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/*
 * Copyright 2001-2004 The Apache Software Foundation.
 * 
 * Licensed 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.
 * 
* Origin of code: Apache Avalon (Excalibur) * * @author Peter Donald * @version CVS $Revision: 1.13 $ $Date: 2004/02/23 04:35:59 $ */ public final class EndianUtils { /** * Instances should NOT be constructed in standard programming. */ public EndianUtils() { } // ========================================== 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 (int)( ( ( 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 (int)( ( ( 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 ) { return (long)( ( ( data[ offset + 0 ] & 0xff ) << 0 ) + ( ( data[ offset + 1 ] & 0xff ) << 8 ) + ( ( data[ offset + 2 ] & 0xff ) << 16 ) + ( ( data[ offset + 3 ] & 0xff ) << 24 ) ); } /** * 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 = (long)( ( ( data[ offset + 0 ] & 0xff ) << 0 ) + ( ( data[ offset + 1 ] & 0xff ) << 8 ) + ( ( data[ offset + 2 ] & 0xff ) << 16 ) + ( ( data[ offset + 3 ] & 0xff ) << 24 ) ); long high = (long)( ( ( data[ offset + 4 ] & 0xff ) << 0 ) + ( ( data[ offset + 5 ] & 0xff ) << 8 ) + ( ( data[ offset + 6 ] & 0xff ) << 16 ) + ( ( data[ offset + 7 ] & 0xff ) << 24 ) ); return low + (high << 32); } /** * 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 (int)( ( ( 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 (int)( ( ( 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 ); return (long)( ( ( value1 & 0xff ) << 0 ) + ( ( value2 & 0xff ) << 8 ) + ( ( value3 & 0xff ) << 16 ) + ( ( value4 & 0xff ) << 24 ) ); } /** * 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]; input.read( bytes ); 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 ) ); } private static int read( InputStream input ) throws IOException { int value = input.read(); if( -1 == value ) { throw new EOFException( "Unexpected EOF reached" ); } return value; } }
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