1 /*
2 * Copyright (c) 1997, 2008, 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * 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
26
27 /*
28 * The Original Code is HAT. The Initial Developer of the
29 * Original Code is Bill Foote, with contributions from others
30 * at JavaSoft/Sun.
31 */
32
33 package com.sun.tools.hat.internal.model;
34
35 import java.io.IOException;
36 import com.sun.tools.hat.internal.parser.ReadBuffer;
37
38 /*
39 * Base class for lazily read Java heap objects.
40 */
41 public abstract class JavaLazyReadObject extends JavaHeapObject {
42
43 // file offset from which this object data starts
44 private final long offset;
45
46 protected JavaLazyReadObject(long offset) {
47 this.offset = offset;
48 }
49
50 public final int getSize() {
51 return getValueLength() + getClazz().getMinimumObjectSize();
52 }
53
54 protected final long getOffset() {
55 return offset;
56 }
57
58 // return the length of the data for this object
59 protected final int getValueLength() {
60 try {
61 return readValueLength();
62 } catch (IOException exp) {
63 System.err.println("lazy read failed at offset " + offset);
64 exp.printStackTrace();
65 return 0;
66 }
67 }
68
69 // get this object's content as byte array
70 protected final byte[] getValue() {
71 try {
72 return readValue();
73 } catch (IOException exp) {
74 System.err.println("lazy read failed at offset " + offset);
75 exp.printStackTrace();
76 return Snapshot.EMPTY_BYTE_ARRAY;
77 }
78 }
79
80 // get ID of this object
81 public final long getId() {
82 try {
83 ReadBuffer buf = getClazz().getReadBuffer();
84 int idSize = getClazz().getIdentifierSize();
85 if (idSize == 4) {
86 return ((long)buf.getInt(offset)) & Snapshot.SMALL_ID_MASK;
87 } else {
88 return buf.getLong(offset);
89 }
90 } catch (IOException exp) {
91 System.err.println("lazy read failed at offset " + offset);
92 exp.printStackTrace();
93 return -1;
94 }
95 }
96
97 protected abstract int readValueLength() throws IOException;
98 protected abstract byte[] readValue() throws IOException;
99
100 // make Integer or Long for given object ID
101 protected static Number makeId(long id) {
102 if ((id & ~Snapshot.SMALL_ID_MASK) == 0) {
103 return new Integer((int)id);
104 } else {
105 return new Long(id);
106 }
107 }
108
109 // get ID as long value from Number
110 protected static long getIdValue(Number num) {
111 long id = num.longValue();
112 if (num instanceof Integer) {
113 id &= Snapshot.SMALL_ID_MASK;
114 }
115 return id;
116 }
117
118 // read object ID from given index from given byte array
119 protected final long objectIdAt(int index, byte[] data) {
120 int idSize = getClazz().getIdentifierSize();
121 if (idSize == 4) {
122 return ((long)intAt(index, data)) & Snapshot.SMALL_ID_MASK;
123 } else {
124 return longAt(index, data);
125 }
126 }
127
128 // utility methods to read primitive types from byte array
129 protected static byte byteAt(int index, byte[] value) {
130 return value[index];
131 }
132
133 protected static boolean booleanAt(int index, byte[] value) {
134 return (value[index] & 0xff) == 0? false: true;
135 }
136
137 protected static char charAt(int index, byte[] value) {
138 int b1 = ((int) value[index++] & 0xff);
139 int b2 = ((int) value[index++] & 0xff);
140 return (char) ((b1 << 8) + b2);
141 }
142
143 protected static short shortAt(int index, byte[] value) {
144 int b1 = ((int) value[index++] & 0xff);
145 int b2 = ((int) value[index++] & 0xff);
146 return (short) ((b1 << 8) + b2);
147 }
148
149 protected static int intAt(int index, byte[] value) {
150 int b1 = ((int) value[index++] & 0xff);
151 int b2 = ((int) value[index++] & 0xff);
152 int b3 = ((int) value[index++] & 0xff);
153 int b4 = ((int) value[index++] & 0xff);
154 return ((b1 << 24) + (b2 << 16) + (b3 << 8) + b4);
155 }
156
157 protected static long longAt(int index, byte[] value) {
158 long val = 0;
159 for (int j = 0; j < 8; j++) {
160 val = val << 8;
161 int b = ((int)value[index++]) & 0xff;
162 val |= b;
163 }
164 return val;
165 }
166
167 protected static float floatAt(int index, byte[] value) {
168 int val = intAt(index, value);
169 return Float.intBitsToFloat(val);
170 }
171
172 protected static double doubleAt(int index, byte[] value) {
173 long val = longAt(index, value);
174 return Double.longBitsToDouble(val);
175 }
176 }