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/*
* Copyright 2012-2017 UnboundID Corp.
* All Rights Reserved.
*/
/*
* Copyright (C) 2012-2017 UnboundID Corp.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License (GPLv2 only)
* or the terms of the GNU Lesser General Public License (LGPLv2.1 only)
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see .
*/
package com.unboundid.util;
import java.io.IOException;
import java.text.ParseException;
import static com.unboundid.util.UtilityMessages.*;
import static com.unboundid.util.Validator.*;
/**
* This class provides methods for encoding and decoding data in base32 as
* defined in RFC 4648. It
* provides a somewhat compact way of representing binary data using only
* printable characters (a subset of ASCII letters and numeric digits selected
* to avoid ambiguity, like confusion between the number 1 and the uppercase
* letter I, and between the number 0 and the uppercase letter O). It uses a
* five-bit encoding mechanism in which every five bytes of raw data is
* converted into eight bytes of base32-encoded data.
*
*
Example
* The following examples demonstrate the process for base32-encoding raw data,
* and for decoding a string containing base32-encoded data back to the raw
* data used to create it:
*
* // Base32-encode some raw data:
* String base32String = Base32.encode(rawDataBytes);
*
* // Decode a base32 string back to raw data:
* byte[] decodedRawDataBytes;
* try
* {
* decodedRawDataBytes = Base32.decode(base32String);
* }
* catch (ParseException pe)
* {
* // The string did not represent a valid base32 encoding.
* decodedRawDataBytes = null;
* }
*
*/
@ThreadSafety(level=ThreadSafetyLevel.COMPLETELY_THREADSAFE)
public final class Base32
{
/**
* The set of characters in the base32 alphabet.
*/
private static final char[] BASE32_ALPHABET =
("ABCDEFGHIJKLMNOPQRSTUVWXYZ234567").toCharArray();
/**
* Prevent this class from being instantiated.
*/
private Base32()
{
// No implementation is required.
}
/**
* Encodes the UTF-8 representation of the provided string in base32 format.
*
* @param data The raw data to be encoded. It must not be {@code null}.
*
* @return The base32-encoded representation of the provided data.
*/
public static String encode(final String data)
{
ensureNotNull(data);
return encode(StaticUtils.getBytes(data));
}
/**
* Encodes the provided data in base32 format.
*
* @param data The raw data to be encoded. It must not be {@code null}.
*
* @return The base32-encoded representation of the provided data.
*/
public static String encode(final byte[] data)
{
ensureNotNull(data);
final StringBuilder buffer = new StringBuilder(4*data.length/3+1);
encodeInternal(data, 0, data.length, buffer);
return buffer.toString();
}
/**
* Appends a base32-encoded version of the contents of the provided buffer
* (using a UTF-8 representation) to the given buffer.
*
* @param data The raw data to be encoded. It must not be {@code null}.
* @param buffer The buffer to which the base32-encoded data is to be
* written.
*/
public static void encode(final String data, final StringBuilder buffer)
{
ensureNotNull(data);
encode(StaticUtils.getBytes(data), buffer);
}
/**
* Appends a base32-encoded version of the contents of the provided buffer
* (using a UTF-8 representation) to the given buffer.
*
* @param data The raw data to be encoded. It must not be {@code null}.
* @param buffer The buffer to which the base32-encoded data is to be
* written.
*/
public static void encode(final String data, final ByteStringBuffer buffer)
{
ensureNotNull(data);
encode(StaticUtils.getBytes(data), buffer);
}
/**
* Appends a base32-encoded representation of the provided data to the given
* buffer.
*
* @param data The raw data to be encoded. It must not be {@code null}.
* @param buffer The buffer to which the base32-encoded data is to be
* written.
*/
public static void encode(final byte[] data, final StringBuilder buffer)
{
encodeInternal(data, 0, data.length, buffer);
}
/**
* Appends a base32-encoded representation of the provided data to the given
* buffer.
*
* @param data The array containing the raw data to be encoded. It must
* not be {@code null}.
* @param off The offset in the array at which the data to encode begins.
* @param length The number of bytes to be encoded.
* @param buffer The buffer to which the base32-encoded data is to be
* written.
*/
public static void encode(final byte[] data, final int off, final int length,
final StringBuilder buffer)
{
encodeInternal(data, off, length, buffer);
}
/**
* Appends a base32-encoded representation of the provided data to the given
* buffer.
*
* @param data The raw data to be encoded. It must not be {@code null}.
* @param buffer The buffer to which the base32-encoded data is to be
* written.
*/
public static void encode(final byte[] data, final ByteStringBuffer buffer)
{
encodeInternal(data, 0, data.length, buffer);
}
/**
* Appends a base32-encoded representation of the provided data to the given
* buffer.
*
* @param data The raw data to be encoded. It must not be {@code null}.
* @param off The offset in the array at which the data to encode begins.
* @param length The number of bytes to be encoded.
* @param buffer The buffer to which the base32-encoded data is to be
* written.
*/
public static void encode(final byte[] data, final int off, final int length,
final ByteStringBuffer buffer)
{
encodeInternal(data, off, length, buffer);
}
/**
* Appends a base32-encoded representation of the provided data to the given
* buffer.
*
* @param data The raw data to be encoded. It must not be {@code null}.
* @param off The offset in the array at which the data to encode begins.
* @param length The number of bytes to be encoded.
* @param buffer The buffer to which the base32-encoded data is to be
* written.
*/
private static void encodeInternal(final byte[] data, final int off,
final int length, final Appendable buffer)
{
ensureNotNull(data);
ensureTrue(data.length >= off);
ensureTrue(data.length >= (off+length));
if (length == 0)
{
return;
}
try
{
int pos = off;
for (int i=0; i < (length / 5); i++)
{
final long longValue =
(((data[pos++] & 0xFFL) << 32) |
((data[pos++] & 0xFFL) << 24) |
((data[pos++] & 0xFFL) << 16) |
((data[pos++] & 0xFFL) << 8) |
(data[pos++] & 0xFFL));
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 35) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 30) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 25) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 20) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 15) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 10) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 5) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) (longValue & 0x1FL)]);
}
switch ((off+length) - pos)
{
case 1:
long longValue = ((data[pos] & 0xFFL) << 32);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 35) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 30) & 0x1FL)]);
buffer.append("======");
return;
case 2:
longValue = (((data[pos++] & 0xFFL) << 32) |
((data[pos] & 0xFFL) << 24));
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 35) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 30) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 25) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 20) & 0x1FL)]);
buffer.append("====");
return;
case 3:
longValue = (((data[pos++] & 0xFFL) << 32) |
((data[pos++] & 0xFFL) << 24) |
((data[pos] & 0xFFL) << 16));
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 35) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 30) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 25) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 20) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 15) & 0x1FL)]);
buffer.append("===");
return;
case 4:
longValue = (((data[pos++] & 0xFFL) << 32) |
((data[pos++] & 0xFFL) << 24) |
((data[pos++] & 0xFFL) << 16) |
((data[pos] & 0xFFL) << 8));
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 35) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 30) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 25) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 20) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 15) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 10) & 0x1FL)]);
buffer.append(BASE32_ALPHABET[(int) ((longValue >> 5) & 0x1FL)]);
buffer.append("=");
return;
}
}
catch (final IOException ioe)
{
Debug.debugException(ioe);
// This should never happen.
throw new RuntimeException(ioe.getMessage(), ioe);
}
}
/**
* Decodes the contents of the provided base32-encoded string.
*
* @param data The base32-encoded string to decode. It must not be
* {@code null}.
*
* @return A byte array containing the decoded data.
*
* @throws ParseException If the contents of the provided string cannot be
* parsed as base32-encoded data.
*/
public static byte[] decode(final String data)
throws ParseException
{
ensureNotNull(data);
final int length = data.length();
if (length == 0)
{
return new byte[0];
}
if ((length % 8) != 0)
{
throw new ParseException(ERR_BASE32_DECODE_INVALID_LENGTH.get(), length);
}
final ByteStringBuffer buffer = new ByteStringBuffer(5 * (length / 8));
int stringPos = 0;
while (stringPos < length)
{
long longValue = 0x00;
for (int i=0; i < 8; i++)
{
longValue <<= 5;
switch (data.charAt(stringPos++))
{
case 'A':
case 'a':
longValue |= 0x00L;
break;
case 'B':
case 'b':
longValue |= 0x01L;
break;
case 'C':
case 'c':
longValue |= 0x02L;
break;
case 'D':
case 'd':
longValue |= 0x03L;
break;
case 'E':
case 'e':
longValue |= 0x04L;
break;
case 'F':
case 'f':
longValue |= 0x05L;
break;
case 'G':
case 'g':
longValue |= 0x06L;
break;
case 'H':
case 'h':
longValue |= 0x07L;
break;
case 'I':
case 'i':
longValue |= 0x08L;
break;
case 'J':
case 'j':
longValue |= 0x09L;
break;
case 'K':
case 'k':
longValue |= 0x0AL;
break;
case 'L':
case 'l':
longValue |= 0x0BL;
break;
case 'M':
case 'm':
longValue |= 0x0CL;
break;
case 'N':
case 'n':
longValue |= 0x0DL;
break;
case 'O':
case 'o':
longValue |= 0x0EL;
break;
case 'P':
case 'p':
longValue |= 0x0FL;
break;
case 'Q':
case 'q':
longValue |= 0x10L;
break;
case 'R':
case 'r':
longValue |= 0x11L;
break;
case 'S':
case 's':
longValue |= 0x12L;
break;
case 'T':
case 't':
longValue |= 0x13L;
break;
case 'U':
case 'u':
longValue |= 0x14L;
break;
case 'V':
case 'v':
longValue |= 0x15L;
break;
case 'W':
case 'w':
longValue |= 0x16L;
break;
case 'X':
case 'x':
longValue |= 0x17L;
break;
case 'Y':
case 'y':
longValue |= 0x18L;
break;
case 'Z':
case 'z':
longValue |= 0x19L;
break;
case '2':
longValue |= 0x1AL;
break;
case '3':
longValue |= 0x1BL;
break;
case '4':
longValue |= 0x1CL;
break;
case '5':
longValue |= 0x1DL;
break;
case '6':
longValue |= 0x1EL;
break;
case '7':
longValue |= 0x1FL;
break;
case '=':
switch (length - stringPos)
{
case 0:
// The string ended with a single equal sign, so there are
// four bytes left.
buffer.append((byte) ((longValue >> 32) & 0xFFL));
buffer.append((byte) ((longValue >> 24) & 0xFFL));
buffer.append((byte) ((longValue >> 16) & 0xFFL));
buffer.append((byte) ((longValue >> 8) & 0xFFL));
return buffer.toByteArray();
case 2:
// The string ended with three equal signs, so there are three
// bytes left.
longValue <<= 10;
buffer.append((byte) ((longValue >> 32) & 0xFFL));
buffer.append((byte) ((longValue >> 24) & 0xFFL));
buffer.append((byte) ((longValue >> 16) & 0xFFL));
return buffer.toByteArray();
case 3:
// The string ended with four equal signs, so there are two
// bytes left.
longValue <<= 15;
buffer.append((byte) ((longValue >> 32) & 0xFFL));
buffer.append((byte) ((longValue >> 24) & 0xFFL));
return buffer.toByteArray();
case 5:
// The string ended with six equal signs, so there is one byte
// left.
longValue <<= 25;
buffer.append((byte) ((longValue >> 32) & 0xFFL));
return buffer.toByteArray();
default:
throw new ParseException(
ERR_BASE32_DECODE_UNEXPECTED_EQUAL.get((stringPos-1)),
(stringPos-1));
}
default:
throw new ParseException(
ERR_BASE32_DECODE_UNEXPECTED_CHAR.get(
data.charAt(stringPos-1)),
(stringPos-1));
}
}
buffer.append((byte) ((longValue >> 32) & 0xFFL));
buffer.append((byte) ((longValue >> 24) & 0xFFL));
buffer.append((byte) ((longValue >> 16) & 0xFFL));
buffer.append((byte) ((longValue >> 8) & 0xFFL));
buffer.append((byte) (longValue & 0xFFL));
}
return buffer.toByteArray();
}
/**
* Decodes the contents of the provided base32-encoded string to a string
* containing the raw data using the UTF-8 encoding.
*
* @param data The base32-encoded string to decode. It must not be
* {@code null}.
*
* @return A string containing the decoded data.
*
* @throws ParseException If the contents of the provided string cannot be
* parsed as base32-encoded data using the UTF-8
* encoding.
*/
public static String decodeToString(final String data)
throws ParseException
{
ensureNotNull(data);
final byte[] decodedBytes = decode(data);
return StaticUtils.toUTF8String(decodedBytes);
}
}
