001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.commons.io.input; 018 019 import java.io.IOException; 020 import java.io.InputStream; 021 022 /** 023 * A decorating input stream that counts the number of bytes that have passed 024 * through the stream so far. 025 * <p> 026 * A typical use case would be during debugging, to ensure that data is being 027 * read as expected. 028 * 029 * @author Marcelo Liberato 030 * @version $Id: CountingInputStream.java 471628 2006-11-06 04:06:45Z bayard $ 031 */ 032 public class CountingInputStream extends ProxyInputStream { 033 034 /** The count of bytes that have passed. */ 035 private long count; 036 037 /** 038 * Constructs a new CountingInputStream. 039 * 040 * @param in the InputStream to delegate to 041 */ 042 public CountingInputStream(InputStream in) { 043 super(in); 044 } 045 046 //----------------------------------------------------------------------- 047 /** 048 * Reads a number of bytes into the byte array, keeping count of the 049 * number read. 050 * 051 * @param b the buffer into which the data is read, not null 052 * @return the total number of bytes read into the buffer, -1 if end of stream 053 * @throws IOException if an I/O error occurs 054 * @see java.io.InputStream#read(byte[]) 055 */ 056 public int read(byte[] b) throws IOException { 057 int found = super.read(b); 058 this.count += (found >= 0) ? found : 0; 059 return found; 060 } 061 062 /** 063 * Reads a number of bytes into the byte array at a specific offset, 064 * keeping count of the number read. 065 * 066 * @param b the buffer into which the data is read, not null 067 * @param off the start offset in the buffer 068 * @param len the maximum number of bytes to read 069 * @return the total number of bytes read into the buffer, -1 if end of stream 070 * @throws IOException if an I/O error occurs 071 * @see java.io.InputStream#read(byte[], int, int) 072 */ 073 public int read(byte[] b, int off, int len) throws IOException { 074 int found = super.read(b, off, len); 075 this.count += (found >= 0) ? found : 0; 076 return found; 077 } 078 079 /** 080 * Reads the next byte of data adding to the count of bytes received 081 * if a byte is successfully read. 082 * 083 * @return the byte read, -1 if end of stream 084 * @throws IOException if an I/O error occurs 085 * @see java.io.InputStream#read() 086 */ 087 public int read() throws IOException { 088 int found = super.read(); 089 this.count += (found >= 0) ? 1 : 0; 090 return found; 091 } 092 093 /** 094 * Skips the stream over the specified number of bytes, adding the skipped 095 * amount to the count. 096 * 097 * @param length the number of bytes to skip 098 * @return the actual number of bytes skipped 099 * @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 }