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   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
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       http://www.apache.org/licenses/LICENSE-2.0

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   distributed under the License is distributed on an "AS IS" BASIS,
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package org.apache.poi.util;

import org.apache.poi.util.LittleEndian.BufferUnderrunException;

import java.io.*;
import java.nio.BufferUnderflowException;

representation of a byte (8-bit) field at a fixed location within a
byte array
Author:
Marc Johnson (mjohnson at apache dot org/**
 * representation of a byte (8-bit) field at a fixed location within a
 * byte array
 *
 * @author Marc Johnson (mjohnson at apache dot org
 */

public class ByteField
    implements FixedField
{
    private static final byte _default_value = 0;
    private byte              _value;
    private final int         _offset;

    
construct the ByteField with its offset into its containing
byte array and a default value of 0
Params:
offset – of the field within its byte array
Throws:
ArrayIndexOutOfBoundsException – if offset is negative/**
     * construct the ByteField with its offset into its containing
     * byte array and a default value of 0
     *
     * @param offset of the field within its byte array
     *
     * @exception ArrayIndexOutOfBoundsException if offset is negative
     */

    public ByteField(final int offset)
        throws ArrayIndexOutOfBoundsException
    {
        this(offset, _default_value);
    }

    
construct the ByteField with its offset into its containing
byte array and initialize its value
Params:
offset – of the field within its byte array
value – the initial value
Throws:
ArrayIndexOutOfBoundsException – if offset is negative/**
     * construct the ByteField with its offset into its containing
     * byte array and initialize its value
     *
     * @param offset of the field within its byte array
     * @param value the initial value
     *
     * @exception ArrayIndexOutOfBoundsException if offset is negative
     */

    public ByteField(final int offset, final byte value)
        throws ArrayIndexOutOfBoundsException
    {
        if (offset < 0)
        {
            throw new ArrayIndexOutOfBoundsException(
                "offset cannot be negative");
        }
        _offset = offset;
        set(value);
    }

    
Construct the ByteField with its offset into its containing
byte array and initialize its value from its byte array
Params:
offset – of the field within its byte array
data – the byte array to read the value from
Throws:
ArrayIndexOutOfBoundsException – if the offset is not
           within the range of 0..(data.length - 1)/**
     * Construct the ByteField with its offset into its containing
     * byte array and initialize its value from its byte array
     *
     * @param offset of the field within its byte array
     * @param data the byte array to read the value from
     *
     * @exception ArrayIndexOutOfBoundsException if the offset is not
     *            within the range of 0..(data.length - 1)
     */

    public ByteField(final int offset, final byte [] data)
        throws ArrayIndexOutOfBoundsException
    {
        this(offset);
        readFromBytes(data);
    }

    
construct the ByteField with its offset into its containing
byte array, initialize its value, and write its value to its
byte array
Params:
offset – of the field within its byte array
value – the initial value
data – the byte array to write the value to
Throws:
ArrayIndexOutOfBoundsException – if the offset is not
           within the range of 0..(data.length - 1)/**
     * construct the ByteField with its offset into its containing
     * byte array, initialize its value, and write its value to its
     * byte array
     *
     * @param offset of the field within its byte array
     * @param value the initial value
     * @param data the byte array to write the value to
     *
     * @exception ArrayIndexOutOfBoundsException if the offset is not
     *            within the range of 0..(data.length - 1)
     */

    public ByteField(final int offset, final byte value, final byte [] data)
        throws ArrayIndexOutOfBoundsException
    {
        this(offset, value);
        writeToBytes(data);
    }

    
get the ByteField's current value
Returns:
current value/**
     * get the ByteField's current value
     *
     * @return current value
     */

    public byte get()
    {
        return _value;
    }

    
set the ByteField's current value
Params:
value – to be set/**
     * set the ByteField's current value
     *
     * @param value to be set
     */

    public void set(final byte value)
    {
        _value = value;
    }

    
set the ByteField's current value and write it to a byte array
Params:
value – to be set
data – the byte array to write the value to
Throws:
ArrayIndexOutOfBoundsException – if the offset is out
           of the byte array's range/**
     * set the ByteField's current value and write it to a byte array
     *
     * @param value to be set
     * @param data the byte array to write the value to
     *
     * @exception ArrayIndexOutOfBoundsException if the offset is out
     *            of the byte array's range
     */

    public void set(final byte value, final byte [] data)
        throws ArrayIndexOutOfBoundsException
    {
        set(value);
        writeToBytes(data);
    }

    /* ********** START implementation of FixedField ********** */

    
set the value from its offset into an array of bytes
Params:
data – the byte array from which the value is to be read
Throws:
ArrayIndexOutOfBoundsException – if the offset is out
           of range of the bte array/**
     * set the value from its offset into an array of bytes
     *
     * @param data the byte array from which the value is to be read
     *
     * @exception ArrayIndexOutOfBoundsException if the offset is out
     *            of range of the bte array
     */

    public void readFromBytes(final byte [] data)
        throws ArrayIndexOutOfBoundsException
    {
        _value = data[ _offset ];
    }

    
set the value from an InputStream
Params:
stream – the InputStream from which the value is to be
              read
Throws:
BufferUnderrunException – if there is not enough data
           available from the InputStream
IOException – if an IOException is thrown from reading
           the InputStream/**
     * set the value from an InputStream
     *
     * @param stream the InputStream from which the value is to be
     *               read
     *
     * @exception BufferUnderrunException if there is not enough data
     *            available from the InputStream
     * @exception IOException if an IOException is thrown from reading
     *            the InputStream
     */

    public void readFromStream(final InputStream stream)
        throws IOException
    {
    	// TODO - are these ~Field used / necessary
    	int ib = stream.read();
    	if (ib < 0) {
    		throw new BufferUnderflowException();
    	}
        _value = (byte) ib;
    }

    
write the value out to an array of bytes at the appropriate
offset
Params:
data – the array of bytes to which the value is to be
            written
Throws:
ArrayIndexOutOfBoundsException – if the offset is out
           of the byte array's range/**
     * write the value out to an array of bytes at the appropriate
     * offset
     *
     * @param data the array of bytes to which the value is to be
     *             written
     *
     * @exception ArrayIndexOutOfBoundsException if the offset is out
     *            of the byte array's range
     */

    public void writeToBytes(final byte [] data)
        throws ArrayIndexOutOfBoundsException
    {
        data[ _offset ] = _value;
    }

    
return the value as a String
Returns:
the value as a String/**
     * return the value as a String
     *
     * @return the value as a String
     */

    public String toString()
    {
        return String.valueOf(_value);
    }

    /* **********  END  implementation of FixedField ********** */
}   // end public class ByteField