ImageHeader.java revision 10967:e336cbd8b15e 
1232633Smp/*
259243Sobrien * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
359243Sobrien * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
459243Sobrien *
559243Sobrien * This code is free software; you can redistribute it and/or modify it
659243Sobrien * under the terms of the GNU General Public License version 2 only, as
759243Sobrien * published by the Free Software Foundation.  Oracle designates this
859243Sobrien * particular file as subject to the "Classpath" exception as provided
959243Sobrien * by Oracle in the LICENSE file that accompanied this code.
10232633Smp *
1159243Sobrien * This code is distributed in the hope that it will be useful, but WITHOUT
1259243Sobrien * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1359243Sobrien * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24*/
25
26package jdk.internal.jimage;
27
28import java.nio.ByteOrder;
29import java.nio.IntBuffer;
30
31public final class ImageHeader {
32    public static final int MAGIC = 0xCAFEDADA;
33    public static final int BADMAGIC = 0xDADAFECA;
34    public static final short MAJOR_VERSION = 0;
35    public static final short MINOR_VERSION = 1;
36
37    private final int magic;
38    private final short majorVersion;
39    private final short minorVersion;
40    private final int locationCount;
41    private final int locationsSize;
42    private final int stringsSize;
43
44    ImageHeader(int locationCount, int locationsSize, int stringsSize) {
45        this(MAGIC, MAJOR_VERSION, MINOR_VERSION, locationCount, locationsSize, stringsSize);
46    }
47
48    ImageHeader(int magic, short majorVersion, short minorVersion, int locationCount,
49                int locationsSize, int stringsSize)
50    {
51        this.magic = magic;
52        this.majorVersion = majorVersion;
53        this.minorVersion = minorVersion;
54        this.locationCount = locationCount;
55        this.locationsSize = locationsSize;
56        this.stringsSize = stringsSize;
57    }
58
59    static int getHeaderSize() {
60       return 4 +
61              2 + 2 +
62              4 +
63              4 +
64              4;
65    }
66
67    static ImageHeader readFrom(ByteOrder byteOrder, IntBuffer buffer) {
68        int magic = buffer.get(0);
69        int version = buffer.get(1);
70        short majorVersion = (short)(byteOrder == ByteOrder.BIG_ENDIAN ?
71            version >>> 16 : (version & 0xFFFF));
72        short minorVersion = (short)(byteOrder == ByteOrder.BIG_ENDIAN ?
73            (version & 0xFFFF) : version >>> 16);
74        int locationCount = buffer.get(2);
75        int locationsSize = buffer.get(3);
76        int stringsSize = buffer.get(4);
77
78        return new ImageHeader(magic, majorVersion, minorVersion, locationCount,
79                               locationsSize, stringsSize);
80    }
81
82    void writeTo(ImageStream stream) {
83        stream.putInt(magic);
84        stream.putShort(majorVersion);
85        stream.putShort(minorVersion);
86        stream.putInt(locationCount);
87        stream.putInt(locationsSize);
88        stream.putInt(stringsSize);
89    }
90
91    public int getMagic() {
92        return magic;
93    }
94
95    public int getMajorVersion() {
96        return majorVersion;
97    }
98
99    public int getMinorVersion() {
100        return minorVersion;
101    }
102
103    public int getLocationCount() {
104        return locationCount;
105    }
106
107    public int getRedirectSize() {
108        return locationCount* 4;
109    }
110
111    public int getOffsetsSize() {
112        return locationCount* 4;
113    }
114
115    public int getLocationsSize() {
116        return locationsSize;
117    }
118
119    public int getStringsSize() {
120        return stringsSize;
121    }
122
123    public int getIndexSize() {
124        return getHeaderSize() +
125               getRedirectSize() +
126               getOffsetsSize() +
127               getLocationsSize() +
128               getStringsSize();
129    }
130
131    int getRedirectOffset() {
132        return getHeaderSize();
133    }
134
135    int getOffsetsOffset() {
136        return getRedirectOffset() +
137               getRedirectSize();
138    }
139
140    int getLocationsOffset() {
141        return getOffsetsOffset() +
142               getOffsetsSize();
143    }
144
145    int getStringsOffset() {
146        return getLocationsOffset() +
147               getLocationsSize();
148    }
149}
150