Merge pull request #2 from noxdafox/master

issue #1: provide img_murphy source code

Author: noxdafox

murphy/img_murphy.c

@@ -0,0 +1,111 @@
+#include <stdio.h>
+#include <stdint.h>
+
+#define BYTE uint8_t
+#define DWORD uint32_t
+
+#ifdef _WIN64
+	#define EXPORT __declspec(dllexport)
+	#define CALL_TYPE __stdcall
+#elif _WIN32
+	#define EXPORT __declspec(dllexport)
+	#define CALL_TYPE __stdcall
+#elif linux
+	#define EXPORT
+	#define CALL_TYPE
+#endif
+
+#ifdef __cplusplus
+extern "C" {  // only need to export C interface if
+             // used by C++ source code
+#endif
+
+// On linux use:
+// gcc -c -Werror -fpic img_murphy.c
+// gcc -shared -o img_murphy.so img_murphy.o
+// On windows, create a solution
+
+//hint: h_x1, h_y1, h_x2, h_y2
+EXPORT int CALL_TYPE find(BYTE* search_for, int for_width, int for_height, BYTE* search_in, int in_width, int in_height, int *best_x, int *best_y, BYTE* mask)
+{
+	int x0, y0, x1, y1;
+
+	int in_ptr, for_ptr;
+
+	int right_gap, right_limit;
+	int bottom_limit;
+	int matches, mismatches, best_match;
+	int diff, half_for_height;
+
+	int xx, yy;
+	BYTE mask_val;
+
+	right_limit = in_width - for_width;
+	right_gap = right_limit;
+	bottom_limit = in_height - for_height;
+	half_for_height = 2;
+
+	in_ptr = 0;
+	for_ptr = 0;
+	best_match = -1;
+
+	xx = *best_x;
+	yy = *best_y;
+	if( xx < 0 ) {
+		xx = -xx;
+		right_limit = xx + 1;
+	}
+	if( yy < 0 ) {
+		yy = -yy;
+		bottom_limit = yy + 1;
+	}
+	//printf("Search starts at %i %i ends at %i %i with mask %i\n", xx, yy, right_limit, bottom_limit, mask);
+
+	for( y0 = yy; y0 <= bottom_limit; y0++ ) {
+		for( x0 = xx; x0 <= right_limit; x0++ ) {
+			in_ptr = (y0 * in_width) + x0;
+			for_ptr = 0;
+			matches = 0;
+			mismatches = 0;
+			for( y1 = 0; y1 < for_height; y1++ ) {
+				for( x1 = 0; x1 < for_width; x1++ ) {
+					if( mask == NULL) {
+						diff = (search_in[in_ptr++] - search_for[for_ptr++]) & 0xfff;
+					} else {
+						mask_val = mask[for_ptr];
+						if(mask_val == 0) {
+							diff = (search_in[in_ptr++] - search_for[for_ptr++]) & 0xfff;
+						} else {
+							in_ptr++;
+							for_ptr++;
+							diff = 0;
+						}
+					}
+					if( diff < 2 ) {
+						matches++;
+					} else {
+						mismatches++;
+						if( mismatches > matches && y1 > half_for_height )
+							break;
+					}
+				}
+				if( mismatches > matches && y1 > half_for_height )
+					break;
+				in_ptr += right_gap;
+			}
+
+			if( matches > best_match ) {
+				best_match = matches;
+				*best_x = x0;
+				*best_y = y0;
+			}
+		}
+	}
+
+	return best_match;
+
+}
+
+#ifdef __cplusplus
+}
+#endif