mirror of https://github.com/M66B/FairEmail.git
59 lines
2.1 KiB
Java
59 lines
2.1 KiB
Java
/*
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* BIP39 library, a Java implementation of BIP39
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* Copyright (C) 2017-2019 Alan Evans, NovaCrypto
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*
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* Original source: https://github.com/NovaCrypto/BIP39
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* You can contact the authors via github issues.
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*/
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package io.github.novacrypto.bip39;
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final class ByteUtils {
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static int next11Bits(byte[] bytes, int offset) {
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final int skip = offset / 8;
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final int lowerBitsToRemove = (3 * 8 - 11) - (offset % 8);
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return (((int) bytes[skip] & 0xff) << 16 |
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((int) bytes[skip + 1] & 0xff) << 8 |
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(lowerBitsToRemove < 8
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? ((int) bytes[skip + 2] & 0xff)
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: 0)) >> lowerBitsToRemove & (1 << 11) - 1;
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}
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static void writeNext11(byte[] bytes, int value, int offset) {
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int skip = offset / 8;
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int bitSkip = offset % 8;
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{//byte 0
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byte firstValue = bytes[skip];
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byte toWrite = (byte) (value >> (3 + bitSkip));
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bytes[skip] = (byte) (firstValue | toWrite);
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}
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{//byte 1
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byte valueInByte = bytes[skip + 1];
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final int i = 5 - bitSkip;
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byte toWrite = (byte) (i > 0 ? (value << i) : (value >> -i));
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bytes[skip + 1] = (byte) (valueInByte | toWrite);
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}
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if (bitSkip >= 6) {//byte 2
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byte valueInByte = bytes[skip + 2];
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byte toWrite = (byte) (value << 13 - bitSkip);
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bytes[skip + 2] = (byte) (valueInByte | toWrite);
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}
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}
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}
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