Android example source code file (QuotedPrintable.java)

This example Android source code file (QuotedPrintable.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

arrayindexoutofboundsexception, bytearrayoutputstream, escape_char, io, quotedprintable

The QuotedPrintable.java Android example source code

/*
 * Copyright (C) 2007 Esmertec AG.
 * Copyright (C) 2007 The Android Open Source Project
 *
 * 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.google.android.mms.pdu;

import java.io.ByteArrayOutputStream;

public class QuotedPrintable {
    private static byte ESCAPE_CHAR = '=';

    /**
     * Decodes an array quoted-printable characters into an array of original bytes.
     * Escaped characters are converted back to their original representation.
     *
     * <p>
     * This function implements a subset of
     * quoted-printable encoding specification (rule #1 and rule #2)
     * as defined in RFC 1521.
     * </p>
     *
     * @param bytes array of quoted-printable characters
     * @return array of original bytes,
     *         null if quoted-printable decoding is unsuccessful.
     */
    public static final byte[] decodeQuotedPrintable(byte[] bytes) {
        if (bytes == null) {
            return null;
        }
        ByteArrayOutputStream buffer = new ByteArrayOutputStream();
        for (int i = 0; i < bytes.length; i++) {
            int b = bytes[i];
            if (b == ESCAPE_CHAR) {
                try {
                    if('\r' == (char)bytes[i + 1] &&
                            '\n' == (char)bytes[i + 2]) {
                        i += 2;
                        continue;
                    }
                    int u = Character.digit((char) bytes[++i], 16);
                    int l = Character.digit((char) bytes[++i], 16);
                    if (u == -1 || l == -1) {
                        return null;
                    }
                    buffer.write((char) ((u << 4) + l));
                } catch (ArrayIndexOutOfBoundsException e) {
                    return null;
                }
            } else {
                buffer.write(b);
            }
        }
        return buffer.toByteArray();
    }
}