/*
* 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.pdfbox.filter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.persistence.util.COSHEXTable;
/**
* This is the used for the ASCIIHexDecode filter.
*
* @author <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a>
* @version $Revision: 1.9 $
*/
public class ASCIIHexFilter implements Filter
{
/**
* Log instance.
*/
private static final Log log = LogFactory.getLog(ASCIIHexFilter.class);
/**
* Whitespace.
* 0 0x00 Null (NUL)
* 9 0x09 Tab (HT)
* 10 0x0A Line feed (LF)
* 12 0x0C Form feed (FF)
* 13 0x0D Carriage return (CR)
* 32 0x20 Space (SP)
*/
private boolean isWhitespace(int c)
{
return c == 0 || c == 9 || c == 10 || c == 12 || c == 13 || c == 32;
}
private boolean isEOD(int c)
{
return (c == 62); // '>' - EOD
}
/**
* {@inheritDoc}
*/
public void decode( InputStream compressedData, OutputStream result, COSDictionary options, int filterIndex )
throws IOException
{
int value = 0;
int firstByte = 0;
int secondByte = 0;
while ((firstByte = compressedData.read()) != -1)
{
// always after first char
while(isWhitespace(firstByte))
{
firstByte = compressedData.read();
}
if(isEOD(firstByte))
{
break;
}
if(REVERSE_HEX[firstByte] == -1)
{
log.error("Invalid Hex Code; int: " + firstByte + " char: " + (char) firstByte);
}
value = REVERSE_HEX[firstByte] * 16;
secondByte = compressedData.read();
if(isEOD(secondByte))
{
// second value behaves like 0 in case of EOD
result.write( value );
break;
}
if(secondByte >= 0)
{
if(REVERSE_HEX[secondByte] == -1)
{
log.error("Invalid Hex Code; int: " + secondByte + " char: " + (char) secondByte);
}
value += REVERSE_HEX[secondByte];
}
result.write( value );
}
result.flush();
}
private static final int[] REVERSE_HEX =
{
-1, //0
-1, //1
-1, //2
-1, //3
-1, //4
-1, //5
-1, //6
-1, //7
-1, //8
-1, //9
-1, //10
-1, //11
-1, //12
-1, //13
-1, //14
-1, //15
-1, //16
-1, //17
-1, //18
-1, //19
-1, //20
-1, //21
-1, //22
-1, //23
-1, //24
-1, //25
-1, //26
-1, //27
-1, //28
-1, //29
-1, //30
-1, //31
-1, //32
-1, //33
-1, //34
-1, //35
-1, //36
-1, //37
-1, //38
-1, //39
-1, //40
-1, //41
-1, //42
-1, //43
-1, //44
-1, //45
-1, //46
-1, //47
0, //48
1, //49
2, //50
3, //51
4, //52
5, //53
6, //54
7, //55
8, //56
9, //57
-1, //58
-1, //59
-1, //60
-1, //61
-1, //62
-1, //63
-1, //64
10, //65
11, //66
12, //67
13, //68
14, //69
15, //70
-1, //71
-1, //72
-1, //73
-1, //74
-1, //75
-1, //76
-1, //77
-1, //78
-1, //79
-1, //80
-1, //81
-1, //82
-1, //83
-1, //84
-1, //85
-1, //86
-1, //87
-1, //88
-1, //89
-1, //90
-1, //91
-1, //92
-1, //93
-1, //94
-1, //95
-1, //96
10, //97
11, //98
12, //99
13, //100
14, //101
15, //102
};
/**
* {@inheritDoc}
*/
public void encode( InputStream rawData, OutputStream result, COSDictionary options, int filterIndex )
throws IOException
{
int byteRead = 0;
while( (byteRead = rawData.read()) != -1 )
{
int value = (byteRead+256)%256;
result.write( COSHEXTable.TABLE[value] );
}
result.flush();
}
}