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
26package com.sun.tools.javac.util;
27
28import 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 */
39public 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    /** Append byte to this buffer.
64     */
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     */
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     */
81    public void appendBytes(byte[] bs) {
82        appendBytes(bs, 0, bs.length);
83    }
84
85    /** Append a character as a two byte number.
86     */
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     */
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     */
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     */
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     */
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     */
146    public void appendName(Name name) {
147        appendBytes(name.getByteArray(), name.getByteOffset(), name.getByteLength());
148    }
149
150    /** Reset to zero length.
151     */
152    public void reset() {
153        length = 0;
154    }
155
156    /** Convert contents to name.
157     */
158    public Name toName(Names names) {
159        return names.fromUtf(elems, 0, length);
160    }
161}
162