Updated on 2026-08-14

app/src/main/java/com/tangem/wallet/bch/BitcoinCashBitArrayConverter.java

@@ -0,0 +1,60 @@
+package com.tangem.wallet.bch;
+/**
+ * Copyright (c) 2018 Tobias Brandt
+ * 
+ * Copyright (c) 2017 Pieter Wuille
+ * 
+ * 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.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ * 
+ */
+public class BitcoinCashBitArrayConverter {
+
+	public static byte[] convertBits(byte[] bytes8Bits, int from, int to, boolean strictMode) {
+		int length = (int) (strictMode ? Math.floor((double) bytes8Bits.length * from / to)
+				: Math.ceil((double) bytes8Bits.length * from / to));
+		int mask = ((1 << to) - 1) & 0xff;
+		byte[] result = new byte[length];
+		int index = 0;
+		int accumulator = 0;
+		int bits = 0;
+		for (int i = 0; i < bytes8Bits.length; i++) {
+			byte value = bytes8Bits[i];
+			accumulator = (((accumulator & 0xff) << from) | (value & 0xff));
+			bits += from;
+			while (bits >= to) {
+				bits -= to;
+				result[index] = (byte) ((accumulator >> bits) & mask);
+				++index;
+			}
+		}
+		if (!strictMode) {
+			if (bits > 0) {
+				result[index] = (byte) ((accumulator << (to - bits)) & mask);
+				++index;
+			}
+		} else {
+			if (!(bits < from && ((accumulator << (to - bits)) & mask) == 0)) {
+				throw new RuntimeException("Strict mode was used but input couldn't be converted without padding");
+			}
+		}
+
+		return result;
+	}
+
+}