1/*
2 * Copyright (c) 2001, 2005, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25package sun.jvm.hotspot.oops;
26
27import sun.jvm.hotspot.code.*;
28import sun.jvm.hotspot.debugger.*;
29
30public class CompressedLineNumberReadStream extends CompressedReadStream {
31  /** Equivalent to CompressedLineNumberReadStream(buffer, 0) */
32  public CompressedLineNumberReadStream(Address buffer) {
33    this(buffer, 0);
34  }
35
36  public CompressedLineNumberReadStream(Address buffer, int position) {
37    super(buffer, position);
38  }
39
40  /** Read (bci, line number) pair from stream. Returns false at end-of-stream. */
41  public boolean readPair() {
42    int next = readByte() & 0xFF;
43    // Check for terminator
44    if (next == 0) return false;
45    if (next == 0xFF) {
46      // Escape character, regular compression used
47      bci  += readSignedInt();
48      line += readSignedInt();
49    } else {
50      // Single byte compression used
51      bci  += next >> 3;
52      line += next & 0x7;
53    }
54    return true;
55  }
56
57  public int bci()  { return bci;  }
58  public int line() { return line; }
59
60  //--------------------------------------------------------------------------------
61  // Internals only below this point
62  //
63
64  private int bci;
65  private int line;
66}
67