org.apache.pdfbox.io.ASCII85OutputStream Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of pdfbox Show documentation
Show all versions of pdfbox Show documentation
The Apache PDFBox library is an open source Java tool for working with PDF documents.
/*
* 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.io;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
/**
* This class represents an ASCII85 output stream.
*
* @author Ben Litchfield
*
*/
public class ASCII85OutputStream extends FilterOutputStream
{
private int lineBreak;
private int count;
private byte[] indata;
private byte[] outdata;
/**
* Function produces five ASCII printing characters from
* four bytes of binary data.
*/
private int maxline;
private boolean flushed;
private char terminator;
private static final char OFFSET = '!';
private static final char NEWLINE = '\n';
private static final char Z = 'z';
/**
* Constructor.
*
* @param out The output stream to write to.
*/
public ASCII85OutputStream(OutputStream out)
{
super(out);
lineBreak = 36 * 2;
maxline = 36 * 2;
count = 0;
indata = new byte[4];
outdata = new byte[5];
flushed = true;
terminator = '~';
}
/**
* This will set the terminating character.
*
* @param term The terminating character.
*/
public void setTerminator(char term)
{
if (term < 118 || term > 126 || term == Z)
{
throw new IllegalArgumentException("Terminator must be 118-126 excluding z");
}
terminator = term;
}
/**
* This will get the terminating character.
*
* @return The terminating character.
*/
public char getTerminator()
{
return terminator;
}
/**
* This will set the line length that will be used.
*
* @param l The length of the line to use.
*/
public void setLineLength(int l)
{
if (lineBreak > l)
{
lineBreak = l;
}
maxline = l;
}
/**
* This will get the length of the line.
*
* @return The line length attribute.
*/
public int getLineLength()
{
return maxline;
}
/**
* This will transform the next four ascii bytes.
*/
private final void transformASCII85()
{
long word = ((((indata[0] << 8) | (indata[1] & 0xFF)) << 16) | ((indata[2] & 0xFF) << 8) | (indata[3] & 0xFF)) & 0xFFFFFFFFL;
if (word == 0)
{
outdata[0] = (byte) Z;
outdata[1] = 0;
return;
}
long x;
x = word / (85L * 85L * 85L * 85L);
outdata[0] = (byte) (x + OFFSET);
word -= x * 85L * 85L * 85L * 85L;
x = word / (85L * 85L * 85L);
outdata[1] = (byte) (x + OFFSET);
word -= x * 85L * 85L * 85L;
x = word / (85L * 85L);
outdata[2] = (byte) (x + OFFSET);
word -= x * 85L * 85L;
x = word / 85L;
outdata[3] = (byte) (x + OFFSET);
outdata[4] = (byte) ((word % 85L) + OFFSET);
}
/**
* This will write a single byte.
*
* @param b The byte to write.
*
* @throws IOException If there is an error writing to the stream.
*/
public final void write(int b) throws IOException
{
flushed = false;
indata[count++] = (byte) b;
if (count < 4)
{
return;
}
transformASCII85();
for (int i = 0; i < 5; i++)
{
if (outdata[i] == 0)
{
break;
}
out.write(outdata[i]);
if (--lineBreak == 0)
{
out.write(NEWLINE);
lineBreak = maxline;
}
}
count = 0;
}
/**
* This will flush the data to the stream.
*
* @throws IOException If there is an error writing the data to the stream.
*/
public final void flush() throws IOException
{
if (flushed)
{
return;
}
if (count > 0)
{
for (int i = count; i < 4; i++)
{
indata[i] = 0;
}
transformASCII85();
if (outdata[0] == Z)
{
for (int i = 0; i < 5; i++) // expand 'z',
{
outdata[i] = (byte) OFFSET;
}
}
for (int i = 0; i < count + 1; i++)
{
out.write(outdata[i]);
if (--lineBreak == 0)
{
out.write(NEWLINE);
lineBreak = maxline;
}
}
}
if (--lineBreak == 0)
{
out.write(NEWLINE);
}
out.write(terminator);
out.write('>');
out.write(NEWLINE);
count = 0;
lineBreak = maxline;
flushed = true;
super.flush();
}
/**
* This will close the stream.
*
* @throws IOException If there is an error closing the wrapped stream.
*/
public void close() throws IOException
{
try
{
flush();
super.close();
}
finally
{
indata = outdata = null;
}
}
}