deltarecord.java

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/* ====================================================================
   Copyright 2002-2004   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.poi.hssf.record;

import org.apache.poi.util.LittleEndian;

/**
 * Title:        Delta Record<P>
 * Description:  controls the accuracy of the calculations<P>
 * REFERENCE:  PG 303 Microsoft Excel 97 Developer's Kit (ISBN: 1-57231-498-2)<P>
 * @author Andrew C. Oliver (acoliver at apache dot org)
 * @author Jason Height (jheight at chariot dot net dot au)
 * @version 2.0-pre
 */

public class DeltaRecord
    extends Record
{
    public final static short  sid           = 0x10;
    public final static double DEFAULT_VALUE = 0.0010;   // should be .001

    // a double is an IEEE 8-byte float...damn IEEE and their goofy standards an
    // ambiguous numeric identifiers
    private double             field_1_max_change;

    public DeltaRecord()
    {
    }

    /**
     * Constructs a Delta record and sets its fields appropriately.
     *
     * @param id     id must be 0x10 or an exception will be throw upon validation
     * @param size  the size of the data area of the record
     * @param data  data of the record (should not contain sid/len)
     */

    public DeltaRecord(short id, short size, byte [] data)
    {
        super(id, size, data);
    }

    /**
     * Constructs a Delta record and sets its fields appropriately.
     *
     * @param id     id must be 0x10 or an exception will be throw upon validation
     * @param size  the size of the data area of the record
     * @param data  data of the record (should not contain sid/len)
     * @param offset of record data
     */

    public DeltaRecord(short id, short size, byte [] data, int offset)
    {
        super(id, size, data, offset);
    }

    protected void validateSid(short id)
    {
        if (id != sid)
        {
            throw new RecordFormatException("NOT A DELTA RECORD");
        }
    }

    protected void fillFields(byte [] data, short size, int offset)
    {
        field_1_max_change = LittleEndian.getDouble(data, 0 + offset);
    }

    /**
     * set the maximum change
     * @param maxChange - maximum rounding error
     */

    public void setMaxChange(double maxChange)
    {
        field_1_max_change = maxChange;
    }

    /**
     * get the maximum change
     * @return maxChange - maximum rounding error
     */

    public double getMaxChange()
    {
        return field_1_max_change;
    }

    public String toString()
    {
        StringBuffer buffer = new StringBuffer();

        buffer.append("[DELTA]\n");
        buffer.append("    .maxchange      = ").append(getMaxChange())
            .append("\n");
        buffer.append("[/DELTA]\n");
        return buffer.toString();
    }

    public int serialize(int offset, byte [] data)
    {
        LittleEndian.putShort(data, 0 + offset, sid);
        LittleEndian.putShort(data, 2 + offset, ( short ) 0x8);
        LittleEndian.putDouble(data, 4 + offset, getMaxChange());
        return getRecordSize();
    }

    public int getRecordSize()
    {
        return 12;
    }

    public short getSid()
    {
        return this.sid;
    }

    public Object clone() {
      DeltaRecord rec = new DeltaRecord();
      rec.field_1_max_change = field_1_max_change;
      return rec;
    }
}