1/*
2 *  Licensed to the Apache Software Foundation (ASF) under one or more
3 *  contributor license agreements.  See the NOTICE file distributed with
4 *  this work for additional information regarding copyright ownership.
5 *  The ASF licenses this file to You under the Apache License, Version 2.0
6 *  (the "License"); you may not use this file except in compliance with
7 *  the License.  You may obtain a copy of the License at
8 *
9 *     http://www.apache.org/licenses/LICENSE-2.0
10 *
11 *  Unless required by applicable law or agreed to in writing, software
12 *  distributed under the License is distributed on an "AS IS" BASIS,
13 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 *  See the License for the specific language governing permissions and
15 *  limitations under the License.
16 */
17
18package java.io;
19
20import java.nio.ByteOrder;
21import java.nio.charset.ModifiedUtf8;
22import libcore.io.Memory;
23import libcore.io.SizeOf;
24
25/**
26 * Wraps an existing {@link OutputStream} and writes big-endian typed data to it.
27 * Typically, this stream can be read in by DataInputStream. Types that can be
28 * written include byte, 16-bit short, 32-bit int, 32-bit float, 64-bit long,
29 * 64-bit double, byte strings, and {@link DataInput MUTF-8} encoded strings.
30 *
31 * @see DataInputStream
32 */
33public class DataOutputStream extends FilterOutputStream implements DataOutput {
34    private final byte[] scratch = new byte[8];
35
36    /**
37     * The number of bytes written out so far.
38     */
39    protected int written;
40
41    /**
42     * Constructs a new {@code DataOutputStream} on the {@code OutputStream}
43     * {@code out}. Note that data written by this stream is not in a human
44     * readable form but can be reconstructed by using a {@link DataInputStream}
45     * on the resulting output.
46     *
47     * @param out
48     *            the target stream for writing.
49     */
50    public DataOutputStream(OutputStream out) {
51        super(out);
52    }
53
54    /**
55     * Flushes this stream to ensure all pending data is sent out to the target
56     * stream. This implementation then also flushes the target stream.
57     *
58     * @throws IOException
59     *             if an error occurs attempting to flush this stream.
60     */
61    @Override
62    public void flush() throws IOException {
63        super.flush();
64    }
65
66    /**
67     * Returns the total number of bytes written to the target stream so far.
68     *
69     * @return the number of bytes written to the target stream.
70     */
71    public final int size() {
72        if (written < 0) {
73            written = Integer.MAX_VALUE;
74        }
75        return written;
76    }
77
78    /**
79     * Writes {@code count} bytes from the byte array {@code buffer} starting at
80     * {@code offset} to the target stream.
81     *
82     * @param buffer
83     *            the buffer to write to the target stream.
84     * @param offset
85     *            the index of the first byte in {@code buffer} to write.
86     * @param count
87     *            the number of bytes from the {@code buffer} to write.
88     * @throws IOException
89     *             if an error occurs while writing to the target stream.
90     * @throws NullPointerException
91     *             if {@code buffer} is {@code null}.
92     */
93    @Override
94    public void write(byte[] buffer, int offset, int count) throws IOException {
95        if (buffer == null) {
96            throw new NullPointerException("buffer == null");
97        }
98        out.write(buffer, offset, count);
99        written += count;
100    }
101
102    /**
103     * Writes a byte to the target stream. Only the least significant byte of
104     * the integer {@code oneByte} is written.
105     *
106     * @param oneByte
107     *            the byte to write to the target stream.
108     * @throws IOException
109     *             if an error occurs while writing to the target stream.
110     * @see DataInputStream#readByte()
111     */
112    @Override
113    public void write(int oneByte) throws IOException {
114        out.write(oneByte);
115        written++;
116    }
117
118    /**
119     * Writes a boolean to the target stream.
120     *
121     * @param val
122     *            the boolean value to write to the target stream.
123     * @throws IOException
124     *             if an error occurs while writing to the target stream.
125     * @see DataInputStream#readBoolean()
126     */
127    public final void writeBoolean(boolean val) throws IOException {
128        out.write(val ? 1 : 0);
129        written++;
130    }
131
132    /**
133     * Writes an 8-bit byte to the target stream. Only the least significant
134     * byte of the integer {@code val} is written.
135     *
136     * @param val
137     *            the byte value to write to the target stream.
138     * @throws IOException
139     *             if an error occurs while writing to the target stream.
140     * @see DataInputStream#readByte()
141     * @see DataInputStream#readUnsignedByte()
142     */
143    public final void writeByte(int val) throws IOException {
144        out.write(val);
145        written++;
146    }
147
148    public final void writeBytes(String str) throws IOException {
149        if (str.length() == 0) {
150            return;
151        }
152        byte[] bytes = new byte[str.length()];
153        for (int index = 0; index < str.length(); index++) {
154            bytes[index] = (byte) str.charAt(index);
155        }
156        out.write(bytes);
157        written += bytes.length;
158    }
159
160    public final void writeChar(int val) throws IOException {
161        writeShort(val);
162    }
163
164    public final void writeChars(String str) throws IOException {
165        byte[] bytes = str.getBytes("UTF-16BE");
166        out.write(bytes);
167        written += bytes.length;
168    }
169
170    public final void writeDouble(double val) throws IOException {
171        writeLong(Double.doubleToLongBits(val));
172    }
173
174    public final void writeFloat(float val) throws IOException {
175        writeInt(Float.floatToIntBits(val));
176    }
177
178    public final void writeInt(int val) throws IOException {
179        Memory.pokeInt(scratch, 0, val, ByteOrder.BIG_ENDIAN);
180        out.write(scratch, 0, SizeOf.INT);
181        written += SizeOf.INT;
182    }
183
184    public final void writeLong(long val) throws IOException {
185        Memory.pokeLong(scratch, 0, val, ByteOrder.BIG_ENDIAN);
186        out.write(scratch, 0, SizeOf.LONG);
187        written += SizeOf.LONG;
188    }
189
190    public final void writeShort(int val) throws IOException {
191        Memory.pokeShort(scratch, 0, (short) val, ByteOrder.BIG_ENDIAN);
192        out.write(scratch, 0, SizeOf.SHORT);
193        written += SizeOf.SHORT;
194    }
195
196    public final void writeUTF(String str) throws IOException {
197        write(ModifiedUtf8.encode(str));
198    }
199}
200