instance | BindingFlags.NonPublic);
}
return ((byte[])_streamReaderPreambleProperty.GetValue(sr)).Length;
}
private static PropertyInfo _streamReaderByteLenProperty;
private static long GetStreamReaderBufferLength(StreamReader sr)
{
if (_streamReaderByteLenProperty == null)
{
_streamReaderByteLenProperty = sr.GetType()
.GetProperty("ByteLen_Prop",
BindingFlags.Instance | BindingFlags.NonPublic);
}
return (int)_streamReaderByteLenProperty.GetValue(sr);
}
private static PropertyInfo _streamReaderBufferPositionProperty;
private static int GetStreamReaderBufferPos(StreamReader sr)
{
if (_streamReaderBufferPositionProperty == null)
{
_streamReaderBufferPositionProperty = sr.GetType()
.GetProperty("CharPos_Prop",
BindingFlags.Instance | BindingFlags.NonPublic);
}
return (int)_streamReaderBufferPositionProperty.GetValue(sr);
}
#endregion
}
}