org.libj.util.Base32 Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of util Show documentation
Show all versions of util Show documentation
Supplementary utilities for classes that belong to java.util, or are considered essential as to justify existence in java.util.
/* Copyright (c) 2018 LibJ
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* You should have received a copy of The MIT License (MIT) along with this
* program. If not, see {
private static final long serialVersionUID = 3283110401340470031L;
private static final String alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
private static final int[] lookup = {
0xFF, 0xFF, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
0x17, 0x18, 0x19, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
0x17, 0x18, 0x19, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF
};
/**
* Returns the base32 encoding of the provided {@code bytes} array.
*
* @param bytes The bytes to encode.
* @return The base32 encoding of the provided {@code bytes} array.
* @throws NullPointerException If {@code bytes} is null.
*/
public static String encode(final byte[] bytes) {
return encode(bytes, 0, bytes.length);
}
/**
* Returns the base32 encoding of the provided {@code bytes} array.
*
* @param bytes The bytes to encode.
* @param offset The initial offset.
* @param len The length.
* @return The base32 encoding of the provided {@code bytes} array.
* @throws NullPointerException If {@code bytes} is null.
*/
public static String encode(final byte[] bytes, final int offset, final int len) {
final StringBuilder base32 = new StringBuilder((bytes.length + 7) * 8 / 5);
for (int i = offset, index = 0, digit, by0, by1; i < len + offset;) {
by0 = (bytes[i] >= 0) ? bytes[i] : (bytes[i] + 256);
if (index > 3) {
by1 = i + 1 < bytes.length ? bytes[i + 1] < 0 ? bytes[i + 1] + 256 : bytes[i + 1] : 0;
digit = by0 & (0xFF >> index);
index = (index + 5) % 8;
digit <<= index;
digit |= by1 >> (8 - index);
++i;
}
else {
digit = (by0 >> (8 - (index + 5))) & 0x1F;
index = (index + 5) % 8;
if (index == 0)
++i;
}
base32.append(alphabet.charAt(digit));
}
return base32.toString();
}
/**
* Returns a {@code new byte[]} of the decoded {@code base32} string.
*
* @param base32 The base32 string.
* @return A {@code new byte[]} of the decoded {@code base32} string.
* @throws NullPointerException If {@code base32} is null.
*/
public static byte[] decode(final String base32) {
final byte[] bytes = new byte[base32.length() * 5 / 8];
decode(base32, bytes, 0);
return bytes;
}
/**
* Decode the {@code base32} string into the provided {@code bytes} array.
*
* @param base32 The base32 string.
* @param bytes The {@code bytes} array.
* @param offset The offset into the {@code bytes} array.
* @throws ArrayIndexOutOfBoundsException If the size of {@code bytes} is not
* big enough, or if {@code offset} causes the index to go out of
* bounds.
* @throws NullPointerException If {@code base32} or {@code bytes} is null.
*/
public static void decode(final String base32, final byte[] bytes, int offset) {
for (int i = 0, index = 0, ch, digit; i < base32.length(); ++i) {
ch = base32.charAt(i) - '0';
if (ch < 0 || lookup.length < ch)
continue;
digit = lookup[ch];
if (digit == 0xFF)
continue;
if (index <= 3) {
index = (index + 5) % 8;
if (index == 0) {
bytes[offset] |= digit;
if (++offset >= bytes.length)
break;
}
else {
bytes[offset] |= digit << (8 - index);
}
}
else {
index = (index + 5) % 8;
bytes[offset] |= (digit >>> index);
if (++offset >= bytes.length)
break;
bytes[offset] |= digit << (8 - index);
}
}
}
/**
* Create a new {@link Base32} object with the provided raw bytes.
*
* @param bytes The raw bytes.
*/
public Base32(final byte[] bytes) {
super(bytes, null);
}
/**
* Create a new {@link Base32} object with the provided base32-encoded string
* value.
*
* @param base32 The base32-encoded string value.
*/
public Base32(final String base32) {
super(null, base32);
}
@Override
public byte[] getData() {
return data == null ? data = decode(encoded) : data;
}
@Override
public String getEncoded() {
return encoded == null ? encoded = encode(data) : encoded;
}
@Override
public boolean equals(final Object obj) {
if (obj == this)
return true;
if (!(obj instanceof Base32))
return false;
final Base32 that = (Base32)obj;
return encoded != null && that.encoded != null ? encoded.equalsIgnoreCase(that.encoded) : Arrays.equals(getData(), that.getData());
}
@Override
public int hashCode() {
return 31 + Arrays.hashCode(getData());
}
@Override
public String toString() {
return getEncoded();
}
}