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.DataInput; 20 import java.io.EOFException; 21 import java.io.IOException; 22 import java.io.InputStream; 23 24 import org.apache.commons.io.EndianUtils; 25 26 /** 27 * DataInput for systems relying on little endian data formats. 28 * When read, values will be changed from little endian to big 29 * endian formats for internal usage. 30 * <p> 31 * <b>Origin of code: </b>Avalon Excalibur (IO) 32 * 33 * @author <a href="mailto:peter (at) apache.org">Peter Donald</a> 34 * @version CVS $Revision: 610010 $ $Date: 2008-01-08 14:50:59 +0000 (Tue, 08 Jan 2008) $ 35 */ 36 public class SwappedDataInputStream extends ProxyInputStream 37 implements DataInput 38 { 39 40 /** 41 * Constructs a SwappedDataInputStream. 42 * 43 * @param input InputStream to read from 44 */ 45 public SwappedDataInputStream( InputStream input ) 46 { 47 super( input ); 48 } 49 50 /** 51 * Return <code>{@link #readByte()} == 0</code> 52 * @return the true if the byte read is zero, otherwise false 53 * @throws IOException if an I/O error occurs 54 * @throws EOFException if an end of file is reached unexpectedly 55 */ 56 public boolean readBoolean() 57 throws IOException, EOFException 58 { 59 return ( 0 == readByte() ); 60 } 61 62 /** 63 * Invokes the delegate's <code>read()</code> method. 64 * @return the byte read or -1 if the end of stream 65 * @throws IOException if an I/O error occurs 66 * @throws EOFException if an end of file is reached unexpectedly 67 */ 68 public byte readByte() 69 throws IOException, EOFException 70 { 71 return (byte)in.read(); 72 } 73 74 /** 75 * Reads a character delegating to {@link #readShort()}. 76 * @return the byte read or -1 if the end of stream 77 * @throws IOException if an I/O error occurs 78 * @throws EOFException if an end of file is reached unexpectedly 79 */ 80 public char readChar() 81 throws IOException, EOFException 82 { 83 return (char)readShort(); 84 } 85 86 /** 87 * Delegates to {@link EndianUtils#readSwappedDouble(InputStream)}. 88 * @return the read long 89 * @throws IOException if an I/O error occurs 90 * @throws EOFException if an end of file is reached unexpectedly 91 */ 92 public double readDouble() 93 throws IOException, EOFException 94 { 95 return EndianUtils.readSwappedDouble( in ); 96 } 97 98 /** 99 * Delegates to {@link EndianUtils#readSwappedFloat(InputStream)}. 100 * @return the read long 101 * @throws IOException if an I/O error occurs 102 * @throws EOFException if an end of file is reached unexpectedly 103 */ 104 public float readFloat() 105 throws IOException, EOFException 106 { 107 return EndianUtils.readSwappedFloat( in ); 108 } 109 110 /** 111 * Invokes the delegate's <code>read(byte[] data, int, int)</code> method. 112 * 113 * @param data the buffer to read the bytes into 114 * @throws EOFException if an end of file is reached unexpectedly 115 * @throws IOException if an I/O error occurs 116 */ 117 public void readFully( byte[] data ) 118 throws IOException, EOFException 119 { 120 readFully( data, 0, data.length ); 121 } 122 123 124 /** 125 * Invokes the delegate's <code>read(byte[] data, int, int)</code> method. 126 * 127 * @param data the buffer to read the bytes into 128 * @param offset The start offset 129 * @param length The number of bytes to read 130 * @throws EOFException if an end of file is reached unexpectedly 131 * @throws IOException if an I/O error occurs 132 */ 133 public void readFully( byte[] data, int offset, int length ) 134 throws IOException, EOFException 135 { 136 int remaining = length; 137 138 while( remaining > 0 ) 139 { 140 int location = offset + ( length - remaining ); 141 int count = read( data, location, remaining ); 142 143 if( -1 == count ) 144 { 145 throw new EOFException(); 146 } 147 148 remaining -= count; 149 } 150 } 151 152 /** 153 * Delegates to {@link EndianUtils#readSwappedInteger(InputStream)}. 154 * @return the read long 155 * @throws EOFException if an end of file is reached unexpectedly 156 * @throws IOException if an I/O error occurs 157 */ 158 public int readInt() 159 throws IOException, EOFException 160 { 161 return EndianUtils.readSwappedInteger( in ); 162 } 163 164 /** 165 * Not currently supported - throws {@link UnsupportedOperationException}. 166 * @return the line read 167 * @throws EOFException if an end of file is reached unexpectedly 168 * @throws IOException if an I/O error occurs 169 */ 170 public String readLine() 171 throws IOException, EOFException 172 { 173 throw new UnsupportedOperationException( 174 "Operation not supported: readLine()" ); 175 } 176 177 /** 178 * Delegates to {@link EndianUtils#readSwappedLong(InputStream)}. 179 * @return the read long 180 * @throws EOFException if an end of file is reached unexpectedly 181 * @throws IOException if an I/O error occurs 182 */ 183 public long readLong() 184 throws IOException, EOFException 185 { 186 return EndianUtils.readSwappedLong( in ); 187 } 188 189 /** 190 * Delegates to {@link EndianUtils#readSwappedShort(InputStream)}. 191 * @return the read long 192 * @throws EOFException if an end of file is reached unexpectedly 193 * @throws IOException if an I/O error occurs 194 */ 195 public short readShort() 196 throws IOException, EOFException 197 { 198 return EndianUtils.readSwappedShort( in ); 199 } 200 201 /** 202 * Invokes the delegate's <code>read()</code> method. 203 * @return the byte read or -1 if the end of stream 204 * @throws EOFException if an end of file is reached unexpectedly 205 * @throws IOException if an I/O error occurs 206 */ 207 public int readUnsignedByte() 208 throws IOException, EOFException 209 { 210 return in.read(); 211 } 212 213 /** 214 * Delegates to {@link EndianUtils#readSwappedUnsignedShort(InputStream)}. 215 * @return the read long 216 * @throws EOFException if an end of file is reached unexpectedly 217 * @throws IOException if an I/O error occurs 218 */ 219 public int readUnsignedShort() 220 throws IOException, EOFException 221 { 222 return EndianUtils.readSwappedUnsignedShort( in ); 223 } 224 225 /** 226 * Not currently supported - throws {@link UnsupportedOperationException}. 227 * @return UTF String read 228 * @throws EOFException if an end of file is reached unexpectedly 229 * @throws IOException if an I/O error occurs 230 */ 231 public String readUTF() 232 throws IOException, EOFException 233 { 234 throw new UnsupportedOperationException( 235 "Operation not supported: readUTF()" ); 236 } 237 238 /** 239 * Invokes the delegate's <code>skip(int)</code> method. 240 * @param count the number of bytes to skip 241 * @return the number of bytes to skipped or -1 if the end of stream 242 * @throws EOFException if an end of file is reached unexpectedly 243 * @throws IOException if an I/O error occurs 244 */ 245 public int skipBytes( int count ) 246 throws IOException, EOFException 247 { 248 return (int)in.skip( count ); 249 } 250 251 } 252
