Doubt on the symbol decoding function

[Algafix]

Hello!

I have a question about the following code snipped in the symbol decoding function.

dump1090/dump1090.c

Lines 1430 to 1448 in de61bd5

	low = m[j+i+MODES_PREAMBLE_US*2];
	high = m[j+i+MODES_PREAMBLE_US*2+1];
	delta = low-high;
	if (delta < 0) delta = -delta;
	if (i > 0 && delta < 256) {
	bits[i/2] = bits[i/2-1];
	} else if (low == high) {
	/* Checking if two adiacent samples have the same magnitude
	* is an effective way to detect if it's just random noise
	* that was detected as a valid preamble. */
	bits[i/2] = 2; /* error */
	if (i < MODES_SHORT_MSG_BITS*2) errors++;
	} else if (low > high) {
	bits[i/2] = 1;
	} else {
	/* (low < high) for exclusion */
	bits[i/2] = 0;
	}

Is this first condition attempting to solve the same problem as the "outOfPhase" correction? Making it easier to detect sequences of bits with the same value.

If that is the case, then I think the error count is not working as intended, because a delta of 0 falls inside the first condition. Hence, it will only count errors on the first bit, before i>0. I'm not sure if this implication is taken into account in the rest of the code, it seems to me that it is expecting values greater than 1 in the error count.

Thanks for the clarification!