NFC adapter: Difference between revisions

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@@ Line 146: / Line 146: @@
 	uint16_t * plain = (uint16_t *) voidplain;
 	uint16_t * cipher = (uint16_t *) voidcipher;
-	size_t halfCount = size / sizeof(uint16_t);
+	size_t halfCount = size >> 1; // Divide by 2 rounding towards zero
 	uint16_t xorval = htobe16(0xE963);
@@ Line 160: / Line 160: @@
 	uint16_t * cipher = (uint16_t *) voidcipher;
 	uint16_t * plain = (uint16_t *) voidplain;
-	size_t halfCount = size / sizeof(uint16_t);
+	size_t halfCount = size >> 1; // Divide by 2 rounding towards zero
-	if (halfCount) {
+	uint16_t xorval = htobe16(0xE963);
-		size_t i;
+	size_t i;
-		for (i = halfCount - 1; i > 0; i--) {
-			plain[i] = cipher[i] ^ cipher[i - 1];
-		}
-		plain[0] = cipher[0] ^ htobe16(0xE963);
+	for (i = 0; i < halfCount; i++) {
+		uint16_t word = plain[i];
+		cipher[i] = xorval ^ word;
+		xorval = word;
 	}
 }</nowiki>