1 /* 2 * Copyright (c) 2017, 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 24 package jdk.experimental.bytecode; 25 26 import java.util.function.Consumer; 27 28 public class GrowableByteBuffer { 29 30 public GrowableByteBuffer() { 31 } 32 33 byte[] elems = new byte[64]; 34 int offset = 0; 35 36 public GrowableByteBuffer writeByte(int b) { 37 return writeBytes(1, b); 38 } 39 40 public GrowableByteBuffer writeChar(int x) { 41 return writeBytes(2, x); 42 } 43 44 public GrowableByteBuffer writeInt(int x) { 45 return writeBytes(4, x); 46 } 47 48 public GrowableByteBuffer writeFloat(float x) { 49 return writeInt(Float.floatToIntBits(x)); 50 } 51 52 public GrowableByteBuffer writeLong(long x) { 53 return writeBytes(8, x); 54 } 55 56 public GrowableByteBuffer writeDouble(double x) { 57 writeLong(Double.doubleToLongBits(x)); 58 return this; 59 } 60 61 public GrowableByteBuffer writeBytes(byte[] barr) { 62 expandIfNeeded(barr.length); 63 System.arraycopy(barr, 0, elems, offset, barr.length); 64 offset += barr.length; 65 return this; 66 } 67 68 public GrowableByteBuffer writeBytes(GrowableByteBuffer bb) { 69 expandIfNeeded(bb.offset); 70 System.arraycopy(bb.elems, 0, elems, offset, bb.offset); 71 offset += bb.offset; 72 return this; 73 } 74 75 public GrowableByteBuffer withOffset(int offset, Consumer<GrowableByteBuffer> actions) { 76 int prevOffset = this.offset; 77 this.offset = offset; 78 actions.accept(this); 79 this.offset = prevOffset; 80 return this; 81 } 82 83 private GrowableByteBuffer writeBytes(int size, long x) { 84 expandIfNeeded(size); 85 for (int i = 0; i < size; i++) { 86 elems[offset++] = (byte) ((x >> 8 * (size - i - 1)) & 0xFF); 87 } 88 return this; 89 } 90 91 void expandIfNeeded(int increment) { 92 if (offset + increment > elems.length) { 93 int newsize = elems.length * 2; 94 while (offset + increment > newsize) { 95 newsize *= 2; 96 } 97 byte[] newelems = new byte[newsize]; 98 System.arraycopy(elems, 0, newelems, 0, offset); 99 elems = newelems; 100 } 101 } 102 103 public byte[] bytes() { 104 byte[] bytes = new byte[offset]; 105 System.arraycopy(elems, 0, bytes, 0, offset); 106 return bytes; 107 } 108 }