001/* 002 * Copyright 2015-2020 the original author or authors 003 * 004 * This software is licensed under the Apache License, Version 2.0, 005 * the GNU Lesser General Public License version 2 or later ("LGPL") 006 * and the WTFPL. 007 * You may choose either license to govern your use of this software only 008 * upon the condition that you accept all of the terms of either 009 * the Apache License 2.0, the LGPL 2.1+ or the WTFPL. 010 */ 011package org.minidns.util; 012 013/** 014 * Very minimal Base32 encoder. 015 */ 016public final class Base32 { 017 private static final String ALPHABET = "0123456789ABCDEFGHIJKLMNOPQRSTUV"; 018 private static final String PADDING = "======"; 019 020 /** 021 * Do not allow to instantiate Base32 022 */ 023 private Base32() { 024 } 025 026 public static String encodeToString(byte[] bytes) { 027 int paddingCount = (int) (8 - (bytes.length % 5) * 1.6) % 8; 028 byte[] padded = new byte[bytes.length + paddingCount]; 029 System.arraycopy(bytes, 0, padded, 0, bytes.length); 030 StringBuilder sb = new StringBuilder(); 031 for (int i = 0; i < bytes.length; i += 5) { 032 long j = ((long) (padded[i] & 0xff) << 32) + ((long) (padded[i + 1] & 0xff) << 24) 033 + ((padded[i + 2] & 0xff) << 16) + ((padded[i + 3] & 0xff) << 8) + (padded[i + 4] & 0xff); 034 sb.append(ALPHABET.charAt((int) ((j >> 35) & 0x1f))).append(ALPHABET.charAt((int) ((j >> 30) & 0x1f))) 035 .append(ALPHABET.charAt((int) ((j >> 25) & 0x1f))).append(ALPHABET.charAt((int) ((j >> 20) & 0x1f))) 036 .append(ALPHABET.charAt((int) ((j >> 15) & 0x1f))).append(ALPHABET.charAt((int) ((j >> 10) & 0x1f))) 037 .append(ALPHABET.charAt((int) ((j >> 5) & 0x1f))).append(ALPHABET.charAt((int) (j & 0x1f))); 038 } 039 return sb.substring(0, sb.length() - paddingCount) + PADDING.substring(0, paddingCount); 040 } 041}