/* ====================================================================
   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.poi.hpsf;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

/**
 * <p>The <em>Variant</em> types as defined by Microsoft's COM. I
 * found this information in <a
 * href="http://www.marin.clara.net/COM/variant_type_definitions.htm">
 * http://www.marin.clara.net/COM/variant_type_definitions.htm</a>.</p>
 *
 * <p>In the variant types descriptions the following shortcuts are
 * used: <strong> [V]</strong> - may appear in a VARIANT,
 * <strong>[T]</strong> - may appear in a TYPEDESC,
 * <strong>[P]</strong> - may appear in an OLE property set,
 * <strong>[S]</strong> - may appear in a Safe Array.</p>
 *
 * @author Rainer Klute (klute@rainer-klute.de)
 */
public class Variant
{

    /**
     * <p>[V][P] Nothing, i.e. not a single byte of data.</p>
     */
    public static final int VT_EMPTY = 0;

    /**
     * <p>[V][T][P][S] 2 byte signed int.</p>
     */
    public static final int VT_I2 = 2;

    /**
     * <p>[V][T][P][S] 4 byte signed int.</p>
     */
    public static final int VT_I4 = 3;

    /**
     * <p>[V][T][P][S] 8 byte real.</p>
     */
    public static final int VT_R8 = 5;

    /**
     * <p>[V][T][P][S] True=-1, False=0.</p>
     */
    public static final int VT_BOOL = 11;

    /**
     * <p>[T][P] signed 64-bit int.</p>
     */
    public static final int VT_I8 = 20;

    /**
     * <p>[T][P] null terminated string.</p>
     */
    public static final int VT_LPSTR = 30;

    /**
     * <p>[T][P] wide (Unicode) null terminated string.</p>
     */
    public static final int VT_LPWSTR = 31;

    /**
     * <p>[P] FILETIME. The FILETIME structure holds a date and time
     * associated with a file. The structure identifies a 64-bit
     * integer specifying the number of 100-nanosecond intervals which
     * have passed since January 1, 1601. This 64-bit value is split
     * into the two dwords stored in the structure.</p>
     */
    public static final int VT_FILETIME = 64;

    /**
     * <p>[P] Clipboard format. <span style="background-color:
     * #ffff00">How long is this? How is it to be
     * interpreted?</span></p>
     */
    public static final int VT_CF = 71;

    /**
     * <p>Maps the numbers denoting the variant types to their corresponding
     * variant type names.</p>
     */
    private static Map<Long, Object> numberToName;

    /**
     * <p>Denotes a variant type with a length that is unknown to HPSF yet.</p>
     */
    public static final Integer LENGTH_UNKNOWN = Integer.valueOf(-2);

    /**
     * <p>Denotes a variant type with a variable length.</p>
     */
    public static final Integer LENGTH_VARIABLE = Integer.valueOf(-1);

    /**
     * <p>Denotes a variant type with a length of 0 bytes.</p>
     */
    public static final Integer LENGTH_0 = Integer.valueOf(0);

    /**
     * <p>Denotes a variant type with a length of 2 bytes.</p>
     */
    public static final Integer LENGTH_2 = Integer.valueOf(2);

    /**
     * <p>Denotes a variant type with a length of 4 bytes.</p>
     */
    public static final Integer LENGTH_4 = Integer.valueOf(4);

    /**
     * <p>Denotes a variant type with a length of 8 bytes.</p>
     */
    public static final Integer LENGTH_8 = Integer.valueOf(8);



    static
    {
        /* Initialize the number-to-name map: */
        Map<Long, Object> tm1 = new HashMap<Long, Object>();
        tm1.put(Long.valueOf(0), "VT_EMPTY");
        tm1.put(Long.valueOf(1), "VT_NULL");
        tm1.put(Long.valueOf(2), "VT_I2");
        tm1.put(Long.valueOf(3), "VT_I4");
        tm1.put(Long.valueOf(4), "VT_R4");
        tm1.put(Long.valueOf(5), "VT_R8");
        tm1.put(Long.valueOf(6), "VT_CY");
        tm1.put(Long.valueOf(7), "VT_DATE");
        tm1.put(Long.valueOf(8), "VT_BSTR");
        tm1.put(Long.valueOf(9), "VT_DISPATCH");
        tm1.put(Long.valueOf(10), "VT_ERROR");
        tm1.put(Long.valueOf(11), "VT_BOOL");
        tm1.put(Long.valueOf(12), "VT_VARIANT");
        tm1.put(Long.valueOf(13), "VT_UNKNOWN");
        tm1.put(Long.valueOf(14), "VT_DECIMAL");
        tm1.put(Long.valueOf(16), "VT_I1");
        tm1.put(Long.valueOf(17), "VT_UI1");
        tm1.put(Long.valueOf(18), "VT_UI2");
        tm1.put(Long.valueOf(19), "VT_UI4");
        tm1.put(Long.valueOf(20), "VT_I8");
        tm1.put(Long.valueOf(21), "VT_UI8");
        tm1.put(Long.valueOf(22), "VT_INT");
        tm1.put(Long.valueOf(23), "VT_UINT");
        tm1.put(Long.valueOf(24), "VT_VOID");
        tm1.put(Long.valueOf(25), "VT_HRESULT");
        tm1.put(Long.valueOf(26), "VT_PTR");
        tm1.put(Long.valueOf(27), "VT_SAFEARRAY");
        tm1.put(Long.valueOf(28), "VT_CARRAY");
        tm1.put(Long.valueOf(29), "VT_USERDEFINED");
        tm1.put(Long.valueOf(30), "VT_LPSTR");
        tm1.put(Long.valueOf(31), "VT_LPWSTR");
        tm1.put(Long.valueOf(64), "VT_FILETIME");
        tm1.put(Long.valueOf(65), "VT_BLOB");
        tm1.put(Long.valueOf(66), "VT_STREAM");
        tm1.put(Long.valueOf(67), "VT_STORAGE");
        tm1.put(Long.valueOf(68), "VT_STREAMED_OBJECT");
        tm1.put(Long.valueOf(69), "VT_STORED_OBJECT");
        tm1.put(Long.valueOf(70), "VT_BLOB_OBJECT");
        tm1.put(Long.valueOf(71), "VT_CF");
        tm1.put(Long.valueOf(72), "VT_CLSID");
        Map<Long, Object> tm2 = new HashMap<Long, Object>(tm1.size(), 1.0F);
        tm2.putAll(tm1);
        numberToName = Collections.unmodifiableMap(tm2);

        /* Initialize the number-to-length map: */
        tm1.clear();
        tm1.put(Long.valueOf(0), LENGTH_0);
        tm1.put(Long.valueOf(1), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(2), LENGTH_2);
        tm1.put(Long.valueOf(3), LENGTH_4);
        tm1.put(Long.valueOf(4), LENGTH_4);
        tm1.put(Long.valueOf(5), LENGTH_8);
        tm1.put(Long.valueOf(6), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(7), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(8), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(9), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(10), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(11), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(12), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(13), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(14), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(16), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(17), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(18), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(19), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(20), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(21), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(22), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(23), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(24), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(25), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(26), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(27), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(28), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(29), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(30), LENGTH_VARIABLE);
        tm1.put(Long.valueOf(31), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(64), LENGTH_8);
        tm1.put(Long.valueOf(65), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(66), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(67), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(68), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(69), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(70), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(71), LENGTH_UNKNOWN);
        tm1.put(Long.valueOf(72), LENGTH_UNKNOWN);
        tm2 = new HashMap<Long, Object>(tm1.size(), 1.0F);
        tm2.putAll(tm1);
    }



    /**
     * <p>Returns the variant type name associated with a variant type
     * number.</p>
     *
     * @param variantType The variant type number
     * @return The variant type name or the string "unknown variant type"
     */
    public static String getVariantName(final long variantType)
    {
        final String name = (String) numberToName.get(Long.valueOf(variantType));
        return name != null ? name : "unknown variant type";
    }


}
