001 /*
002 * Copyright 1999-2008 Sun Microsystems, Inc. All Rights Reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation. Sun designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Sun in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022 * CA 95054 USA or visit www.sun.com if you need additional information or
023 * have any questions.
024 */
025
026 package com.sun.tools.javac.util;
027
028 import java.io.*;
029
030 /** A byte buffer is a flexible array which grows when elements are
031 * appended. There are also methods to append names to byte buffers
032 * and to convert byte buffers to names.
033 *
034 * <p><b>This is NOT part of any API supported by Sun Microsystems. If
035 * you write code that depends on this, you do so at your own risk.
036 * This code and its internal interfaces are subject to change or
037 * deletion without notice.</b>
038 */
039 public class ByteBuffer {
040
041 /** An array holding the bytes in this buffer; can be grown.
042 */
043 public byte[] elems;
044
045 /** The current number of defined bytes in this buffer.
046 */
047 public int length;
048
049 /** Create a new byte buffer.
050 */
051 public ByteBuffer() {
052 this(64);
053 }
054
055 /** Create a new byte buffer with an initial elements array
056 * of given size.
057 */
058 public ByteBuffer(int initialSize) {
059 elems = new byte[initialSize];
060 length = 0;
061 }
062
063 private void copy(int size) {
064 byte[] newelems = new byte[size];
065 System.arraycopy(elems, 0, newelems, 0, elems.length);
066 elems = newelems;
067 }
068
069 /** Append byte to this buffer.
070 */
071 public void appendByte(int b) {
072 if (length >= elems.length) copy(elems.length * 2);
073 elems[length++] = (byte)b;
074 }
075
076 /** Append `len' bytes from byte array,
077 * starting at given `start' offset.
078 */
079 public void appendBytes(byte[] bs, int start, int len) {
080 while (length + len > elems.length) copy(elems.length * 2);
081 System.arraycopy(bs, start, elems, length, len);
082 length += len;
083 }
084
085 /** Append all bytes from given byte array.
086 */
087 public void appendBytes(byte[] bs) {
088 appendBytes(bs, 0, bs.length);
089 }
090
091 /** Append a character as a two byte number.
092 */
093 public void appendChar(int x) {
094 while (length + 1 >= elems.length) copy(elems.length * 2);
095 elems[length ] = (byte)((x >> 8) & 0xFF);
096 elems[length+1] = (byte)((x ) & 0xFF);
097 length = length + 2;
098 }
099
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.getByteArray(), name.getByteOffset(), name.getByteLength());
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(Names names) {
165 return names.fromUtf(elems, 0, length);
166 }
167 }