| /* |
| * 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.commons.fileupload.util.mime; |
| |
| import java.io.IOException; |
| import java.io.OutputStream; |
| |
| /** |
| * @since 1.3 |
| */ |
| final class QuotedPrintableDecoder { |
| |
| /** |
| * set up the encoding table. |
| */ |
| private static final byte[] ENCODING_TABLE = |
| { |
| (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6', (byte)'7', |
| (byte)'8', (byte)'9', (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F' |
| }; |
| |
| /** |
| * set up the decoding table. |
| */ |
| private static final byte[] DECODING_TABLE = new byte[128]; |
| |
| static { |
| // initialize the decoding table |
| for (int i = 0; i < ENCODING_TABLE.length; i++) { |
| DECODING_TABLE[ENCODING_TABLE[i]] = (byte)i; |
| } |
| } |
| |
| // default number of characters we will write per line. |
| static private final int DEFAULT_CHARS_PER_LINE = 76; |
| |
| // the output stream we're wrapped around |
| protected OutputStream out; |
| |
| // the number of bytes written; |
| protected int bytesWritten = 0; |
| |
| // number of bytes written on the current line |
| protected int lineCount = 0; |
| |
| // line length we're dealing with |
| protected int lineLength; |
| |
| // number of deferred whitespace characters in decode mode. |
| protected int deferredWhitespace = 0; |
| |
| protected int cachedCharacter = -1; |
| |
| // indicates whether the last character was a '\r', potentially part of a CRLF sequence. |
| protected boolean lastCR = false; |
| |
| // remember whether last character was a white space. |
| protected boolean lastWhitespace = false; |
| |
| public QuotedPrintableDecoder() { |
| this(null, DEFAULT_CHARS_PER_LINE); |
| } |
| |
| public QuotedPrintableDecoder(OutputStream out) { |
| this(out, DEFAULT_CHARS_PER_LINE); |
| } |
| |
| public QuotedPrintableDecoder(OutputStream out, int lineLength) { |
| this.out = out; |
| this.lineLength = lineLength; |
| } |
| |
| /** |
| * decode the uuencoded byte data writing it to the given output stream |
| * |
| * @param data The array of byte data to decode. |
| * @param off Starting offset within the array. |
| * @param length The length of data to encode. |
| * @param out The output stream used to return the decoded data. |
| * |
| * @return the number of bytes produced. |
| * @exception IOException |
| */ |
| public int decodeWord(byte[] data, int off, int length, OutputStream out) throws IOException { |
| // make sure we're writing to the correct stream |
| this.out = out; |
| |
| int endOffset = off + length; |
| int bytesWritten = 0; |
| |
| while (off < endOffset) { |
| byte ch = data[off++]; |
| |
| // space characters were translated to '_' on encode, so we need to translate them back. |
| if (ch == '_') { |
| out.write(' '); |
| } else if (ch == '=') { |
| // we found an encoded character. Reduce the 3 char sequence to one. |
| // but first, make sure we have two characters to work with. |
| if (off + 1 >= endOffset) { |
| throw new IOException("Invalid quoted printable encoding"); |
| } |
| // convert the two bytes back from hex. |
| byte b1 = data[off++]; |
| byte b2 = data[off++]; |
| |
| // we've found an encoded carriage return. The next char needs to be a newline |
| if (b1 == '\r') { |
| if (b2 != '\n') { |
| throw new IOException("Invalid quoted printable encoding"); |
| } |
| // this was a soft linebreak inserted by the encoding. We just toss this away |
| // on decode. |
| } else { |
| // this is a hex pair we need to convert back to a single byte. |
| byte c1 = DECODING_TABLE[b1]; |
| byte c2 = DECODING_TABLE[b2]; |
| out.write((c1 << 4) | c2); |
| // 3 bytes in, one byte out |
| bytesWritten++; |
| } |
| } else { |
| // simple character, just write it out. |
| out.write(ch); |
| bytesWritten++; |
| } |
| } |
| |
| return bytesWritten; |
| } |
| |
| } |