include <mach.h>

# BST_LINE[SIL] -- Process single image line and update the counters
# for ones and zeroes.

$for (sil)

procedure bst_line$t (line, npix, maxbits, zero, one)

PIXEL	line[npix]		# image line
int	npix			# line length
int	maxbits			# max number of bits in data type
long	zero[NBITS_INT]		# "0" counter (modified)
long	one[NBITS_INT]		# "1" counter (modified)

int	i, bit
PIXEL	$tval

begin
	# Loop over the image line
	do i = 1, npix {

	    # Get the next pixel value
	    $tval = line[i]

	    # Loop over all the bits in each pixel until all the pixels
	    # are traversed. The pixel value is divided by two each time
	    # in order to have the bit in the LSB position.
	    for (bit = 1; bit <= maxbits; bit = bit + 1) {
		if (mod ($tval, 2) == 0)
		    zero[bit] = zero[bit] + 1
		else
		    one[bit] = one[bit] + 1
		$tval = $tval / 2
	    }
	}
end

$endfor