1 /* 2 * Copyright (C) 2007 Esmertec AG. 3 * Copyright (C) 2007 The Android Open Source Project 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * 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 18 package com.android.messaging.mmslib.pdu; 19 20 import java.io.ByteArrayOutputStream; 21 22 public class QuotedPrintable { 23 private static byte ESCAPE_CHAR = '='; 24 25 /** 26 * Decodes an array quoted-printable characters into an array of original bytes. 27 * Escaped characters are converted back to their original representation. 28 * 29 * <p> 30 * This function implements a subset of 31 * quoted-printable encoding specification (rule #1 and rule #2) 32 * as defined in RFC 1521. 33 * </p> 34 * 35 * @param bytes array of quoted-printable characters 36 * @return array of original bytes, 37 * null if quoted-printable decoding is unsuccessful. 38 */ 39 public static final byte[] decodeQuotedPrintable(byte[] bytes) { 40 if (bytes == null) { 41 return null; 42 } 43 ByteArrayOutputStream buffer = new ByteArrayOutputStream(); 44 for (int i = 0; i < bytes.length; i++) { 45 int b = bytes[i]; 46 if (b == ESCAPE_CHAR) { 47 try { 48 if ('\r' == (char) bytes[i + 1] && 49 '\n' == (char) bytes[i + 2]) { 50 i += 2; 51 continue; 52 } 53 int u = Character.digit((char) bytes[++i], 16); 54 int l = Character.digit((char) bytes[++i], 16); 55 if (u == -1 || l == -1) { 56 return null; 57 } 58 buffer.write((char) ((u << 4) + l)); 59 } catch (ArrayIndexOutOfBoundsException e) { 60 return null; 61 } 62 } else { 63 buffer.write(b); 64 } 65 } 66 return buffer.toByteArray(); 67 } 68 } 69
