1 /* 2 * Copyright (c) 1999, 2012, 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 com.sun.tools.javac.util; 27 28 import java.io.*; 29 30 /** A byte buffer is a flexible array which grows when elements are 31 * appended. There are also methods to append names to byte buffers 32 * and to convert byte buffers to names. 33 * 34 * <p><b>This is NOT part of any supported API. 35 * If you write code that depends on this, you do so at your own risk. 36 * This code and its internal interfaces are subject to change or 37 * deletion without notice.</b> 38 */ 39 public class ByteBuffer { 40 41 /** An array holding the bytes in this buffer; can be grown. 42 */ 43 public byte[] elems; 44 45 /** The current number of defined bytes in this buffer. 46 */ 47 public int length; 48 49 /** Create a new byte buffer. 50 */ ByteBuffer()51 public ByteBuffer() { 52 this(64); 53 } 54 55 /** Create a new byte buffer with an initial elements array 56 * of given size. 57 */ ByteBuffer(int initialSize)58 public ByteBuffer(int initialSize) { 59 elems = new byte[initialSize]; 60 length = 0; 61 } 62 63 /** Append byte to this buffer. 64 */ appendByte(int b)65 public void appendByte(int b) { 66 elems = ArrayUtils.ensureCapacity(elems, length); 67 elems[length++] = (byte)b; 68 } 69 70 /** Append `len' bytes from byte array, 71 * starting at given `start' offset. 72 */ appendBytes(byte[] bs, int start, int len)73 public void appendBytes(byte[] bs, int start, int len) { 74 elems = ArrayUtils.ensureCapacity(elems, length + len); 75 System.arraycopy(bs, start, elems, length, len); 76 length += len; 77 } 78 79 /** Append all bytes from given byte array. 80 */ appendBytes(byte[] bs)81 public void appendBytes(byte[] bs) { 82 appendBytes(bs, 0, bs.length); 83 } 84 85 /** Append a character as a two byte number. 86 */ appendChar(int x)87 public void appendChar(int x) { 88 elems = ArrayUtils.ensureCapacity(elems, length + 1); 89 elems[length ] = (byte)((x >> 8) & 0xFF); 90 elems[length+1] = (byte)((x ) & 0xFF); 91 length = length + 2; 92 } 93 94 /** Append an integer as a four byte number. 95 */ appendInt(int x)96 public void appendInt(int x) { 97 elems = ArrayUtils.ensureCapacity(elems, length + 3); 98 elems[length ] = (byte)((x >> 24) & 0xFF); 99 elems[length+1] = (byte)((x >> 16) & 0xFF); 100 elems[length+2] = (byte)((x >> 8) & 0xFF); 101 elems[length+3] = (byte)((x ) & 0xFF); 102 length = length + 4; 103 } 104 105 /** Append a long as an eight byte number. 106 */ appendLong(long x)107 public void appendLong(long x) { 108 ByteArrayOutputStream buffer = new ByteArrayOutputStream(8); 109 DataOutputStream bufout = new DataOutputStream(buffer); 110 try { 111 bufout.writeLong(x); 112 appendBytes(buffer.toByteArray(), 0, 8); 113 } catch (IOException e) { 114 throw new AssertionError("write"); 115 } 116 } 117 118 /** Append a float as a four byte number. 119 */ appendFloat(float x)120 public void appendFloat(float x) { 121 ByteArrayOutputStream buffer = new ByteArrayOutputStream(4); 122 DataOutputStream bufout = new DataOutputStream(buffer); 123 try { 124 bufout.writeFloat(x); 125 appendBytes(buffer.toByteArray(), 0, 4); 126 } catch (IOException e) { 127 throw new AssertionError("write"); 128 } 129 } 130 131 /** Append a double as a eight byte number. 132 */ appendDouble(double x)133 public void appendDouble(double x) { 134 ByteArrayOutputStream buffer = new ByteArrayOutputStream(8); 135 DataOutputStream bufout = new DataOutputStream(buffer); 136 try { 137 bufout.writeDouble(x); 138 appendBytes(buffer.toByteArray(), 0, 8); 139 } catch (IOException e) { 140 throw new AssertionError("write"); 141 } 142 } 143 144 /** Append a name. 145 */ appendName(Name name)146 public void appendName(Name name) { 147 appendBytes(name.getByteArray(), name.getByteOffset(), name.getByteLength()); 148 } 149 150 /** Append the content of a given input stream. 151 */ appendStream(InputStream is)152 public void appendStream(InputStream is) throws IOException { 153 try { 154 int start = length; 155 int initialSize = is.available(); 156 elems = ArrayUtils.ensureCapacity(elems, length + initialSize); 157 int r = is.read(elems, start, initialSize); 158 int bp = start; 159 while (r != -1) { 160 bp += r; 161 elems = ArrayUtils.ensureCapacity(elems, bp); 162 r = is.read(elems, bp, elems.length - bp); 163 } 164 } finally { 165 try { 166 is.close(); 167 } catch (IOException e) { 168 /* Ignore any errors, as this stream may have already 169 * thrown a related exception which is the one that 170 * should be reported. 171 */ 172 } 173 } 174 } 175 176 /** Extract an integer at position bp from elems. 177 */ getInt(int bp)178 public int getInt(int bp) { 179 return 180 ((elems[bp] & 0xFF) << 24) + 181 ((elems[bp+1] & 0xFF) << 16) + 182 ((elems[bp+2] & 0xFF) << 8) + 183 (elems[bp+3] & 0xFF); 184 } 185 186 187 /** Extract a long integer at position bp from elems. 188 */ getLong(int bp)189 public long getLong(int bp) { 190 DataInputStream elemsin = 191 new DataInputStream(new ByteArrayInputStream(elems, bp, 8)); 192 try { 193 return elemsin.readLong(); 194 } catch (IOException e) { 195 throw new AssertionError(e); 196 } 197 } 198 199 /** Extract a float at position bp from elems. 200 */ getFloat(int bp)201 public float getFloat(int bp) { 202 DataInputStream elemsin = 203 new DataInputStream(new ByteArrayInputStream(elems, bp, 4)); 204 try { 205 return elemsin.readFloat(); 206 } catch (IOException e) { 207 throw new AssertionError(e); 208 } 209 } 210 211 /** Extract a double at position bp from elems. 212 */ getDouble(int bp)213 public double getDouble(int bp) { 214 DataInputStream elemsin = 215 new DataInputStream(new ByteArrayInputStream(elems, bp, 8)); 216 try { 217 return elemsin.readDouble(); 218 } catch (IOException e) { 219 throw new AssertionError(e); 220 } 221 } 222 223 /** Extract a character at position bp from elems. 224 */ getChar(int bp)225 public char getChar(int bp) { 226 return 227 (char)(((elems[bp] & 0xFF) << 8) + (elems[bp+1] & 0xFF)); 228 } 229 getByte(int bp)230 public byte getByte(int bp) { 231 return elems[bp]; 232 } 233 234 /** Reset to zero length. 235 */ reset()236 public void reset() { 237 length = 0; 238 } 239 240 /** Convert contents to name. 241 */ toName(Names names)242 public Name toName(Names names) { 243 return names.fromUtf(elems, 0, length); 244 } 245 } 246