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comparison Implab/Formats/InputScanner.cs @ 228:6fa235c5a760 v2

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Rewritten JsonScanner, JsonParser, fixed naming style
author cin
date Tue, 12 Sep 2017 01:19:12 +0300
parents
children 5f7a3e1d32b9
comparison
equal deleted inserted replaced
227:8d5de4eb9c2c 228:6fa235c5a760
1 using Implab.Automaton;
2 using System;
3 using System.Collections.Generic;
4 using System.Linq;
5 using System.Text;
6 using System.Threading.Tasks;
7
8 namespace Implab.Formats {
9 public class InputScanner<TTag> {
10 readonly TTag[] m_tags;
11 readonly int m_initialState;
12 readonly int[,] m_dfa;
13 readonly CharMap m_alphabet;
14 readonly bool[] m_final;
15
16 int m_position;
17 int m_state;
18
19 public InputScanner(int[,] dfaTable, bool[] finalStates, TTag[] tags, int initialState, CharMap alphabet) {
20 Safe.ArgumentNotNull(dfaTable, nameof(dfaTable));
21 Safe.ArgumentNotNull(finalStates, nameof(finalStates));
22 Safe.ArgumentNotNull(tags, nameof(tags));
23 Safe.ArgumentNotNull(alphabet, nameof(alphabet));
24
25 m_dfa = dfaTable;
26 m_final = finalStates;
27 m_tags = tags;
28 m_initialState = initialState;
29 m_alphabet = alphabet;
30 }
31
32 public TTag Tag {
33 get {
34 return m_tags[m_state];
35 }
36 }
37
38 public int Position {
39 get {
40 return m_position;
41 }
42 }
43
44 public bool IsFinal {
45 get {
46 return m_final[m_state];
47 }
48 }
49
50 public void Reset() {
51 m_state = m_initialState;
52 }
53
54 public InputScanner<TTag> Clone() {
55 var clone = new InputScanner<TTag>(m_dfa, m_final, m_tags, m_initialState, m_alphabet);
56 clone.m_state = m_state;
57 clone.m_position = m_position;
58 return clone;
59 }
60
61 public bool Scan(char[] data, int offset, int length) {
62 if (length <= 0) {
63 m_position = offset;
64 return false; // EOF
65 }
66
67 var max = offset + length;
68 var next = m_state;
69
70 while(offset < max) {
71 next = m_dfa[next, m_alphabet.Translate(data[offset])];
72 if (next == AutomatonConst.UNREACHABLE_STATE) {
73 // scanner stops on the next position after last recognized symbol
74 m_position = offset;
75 return false;
76 }
77 m_state = next;
78 offset++;
79 }
80 m_position = offset;
81 return true;
82 }
83 }
84 }