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PDF renderer implementation supporting the subset of PDF 1.4 specification.
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/*
* Copyright 2008 Pirion Systems Pty Ltd, 139 Warry St,
* Fortitude Valley, Queensland, Australia
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package com.sun.pdfview;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CoderResult;
import java.util.HashMap;
import java.util.Map;
/**
* Encodes into a PDFDocEncoding representation. Note that only 256 characters
* (if that) are represented in the PDFDocEncoding, so users should be
* prepared to deal with unmappable character exceptions.
*
* @see "PDF Reference version 1.7, Appendix D"
*
* @author Luke Kirby
*/
public class PDFDocCharsetEncoder extends CharsetEncoder {
/**
* Identify whether a particular character preserves the same byte value
* upon encoding in PDFDocEncoding
* @param ch the character
* @return whether the character is identity encoded
*/
public static boolean isIdentityEncoding(char ch) {
return ch >= 0 && ch <= 255 && IDENT_PDF_DOC_ENCODING_MAP[ch];
}
/**
* For each character that exists in PDFDocEncoding, identifies whether
* the byte value in UTF-16BE is the same as it is in PDFDocEncoding
*/
final static boolean[] IDENT_PDF_DOC_ENCODING_MAP = new boolean[256];
/**
* For non-identity encoded characters, maps from the character to
* the byte value in PDFDocEncoding. If an entry for a non-identity
* coded character is absent from this map, that character is unmappable
* in the PDFDocEncoding.
*/
final static Map EXTENDED_TO_PDF_DOC_ENCODING_MAP =
new HashMap();
static
{
for (int i = 0; i < PDFStringUtil.PDF_DOC_ENCODING_MAP.length; ++i) {
final char c = PDFStringUtil.PDF_DOC_ENCODING_MAP[i];
final boolean identical = (c == i);
IDENT_PDF_DOC_ENCODING_MAP[i] = identical;
if (!identical) {
EXTENDED_TO_PDF_DOC_ENCODING_MAP.put(c, (byte)i);
}
}
}
public PDFDocCharsetEncoder() {
super(null, 1, 1);
}
protected CoderResult encodeLoop(CharBuffer in, ByteBuffer out) {
while (in.remaining() > 0) {
if (out.remaining() < 1) {
return CoderResult.OVERFLOW;
}
final char c = in.get();
if (c >= 0 && c < 256 && IDENT_PDF_DOC_ENCODING_MAP[c]) {
out.put((byte) c);
} else {
final Byte mapped = EXTENDED_TO_PDF_DOC_ENCODING_MAP.get(c);
if (mapped != null) {
out.put(mapped);
} else {
return CoderResult.unmappableForLength(1);
}
}
}
return CoderResult.UNDERFLOW;
}
@Override
public boolean isLegalReplacement(byte[] repl) {
// avoid referencing the non-existent character set
return true;
}
}