Java Base64 Encode toBase64Impl(byte[] data)

Description

to Base Impl

License

Apache License

Declaration

private static String toBase64Impl(byte[] data) 

Method Source Code

//package com.java2s;
/*/*from ww  w .  ja  v  a 2  s .c o m*/
 * Copyright 2009 Google Inc.
 * 
 * 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.
 */

public class Main {
    /**
     * An array mapping size but values to the characters that will be used to represent them.
     * Note that this is not identical to the set of characters used by MIME-Base64.
     */
    private static final char[] base64Chars = new char[] { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K',
            'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
            'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0',
            '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' };

    private static String toBase64Impl(byte[] data) {
        if (data == null) {
            return null;
        }

        int len = data.length;
        if (len == 0) {
            return "";
        }

        int olen = 4 * ((len + 2) / 3);
        char[] chars = new char[olen];

        int iidx = 0;
        int oidx = 0;
        int charsLeft = len;
        while (charsLeft > 0) {
            int b0 = data[iidx++] & 0xff;
            int b1 = (charsLeft > 1) ? data[iidx++] & 0xff : 0;
            int b2 = (charsLeft > 2) ? data[iidx++] & 0xff : 0;
            int b24 = (b0 << 16) | (b1 << 8) | b2;

            int c0 = (b24 >> 18) & 0x3f;
            int c1 = (b24 >> 12) & 0x3f;
            int c2 = (b24 >> 6) & 0x3f;
            int c3 = b24 & 0x3f;

            chars[oidx++] = base64Chars[c0];
            chars[oidx++] = base64Chars[c1];
            chars[oidx++] = (charsLeft > 1) ? base64Chars[c2] : '=';
            chars[oidx++] = (charsLeft > 2) ? base64Chars[c3] : '=';

            charsLeft -= 3;
        }

        return new String(chars);
    }
}

Related

1. toBase64(final String str)
2. toBase64(int x)
3. toBase64(long num)
4. toBase64(long value)
5. toBase64(String value)
6. toBase64String(byte[] array)
7. toBase64String(byte[] data)