60 lines
No EOL
2.2 KiB
Java
60 lines
No EOL
2.2 KiB
Java
package com.tangem.wallet.bch;
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/**
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* Copyright (c) 2018 Tobias Brandt
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*
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* Copyright (c) 2017 Pieter Wuille
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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*/
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public class BitcoinCashBitArrayConverter {
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public static byte[] convertBits(byte[] bytes8Bits, int from, int to, boolean strictMode) {
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int length = (int) (strictMode ? Math.floor((double) bytes8Bits.length * from / to)
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: Math.ceil((double) bytes8Bits.length * from / to));
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int mask = ((1 << to) - 1) & 0xff;
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byte[] result = new byte[length];
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int index = 0;
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int accumulator = 0;
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int bits = 0;
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for (int i = 0; i < bytes8Bits.length; i++) {
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byte value = bytes8Bits[i];
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accumulator = (((accumulator & 0xff) << from) | (value & 0xff));
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bits += from;
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while (bits >= to) {
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bits -= to;
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result[index] = (byte) ((accumulator >> bits) & mask);
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++index;
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}
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}
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if (!strictMode) {
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if (bits > 0) {
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result[index] = (byte) ((accumulator << (to - bits)) & mask);
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++index;
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}
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} else {
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if (!(bits < from && ((accumulator << (to - bits)) & mask) == 0)) {
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throw new RuntimeException("Strict mode was used but input couldn't be converted without padding");
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}
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}
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return result;
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}
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} |