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Java > Open Source Codes > org > eclipse > jdt > internal > compiler > classfmt > ClassFileStruct


1 /*******************************************************************************
2  * Copyright (c) 2000, 2007 IBM Corporation and others.
3  * All rights reserved. This program and the accompanying materials
4  * are made available under the terms of the Eclipse Public License v1.0
5  * which accompanies this distribution, and is available at
6  * http://www.eclipse.org/legal/epl-v10.html
7  *
8  * Contributors:
9  * IBM Corporation - initial API and implementation
10  *******************************************************************************/
11 package org.eclipse.jdt.internal.compiler.classfmt;
12
13 abstract public class ClassFileStruct {
14     byte[] reference;
15     int[] constantPoolOffsets;
16     int structOffset;
17 public ClassFileStruct(byte[] classFileBytes, int[] offsets, int offset) {
18     reference = classFileBytes;
19     constantPoolOffsets = offsets;
20     structOffset = offset;
21 }
22 public double doubleAt(int relativeOffset) {
23     return (Double.longBitsToDouble(this.i8At(relativeOffset)));
24 }
25 public float floatAt(int relativeOffset) {
26     return (Float.intBitsToFloat(this.i4At(relativeOffset)));
27 }
28 public int i4At(int relativeOffset) {
29     int position = relativeOffset + structOffset;
30     return ((reference[position++] & 0xFF) << 24) | ((reference[position++] & 0xFF) << 16) | ((reference[position++] & 0xFF) << 8) + (reference[position] & 0xFF);
31 }
32 public long i8At(int relativeOffset) {
33     int position = relativeOffset + structOffset;
34     return (((long) (reference[position++] & 0xFF)) << 56)
35                     | (((long) (reference[position++] & 0xFF)) << 48)
36                     | (((long) (reference[position++] & 0xFF)) << 40)
37                     | (((long) (reference[position++] & 0xFF)) << 32)
38                     | (((long) (reference[position++] & 0xFF)) << 24)
39                     | (((long) (reference[position++] & 0xFF)) << 16)
40                     | (((long) (reference[position++] & 0xFF)) << 8)
41                     | (reference[position++] & 0xFF);
42 }
43 protected void reset() {
44     this.reference = null;
45     this.constantPoolOffsets = null;
46 }
47 public int u1At(int relativeOffset) {
48     return (reference[relativeOffset + structOffset] & 0xFF);
49 }
50 public int u2At(int relativeOffset) {
51     int position = relativeOffset + structOffset;
52     return ((reference[position++] & 0xFF) << 8) | (reference[position] & 0xFF);
53 }
54 public long u4At(int relativeOffset) {
55     int position = relativeOffset + structOffset;
56     return (((reference[position++] & 0xFFL) << 24) | ((reference[position++] & 0xFF) << 16) | ((reference[position++] & 0xFF) << 8) | (reference[position] & 0xFF));
57 }
58 public char[] utf8At(int relativeOffset, int bytesAvailable) {
59     int length = bytesAvailable;
60     char outputBuf[] = new char[bytesAvailable];
61     int outputPos = 0;
62     int readOffset = this.structOffset + relativeOffset;
63     
64     while (length != 0) {
65         int x = this.reference[readOffset++] & 0xFF;
66         length--;
67         if ((0x80 & x) != 0) {
68             if ((x & 0x20) != 0) {
69                 length-=2;
70                 x = ((x & 0xF) << 12) | ((this.reference[readOffset++] & 0x3F) << 6) | (this.reference[readOffset++] & 0x3F);
71             } else {
72                 length--;
73                 x = ((x & 0x1F) << 6) | (this.reference[readOffset++] & 0x3F);
74             }
75         }
76         outputBuf[outputPos++] = (char) x;
77     }
78
79     if (outputPos != bytesAvailable) {
80         System.arraycopy(outputBuf, 0, (outputBuf = new char[outputPos]), 0, outputPos);
81     }
82     return outputBuf;
83 }
84 }
85
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