1 /* 2 * Copyright (C) 2007 Google Inc. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.common.io; 18 19 import java.io.FilterInputStream; 20 import java.io.IOException; 21 import java.io.InputStream; 22 23 /** 24 * An {@link InputStream} that counts the number of bytes read. 25 * 26 * @author Chris Nokleberg 27 * @since 2009.09.15 <b>tentative</b> 28 */ 29 public class CountingInputStream extends FilterInputStream { 30 31 private long count; 32 private long mark = -1; 33 34 /** 35 * Wraps another input stream, counting the number of bytes read. 36 * 37 * @param in the input stream to be wrapped 38 */ 39 public CountingInputStream(InputStream in) { 40 super(in); 41 } 42 43 /** Returns the number of bytes read. */ 44 public long getCount() { 45 return count; 46 } 47 48 @Override public int read() throws IOException { 49 int result = in.read(); 50 if (result != -1) { 51 count++; 52 } 53 return result; 54 } 55 56 @Override public int read(byte[] b, int off, int len) throws IOException { 57 int result = in.read(b, off, len); 58 if (result != -1) { 59 count += result; 60 } 61 return result; 62 } 63 64 @Override public long skip(long n) throws IOException { 65 long result = in.skip(n); 66 count += result; 67 return result; 68 } 69 70 @Override public void mark(int readlimit) { 71 in.mark(readlimit); 72 mark = count; 73 // it's okay to mark even if mark isn't supported, as reset won't work 74 } 75 76 @Override public void reset() throws IOException { 77 if (!in.markSupported()) { 78 throw new IOException("Mark not supported"); 79 } 80 if (mark == -1) { 81 throw new IOException("Mark not set"); 82 } 83 84 in.reset(); 85 count = mark; 86 } 87 } 88
