@Override BaseEncoding newInstance(Alphabet alphabet, @Nullable Character paddingChar) { return new Base64Encoding(alphabet, paddingChar); } }
@Override int decodeTo(byte[] target, CharSequence chars) throws DecodingException { checkNotNull(target); chars = padding().trimTrailingFrom(chars); if (!alphabet.isValidPaddingStartPosition(chars.length())) { throw new DecodingException("Invalid input length " + chars.length()); } int bytesWritten = 0; for (int i = 0; i < chars.length(); ) { int chunk = alphabet.decode(chars.charAt(i++)) << 18; chunk |= alphabet.decode(chars.charAt(i++)) << 12; target[bytesWritten++] = (byte) (chunk >>> 16); if (i < chars.length()) { chunk |= alphabet.decode(chars.charAt(i++)) << 6; target[bytesWritten++] = (byte) ((chunk >>> 8) & 0xFF); if (i < chars.length()) { chunk |= alphabet.decode(chars.charAt(i++)); target[bytesWritten++] = (byte) (chunk & 0xFF); } } } return bytesWritten; }
@Override void encodeTo(Appendable target, byte[] bytes, int off, int len) throws IOException { checkNotNull(target); checkPositionIndexes(off, off + len, bytes.length); int i = off; for (int remaining = len; remaining >= 3; remaining -= 3) { int chunk = (bytes[i++] & 0xFF) << 16 | (bytes[i++] & 0xFF) << 8 | bytes[i++] & 0xFF; target.append(alphabet.encode(chunk >>> 18)); target.append(alphabet.encode((chunk >>> 12) & 0x3F)); target.append(alphabet.encode((chunk >>> 6) & 0x3F)); target.append(alphabet.encode(chunk & 0x3F)); } if (i < off + len) { encodeChunkTo(target, bytes, i, off + len - i); } }