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.GwtIncompatible; 20 import com.google.common.annotations.J2ktIncompatible; 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 @J2ktIncompatible 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 */ CountingInputStream(InputStream in)44 public CountingInputStream(InputStream in) { 45 super(checkNotNull(in)); 46 } 47 48 /** Returns the number of bytes read. */ getCount()49 public long getCount() { 50 return count; 51 } 52 53 @Override read()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 read(byte[] b, int off, int len)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 skip(long n)72 public long skip(long n) throws IOException { 73 long result = in.skip(n); 74 count += result; 75 return result; 76 } 77 78 @Override mark(int readlimit)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 reset()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 } 98