Geografic-Information-System/raster/r.geomorphon/multires.c

#include "local_proto.h"

int pattern_matching(int *pattern)
{
    int n, i;
    unsigned char binary = 0, result = 255, test = 0;
    unsigned char source = 32;
    int sign = -1;

    for (i = 0, n = 1; i < 8; i++, n *= 2)
	binary += (pattern[i] == sign) ? n : 0;
    /* rotate */
    for (i = 0; i < 8; ++i) {
	if ((i &= 7) == 0)
	    test = binary;
	else
	    test = (binary << i) | (binary >> (8 - i));
	result = (result < test) ? result : test;
    }
    return (result & source == source) ? 1 : 0;

}