1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
|
// $Id: LexStream.java,v 1.3 1999/11/04 14:02:16 shields Exp $
// This software is subject to the terms of the IBM Jikes Compiler
// License Agreement available at the following URL:
// http://www.ibm.com/research/jikes.
// Copyright (C) 1983, 1999, International Business Machines Corporation
// and others. All Rights Reserved.
// You must accept the terms of that agreement to use this software.
import java.util.Vector;
import java.io.FileInputStream;
//
// LexStream holds a stream of tokens generated from an input and
// provides methods to retrieve information from the stream.
//
public class LexStream implements bnfsym
{
private int index;
final static int INFINITY = Integer.MAX_VALUE;
int Next(int i) { return (++i < tokens.size() ? i : tokens.size() - 1); }
int Previous(int i) { return (i <= 0 ? 0 : i - 1); }
int Peek() { return Next(index); }
void Reset(int i) { index = Previous(i); }
void Reset() { index = 0; }
int Gettoken() { return index = Next(index); }
int Gettoken(int end_token)
{ return index = (index < end_token ? Next(index) : tokens.size() - 1); }
int Badtoken() { return 0; }
int Kind(int i) { return ((Token) tokens.elementAt(i)).kind; }
String Name(int i) { return ((Token) tokens.elementAt(i)).name; }
//*
//* Constructors and Destructor.
//*
LexStream(String filename) throws java.io.FileNotFoundException
{
srcfile = new FileInputStream(filename);
}
void dump()
{
for (int i = 1; i < tokens.size(); i++)
{
System.out.print(" (");
switch(((Token) tokens.elementAt(i)).kind)
{
case TK_SYMBOL: System.out.print("SYMBOL"); break;
case TK_OR: System.out.print("|"); break;
case TK_PRODUCES: System.out.print("::="); break;
case TK_EOF: System.out.print("EOF"); break;
default: System.out.print(((Token) tokens.elementAt(i)).kind);
}
System.out.print(") : \"");
System.out.print(((Token) tokens.elementAt(i)).name);
System.out.println("\"");
}
}
Vector tokens = new Vector();
FileInputStream srcfile;
}
|
