1 /* 2 * Copyright (c) 2014, 2016, 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 package jdk.internal.jimage; 27 28 import java.nio.ByteBuffer; 29 import java.nio.ByteOrder; 30 import java.util.Arrays; 31 import java.util.Objects; 32 33 /** 34 * @implNote This class needs to maintain JDK 8 source compatibility. 35 * 36 * It is used internally in the JDK to implement jimage/jrtfs access, 37 * but also compiled and delivered as part of the jrtfs.jar to support access 38 * to the jimage file provided by the shipped JDK by tools running on JDK 8. 39 */ 40 public class ImageStream { 41 private ByteBuffer buffer; 42 43 public ImageStream() { 44 this(1024, ByteOrder.nativeOrder()); 45 } 46 47 public ImageStream(int size) { 48 this(size, ByteOrder.nativeOrder()); 49 } 50 51 public ImageStream(byte[] bytes) { 52 this(bytes, ByteOrder.nativeOrder()); 53 } 54 55 public ImageStream(ByteOrder byteOrder) { 56 this(1024, byteOrder); 57 } 58 59 public ImageStream(int size, ByteOrder byteOrder) { 60 buffer = ByteBuffer.allocate(size); 61 buffer.order(Objects.requireNonNull(byteOrder)); 62 } 63 64 public ImageStream(byte[] bytes, ByteOrder byteOrder) { 65 buffer = ByteBuffer.wrap(Objects.requireNonNull(bytes)); 66 buffer.order(Objects.requireNonNull(byteOrder)); 67 } 68 69 public ImageStream(ByteBuffer buffer) { 70 this.buffer = Objects.requireNonNull(buffer); 71 } 72 73 public ImageStream align(int alignment) { 74 int padding = (getSize() - 1) & ((1 << alignment) - 1); 75 76 for (int i = 0; i < padding; i++) { 77 put((byte)0); 78 } 79 80 return this; 81 } 82 83 public void ensure(int needs) { 84 if (needs < 0) { 85 throw new IndexOutOfBoundsException("Bad value: " + needs); 86 } 87 88 if (needs > buffer.remaining()) { 89 byte[] bytes = buffer.array(); 90 ByteOrder byteOrder = buffer.order(); 91 int position = buffer.position(); 92 int newSize = needs <= bytes.length ? bytes.length << 1 : position + needs; 93 buffer = ByteBuffer.allocate(newSize); 94 buffer.order(byteOrder); 95 buffer.put(bytes, 0, position); 96 } 97 } 98 99 public boolean hasByte() { 100 return buffer.remaining() != 0; 101 } 102 103 public boolean hasBytes(int needs) { 104 return needs <= buffer.remaining(); 105 } 106 107 public void skip(int n) { 108 if (n < 0) { 109 throw new IndexOutOfBoundsException("skip value = " + n); 110 } 111 112 buffer.position(buffer.position() + n); 113 } 114 115 public int get() { 116 return buffer.get() & 0xFF; 117 } 118 119 public void get(byte[] bytes, int offset, int size) { 120 buffer.get(bytes, offset, size); 121 } 122 123 public int getShort() { 124 return buffer.getShort(); 125 } 126 127 public int getInt() { 128 return buffer.getInt(); 129 } 130 131 public long getLong() { 132 return buffer.getLong(); 133 } 134 135 public ImageStream put(byte byt) { 136 ensure(1); 137 buffer.put(byt); 138 139 return this; 140 } 141 142 public ImageStream put(int byt) { 143 return put((byte)byt); 144 } 145 146 public ImageStream put(byte[] bytes, int offset, int size) { 147 ensure(size); 148 buffer.put(bytes, offset, size); 149 150 return this; 151 } 152 153 public ImageStream put(ImageStream stream) { 154 put(stream.buffer.array(), 0, stream.buffer.position()); 155 156 return this; 157 } 158 159 public ImageStream putShort(short value) { 160 ensure(2); 161 buffer.putShort(value); 162 163 return this; 164 } 165 166 public ImageStream putShort(int value) { 167 return putShort((short)value); 168 } 169 170 public ImageStream putInt(int value) { 171 ensure(4); 172 buffer.putInt(value); 173 174 return this; 175 } 176 177 public ImageStream putLong(long value) { 178 ensure(8); 179 buffer.putLong(value); 180 181 return this; 182 } 183 184 public ByteBuffer getBuffer() { 185 return buffer; 186 } 187 188 public int getPosition() { 189 return buffer.position(); 190 } 191 192 public int getSize() { 193 return buffer.position(); 194 } 195 196 public byte[] getBytes() { 197 return buffer.array(); 198 } 199 200 public void setPosition(int offset) { 201 buffer.position(offset); 202 } 203 204 public byte[] toArray() { 205 return Arrays.copyOf(buffer.array(), buffer.position()); 206 } 207 }