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comparison graal/com.oracle.max.asmdis/src/com/sun/max/asm/InlineDataDecoder.java @ 3733:e233f5660da4

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Added Java files from Maxine project.
author Thomas Wuerthinger <thomas.wuerthinger@oracle.com>
date Sat, 17 Dec 2011 19:59:18 +0100
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children bc8527f3071c
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3732:3e2e8b8abdaf 3733:e233f5660da4
1 /*
2 * Copyright (c) 2007, 2011, 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 package com.sun.max.asm;
24
25 import java.io.*;
26 import java.util.*;
27
28 import com.sun.max.asm.InlineDataDescriptor.*;
29 import com.sun.max.io.*;
30 import com.sun.max.program.*;
31
32 /**
33 * A decoder for a sequence of {@linkplain InlineDataDescriptor inline data descriptors} associated with an
34 * instruction stream. The decoder is initialized either from an encoded or inflated sequence of descriptors.
35 *
36 * Once initialized, a inline data decoder can be {@linkplain #decode(int, BufferedInputStream) queried} for the
37 * inline data descriptor describing the inline data at a given position in an instruction stream.
38 */
39 public class InlineDataDecoder {
40
41 protected final Map<Integer, InlineDataDescriptor> positionToDescriptorMap;
42
43 /**
44 * Creates a decoder from an encoded sequence of inline data descriptors.
45 *
46 * @param encodedDescriptors a sequence of descriptors encoded in a byte array whose format complies with that used
47 * by {@link InlineDataRecorder#encodedDescriptors()}. This value can be null.
48 * @return null if {@code encodedDescriptors} is null
49 */
50 public static InlineDataDecoder createFrom(byte[] encodedDescriptors) {
51 if (encodedDescriptors != null) {
52 return new InlineDataDecoder(encodedDescriptors);
53 }
54 return null;
55 }
56
57 /**
58 * Creates a decoder based on the descriptors in a given recorder.
59 *
60 * @param inlineDataRecorder
61 * @return null if {@code inlineDataRecorder} does not contain any entries
62 */
63 public static InlineDataDecoder createFrom(InlineDataRecorder inlineDataRecorder) {
64 final List<InlineDataDescriptor> descriptors = inlineDataRecorder.descriptors();
65 if (descriptors != null) {
66 return new InlineDataDecoder(descriptors);
67 }
68 return null;
69 }
70
71 public InlineDataDecoder(List<InlineDataDescriptor> descriptors) {
72 positionToDescriptorMap = new TreeMap<Integer, InlineDataDescriptor>();
73 for (InlineDataDescriptor descriptor : descriptors) {
74 positionToDescriptorMap.put(descriptor.startPosition(), descriptor);
75 }
76 }
77
78 /**
79 * Creates a decoder from an encoded sequence of inline data descriptors.
80 *
81 * @param encodedDescriptors a sequence of descriptors encoded in a byte array whose format complies with that used
82 * by {@link InlineDataRecorder#encodedDescriptors()}
83 */
84 public InlineDataDecoder(byte[] encodedDescriptors) {
85 try {
86 final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(encodedDescriptors);
87 final DataInputStream dataInputStream = new DataInputStream(byteArrayInputStream);
88 final int numberOfEntries = dataInputStream.readInt();
89 positionToDescriptorMap = new TreeMap<Integer, InlineDataDescriptor>();
90 for (int i = 0; i < numberOfEntries; ++i) {
91 final Tag tag = InlineDataDescriptor.Tag.VALUES.get(dataInputStream.readByte());
92 final InlineDataDescriptor inlineDataDescriptor = tag.decode(dataInputStream);
93 positionToDescriptorMap.put(inlineDataDescriptor.startPosition(), inlineDataDescriptor);
94 }
95 assert byteArrayInputStream.available() == 0;
96 } catch (IOException ioException) {
97 throw ProgramError.unexpected(ioException);
98 }
99 }
100
101 /**
102 * Decodes the data (if any) from the current read position of a given stream.
103 *
104 * @param currentPosition the stream's current read position with respect to the start of the stream
105 * @param stream the instruction stream being disassembled
106 * @return the inline data decoded from the stream or null if there is no inline data at {@code currentPosition}
107 */
108 public InlineData decode(int currentPosition, BufferedInputStream stream) throws IOException {
109 final InlineDataDescriptor inlineDataDescriptor = positionToDescriptorMap.get(currentPosition);
110 if (inlineDataDescriptor != null) {
111 final int size = inlineDataDescriptor.size();
112 final byte[] data = new byte[size];
113 Streams.readFully(stream, data);
114 return new InlineData(inlineDataDescriptor, data);
115 }
116 return null;
117 }
118 }