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1
23 package com.tc.jrexx.regex;
24
25 import java.util.Vector  ;
26 import java.text.ParsePosition ;
27
28 class PScanner {
29 public static final int UNLIMITED_MAX_LENGTH = Integer.MAX_VALUE;
30
31 private final Automaton_Pattern.TerminalFormat[] terminalFormats;
32 private final int[] terminalsMaxLength;
33 private final boolean terminalFormatsAreExclusive;
34
35 public PScanner(Automaton_Pattern.TerminalFormat[] terminalFormats) {
36 this(terminalFormats,false);
37 }
38
39 public PScanner(Automaton_Pattern.TerminalFormat[] terminalFormats, boolean terminalFormatsAreExclusive) {
40 this.terminalFormats = terminalFormats;
41 this.terminalFormatsAreExclusive = terminalFormatsAreExclusive;
42
43 final int n = this.terminalFormats.length;
44 if (!this.terminalFormatsAreExclusive) {
45 for (int i= (n-1)>>1; i>=0; --i) {
47 Automaton_Pattern.TerminalFormat temp = this.terminalFormats[i];
48 this.terminalFormats[i] = this.terminalFormats[n-i];
49 this.terminalFormats[n-i] = temp;
50 }
51 }
52 this.terminalsMaxLength = new int[n];
53 for (int i=0; i<n; i++) {
54 this.terminalsMaxLength[i] = this.terminalFormats[i].maxLength();
55 }
56 }
57
58
59 public Vector scan(String source) {
60 return this.scan(source,0);
61 }
62
63
64 public Vector scan(String source, int startIndex) {
65 if (source==null) {
66 String message = "null source specified";
67 throw new IllegalArgumentException (message);
68 }
69
70 final char[] input = source.toCharArray();
71
72 int firstIndexOfTerminalFormats = -1;
73 int lastIndexOfTerminalFormats = -1;
74
75 for (int i=this.terminalFormats.length-1; i>=0; i--) {
76 if (this.terminalFormats[i]!=null) {
77 lastIndexOfTerminalFormats = i;
78 break;
79 }
80 }
81
82 if (lastIndexOfTerminalFormats==-1) {
83 String message = "no terminal formats added";
84 throw new NullPointerException (message);
85 }
86
87 for (int i=0; i<=lastIndexOfTerminalFormats; i++) {
88 if (this.terminalFormats[i]!=null) {
89 firstIndexOfTerminalFormats = i;
90 break;
91 }
92 }
93
94 final Vector tokenList = new Vector ();
96 final int inputLength = input.length;
97 final ParsePosition pos = new ParsePosition (startIndex);
98 int index = startIndex;
99 while (index<inputLength) {
100 int longestMatch = -1;
101 Object lastToken = null, token;
102 for (int i=lastIndexOfTerminalFormats; i>=firstIndexOfTerminalFormats; i--) {
103 if (this.terminalsMaxLength[i]>=longestMatch) {
104 pos.setIndex(index);
105
106 token = this.terminalFormats[i].parseObject(input,pos);
109 final int matchLength = pos.getIndex()-index;
111 if (token!=null) {
112 if (this.terminalFormatsAreExclusive) {
113 longestMatch = matchLength;
114 lastToken = token;
115 break;
116 } else {
117 if (matchLength>=longestMatch) {
118 longestMatch = matchLength;
119 lastToken = token;
120 }
121 }
122 }
123 }
124 }
125 if (lastToken!=null) tokenList.addElement(lastToken);
127 else {
128 String message = "can not scan input:"
129 +"\n"+new String (input,startIndex,input.length-startIndex)
130 +"\nerrorPosition: "+index
131 +"\n"+new String (input,index,input.length-index);
132 throw new ParseException(message);
133 }
134 index+= longestMatch;
135 }
136
137 return tokenList;
138 }
139
140 public String toString() {
141 StringBuffer answer = new StringBuffer ();
142 answer.append("Scanner(");
143 if (this.terminalFormatsAreExclusive) answer.append("exclusive");
144 answer.append(")");
145 for (int i=0; i<this.terminalFormats.length; i++)
146 if (this.terminalFormats[i]!=null)
147 answer.append('\n').append(this.terminalFormats[i]);
148 return answer.toString();
149 }
150
151 } |
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Java API By Example, From Geeks To Geeks.