##// END OF EJS Templates
implab » ImplabNet
RSS
Working on text scanner
cin -
r173:ecfece82ca11 ref20160224
parent child
Show More
Show file before | Show file after | Hide comments
@@ -0,0 +1,143
1 using System;
2 using Implab.Automaton.RegularExpressions;
3 using Implab.Automaton;
4
5 namespace Implab.Formats {
6 public struct BufferScanner<TTag> {
7 char[] m_buffer;
8 int m_offset;
9 int m_position;
10 int m_hi;
11
12 readonly int m_chunk;
13 readonly int m_limit;
14
15 readonly DFAStateDescriptor<TTag>[] m_dfa;
16 int m_state;
17
18 public BufferScanner(DFAStateDescriptor<TTag>[] dfa, int initialState, int chunk, int limit) {
19 m_dfa = dfa;
20 m_state = initialState;
21 m_chunk = chunk;
22 m_limit = limit;
23 m_buffer = null;
24 m_offset = 0;
25 m_position = 0;
26 m_hi = 0;
27 }
28
29 public char[] Buffer {
30 get {
31 return m_buffer;
32 }
33 }
34
35 public int HiMark {
36 get {
37 return m_hi;
38 }
39 }
40
41 public int Position {
42 get {
43 return m_position;
44 }
45 }
46
47 public int Length {
48 get {
49 return m_hi - m_position;
50 }
51 }
52
53 public int TokenOffset {
54 get {
55 return m_offset;
56 }
57 }
58
59 public int TokenLength {
60 get {
61 return m_position - m_offset;
62 }
63 }
64
65 public void Init(char[] buffer, int position, int length) {
66 m_buffer = buffer;
67 m_position = position;
68 m_offset = position;
69 m_hi = position + length;
70 }
71
72 public int Extend() {
73 // free space
74 var free = m_buffer.Length - m_hi;
75
76 // if the buffer have enough free space
77 if (free > 0)
78 return free;
79
80 // effective size of the buffer
81 var size = m_buffer.Length - m_offset;
82
83 // calculate the new size
84 int grow = Math.Min(m_limit - size, m_chunk);
85 if (grow <= 0)
86 throw new ParserException(String.Format("Input buffer {0} bytes limit exceeded", m_limit));
87
88 var temp = new char[size + grow];
89 Array.Copy(m_buffer, m_offset, temp, 0, m_hi - m_offset);
90 m_position -= m_offset;
91 m_hi -= m_offset;
92 m_offset = 0;
93 m_buffer = temp;
94
95 return free + grow;
96 }
97
98 public void RaiseMark(int size) {
99 m_hi += size;
100 }
101
102 /// <summary>
103 /// Scan this instance.
104 /// </summary>
105 /// <returns><c>true</c> - additional data required</returns>
106 public bool Scan() {
107 while (m_position < m_hi) {
108 var ch = m_buffer[m_position];
109 var next = m_dfa[m_state].transitions[(int)ch];
110 if (next == DFAConst.UNREACHABLE_STATE) {
111 if (m_dfa[m_state].final)
112 return false;
113
114 throw new ParserException(
115 String.Format(
116 "Unexpected token '{0}'",
117 new string(m_buffer, m_offset, m_position - m_offset)
118 )
119 );
120 }
121 m_state = next;
122 m_position++;
123 }
124
125 return true;
126 }
127
128 public void Eof() {
129 if (!m_dfa[m_state].final)
130 throw new ParserException(
131 String.Format(
132 "Unexpected token '{0}'",
133 new string(m_buffer, m_offset, m_position - m_offset)
134 )
135 );
136 }
137
138 public TTag[] GetTokenTags() {
139 return m_dfa[m_state].tags;
140 }
141 }
142 }
143
Show file before | Show file after | Hide comments
@@ -0,0 +1,72
1 using System;
2 using Implab.Components;
3
4 namespace Implab.Formats {
5 public abstract class TextScanner<TTag> : Disposable {
6
7 char[] m_buffer;
8 int m_offset;
9 int m_length;
10 int m_tokenOffset;
11 int m_tokenLength;
12 TTag[] m_tags;
13
14 BufferScanner<TTag> m_scanner;
15
16 protected bool ReadTokenInternal() {
17 if (EOF)
18 return false;
19
20 // create a new scanner from template (scanners are structs)
21 var inst = m_scanner;
22
23 // initialize the scanner
24 inst.Init(m_buffer, m_offset, m_length);
25
26 // do work
27 while (inst.Scan())
28 Feed(ref inst);
29
30 // save result;
31 m_buffer = inst.Buffer;
32 m_length = inst.Length;
33 m_offset = inst.Position;
34 m_tokenOffset = inst.TokenOffset;
35 m_tokenLength = inst.TokenLength;
36
37 m_tags = inst.GetTokenTags();
38 }
39
40 protected string GetToken() {
41 return new String(m_buffer, m_tokenOffset, m_tokenLength);
42 }
43
44 protected TTag[] Tags {
45 get {
46 return m_tags;
47 }
48 }
49
50 /// <summary>
51 /// Feed the specified scanner.
52 /// </summary>
53 /// <param name="scanner">Scanner.</param>
54 /// <example>
55 /// protected override void Feed(ref BufferScanner<TTag> scanner) {
56 /// var size = scanner.Extend();
57 /// var actual = m_reader.Read(scanner.Buffer, scanner.HiMark, size);
58 /// if (actual == 0) {
59 /// m_eof = true;
60 /// scanner.Eof();
61 /// } else {
62 /// scanner.RaiseHiMark(actual);
63 /// }
64 /// }
65 /// </example>
66 protected abstract void Feed(ref BufferScanner<TTag> scanner);
67
68 public abstract bool EOF { get; }
69
70 }
71 }
72
Show file before | Show file after | Hide comments
@@ -191,6 +191,8
191 191 <Compile Include="Automaton\RegularExpressions\RegularExpressionVisitor.cs" />
192 192 <Compile Include="Automaton\RegularExpressions\ITaggedDFABuilder.cs" />
193 193 <Compile Include="Automaton\RegularExpressions\DFAStateDescriptorT.cs" />
194 <Compile Include="Formats\BufferScanner.cs" />
195 <Compile Include="Formats\TextScanner.cs" />
194 196 </ItemGroup>
195 197 <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
196 198 <ItemGroup />
General Comments 0
You need to be logged in to leave comments. Login now