Coverage Report - org.apache.commons.fileupload.util.mime.QuotedPrintableDecoder
 
Classes in this File Line Coverage Branch Coverage Complexity
QuotedPrintableDecoder
93%
29/31
100%
14/14
4,333
 
 1  
 /*
 2  
  * Licensed to the Apache Software Foundation (ASF) under one or more
 3  
  * contributor license agreements.  See the NOTICE file distributed with
 4  
  * this work for additional information regarding copyright ownership.
 5  
  * The ASF licenses this file to You under the Apache License, Version 2.0
 6  
  * (the "License"); you may not use this file except in compliance with
 7  
  * the License.  You may obtain a copy of the License at
 8  
  *
 9  
  *      http://www.apache.org/licenses/LICENSE-2.0
 10  
  *
 11  
  * Unless required by applicable law or agreed to in writing, software
 12  
  * distributed under the License is distributed on an "AS IS" BASIS,
 13  
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 14  
  * See the License for the specific language governing permissions and
 15  
  * limitations under the License.
 16  
  */
 17  
 package org.apache.commons.fileupload.util.mime;
 18  
 
 19  
 import java.io.IOException;
 20  
 import java.io.OutputStream;
 21  
 
 22  
 /**
 23  
  * @since 1.3
 24  
  */
 25  
 final class QuotedPrintableDecoder {
 26  
 
 27  
     /**
 28  
      * The shift value required to create the upper nibble
 29  
      * from the first of 2 byte values converted from ascii hex.
 30  
      */
 31  
     private static final int UPPER_NIBBLE_SHIFT = Byte.SIZE / 2;
 32  
 
 33  
     /**
 34  
      * Hidden constructor, this class must not be instantiated.
 35  
      */
 36  0
     private QuotedPrintableDecoder() {
 37  
         // do nothing
 38  0
     }
 39  
 
 40  
     /**
 41  
      * Decode the encoded byte data writing it to the given output stream.
 42  
      *
 43  
      * @param data   The array of byte data to decode.
 44  
      * @param out    The output stream used to return the decoded data.
 45  
      *
 46  
      * @return the number of bytes produced.
 47  
      * @throws IOException
 48  
      */
 49  
     public static int decode(byte[] data, OutputStream out) throws IOException {
 50  12
         int off = 0;
 51  12
         int length = data.length;
 52  12
         int endOffset = off + length;
 53  12
         int bytesWritten = 0;
 54  
 
 55  245
         while (off < endOffset) {
 56  238
             byte ch = data[off++];
 57  
 
 58  
             // space characters were translated to '_' on encode, so we need to translate them back.
 59  238
             if (ch == '_') {
 60  3
                 out.write(' ');
 61  235
             } else if (ch == '=') {
 62  
                 // we found an encoded character.  Reduce the 3 char sequence to one.
 63  
                 // but first, make sure we have two characters to work with.
 64  27
                 if (off + 1 >= endOffset) {
 65  2
                     throw new IOException("Invalid quoted printable encoding; truncated escape sequence");
 66  
                 }
 67  
 
 68  25
                 byte b1 = data[off++];
 69  25
                 byte b2 = data[off++];
 70  
 
 71  
                 // we've found an encoded carriage return.  The next char needs to be a newline
 72  25
                 if (b1 == '\r') {
 73  3
                     if (b2 != '\n') {
 74  2
                         throw new IOException("Invalid quoted printable encoding; CR must be followed by LF");
 75  
                     }
 76  
                     // this was a soft linebreak inserted by the encoding.  We just toss this away
 77  
                     // on decode.
 78  
                 } else {
 79  
                     // this is a hex pair we need to convert back to a single byte.
 80  22
                     int c1 = hexToBinary(b1);
 81  21
                     int c2 = hexToBinary(b2);
 82  21
                     out.write((c1 << UPPER_NIBBLE_SHIFT) | c2);
 83  
                     // 3 bytes in, one byte out
 84  21
                     bytesWritten++;
 85  
                 }
 86  22
             } else {
 87  
                 // simple character, just write it out.
 88  208
                 out.write(ch);
 89  208
                 bytesWritten++;
 90  
             }
 91  233
         }
 92  
 
 93  7
         return bytesWritten;
 94  
     }
 95  
 
 96  
     /**
 97  
      * Convert a hex digit to the binary value it represents.
 98  
      *
 99  
      * @param b the ascii hex byte to convert (0-0, A-F, a-f)
 100  
      * @return the int value of the hex byte, 0-15
 101  
      * @throws IOException if the byte is not a valid hex digit.
 102  
      */
 103  
     private static int hexToBinary(final byte b) throws IOException {
 104  
         // CHECKSTYLE IGNORE MagicNumber FOR NEXT 1 LINE
 105  43
         final int i = Character.digit((char) b, 16);
 106  43
         if (i == -1) {
 107  1
             throw new IOException("Invalid quoted printable encoding: not a valid hex digit: " + b);
 108  
         }
 109  42
         return i;
 110  
     }
 111  
 
 112  
 }