226 lines
6.2 KiB
Java
226 lines
6.2 KiB
Java
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/* ====================================================================
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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==================================================================== */
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package org.apache.poi.util;
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import org.apache.poi.util.LittleEndian.BufferUnderrunException;
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import java.io.*;
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import java.nio.BufferUnderflowException;
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/**
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* representation of a byte (8-bit) field at a fixed location within a
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* byte array
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*
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* @author Marc Johnson (mjohnson at apache dot org
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*/
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public class ByteField
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implements FixedField
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{
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private static final byte _default_value = 0;
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private byte _value;
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private final int _offset;
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/**
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* construct the ByteField with its offset into its containing
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* byte array and a default value of 0
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*
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* @param offset of the field within its byte array
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*
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* @exception ArrayIndexOutOfBoundsException if offset is negative
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*/
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public ByteField(final int offset)
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throws ArrayIndexOutOfBoundsException
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{
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this(offset, _default_value);
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}
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/**
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* construct the ByteField with its offset into its containing
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* byte array and initialize its value
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*
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* @param offset of the field within its byte array
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* @param value the initial value
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*
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* @exception ArrayIndexOutOfBoundsException if offset is negative
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*/
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public ByteField(final int offset, final byte value)
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throws ArrayIndexOutOfBoundsException
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{
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if (offset < 0)
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{
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throw new ArrayIndexOutOfBoundsException(
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"offset cannot be negative");
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}
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_offset = offset;
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set(value);
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}
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/**
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* Construct the ByteField with its offset into its containing
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* byte array and initialize its value from its byte array
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*
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* @param offset of the field within its byte array
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* @param data the byte array to read the value from
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*
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* @exception ArrayIndexOutOfBoundsException if the offset is not
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* within the range of 0..(data.length - 1)
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*/
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public ByteField(final int offset, final byte [] data)
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throws ArrayIndexOutOfBoundsException
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{
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this(offset);
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readFromBytes(data);
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}
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/**
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* construct the ByteField with its offset into its containing
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* byte array, initialize its value, and write its value to its
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* byte array
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*
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* @param offset of the field within its byte array
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* @param value the initial value
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* @param data the byte array to write the value to
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*
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* @exception ArrayIndexOutOfBoundsException if the offset is not
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* within the range of 0..(data.length - 1)
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*/
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public ByteField(final int offset, final byte value, final byte [] data)
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throws ArrayIndexOutOfBoundsException
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{
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this(offset, value);
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writeToBytes(data);
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}
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/**
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* get the ByteField's current value
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*
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* @return current value
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*/
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public byte get()
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{
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return _value;
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}
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/**
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* set the ByteField's current value
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*
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* @param value to be set
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*/
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public void set(final byte value)
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{
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_value = value;
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}
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/**
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* set the ByteField's current value and write it to a byte array
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*
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* @param value to be set
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* @param data the byte array to write the value to
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*
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* @exception ArrayIndexOutOfBoundsException if the offset is out
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* of the byte array's range
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*/
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public void set(final byte value, final byte [] data)
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throws ArrayIndexOutOfBoundsException
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{
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set(value);
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writeToBytes(data);
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}
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/* ********** START implementation of FixedField ********** */
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/**
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* set the value from its offset into an array of bytes
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*
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* @param data the byte array from which the value is to be read
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*
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* @exception ArrayIndexOutOfBoundsException if the offset is out
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* of range of the bte array
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*/
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public void readFromBytes(final byte [] data)
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throws ArrayIndexOutOfBoundsException
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{
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_value = data[ _offset ];
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}
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/**
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* set the value from an InputStream
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*
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* @param stream the InputStream from which the value is to be
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* read
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*
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* @exception BufferUnderrunException if there is not enough data
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* available from the InputStream
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* @exception IOException if an IOException is thrown from reading
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* the InputStream
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*/
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public void readFromStream(final InputStream stream)
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throws IOException
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{
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// TODO - are these ~Field used / necessary
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int ib = stream.read();
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if (ib < 0) {
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throw new BufferUnderflowException();
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}
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_value = (byte) ib;
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}
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/**
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* write the value out to an array of bytes at the appropriate
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* offset
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*
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* @param data the array of bytes to which the value is to be
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* written
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*
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* @exception ArrayIndexOutOfBoundsException if the offset is out
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* of the byte array's range
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*/
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public void writeToBytes(final byte [] data)
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throws ArrayIndexOutOfBoundsException
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{
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data[ _offset ] = _value;
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}
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/**
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* return the value as a String
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*
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* @return the value as a String
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*/
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public String toString()
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{
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return String.valueOf(_value);
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}
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/* ********** END implementation of FixedField ********** */
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} // end public class ByteField
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