com.phloc.commons.codec.QuotedPrintableCodec Maven / Gradle / Ivy
/**
* Copyright (C) 2006-2015 phloc systems
* http://www.phloc.com
* office[at]phloc[dot]com
*
* Licensed 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 com.phloc.commons.codec;
import java.nio.charset.Charset;
import java.util.BitSet;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import com.phloc.commons.ValueEnforcer;
import com.phloc.commons.annotations.ReturnsMutableCopy;
import com.phloc.commons.charset.CCharset;
import com.phloc.commons.charset.CharsetManager;
import com.phloc.commons.io.streams.NonBlockingByteArrayOutputStream;
import com.phloc.commons.io.streams.StreamUtils;
import com.phloc.commons.string.StringHelper;
/**
* Encoder and decoder for quoted printable stuff
*
* @author Philip Helger
*/
public class QuotedPrintableCodec extends AbstractCodec implements IStringCodec
{
private static final byte ESCAPE_CHAR = '=';
private static final byte TAB = 9;
private static final byte SPACE = 32;
/**
* BitSet of printable characters as defined in RFC 1521.
*/
private static final BitSet PRINTABLE_CHARS = new BitSet (256);
static
{
PRINTABLE_CHARS.set (TAB);
PRINTABLE_CHARS.set (SPACE);
for (int i = 33; i <= 126; i++)
if (i != ESCAPE_CHAR)
PRINTABLE_CHARS.set (i);
}
/**
* The default charset used for string decoding and encoding.
*/
private final Charset m_aCharset;
/**
* Default constructor with the UTF-8 charset.
*/
public QuotedPrintableCodec ()
{
this (CCharset.CHARSET_UTF_8_OBJ);
}
/**
* Constructor which allows for the selection of a default charset
*
* @param aCharset
* the default string charset to use.
*/
public QuotedPrintableCodec (@Nonnull final Charset aCharset)
{
m_aCharset = ValueEnforcer.notNull (aCharset, "Charset");
}
@Nonnull
public Charset getCharset ()
{
return m_aCharset;
}
/**
* @return A copy of the default bit set to be used.
*/
@Nonnull
@ReturnsMutableCopy
public static BitSet getDefaultBitSet ()
{
return (BitSet) PRINTABLE_CHARS.clone ();
}
/**
* Encodes byte into its quoted-printable representation.
*
* @param b
* byte to encode
* @param aBAOS
* the buffer to write to
*/
public static final void encodeQuotedPrintable (final int b, @Nonnull final NonBlockingByteArrayOutputStream aBAOS)
{
final char cHigh = Character.toUpperCase (StringHelper.getHexChar ((b >> 4) & 0xF));
final char cLow = Character.toUpperCase (StringHelper.getHexChar (b & 0xF));
aBAOS.write (ESCAPE_CHAR);
aBAOS.write (cHigh);
aBAOS.write (cLow);
}
@Nonnull
public static byte [] encodeQuotedPrintable (@Nonnull final BitSet aPrintableBitSet,
@Nonnull final byte [] aDecodedBuffer)
{
final NonBlockingByteArrayOutputStream aBAOS = new NonBlockingByteArrayOutputStream (aDecodedBuffer.length * 2);
for (final byte nByte : aDecodedBuffer)
{
final int b = nByte & 0xff;
if (aPrintableBitSet.get (b))
aBAOS.write (b);
else
encodeQuotedPrintable (b, aBAOS);
}
return aBAOS.toByteArray ();
}
@Nullable
public byte [] encode (@Nullable final byte [] aDecodedBuffer)
{
if (aDecodedBuffer == null)
return null;
return encodeQuotedPrintable (PRINTABLE_CHARS, aDecodedBuffer);
}
@Nullable
public static byte [] decodeQuotedPrintable (@Nullable final byte [] aEncodedBuffer)
{
if (aEncodedBuffer == null)
return null;
final NonBlockingByteArrayOutputStream aBAOS = new NonBlockingByteArrayOutputStream ();
try
{
final int nMax = aEncodedBuffer.length;
for (int i = 0; i < nMax; i++)
{
final int b = aEncodedBuffer[i];
if (b == ESCAPE_CHAR)
{
if (i >= nMax - 2)
throw new DecoderException ("Invalid quoted-printable encoding. Premature of string after escape char");
final char cHigh = (char) aEncodedBuffer[++i];
final char cLow = (char) aEncodedBuffer[++i];
final int nDecodedValue = StringHelper.getHexByte (cHigh, cLow);
if (nDecodedValue < 0)
throw new DecoderException ("Invalid quoted-printable encoding for " + cHigh + cLow);
aBAOS.write (nDecodedValue);
}
else
{
aBAOS.write (b);
}
}
return aBAOS.toByteArray ();
}
finally
{
StreamUtils.close (aBAOS);
}
}
@Nullable
public byte [] decode (@Nullable final byte [] aEncodedBuffer)
{
return decodeQuotedPrintable (aEncodedBuffer);
}
@Nullable
public String encodeText (@Nullable final String sDecoded)
{
return encodeText (sDecoded, m_aCharset);
}
@Nullable
public String encodeText (@Nonnull final BitSet aBitSet, @Nullable final String sDecoded)
{
return encodeText (aBitSet, sDecoded, m_aCharset);
}
/**
* Encode the passed text using the default BitSet.
*
* @param sDecoded
* The original string to be encoded. May be null.
* @param aCharset
* The charset to be used. May not be null.
* @return The encoded string in US-ASCII encoding. May be null
* if the original string is null.
*/
@Nullable
public static String encodeText (@Nullable final String sDecoded, @Nonnull final Charset aCharset)
{
return encodeText (PRINTABLE_CHARS, sDecoded, aCharset);
}
/**
* Encode the passed text using a custom BitSet
*
* @param aPrintableBitSet
* The BitSet with all chars to NOT escape. May not be
* null.
* @param sDecoded
* The original string to be encoded. May be null.
* @param aCharset
* The charset to be used. May not be null.
* @return The encoded string in US-ASCII encoding. May be null
* if the original string is null.
*/
@Nullable
public static String encodeText (@Nonnull final BitSet aPrintableBitSet,
@Nullable final String sDecoded,
@Nonnull final Charset aCharset)
{
if (sDecoded == null)
return null;
final byte [] aEncodedData = encodeQuotedPrintable (aPrintableBitSet,
CharsetManager.getAsBytes (sDecoded, aCharset));
return CharsetManager.getAsString (aEncodedData, CCharset.CHARSET_US_ASCII_OBJ);
}
@Nullable
public String decodeText (@Nullable final String sEncoded)
{
return decodeText (sEncoded, m_aCharset);
}
@Nullable
public static String decodeText (@Nullable final String sEncoded, @Nonnull final Charset aCharset)
{
if (sEncoded == null)
return null;
byte [] aData = CharsetManager.getAsBytes (sEncoded, CCharset.CHARSET_US_ASCII_OBJ);
aData = decodeQuotedPrintable (aData);
return CharsetManager.getAsString (aData, aCharset);
}
}