Mask_calcRunLength() has been refactored out from Mask_evaluateSymbol…

…(). New test code for Mask_calcRunLength has been added.

ChangeLog

@@ -1,3 +1,9 @@
+2011.10.16 Kentaro FUKUCHI <kentaro@fukuchi.org>
+	* mask.[ch]:
+	  - Mask_calcRunLength() has been refactored out from Mask_evaluateSymbol().
+	* test/test_mask.c:
+	  - New test code for Mask_calcRunLength has been added.
+
 2011.10.13 Kentaro FUKUCHI <kentaro@fukuchi.org>
 	* mask.[ch]:
 	  - Mask_calcN2() has been refactored out from Mask_evaluateSymbol().

mask.c

@@ -185,7 +185,7 @@ unsigned char *Mask_makeMask(int width, unsigned char *frame, int mask, QRecLeve
 //static int n3;
 //static int n4;
 
-static int Mask_calcN1N3(int length, int *runLength)
+__STATIC int Mask_calcN1N3(int length, int *runLength)
 {
 	int i;
 	int demerit = 0;
@@ -241,58 +241,56 @@ __STATIC int Mask_calcN2(int width, unsigned char *frame)
 	return demerit;
 }
 
+__STATIC int Mask_calcRunLength(int width, unsigned char *frame, int dir, int *runLength)
+{
+	int head;
+	int i;
+	unsigned char *p;
+	int pitch;
+
+	pitch = (dir==0)?1:width;
+	for(i=0; i<width+1; i++) {
+		runLength[i] = 0;
+	}
+	if(frame[0] & 1) {
+		runLength[0] = -1;
+		head = 1;
+	} else {
+		head = 0;
+	}
+	runLength[head] = 1;
+	p = frame + pitch;
+
+	for(i=1; i<width; i++) {
+		if((p[0] ^ p[-pitch]) & 1) {
+			head++;
+			runLength[head] = 1;
+		} else {
+			runLength[head]++;
+		}
+		p += pitch;
+	}
+
+	return head + 1;
+}
+
 __STATIC int Mask_evaluateSymbol(int width, unsigned char *frame)
 {
 	int x, y;
-	unsigned char *p;
-	int head;
 	int demerit = 0;
 	int runLength[QRSPEC_WIDTH_MAX + 1];
+	int length;
 
 	demerit += Mask_calcN2(width, frame);
 
-	p = frame;
 	for(y=0; y<width; y++) {
-		head = 0;
-		runLength[0] = 1;
-		for(x=0; x<width; x++) {
-			if(x == 0 && (p[0] & 1)) {
-				runLength[0] = -1;
-				head = 1;
-				runLength[head] = 1;
-			} else if(x > 0) {
-				if((p[0] ^ p[-1]) & 1) {
-					head++;
-					runLength[head] = 1;
-				} else {
-					runLength[head]++;
-				}
-			}
-			p++;
-		}
-		demerit += Mask_calcN1N3(head+1, runLength);
+		length = Mask_calcRunLength(width, frame + y * width, 0, runLength);
+		demerit += Mask_calcN1N3(length, runLength);
 	}
 
 	for(x=0; x<width; x++) {
-		head = 0;
-		runLength[0] = 1;
-		p = frame + x;
-		for(y=0; y<width; y++) {
-			if(y == 0 && (p[0] & 1)) {
-				runLength[0] = -1;
-				head = 1;
-				runLength[head] = 1;
-			} else if(y > 0) {
-				if((p[0] ^ p[-width]) & 1) {
-					head++;
-					runLength[head] = 1;
-				} else {
-					runLength[head]++;
-				}
-			}
-			p+=width;
-		}
-		demerit += Mask_calcN1N3(head+1, runLength);
+		length = Mask_calcRunLength(width, frame + x, 1, runLength);
+		demerit += Mask_calcN1N3(length, runLength);
 	}
 
 	return demerit;

mask.h

@@ -27,6 +27,7 @@ extern unsigned char *Mask_mask(int width, unsigned char *frame, QRecLevel level
 
 #ifdef WITH_TESTS
 extern int Mask_calcN2(int width, unsigned char *frame);
+extern int Mask_calcRunLength(int width, unsigned char *frame, int dir, int *runLength);
 extern int Mask_evaluateSymbol(int width, unsigned char *frame);
 extern int Mask_writeFormatInformation(int width, unsigned char *frame, int mask, QRecLevel level);
 extern unsigned char *Mask_makeMaskedFrame(int width, unsigned char *frame, int mask);

tests/test_mask.c

@@ -303,6 +303,45 @@ void test_format(void)
 	testFinish();
 }
 
+void test_calcRunLength(void)
+{
+	int width = 5;
+	unsigned char frame[width * width];
+	int runLength[width + 1];
+	int i, j;
+	int length;
+	static unsigned char pattern[6][5] = {
+		{0, 1, 0, 1, 0},
+		{1, 0, 1, 0, 1},
+		{0, 0, 0, 0, 0},
+		{1, 1, 1, 1, 1},
+		{0, 0, 1, 1, 1},
+		{1, 1, 0, 0, 0}
+	};
+	static int expected[6][7] = {
+		{ 1, 1, 1, 1, 1, 0, 5},
+		{-1, 1, 1, 1, 1, 1, 6},
+		{ 5, 0, 0, 0, 0, 0, 1},
+		{-1, 5, 0, 0, 0, 0, 2},
+		{ 2, 3, 0, 0, 0, 0, 2},
+		{-1, 2, 3, 0, 0, 0, 3}
+	};
+
+	testStart("Test runlength calc function");
+	for(i=0; i<6; i++) {
+		length = Mask_calcRunLength(width, pattern[i], 0, runLength);
+		assert_equal(expected[i][6], length, "Length incorrect: %d, expected %d.\n", length, expected[i][6]);
+		assert_zero(memcmp(runLength, expected[i], sizeof(int) * (width + 1)), "Run length does not match: pattern %d, horizontal access.\n", i);
+		for(j=0; j<width; j++) {
+			frame[j * width] = pattern[i][j];
+		}
+		length = Mask_calcRunLength(width, frame, 1, runLength);
+		assert_equal(expected[i][6], length, "Length incorrect: %d, expected %d.\n", length, expected[i][6]);
+		assert_zero(memcmp(runLength, expected[i], sizeof(int) * (width + 1)), "Run length does not match: pattern %d, vertical access.\n", i);
+	}
+	testFinish();
+}
+
 int main(void)
 {
 	//print_masks();
@@ -312,6 +351,7 @@ int main(void)
 	test_eval3();
 	test_format();
 	test_calcN2();
+	test_calcRunLength();
 
 	report();