This is a Kotlin implementation for the receiving end of a Hamming Codes (not extended). Given a matrix of bits organized according to a Hamming Code, it will return the location of an error in the matrix or return 0 if there are no errors. Note: the value of bit index 0 is not included in the result, thus you can't store any data in it.

hammingCodes.kt

fun hammingSyndrome(bits: List<Int>) =
	// gets all the indices of 1 value, and places null in 0 values' indices.
	bits.mapIndexed { index, it -> if (it == 1) index else null }
		// removes all those null values.
		.filterNotNull()
		// XORs the indices together to get the index of the error
		.reduce { acc, i -> acc xor i }