Mercurial > hg > Members > kono > PLparser

comparison src/plparser/PLCharScannerImpl.java @ 11:79d492bce828

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clean up
author one
date Thu, 02 Sep 2010 11:55:56 +0900
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children da8c1569b0c1
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10:0d74081c1309 11:79d492bce828
1 package plparser;
2
3 import java.io.FileNotFoundException;
4 import java.io.FileReader;
5 import java.io.IOException;
6 import java.io.InputStreamReader;
7 import java.nio.CharBuffer;
8
9 public abstract class PLCharScannerImpl<Node> extends PLScannerImpl<Node> {
10
11 public CharBuffer cb;
12
13
14 public PLCharScannerImpl(PLScanner<Node> plScannerImpl, Dictionary<Node> dict,
15 Token<Node> nullToken) {
16 super(plScannerImpl, dict, nullToken);
17 }
18
19 public PLCharScannerImpl() {
20 super();
21 }
22
23 public Token<Node> lookupDict(CharBuffer w, TokenID id) {
24 Token<Node> t;
25 String s = w.flip().toString();
26 if ((t = dict.get(s))==null) {
27 dict.put(s, t = new Token<Node>(s,id));
28 }
29 return nextToken = t;
30 }
31
32 public char nextChar() {
33 if (!cb.hasRemaining()) extendInput();
34 char ch = cb.get();
35 if (ch=='\n') lineno++;
36 return ch;
37 }
38
39 @Override
40 public boolean hasRemaining() {
41 return cb.hasRemaining()||extendInput();
42 }
43
44 protected boolean extendInput() {
45 if (file!=null && cb.position()!=0) {
46 // move remaining data to the top, set position for next read
47 cb.compact();
48 try {
49 if (prompt!=null) System.out.print(prompt);
50 if (file.read(cb)>0) {
51 cb.flip(); // prepare for get
52 return true;
53 } else {
54 throw new IOException();
55 }
56 } catch (IOException e) {
57 file = null ;
58 cb.flip();
59 }
60 }
61 return false;
62 }
63
64 @Override
65 public PLScanner<Node> set(String exp) {
66 cb = CharBuffer.wrap(exp);
67 filename = null; file = null;
68 nextToken = nullToken;
69 return this;
70 }
71
72 @Override
73 public PLScanner<Node> setFile(String file) throws FileNotFoundException {
74 this.filename = file;
75 nextToken = nullToken;
76 set(new FileReader(file));
77 return this;
78 }
79
80 @Override
81 public PLScanner<Node> set(InputStreamReader file) {
82 this.file = file;
83 cb = CharBuffer.allocate(BufferSize);
84 try {
85 if (prompt!=null) System.out.print(prompt);
86 if (file.read(cb) <= 0) {
87 throw new IOException();
88 }
89 } catch (IOException e) {
90 file = null; cb = null;
91 set("");
92 return this;
93 } finally {
94 cb.flip();
95 }
96 lineno = 0;
97 return this;
98 }
99
100 }