1/*
2 * Permission is hereby granted, free of charge, to any person obtaining a copy of
3 * this software and associated documentation files (the "Software"), to deal in
4 * the Software without restriction, including without limitation the rights to
5 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
6 * of the Software, and to permit persons to whom the Software is furnished to do
7 * so, subject to the following conditions:
8 *
9 * The above copyright notice and this permission notice shall be included in all
10 * copies or substantial portions of the Software.
11 *
12 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
13 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
14 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
15 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
16 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
17 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
18 * SOFTWARE.
19 */
20package jdk.nashorn.internal.runtime.regexp.joni;
21
22import jdk.nashorn.internal.runtime.regexp.joni.encoding.IntHolder;
23import jdk.nashorn.internal.runtime.regexp.joni.exception.ErrorMessages;
24
25abstract class ScannerSupport extends IntHolder implements ErrorMessages {
26
27    protected final char[] chars;       // pattern
28    protected int p;                    // current scanner position
29    protected int stop;                 // pattern end (mutable)
30    private int lastFetched;            // last fetched value for unfetch support
31    protected int c;                    // current code point
32
33    private final int begin;            // pattern begin position for reset() support
34    private final int end;              // pattern end position for reset() support
35    protected int _p;                   // used by mark()/restore() to mark positions
36
37    private final static int INT_SIGN_BIT = 1 << 31;
38
39    protected ScannerSupport(final char[] chars, final int p, final int end) {
40        this.chars = chars;
41        this.begin = p;
42        this.end = end;
43
44        reset();
45    }
46
47    protected int getBegin() {
48        return begin;
49    }
50
51    protected int getEnd() {
52        return end;
53    }
54
55    protected final int scanUnsignedNumber() {
56        final int last = c;
57        int num = 0; // long ???
58        while(left()) {
59            fetch();
60            if (Character.isDigit(c)) {
61                final int onum = num;
62                num = num * 10 + EncodingHelper.digitVal(c);
63                if (((onum ^ num) & INT_SIGN_BIT) != 0) {
64                    return -1;
65                }
66            } else {
67                unfetch();
68                break;
69            }
70        }
71        c = last;
72        return num;
73    }
74
75    protected final int scanUnsignedHexadecimalNumber(final int maxLength) {
76        final int last = c;
77        int num = 0;
78        int ml = maxLength;
79        while(left() && ml-- != 0) {
80            fetch();
81            if (EncodingHelper.isXDigit(c)) {
82                final int onum = num;
83                final int val = EncodingHelper.xdigitVal(c);
84                num = (num << 4) + val;
85                if (((onum ^ num) & INT_SIGN_BIT) != 0) {
86                    return -1;
87                }
88            } else {
89                unfetch();
90                break;
91            }
92        }
93        c = last;
94        return num;
95    }
96
97    protected final int scanUnsignedOctalNumber(final int maxLength) {
98        final int last = c;
99        int num = 0;
100        int ml = maxLength;
101        while(left() && ml-- != 0) {
102            fetch();
103            if (Character.isDigit(c) && c < '8') {
104                final int onum = num;
105                final int val = EncodingHelper.odigitVal(c);
106                num = (num << 3) + val;
107                if (((onum ^ num) & INT_SIGN_BIT) != 0) {
108                    return -1;
109                }
110            } else {
111                unfetch();
112                break;
113            }
114        }
115        c = last;
116        return num;
117    }
118
119    protected final void reset() {
120        p = begin;
121        stop = end;
122    }
123
124    protected final void mark() {
125        _p = p;
126    }
127
128    protected final void restore() {
129        p = _p;
130    }
131
132    protected final void inc() {
133        lastFetched = p;
134        p++;
135    }
136
137    protected final void fetch() {
138        lastFetched = p;
139        c = chars[p++];
140    }
141
142    protected int fetchTo() {
143        lastFetched = p;
144        return chars[p++];
145    }
146
147    protected final void unfetch() {
148        p = lastFetched;
149    }
150
151    protected final int peek() {
152        return p < stop ? chars[p] : 0;
153    }
154
155    protected final boolean peekIs(final int ch) {
156        return peek() == ch;
157    }
158
159    protected final boolean left() {
160        return p < stop;
161    }
162
163}
164