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 */
17package org.apache.commons.io.output;
18
19import java.io.IOException;
20import java.io.OutputStream;
21
22/**
23 * A decorating output stream that counts the number of bytes that have passed
24 * through the stream so far.
25 * <p>
26 * A typical use case would be during debugging, to ensure that data is being
27 * written as expected.
28 *
29 * @version $Id: CountingOutputStream.java 471628 2006-11-06 04:06:45Z bayard $
30 */
31public class CountingOutputStream extends ProxyOutputStream {
32
33    /** The count of bytes that have passed. */
34    private long count;
35
36    /**
37     * Constructs a new CountingOutputStream.
38     *
39     * @param out  the OutputStream to write to
40     */
41    public CountingOutputStream( OutputStream out ) {
42        super(out);
43    }
44
45    //-----------------------------------------------------------------------
46    /**
47     * Writes the contents of the specified byte array to this output stream
48     * keeping count of the number of bytes written.
49     *
50     * @param b  the bytes to write, not null
51     * @throws IOException if an I/O error occurs
52     * @see java.io.OutputStream#write(byte[])
53     */
54    public void write(byte[] b) throws IOException {
55        count += b.length;
56        super.write(b);
57    }
58
59    /**
60     * Writes a portion of the specified byte array to this output stream
61     * keeping count of the number of bytes written.
62     *
63     * @param b  the bytes to write, not null
64     * @param off  the start offset in the buffer
65     * @param len  the maximum number of bytes to write
66     * @throws IOException if an I/O error occurs
67     * @see java.io.OutputStream#write(byte[], int, int)
68     */
69    public void write(byte[] b, int off, int len) throws IOException {
70        count += len;
71        super.write(b, off, len);
72    }
73
74    /**
75     * Writes a single byte to the output stream adding to the count of the
76     * number of bytes written.
77     *
78     * @param b  the byte to write
79     * @throws IOException if an I/O error occurs
80     * @see java.io.OutputStream#write(int)
81     */
82    public void write(int b) throws IOException {
83        count++;
84        super.write(b);
85    }
86
87    //-----------------------------------------------------------------------
88    /**
89     * The number of bytes that have passed through this stream.
90     * <p>
91     * NOTE: From v1.3 this method throws an ArithmeticException if the
92     * count is greater than can be expressed by an <code>int</code>.
93     * See {@link #getByteCount()} for a method using a <code>long</code>.
94     *
95     * @return the number of bytes accumulated
96     * @throws ArithmeticException if the byte count is too large
97     */
98    public synchronized int getCount() {
99        long result = getByteCount();
100        if (result > Integer.MAX_VALUE) {
101            throw new ArithmeticException("The byte count " + result + " is too large to be converted to an int");
102        }
103        return (int) result;
104    }
105
106    /**
107     * Set the byte count back to 0.
108     * <p>
109     * NOTE: From v1.3 this method throws an ArithmeticException if the
110     * count is greater than can be expressed by an <code>int</code>.
111     * See {@link #resetByteCount()} for a method using a <code>long</code>.
112     *
113     * @return the count previous to resetting
114     * @throws ArithmeticException if the byte count is too large
115     */
116    public synchronized int resetCount() {
117        long result = resetByteCount();
118        if (result > Integer.MAX_VALUE) {
119            throw new ArithmeticException("The byte count " + result + " is too large to be converted to an int");
120        }
121        return (int) result;
122    }
123
124    /**
125     * The number of bytes that have passed through this stream.
126     * <p>
127     * NOTE: This method is an alternative for <code>getCount()</code>.
128     * It was added because that method returns an integer which will
129     * result in incorrect count for files over 2GB.
130     *
131     * @return the number of bytes accumulated
132     * @since Commons IO 1.3
133     */
134    public synchronized long getByteCount() {
135        return this.count;
136    }
137
138    /**
139     * Set the byte count back to 0.
140     * <p>
141     * NOTE: This method is an alternative for <code>resetCount()</code>.
142     * It was added because that method returns an integer which will
143     * result in incorrect count for files over 2GB.
144     *
145     * @return the count previous to resetting
146     * @since Commons IO 1.3
147     */
148    public synchronized long resetByteCount() {
149        long tmp = this.count;
150        this.count = 0;
151        return tmp;
152    }
153
154}
155