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 package org.apache.commons.io.input; 18 19 import java.io.IOException; 20 import java.io.InputStream; 21 22 /** 23 * A decorating input 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 * read as expected. 28 * 29 * @author Marcelo Liberato 30 * @version $Id: CountingInputStream.java 471628 2006-11-06 04:06:45Z bayard $ 31 */ 32 public class CountingInputStream extends ProxyInputStream { 33 34 /** The count of bytes that have passed. */ 35 private long count; 36 37 /** 38 * Constructs a new CountingInputStream. 39 * 40 * @param in the InputStream to delegate to 41 */ 42 public CountingInputStream(InputStream in) { 43 super(in); 44 } 45 46 //----------------------------------------------------------------------- 47 /** 48 * Reads a number of bytes into the byte array, keeping count of the 49 * number read. 50 * 51 * @param b the buffer into which the data is read, not null 52 * @return the total number of bytes read into the buffer, -1 if end of stream 53 * @throws IOException if an I/O error occurs 54 * @see java.io.InputStream#read(byte[]) 55 */ 56 public int read(byte[] b) throws IOException { 57 int found = super.read(b); 58 this.count += (found >= 0) ? found : 0; 59 return found; 60 } 61 62 /** 63 * Reads a number of bytes into the byte array at a specific offset, 64 * keeping count of the number read. 65 * 66 * @param b the buffer into which the data is read, not null 67 * @param off the start offset in the buffer 68 * @param len the maximum number of bytes to read 69 * @return the total number of bytes read into the buffer, -1 if end of stream 70 * @throws IOException if an I/O error occurs 71 * @see java.io.InputStream#read(byte[], int, int) 72 */ 73 public int read(byte[] b, int off, int len) throws IOException { 74 int found = super.read(b, off, len); 75 this.count += (found >= 0) ? found : 0; 76 return found; 77 } 78 79 /** 80 * Reads the next byte of data adding to the count of bytes received 81 * if a byte is successfully read. 82 * 83 * @return the byte read, -1 if end of stream 84 * @throws IOException if an I/O error occurs 85 * @see java.io.InputStream#read() 86 */ 87 public int read() throws IOException { 88 int found = super.read(); 89 this.count += (found >= 0) ? 1 : 0; 90 return found; 91 } 92 93 /** 94 * Skips the stream over the specified number of bytes, adding the skipped 95 * amount to the count. 96 * 97 * @param length the number of bytes to skip 98 * @return the actual number of bytes skipped 99 * @throws IOException if an I/O error occurs 100 * @see java.io.InputStream#skip(long) 101 */ 102 public long skip(final long length) throws IOException { 103 final long skip = super.skip(length); 104 this.count += skip; 105 return skip; 106 } 107 108 //----------------------------------------------------------------------- 109 /** 110 * The number of bytes that have passed through this stream. 111 * <p> 112 * NOTE: From v1.3 this method throws an ArithmeticException if the 113 * count is greater than can be expressed by an <code>int</code>. 114 * See {@link #getByteCount()} for a method using a <code>long</code>. 115 * 116 * @return the number of bytes accumulated 117 * @throws ArithmeticException if the byte count is too large 118 */ 119 public synchronized int getCount() { 120 long result = getByteCount(); 121 if (result > Integer.MAX_VALUE) { 122 throw new ArithmeticException("The byte count " + result + " is too large to be converted to an int"); 123 } 124 return (int) result; 125 } 126 127 /** 128 * Set the byte count back to 0. 129 * <p> 130 * NOTE: From v1.3 this method throws an ArithmeticException if the 131 * count is greater than can be expressed by an <code>int</code>. 132 * See {@link #resetByteCount()} for a method using a <code>long</code>. 133 * 134 * @return the count previous to resetting 135 * @throws ArithmeticException if the byte count is too large 136 */ 137 public synchronized int resetCount() { 138 long result = resetByteCount(); 139 if (result > Integer.MAX_VALUE) { 140 throw new ArithmeticException("The byte count " + result + " is too large to be converted to an int"); 141 } 142 return (int) result; 143 } 144 145 /** 146 * The number of bytes that have passed through this stream. 147 * <p> 148 * NOTE: This method is an alternative for <code>getCount()</code> 149 * and was added because that method returns an integer which will 150 * result in incorrect count for files over 2GB. 151 * 152 * @return the number of bytes accumulated 153 * @since Commons IO 1.3 154 */ 155 public synchronized long getByteCount() { 156 return this.count; 157 } 158 159 /** 160 * Set the byte count back to 0. 161 * <p> 162 * NOTE: This method is an alternative for <code>resetCount()</code> 163 * and was added because that method returns an integer which will 164 * result in incorrect count for files over 2GB. 165 * 166 * @return the count previous to resetting 167 * @since Commons IO 1.3 168 */ 169 public synchronized long resetByteCount() { 170 long tmp = this.count; 171 this.count = 0; 172 return tmp; 173 } 174 175 } 176
