Coverage Summary for Class: CountingInputStream (com.google.common.io)

1 /*
2  * Copyright (C) 2007 The Guava Authors
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
5  * in compliance with the License. You may obtain a copy of the License at
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software distributed under the License
10  * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
11  * or implied. See the License for the specific language governing permissions and limitations under
12  * the License.
13  */
14 
15 package com.google.common.io;
16 
17 import static com.google.common.base.Preconditions.checkNotNull;
18 
19 import com.google.common.annotations.Beta;
20 import com.google.common.annotations.GwtIncompatible;
21 import java.io.FilterInputStream;
22 import java.io.IOException;
23 import java.io.InputStream;
24 
25 /**
26  * An {@link InputStream} that counts the number of bytes read.
27  *
28  * @author Chris Nokleberg
29  * @since 1.0
30  */
31 @Beta
32 @GwtIncompatible
33 @ElementTypesAreNonnullByDefault
34 public final class CountingInputStream extends FilterInputStream {
35 
36   private long count;
37   private long mark = -1;
38 
39   /**
40    * Wraps another input stream, counting the number of bytes read.
41    *
42    * @param in the input stream to be wrapped
43    */
44   public CountingInputStream(InputStream in) {
45     super(checkNotNull(in));
46   }
47 
48   /** Returns the number of bytes read. */
49   public long getCount() {
50     return count;
51   }
52 
53   @Override
54   public int read() throws IOException {
55     int result = in.read();
56     if (result != -1) {
57       count++;
58     }
59     return result;
60   }
61 
62   @Override
63   public int read(byte[] b, int off, int len) throws IOException {
64     int result = in.read(b, off, len);
65     if (result != -1) {
66       count += result;
67     }
68     return result;
69   }
70 
71   @Override
72   public long skip(long n) throws IOException {
73     long result = in.skip(n);
74     count += result;
75     return result;
76   }
77 
78   @Override
79   public synchronized void mark(int readlimit) {
80     in.mark(readlimit);
81     mark = count;
82     // it's okay to mark even if mark isn't supported, as reset won't work
83   }
84 
85   @Override
86   public synchronized void reset() throws IOException {
87     if (!in.markSupported()) {
88       throw new IOException("Mark not supported");
89     }
90     if (mark == -1) {
91       throw new IOException("Mark not set");
92     }
93 
94     in.reset();
95     count = mark;
96   }
97 }