| 1 | /* |
| 2 | * Copyright 1999-2005 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any 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 API supported by Sun Microsystems. If |
| 35 | * 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 | */ |
| 51 | public ByteBuffer() { |
| 52 | this(64); |
| 53 | } |
| 54 | |
| 55 | /** Create a new byte buffer with an initial elements array |
| 56 | * of given size. |
| 57 | */ |
| 58 | public ByteBuffer(int initialSize) { |
| 59 | elems = new byte[initialSize]; |
| 60 | length = 0; |
| 61 | } |
| 62 | |
| 63 | private void copy(int size) { |
| 64 | byte[] newelems = new byte[size]; |
| 65 | System.arraycopy(elems, 0, newelems, 0, elems.length); |
| 66 | elems = newelems; |
| 67 | } |
| 68 | |
| 69 | /** Append byte to this buffer. |
| 70 | */ |
| 71 | public void appendByte(int b) { |
| 72 | if (length >= elems.length) copy(elems.length * 2); |
| 73 | elems[length++] = (byte)b; |
| 74 | } |
| 75 | |
| 76 | /** Append `len' bytes from byte array, |
| 77 | * starting at given `start' offset. |
| 78 | */ |
| 79 | public void appendBytes(byte[] bs, int start, int len) { |
| 80 | while (length + len > elems.length) copy(elems.length * 2); |
| 81 | System.arraycopy(bs, start, elems, length, len); |
| 82 | length += len; |
| 83 | } |
| 84 | |
| 85 | /** Append all bytes from given byte array. |
| 86 | */ |
| 87 | public void appendBytes(byte[] bs) { |
| 88 | appendBytes(bs, 0, bs.length); |
| 89 | } |
| 90 | |
| 91 | /** Append a character as a two byte number. |
| 92 | */ |
| 93 | public void appendChar(int x) { |
| 94 | while (length + 1 >= elems.length) copy(elems.length * 2); |
| 95 | elems[length ] = (byte)((x >> 8) & 0xFF); |
| 96 | elems[length+1] = (byte)((x ) & 0xFF); |
| 97 | length = length + 2; |
| 98 | } |
| 99 | |
| 100 | /** Append an integer as a four byte number. |
| 101 | */ |
| 102 | public void appendInt(int x) { |
| 103 | while (length + 3 >= elems.length) copy(elems.length * 2); |
| 104 | elems[length ] = (byte)((x >> 24) & 0xFF); |
| 105 | elems[length+1] = (byte)((x >> 16) & 0xFF); |
| 106 | elems[length+2] = (byte)((x >> 8) & 0xFF); |
| 107 | elems[length+3] = (byte)((x ) & 0xFF); |
| 108 | length = length + 4; |
| 109 | } |
| 110 | |
| 111 | /** Append a long as an eight byte number. |
| 112 | */ |
| 113 | public void appendLong(long x) { |
| 114 | ByteArrayOutputStream buffer = new ByteArrayOutputStream(8); |
| 115 | DataOutputStream bufout = new DataOutputStream(buffer); |
| 116 | try { |
| 117 | bufout.writeLong(x); |
| 118 | appendBytes(buffer.toByteArray(), 0, 8); |
| 119 | } catch (IOException e) { |
| 120 | throw new AssertionError("write"); |
| 121 | } |
| 122 | } |
| 123 | |
| 124 | /** Append a float as a four byte number. |
| 125 | */ |
| 126 | public void appendFloat(float x) { |
| 127 | ByteArrayOutputStream buffer = new ByteArrayOutputStream(4); |
| 128 | DataOutputStream bufout = new DataOutputStream(buffer); |
| 129 | try { |
| 130 | bufout.writeFloat(x); |
| 131 | appendBytes(buffer.toByteArray(), 0, 4); |
| 132 | } catch (IOException e) { |
| 133 | throw new AssertionError("write"); |
| 134 | } |
| 135 | } |
| 136 | |
| 137 | /** Append a double as a eight byte number. |
| 138 | */ |
| 139 | public void appendDouble(double x) { |
| 140 | ByteArrayOutputStream buffer = new ByteArrayOutputStream(8); |
| 141 | DataOutputStream bufout = new DataOutputStream(buffer); |
| 142 | try { |
| 143 | bufout.writeDouble(x); |
| 144 | appendBytes(buffer.toByteArray(), 0, 8); |
| 145 | } catch (IOException e) { |
| 146 | throw new AssertionError("write"); |
| 147 | } |
| 148 | } |
| 149 | |
| 150 | /** Append a name. |
| 151 | */ |
| 152 | public void appendName(Name name) { |
| 153 | appendBytes(name.table.names, name.index, name.len); |
| 154 | } |
| 155 | |
| 156 | /** Reset to zero length. |
| 157 | */ |
| 158 | public void reset() { |
| 159 | length = 0; |
| 160 | } |
| 161 | |
| 162 | /** Convert contents to name. |
| 163 | */ |
| 164 | public Name toName(Name.Table names) { |
| 165 | return names.fromUtf(elems, 0, length); |
| 166 | } |
| 167 | } |