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comparison Implab/Formats/BufferScanner.cs @ 174:983df35b3ca1 ref20160224

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sync
author cin
date Fri, 18 Mar 2016 18:10:30 +0300
parents ecfece82ca11
children
comparison
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173:ecfece82ca11 174:983df35b3ca1
1 using System; 1 using System;
2 using Implab.Automaton.RegularExpressions; 2 using Implab.Automaton.RegularExpressions;
3 using Implab.Automaton; 3 using Implab.Automaton;
4 using System.Diagnostics;
4 5
5 namespace Implab.Formats { 6 namespace Implab.Formats {
6 public struct BufferScanner<TTag> { 7 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; 8 readonly DFAStateDescriptor<TTag>[] m_dfa;
16 int m_state; 9 int m_state;
10 int m_pos;
17 11
18 public BufferScanner(DFAStateDescriptor<TTag>[] dfa, int initialState, int chunk, int limit) { 12 public BufferScanner(DFAStateDescriptor<TTag>[] dfa, int initialState) {
19 m_dfa = dfa; 13 m_dfa = dfa;
20 m_state = initialState; 14 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 } 15 }
40 16
41 public int Position { 17 public int Position {
42 get { 18 get { return m_pos; }
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 } 19 }
101 20
102 /// <summary> 21 /// <summary>
103 /// Scan this instance. 22 /// Scan this instance.
104 /// </summary> 23 /// </summary>
105 /// <returns><c>true</c> - additional data required</returns> 24 /// <returns><c>true</c> - additional data required</returns>
106 public bool Scan() { 25 public bool Scan(int[] buffer, int position, int length) {
107 while (m_position < m_hi) { 26 var hi = position + length;
108 var ch = m_buffer[m_position]; 27 m_pos = position;
109 var next = m_dfa[m_state].transitions[(int)ch]; 28
29 while (position < hi) {
30 var next = m_dfa[m_state].transitions[buffer[position]];
110 if (next == DFAConst.UNREACHABLE_STATE) { 31 if (next == DFAConst.UNREACHABLE_STATE) {
111 if (m_dfa[m_state].final) 32 if (m_dfa[m_state].final)
112 return false; 33 return false;
113 34
114 throw new ParserException( 35 throw new ParserException(
115 String.Format( 36 String.Format(
116 "Unexpected token '{0}'", 37 "Unexpected symbol"
117 new string(m_buffer, m_offset, m_position - m_offset)
118 ) 38 )
119 ); 39 );
120 } 40 }
41 m_pos++;
121 m_state = next; 42 m_state = next;
122 m_position++;
123 } 43 }
124 44
125 return true; 45 return true;
126 } 46 }
127 47
128 public void Eof() { 48 public void Eof() {
129 if (!m_dfa[m_state].final) 49 if (!m_dfa[m_state].final)
130 throw new ParserException( 50 throw new ParserException(
131 String.Format( 51 String.Format(
132 "Unexpected token '{0}'", 52 "Unexpected EOF"
133 new string(m_buffer, m_offset, m_position - m_offset)
134 ) 53 )
135 ); 54 );
136 } 55 }
137 56
138 public TTag[] GetTokenTags() { 57 public TTag[] GetTokenTags() {