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Commons IO example source code file (EndianUtils.java)
The Commons IO EndianUtils.java source code/* * 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 * @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; } } Other Commons IO examples (source code examples)Here is a short list of links related to this Commons IO EndianUtils.java source code file: |
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