| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.commons.io; |
| |
| import java.io.EOFException; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.OutputStream; |
| |
| /** |
| * Utility code for dealing with different endian systems. |
| * <p> |
| * Different computer architectures adopt different conventions for |
| * byte ordering. In so-called "Little Endian" architectures (eg Intel), |
| * the low-order byte is stored in memory at the lowest address, and |
| * subsequent bytes at higher addresses. For "Big Endian" architectures |
| * (eg Motorola), the situation is reversed. |
| * This class helps you solve this incompatability. |
| * <p> |
| * Origin of code: Excalibur |
| * |
| * @author <a href="mailto:peter@apache.org">Peter Donald</a> |
| * @version $Id: EndianUtils.java 539632 2007-05-18 23:37:59Z bayard $ |
| * @see org.apache.commons.io.input.SwappedDataInputStream |
| */ |
| public class EndianUtils { |
| |
| /** |
| * Instances should NOT be constructed in standard programming. |
| */ |
| public EndianUtils() { |
| super(); |
| } |
| |
| // ========================================== Swapping routines |
| |
| /** |
| * Converts a "short" value between endian systems. |
| * @param value value to convert |
| * @return the converted value |
| */ |
| public static short swapShort(short value) { |
| return (short) ( ( ( ( value >> 0 ) & 0xff ) << 8 ) + |
| ( ( ( value >> 8 ) & 0xff ) << 0 ) ); |
| } |
| |
| /** |
| * Converts a "int" value between endian systems. |
| * @param value value to convert |
| * @return the converted value |
| */ |
| public static int swapInteger(int value) { |
| return |
| ( ( ( value >> 0 ) & 0xff ) << 24 ) + |
| ( ( ( value >> 8 ) & 0xff ) << 16 ) + |
| ( ( ( value >> 16 ) & 0xff ) << 8 ) + |
| ( ( ( value >> 24 ) & 0xff ) << 0 ); |
| } |
| |
| /** |
| * Converts a "long" value between endian systems. |
| * @param value value to convert |
| * @return the converted value |
| */ |
| public static long swapLong(long value) { |
| return |
| ( ( ( value >> 0 ) & 0xff ) << 56 ) + |
| ( ( ( value >> 8 ) & 0xff ) << 48 ) + |
| ( ( ( value >> 16 ) & 0xff ) << 40 ) + |
| ( ( ( value >> 24 ) & 0xff ) << 32 ) + |
| ( ( ( value >> 32 ) & 0xff ) << 24 ) + |
| ( ( ( value >> 40 ) & 0xff ) << 16 ) + |
| ( ( ( value >> 48 ) & 0xff ) << 8 ) + |
| ( ( ( value >> 56 ) & 0xff ) << 0 ); |
| } |
| |
| /** |
| * Converts a "float" value between endian systems. |
| * @param value value to convert |
| * @return the converted value |
| */ |
| public static float swapFloat(float value) { |
| return Float.intBitsToFloat( swapInteger( Float.floatToIntBits( value ) ) ); |
| } |
| |
| /** |
| * Converts a "double" value between endian systems. |
| * @param value value to convert |
| * @return the converted value |
| */ |
| public static double swapDouble(double value) { |
| return Double.longBitsToDouble( swapLong( Double.doubleToLongBits( value ) ) ); |
| } |
| |
| // ========================================== Swapping read/write routines |
| |
| /** |
| * Writes a "short" value to a byte array at a given offset. The value is |
| * converted to the opposed endian system while writing. |
| * @param data target byte array |
| * @param offset starting offset in the byte array |
| * @param value value to write |
| */ |
| public static void writeSwappedShort(byte[] data, int offset, short value) { |
| data[ offset + 0 ] = (byte)( ( value >> 0 ) & 0xff ); |
| data[ offset + 1 ] = (byte)( ( value >> 8 ) & 0xff ); |
| } |
| |
| /** |
| * Reads a "short" value from a byte array at a given offset. The value is |
| * converted to the opposed endian system while reading. |
| * @param data source byte array |
| * @param offset starting offset in the byte array |
| * @return the value read |
| */ |
| public static short readSwappedShort(byte[] data, int offset) { |
| return (short)( ( ( data[ offset + 0 ] & 0xff ) << 0 ) + |
| ( ( data[ offset + 1 ] & 0xff ) << 8 ) ); |
| } |
| |
| /** |
| * Reads an unsigned short (16-bit) value from a byte array at a given |
| * offset. The value is converted to the opposed endian system while |
| * reading. |
| * @param data source byte array |
| * @param offset starting offset in the byte array |
| * @return the value read |
| */ |
| public static int readSwappedUnsignedShort(byte[] data, int offset) { |
| return ( ( ( data[ offset + 0 ] & 0xff ) << 0 ) + |
| ( ( data[ offset + 1 ] & 0xff ) << 8 ) ); |
| } |
| |
| /** |
| * Writes a "int" value to a byte array at a given offset. The value is |
| * converted to the opposed endian system while writing. |
| * @param data target byte array |
| * @param offset starting offset in the byte array |
| * @param value value to write |
| */ |
| public static void writeSwappedInteger(byte[] data, int offset, int value) { |
| data[ offset + 0 ] = (byte)( ( value >> 0 ) & 0xff ); |
| data[ offset + 1 ] = (byte)( ( value >> 8 ) & 0xff ); |
| data[ offset + 2 ] = (byte)( ( value >> 16 ) & 0xff ); |
| data[ offset + 3 ] = (byte)( ( value >> 24 ) & 0xff ); |
| } |
| |
| /** |
| * Reads a "int" value from a byte array at a given offset. The value is |
| * converted to the opposed endian system while reading. |
| * @param data source byte array |
| * @param offset starting offset in the byte array |
| * @return the value read |
| */ |
| public static int readSwappedInteger(byte[] data, int offset) { |
| return ( ( ( data[ offset + 0 ] & 0xff ) << 0 ) + |
| ( ( data[ offset + 1 ] & 0xff ) << 8 ) + |
| ( ( data[ offset + 2 ] & 0xff ) << 16 ) + |
| ( ( data[ offset + 3 ] & 0xff ) << 24 ) ); |
| } |
| |
| /** |
| * Reads an unsigned integer (32-bit) value from a byte array at a given |
| * offset. The value is converted to the opposed endian system while |
| * reading. |
| * @param data source byte array |
| * @param offset starting offset in the byte array |
| * @return the value read |
| */ |
| public static long readSwappedUnsignedInteger(byte[] data, int offset) { |
| long low = ( ( ( data[ offset + 0 ] & 0xff ) << 0 ) + |
| ( ( data[ offset + 1 ] & 0xff ) << 8 ) + |
| ( ( data[ offset + 2 ] & 0xff ) << 16 ) ); |
| |
| long high = data[ offset + 3 ] & 0xff; |
| |
| return (high << 24) + (0xffffffffL & low); |
| } |
| |
| /** |
| * Writes a "long" value to a byte array at a given offset. The value is |
| * converted to the opposed endian system while writing. |
| * @param data target byte array |
| * @param offset starting offset in the byte array |
| * @param value value to write |
| */ |
| public static void writeSwappedLong(byte[] data, int offset, long value) { |
| data[ offset + 0 ] = (byte)( ( value >> 0 ) & 0xff ); |
| data[ offset + 1 ] = (byte)( ( value >> 8 ) & 0xff ); |
| data[ offset + 2 ] = (byte)( ( value >> 16 ) & 0xff ); |
| data[ offset + 3 ] = (byte)( ( value >> 24 ) & 0xff ); |
| data[ offset + 4 ] = (byte)( ( value >> 32 ) & 0xff ); |
| data[ offset + 5 ] = (byte)( ( value >> 40 ) & 0xff ); |
| data[ offset + 6 ] = (byte)( ( value >> 48 ) & 0xff ); |
| data[ offset + 7 ] = (byte)( ( value >> 56 ) & 0xff ); |
| } |
| |
| /** |
| * Reads a "long" value from a byte array at a given offset. The value is |
| * converted to the opposed endian system while reading. |
| * @param data source byte array |
| * @param offset starting offset in the byte array |
| * @return the value read |
| */ |
| public static long readSwappedLong(byte[] data, int offset) { |
| long low = |
| ( ( data[ offset + 0 ] & 0xff ) << 0 ) + |
| ( ( data[ offset + 1 ] & 0xff ) << 8 ) + |
| ( ( data[ offset + 2 ] & 0xff ) << 16 ) + |
| ( ( data[ offset + 3 ] & 0xff ) << 24 ); |
| long high = |
| ( ( data[ offset + 4 ] & 0xff ) << 0 ) + |
| ( ( data[ offset + 5 ] & 0xff ) << 8 ) + |
| ( ( data[ offset + 6 ] & 0xff ) << 16 ) + |
| ( ( data[ offset + 7 ] & 0xff ) << 24 ); |
| return (high << 32) + (0xffffffffL & low); |
| } |
| |
| /** |
| * Writes a "float" value to a byte array at a given offset. The value is |
| * converted to the opposed endian system while writing. |
| * @param data target byte array |
| * @param offset starting offset in the byte array |
| * @param value value to write |
| */ |
| public static void writeSwappedFloat(byte[] data, int offset, float value) { |
| writeSwappedInteger( data, offset, Float.floatToIntBits( value ) ); |
| } |
| |
| /** |
| * Reads a "float" value from a byte array at a given offset. The value is |
| * converted to the opposed endian system while reading. |
| * @param data source byte array |
| * @param offset starting offset in the byte array |
| * @return the value read |
| */ |
| public static float readSwappedFloat(byte[] data, int offset) { |
| return Float.intBitsToFloat( readSwappedInteger( data, offset ) ); |
| } |
| |
| /** |
| * Writes a "double" value to a byte array at a given offset. The value is |
| * converted to the opposed endian system while writing. |
| * @param data target byte array |
| * @param offset starting offset in the byte array |
| * @param value value to write |
| */ |
| public static void writeSwappedDouble(byte[] data, int offset, double value) { |
| writeSwappedLong( data, offset, Double.doubleToLongBits( value ) ); |
| } |
| |
| /** |
| * Reads a "double" value from a byte array at a given offset. The value is |
| * converted to the opposed endian system while reading. |
| * @param data source byte array |
| * @param offset starting offset in the byte array |
| * @return the value read |
| */ |
| public static double readSwappedDouble(byte[] data, int offset) { |
| return Double.longBitsToDouble( readSwappedLong( data, offset ) ); |
| } |
| |
| /** |
| * Writes a "short" value to an OutputStream. The value is |
| * converted to the opposed endian system while writing. |
| * @param output target OutputStream |
| * @param value value to write |
| * @throws IOException in case of an I/O problem |
| */ |
| public static void writeSwappedShort(OutputStream output, short value) |
| throws IOException |
| { |
| output.write( (byte)( ( value >> 0 ) & 0xff ) ); |
| output.write( (byte)( ( value >> 8 ) & 0xff ) ); |
| } |
| |
| /** |
| * Reads a "short" value from an InputStream. The value is |
| * converted to the opposed endian system while reading. |
| * @param input source InputStream |
| * @return the value just read |
| * @throws IOException in case of an I/O problem |
| */ |
| public static short readSwappedShort(InputStream input) |
| throws IOException |
| { |
| return (short)( ( ( read( input ) & 0xff ) << 0 ) + |
| ( ( read( input ) & 0xff ) << 8 ) ); |
| } |
| |
| /** |
| * Reads a unsigned short (16-bit) from an InputStream. The value is |
| * converted to the opposed endian system while reading. |
| * @param input source InputStream |
| * @return the value just read |
| * @throws IOException in case of an I/O problem |
| */ |
| public static int readSwappedUnsignedShort(InputStream input) |
| throws IOException |
| { |
| int value1 = read( input ); |
| int value2 = read( input ); |
| |
| return ( ( ( value1 & 0xff ) << 0 ) + |
| ( ( value2 & 0xff ) << 8 ) ); |
| } |
| |
| /** |
| * Writes a "int" value to an OutputStream. The value is |
| * converted to the opposed endian system while writing. |
| * @param output target OutputStream |
| * @param value value to write |
| * @throws IOException in case of an I/O problem |
| */ |
| public static void writeSwappedInteger(OutputStream output, int value) |
| throws IOException |
| { |
| output.write( (byte)( ( value >> 0 ) & 0xff ) ); |
| output.write( (byte)( ( value >> 8 ) & 0xff ) ); |
| output.write( (byte)( ( value >> 16 ) & 0xff ) ); |
| output.write( (byte)( ( value >> 24 ) & 0xff ) ); |
| } |
| |
| /** |
| * Reads a "int" value from an InputStream. The value is |
| * converted to the opposed endian system while reading. |
| * @param input source InputStream |
| * @return the value just read |
| * @throws IOException in case of an I/O problem |
| */ |
| public static int readSwappedInteger(InputStream input) |
| throws IOException |
| { |
| int value1 = read( input ); |
| int value2 = read( input ); |
| int value3 = read( input ); |
| int value4 = read( input ); |
| |
| return ( ( value1 & 0xff ) << 0 ) + |
| ( ( value2 & 0xff ) << 8 ) + |
| ( ( value3 & 0xff ) << 16 ) + |
| ( ( value4 & 0xff ) << 24 ); |
| } |
| |
| /** |
| * Reads a unsigned integer (32-bit) from an InputStream. The value is |
| * converted to the opposed endian system while reading. |
| * @param input source InputStream |
| * @return the value just read |
| * @throws IOException in case of an I/O problem |
| */ |
| public static long readSwappedUnsignedInteger(InputStream input) |
| throws IOException |
| { |
| int value1 = read( input ); |
| int value2 = read( input ); |
| int value3 = read( input ); |
| int value4 = read( input ); |
| |
| long low = ( ( ( value1 & 0xff ) << 0 ) + |
| ( ( value2 & 0xff ) << 8 ) + |
| ( ( value3 & 0xff ) << 16 ) ); |
| |
| long high = value4 & 0xff; |
| |
| return (high << 24) + (0xffffffffL & low); |
| } |
| |
| /** |
| * Writes a "long" value to an OutputStream. The value is |
| * converted to the opposed endian system while writing. |
| * @param output target OutputStream |
| * @param value value to write |
| * @throws IOException in case of an I/O problem |
| */ |
| public static void writeSwappedLong(OutputStream output, long value) |
| throws IOException |
| { |
| output.write( (byte)( ( value >> 0 ) & 0xff ) ); |
| output.write( (byte)( ( value >> 8 ) & 0xff ) ); |
| output.write( (byte)( ( value >> 16 ) & 0xff ) ); |
| output.write( (byte)( ( value >> 24 ) & 0xff ) ); |
| output.write( (byte)( ( value >> 32 ) & 0xff ) ); |
| output.write( (byte)( ( value >> 40 ) & 0xff ) ); |
| output.write( (byte)( ( value >> 48 ) & 0xff ) ); |
| output.write( (byte)( ( value >> 56 ) & 0xff ) ); |
| } |
| |
| /** |
| * Reads a "long" value from an InputStream. The value is |
| * converted to the opposed endian system while reading. |
| * @param input source InputStream |
| * @return the value just read |
| * @throws IOException in case of an I/O problem |
| */ |
| public static long readSwappedLong(InputStream input) |
| throws IOException |
| { |
| byte[] bytes = new byte[8]; |
| for ( int i=0; i<8; i++ ) { |
| bytes[i] = (byte) read( input ); |
| } |
| return readSwappedLong( bytes, 0 ); |
| } |
| |
| /** |
| * Writes a "float" value to an OutputStream. The value is |
| * converted to the opposed endian system while writing. |
| * @param output target OutputStream |
| * @param value value to write |
| * @throws IOException in case of an I/O problem |
| */ |
| public static void writeSwappedFloat(OutputStream output, float value) |
| throws IOException |
| { |
| writeSwappedInteger( output, Float.floatToIntBits( value ) ); |
| } |
| |
| /** |
| * Reads a "float" value from an InputStream. The value is |
| * converted to the opposed endian system while reading. |
| * @param input source InputStream |
| * @return the value just read |
| * @throws IOException in case of an I/O problem |
| */ |
| public static float readSwappedFloat(InputStream input) |
| throws IOException |
| { |
| return Float.intBitsToFloat( readSwappedInteger( input ) ); |
| } |
| |
| /** |
| * Writes a "double" value to an OutputStream. The value is |
| * converted to the opposed endian system while writing. |
| * @param output target OutputStream |
| * @param value value to write |
| * @throws IOException in case of an I/O problem |
| */ |
| public static void writeSwappedDouble(OutputStream output, double value) |
| throws IOException |
| { |
| writeSwappedLong( output, Double.doubleToLongBits( value ) ); |
| } |
| |
| /** |
| * Reads a "double" value from an InputStream. The value is |
| * converted to the opposed endian system while reading. |
| * @param input source InputStream |
| * @return the value just read |
| * @throws IOException in case of an I/O problem |
| */ |
| public static double readSwappedDouble(InputStream input) |
| throws IOException |
| { |
| return Double.longBitsToDouble( readSwappedLong( input ) ); |
| } |
| |
| /** |
| * Reads the next byte from the input stream. |
| * @param input the stream |
| * @return the byte |
| * @throws IOException if the end of file is reached |
| */ |
| private static int read(InputStream input) |
| throws IOException |
| { |
| int value = input.read(); |
| |
| if( -1 == value ) { |
| throw new EOFException( "Unexpected EOF reached" ); |
| } |
| |
| return value; |
| } |
| } |