/*
* 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.directory.mavibot.btree.serializer;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import java.util.Comparator;
import org.apache.directory.mavibot.btree.comparator.StringComparator;
import org.apache.directory.mavibot.btree.util.Strings;
/**
* The String serializer.
*
* @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
*/
public class StringSerializer extends AbstractElementSerializer<String>
{
public static final StringSerializer INSTANCE = new StringSerializer();
/**
* Create a new instance of StringSerializer
*/
public StringSerializer()
{
super( new StringComparator() );
}
/**
* Create a new instance of StringSerializer with custom comparator
*/
public StringSerializer( Comparator<String> comparator )
{
super( comparator );
}
/**
* A static method used to deserialize a String from a byte array.
* @param in The byte array containing the String
* @return A String
*/
public static String deserialize( byte[] in )
{
return deserialize( in, 0 );
}
/**
* A static method used to deserialize a String from a byte array.
* @param in The byte array containing the String
* @return A String
*/
public static String deserialize( byte[] in, int start )
{
int length = IntSerializer.deserialize( in, start );
if ( length == 0xFFFFFFFF )
{
return null;
}
if ( in.length < length + 4 + start )
{
throw new RuntimeException( "Cannot extract a String from a buffer with not enough bytes" );
}
return Strings.utf8ToString( in, start + 4, length );
}
/**
* A method used to deserialize a String from a byte array.
* @param in The byte array containing the String
* @return A String
*/
public String fromBytes( byte[] in )
{
return deserialize( in, 0 );
}
/**
* A method used to deserialize a String from a byte array.
* @param in The byte array containing the String
* @return A String
*/
public String fromBytes( byte[] in, int start )
{
int length = IntSerializer.deserialize( in, start );
if ( length == 0xFFFFFFFF )
{
return null;
}
if ( in.length < length + start )
{
throw new RuntimeException( "Cannot extract a String from a buffer with not enough bytes" );
}
return Strings.utf8ToString( in, start + 4, length );
}
/**
* Serialize a String. We store the length on 4 bytes, then the String
*
* @param buffer the Buffer that will contain the serialized value
* @param start the position in the buffer we will store the serialized String
* @param value the value to serialize
* @return The byte[] containing the serialized String
*/
public static byte[] serialize( byte[] buffer, int start, String element )
{
int len = -1;
if ( element != null )
{
len = element.length();
}
switch ( len )
{
case 0:
buffer[start] = 0x00;
buffer[start + 1] = 0x00;
buffer[start + 2] = 0x00;
buffer[start + 3] = 0x00;
break;
case -1:
buffer[start] = ( byte ) 0xFF;
buffer[start + 1] = ( byte ) 0xFF;
buffer[start + 2] = ( byte ) 0xFF;
buffer[start + 3] = ( byte ) 0xFF;
break;
default:
try
{
byte[] strBytes = element.getBytes( "UTF-8" );
buffer = new byte[strBytes.length + 4];
System.arraycopy( strBytes, 0, buffer, 4, strBytes.length );
buffer[start] = ( byte ) ( strBytes.length >>> 24 );
buffer[start + 1] = ( byte ) ( strBytes.length >>> 16 );
buffer[start + 2] = ( byte ) ( strBytes.length >>> 8 );
buffer[start + 3] = ( byte ) ( strBytes.length );
}
catch ( UnsupportedEncodingException uee )
{
// if this happens something is really strange
throw new RuntimeException( uee );
}
}
return buffer;
}
/**
* {@inheritDoc}
*/
public byte[] serialize( String element )
{
int len = -1;
if ( element != null )
{
len = element.length();
}
byte[] bytes = null;
switch ( len )
{
case 0:
bytes = new byte[4];
bytes[0] = 0x00;
bytes[1] = 0x00;
bytes[2] = 0x00;
bytes[3] = 0x00;
break;
case -1:
bytes = new byte[4];
bytes[0] = ( byte ) 0xFF;
bytes[1] = ( byte ) 0xFF;
bytes[2] = ( byte ) 0xFF;
bytes[3] = ( byte ) 0xFF;
break;
default:
char[] chars = element.toCharArray();
byte[] tmpBytes = new byte[chars.length * 2];
int pos = 0;
len = 0;
for ( char c : chars )
{
if ( ( c & 0xFF80 ) == 0 )
{
tmpBytes[pos++] = ( byte ) c;
}
else if ( ( c & 0xF800 ) == 0 )
{
tmpBytes[pos++] = ( byte ) ( ( byte ) 0x00C0 | ( byte ) ( ( c & 0x07C0 ) >> 6 ) );
tmpBytes[pos++] = ( byte ) ( ( byte ) 0x80 | ( byte ) ( c & 0x003F ) );
}
else
{
tmpBytes[pos++] = ( byte ) ( ( byte ) 0x80 | ( byte ) ( c & 0x001F ) );
tmpBytes[pos++] = ( byte ) ( ( byte ) 0x80 | ( byte ) ( c & 0x07C0 ) );
tmpBytes[pos++] = ( byte ) ( ( byte ) 0xE0 | ( byte ) ( c & 0x7800 ) );
}
}
bytes = new byte[pos + 4];
bytes[0] = ( byte ) ( pos >>> 24 );
bytes[1] = ( byte ) ( pos >>> 16 );
bytes[2] = ( byte ) ( pos >>> 8 );
bytes[3] = ( byte ) ( pos );
System.arraycopy( tmpBytes, 0, bytes, 4, pos );
}
return bytes;
}
/**
* {@inheritDoc}
* @throws IOException
*/
public String deserialize( BufferHandler bufferHandler ) throws IOException
{
byte[] in = bufferHandler.read( 4 );
int len = IntSerializer.deserialize( in );
switch ( len )
{
case 0:
return "";
case -1:
return null;
default:
in = bufferHandler.read( len );
return Strings.utf8ToString( in );
}
}
/**
* {@inheritDoc}
*/
public String deserialize( ByteBuffer buffer ) throws IOException
{
int len = buffer.getInt();
switch ( len )
{
case 0:
return "";
case -1:
return null;
default:
byte[] bytes = new byte[len];
buffer.get( bytes );
char[] chars = new char[len];
int clen = 0;
for ( int i = 0; i < len; i++ )
{
byte b = bytes[i];
if ( b >= 0 )
{
chars[clen++] = ( char ) b;
}
else
{
if ( ( b & 0xE0 ) == 0 )
{
// 3 bytes long char
i++;
byte b2 = bytes[i];
i++;
byte b3 = bytes[i];
chars[clen++] = ( char ) ( ( ( b & 0x000F ) << 12 ) | ( ( b2 & 0x003F ) << 6 ) | ( ( b3 & 0x003F ) ) );
}
else
{
// 2 bytes long char
i++;
byte b2 = bytes[i];
chars[clen++] = ( char ) ( ( ( b & 0x001F ) << 6 ) | ( b2 & 0x003F ) );
}
}
}
return new String( chars, 0, clen );
}
}
/**
* {@inheritDoc}
*/
@Override
public int compare( String type1, String type2 )
{
if ( type1 == type2 )
{
return 0;
}
if ( type1 == null )
{
if ( type2 == null )
{
return 0;
}
else
{
return -1;
}
}
else
{
if ( type2 == null )
{
return 1;
}
else
{
return type1.compareTo( type2 );
}
}
}
}