/*
*******************************************************************************
* Java Card Bitcoin Hardware Wallet
* (c) 2015 Ledger
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*******************************************************************************
*/
package com.ledger.wallet;
import javacard.framework.Util;
/**
* Base 58 encoding and decoding
* @author BTChip
*
*/
public class Base58 {
public static short encode(byte[] in, short inOffset, short inLength, byte[] out, short outOffset, byte[] scratch, short scratchOffset) {
short zeroCount = (short)0, j, startAt;
while ((zeroCount < inLength) && (in[(short)(inOffset + zeroCount)] == 0)) {
++zeroCount;
}
Util.arrayCopyNonAtomic(in, inOffset, scratch, scratchOffset, inLength);
j = (short)(2 * inLength);
startAt = zeroCount;
while(startAt < inLength) {
short remainder = 0;
short divLoop;
for (divLoop = startAt ; divLoop < inLength; divLoop++) {
short digit256 = (short)(scratch[(short)(scratchOffset + divLoop)] & 0xff);
short tmpDiv = (short)(remainder * 256 + digit256);
scratch[(short)(scratchOffset + divLoop)] = (byte)(tmpDiv / 58);
remainder = (short)(tmpDiv % 58);
}
if (scratch[(short)(scratchOffset + startAt)] == 0) {
++startAt;
}
out[(short)(outOffset + --j)] = (byte)ALPHABET[remainder];
}
while ((j < ((short)(2 * inLength))) && (out[(short)(outOffset + j)] == ALPHABET[0])) {
++j;
}
while (--zeroCount >= 0) {
out[(short)(outOffset + --j)] = (byte)ALPHABET[0];
}
short resultLength = (short)((2 * inLength) - j);
Util.arrayCopyNonAtomic(out, (short)(outOffset + j), out, outOffset, resultLength);
return (short)(outOffset + resultLength);
}
public static short decode(byte[] in, short inOffset, short inLength, byte[] out, short outOffset, byte[] scratch, short scratchOffset) {
try {
short zeroCount = (short)0, j, startAt;
for (short i=0; i<inLength; i++) {
short value = (short)(in[(short)(inOffset + i)] & 0xff);
if (value > 128) {
return (short)-1;
}
byte base58Value = BASE58TABLE[value];
if (base58Value == (byte)0xff) {
return (short)-1;
}
scratch[(short)(scratchOffset + i)] = base58Value;
}
while ((zeroCount < inLength) && (scratch[(short)(scratchOffset + zeroCount)] == 0)) {
++zeroCount;
}
j = inLength;
startAt = zeroCount;
while (startAt < inLength) {
short remainder = 0;
short divLoop;
for (divLoop = startAt ; divLoop < inLength; divLoop++) {
short digit256 = (short)(scratch[(short)(scratchOffset + divLoop)] & 0xff);
short tmpDiv = (short)(remainder * 58 + digit256);
scratch[(short)(scratchOffset + divLoop)] = (byte)(tmpDiv / 256);
remainder = (short)(tmpDiv % 256);
}
if (scratch[(short)(scratchOffset + startAt)] == 0) {
++startAt;
}
out[(short)(outOffset + --j)] = (byte)remainder;
}
while ((j < inLength) && (out[(short)(outOffset + j)] == 0)) {
j++;
}
short resultLength = (short)(inLength - (j - zeroCount));
Util.arrayCopyNonAtomic(out, (short)(outOffset + j - zeroCount), out, outOffset, resultLength);
return resultLength;
}
catch(Throwable t) {
return (short)-1;
}
}
protected static final byte BASE58TABLE[] = {
(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,
(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,
(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0x0,(byte)0x1,(byte)0x2,(byte)0x3,(byte)0x4,(byte)0x5,(byte)0x6,(byte)0x7,(byte)0x8,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,
(byte)0x9,(byte)0xa,(byte)0xb,(byte)0xc,(byte)0xd,(byte)0xe,(byte)0xf,(byte)0x10,(byte)0xff,(byte)0x11,(byte)0x12,(byte)0x13,(byte)0x14,(byte)0x15,(byte)0xff,(byte)0x16,(byte)0x17,(byte)0x18,(byte)0x19,(byte)0x1a,(byte)0x1b,(byte)0x1c,(byte)0x1d,
(byte)0x1e,(byte)0x1f,(byte)0x20,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0x21,(byte)0x22,(byte)0x23,(byte)0x24,(byte)0x25,(byte)0x26,(byte)0x27,(byte)0x28,(byte)0x29,(byte)0x2a,(byte)0x2b,(byte)0xff,(byte)0x2c,
(byte)0x2d,(byte)0x2e,(byte)0x2f,(byte)0x30,(byte)0x31,(byte)0x32,(byte)0x33,(byte)0x34,(byte)0x35,(byte)0x36,(byte)0x37,(byte)0x38,(byte)0x39,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff
};
private static final byte ALPHABET[] = {
'1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
'J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a',
'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'm', 'n', 'o', 'p', 'q', 'r', 's',
't', 'u', 'v', 'w', 'x', 'y', 'z'
};
}