Changed QrCode.getAlignmentPatternPositions() from static function to instance method, tweaked its logic, and updated comment - in all languages but differently in each.

c/qrcodegen.c

@@ -447,8 +447,10 @@ static void drawFormatBits(enum qrcodegen_Ecc ecl, enum qrcodegen_Mask mask, uin
 }
 
 
-// Calculates the positions of alignment patterns in ascending order for the given version number,
+// Calculates and stores an ascending list of positions of alignment patterns
-// storing them to the given array and returning an array length in the range [0, 7].
+// for this version number, returning the length of the list (in the range [0,7)).
+// Each position is in the range [0,177), and are used on both the x and y axes.
+// This could be implemented as lookup table of 40 variable-length lists of unsigned bytes.
 testable int getAlignmentPatternPositions(int version, uint8_t result[7]) {
 	if (version == 1)
 		return 0;

cpp/QrCode.cpp

@@ -205,7 +205,7 @@ void QrCode::drawFunctionPatterns() {
 	drawFinderPattern(3, size - 4);
 	
 	// Draw numerous alignment patterns
-	const vector<int> alignPatPos = getAlignmentPatternPositions(version);
+	const vector<int> alignPatPos = getAlignmentPatternPositions();
 	int numAlign = alignPatPos.size();
 	for (int i = 0; i < numAlign; i++) {
 		for (int j = 0; j < numAlign; j++) {
@@ -495,18 +495,15 @@ long QrCode::getPenaltyScore() const {
 }
 
 
-vector<int> QrCode::getAlignmentPatternPositions(int ver) {
+vector<int> QrCode::getAlignmentPatternPositions() const {
-	if (ver < MIN_VERSION || ver > MAX_VERSION)
+	if (version == 1)
-		throw std::domain_error("Version number out of range");
-	else if (ver == 1)
 		return vector<int>();
 	else {
-		int numAlign = ver / 7 + 2;
+		int numAlign = version / 7 + 2;
-		int step = (ver == 32) ? 26 :
+		int step = (version == 32) ? 26 :
-			(ver*4 + numAlign*2 + 1) / (numAlign*2 - 2) * 2;
+			(version*4 + numAlign*2 + 1) / (numAlign*2 - 2) * 2;
-		
 		vector<int> result;
-		for (int i = 0, pos = ver * 4 + 10; i < numAlign - 1; i++, pos -= step)
+		for (int i = 0, pos = size - 7; i < numAlign - 1; i++, pos -= step)
 			result.insert(result.begin(), pos);
 		result.insert(result.begin(), 6);
 		return result;

cpp/QrCode.hpp

@@ -231,10 +231,10 @@ class QrCode final {
 	
 	/*---- Private static helper functions ----*/
 	
-	// Returns a set of positions of the alignment patterns in ascending order. These positions are
+	// Returns an ascending list of positions of alignment patterns for this version number.
-	// used on both the x and y axes. Each value in the resulting array is in the range [0, 177).
+	// Each position is in the range [0,177), and are used on both the x and y axes.
-	// This stateless pure function could be implemented as table of 40 variable-length lists of unsigned bytes.
+	// This could be implemented as lookup table of 40 variable-length lists of unsigned bytes.
-	private: static std::vector<int> getAlignmentPatternPositions(int ver);
+	private: std::vector<int> getAlignmentPatternPositions() const;
 	
 	
 	// Returns the number of data bits that can be stored in a QR Code of the given version number, after

java/io/nayuki/qrcodegen/QrCode.java

@@ -333,7 +333,7 @@ public final class QrCode {
 		drawFinderPattern(3, size - 4);
 		
 		// Draw numerous alignment patterns
-		int[] alignPatPos = getAlignmentPatternPositions(version);
+		int[] alignPatPos = getAlignmentPatternPositions();
 		int numAlign = alignPatPos.length;
 		for (int i = 0; i < numAlign; i++) {
 			for (int j = 0; j < numAlign; j++) {
@@ -644,25 +644,22 @@ public final class QrCode {
 	
 	/*---- Private static helper functions ----*/
 	
-	// Returns a set of positions of the alignment patterns in ascending order. These positions are
+	// Returns an ascending list of positions of alignment patterns for this version number.
-	// used on both the x and y axes. Each value in the resulting array is in the range [0, 177).
+	// Each position is in the range [0,177), and are used on both the x and y axes.
-	// This stateless pure function could be implemented as table of 40 variable-length lists of unsigned bytes.
+	// This could be implemented as lookup table of 40 variable-length lists of unsigned bytes.
-	private static int[] getAlignmentPatternPositions(int ver) {
+	private int[] getAlignmentPatternPositions() {
-		if (ver < MIN_VERSION || ver > MAX_VERSION)
+		if (version == 1)
-			throw new IllegalArgumentException("Version number out of range");
-		else if (ver == 1)
 			return new int[]{};
 		else {
-			int numAlign = ver / 7 + 2;
+			int numAlign = version / 7 + 2;
 			int step;
-			if (ver == 32)  // Special snowflake
+			if (version == 32)  // Special snowflake
 				step = 26;
 			else  // step = ceil[(size - 13) / (numAlign*2 - 2)] * 2
-				step = (ver*4 + numAlign*2 + 1) / (numAlign*2 - 2) * 2;
+				step = (version*4 + numAlign*2 + 1) / (numAlign*2 - 2) * 2;
-			
 			int[] result = new int[numAlign];
 			result[0] = 6;
-			for (int i = result.length - 1, pos = ver * 4 + 10; i >= 1; i--, pos -= step)
+			for (int i = result.length - 1, pos = size - 7; i >= 1; i--, pos -= step)
 				result[i] = pos;
 			return result;
 		}

javascript/qrcodegen.js

@@ -203,7 +203,7 @@ var qrcodegen = new function() {
 			drawFinderPattern(3, size - 4);
 			
 			// Draw numerous alignment patterns
-			var alignPatPos = QrCode.getAlignmentPatternPositions(version);
+			var alignPatPos = getAlignmentPatternPositions();
 			var numAlign = alignPatPos.length;
 			for (var i = 0; i < numAlign; i++) {
 				for (var j = 0; j < numAlign; j++) {
@@ -488,6 +488,24 @@ var qrcodegen = new function() {
 		}
 		
 		
+		// Returns an ascending list of positions of alignment patterns for this version number.
+		// Each position is in the range [0,177), and are used on both the x and y axes.
+		// This could be implemented as lookup table of 40 variable-length lists of integers.
+		function getAlignmentPatternPositions() {
+			if (version == 1)
+				return [];
+			else {
+				var numAlign = Math.floor(version / 7) + 2;
+				var step = (version == 32) ? 26 :
+					Math.ceil((size - 13) / (numAlign*2 - 2)) * 2;
+				var result = [6];
+				for (var i = 0, pos = size - 7; i < numAlign - 1; i++, pos -= step)
+					result.splice(1, 0, pos);
+				return result;
+			}
+		}
+		
+		
 		// Returns true iff the i'th bit of x is set to 1.
 		function getBit(x, i) {
 			return ((x >>> i) & 1) != 0;
@@ -597,28 +615,6 @@ var qrcodegen = new function() {
 	var QrCode = {};  // Private object to assign properties to. Not the same object as 'this.QrCode'.
 	
 	
-	// Returns a sequence of positions of the alignment patterns in ascending order. These positions are
-	// used on both the x and y axes. Each value in the resulting sequence is in the range [0, 177).
-	// This stateless pure function could be implemented as table of 40 variable-length lists of integers.
-	QrCode.getAlignmentPatternPositions = function(ver) {
-		if (ver < MIN_VERSION || ver > MAX_VERSION)
-			throw "Version number out of range";
-		else if (ver == 1)
-			return [];
-		else {
-			var size = ver * 4 + 17;
-			var numAlign = Math.floor(ver / 7) + 2;
-			var step = (ver == 32) ? 26 :
-				Math.ceil((size - 13) / (numAlign*2 - 2)) * 2;
-			
-			var result = [6];
-			for (var i = 0, pos = size - 7; i < numAlign - 1; i++, pos -= step)
-				result.splice(1, 0, pos);
-			return result;
-		}
-	};
-	
-	
 	// Returns the number of data bits that can be stored in a QR Code of the given version number, after
 	// all function modules are excluded. This includes remainder bits, so it might not be a multiple of 8.
 	// The result is in the range [208, 29648]. This could be implemented as a 40-entry lookup table.

python/qrcodegen.py

@@ -256,7 +256,7 @@ class QrCode(object):
 		self._draw_finder_pattern(3, self._size - 4)
 		
 		# Draw numerous alignment patterns
-		alignpatpos = QrCode._get_alignment_pattern_positions(self._version)
+		alignpatpos = self._get_alignment_pattern_positions()
 		numalign = len(alignpatpos)
 		skips = ((0, 0), (0, numalign - 1), (numalign - 1, 0))
 		for i in range(numalign):
@@ -486,21 +486,18 @@ class QrCode(object):
 	
 	# ---- Private static helper functions ----
 	
-	@staticmethod
+	def _get_alignment_pattern_positions(self):
-	def _get_alignment_pattern_positions(ver):
+		"""Returns an ascending list of positions of alignment patterns for this version number.
-		"""Returns a sequence of positions of the alignment patterns in ascending order. These positions are
+		Each position is in the range [0,177), and are used on both the x and y axes.
-		used on both the x and y axes. Each value in the resulting sequence is in the range [0, 177).
+		This could be implemented as lookup table of 40 variable-length lists of integers."""
-		This stateless pure function could be implemented as table of 40 variable-length lists of integers."""
+		ver = self._version
-		if not (QrCode.MIN_VERSION <= ver <= QrCode.MAX_VERSION):
+		if ver == 1:
-			raise ValueError("Version number out of range")
-		elif ver == 1:
 			return []
 		else:
 			numalign = ver // 7 + 2
 			step = 26 if (ver == 32) else \
 				(ver*4 + numalign*2 + 1) // (numalign*2 - 2) * 2
-			start = ver * 4 + 10
+			result = [(self._size - 7 - i * step) for i in range(numalign - 1)] + [6]
-			result = [(start - i * step) for i in range(numalign - 1)] + [6]
 			return list(reversed(result))
 	
 	

rust/src/lib.rs

@@ -288,7 +288,7 @@ impl QrCode {
 		self.draw_finder_pattern(3, size - 4);
 		
 		// Draw numerous alignment patterns
-		let alignpatpos: Vec<i32> = QrCode::get_alignment_pattern_positions(self.version);
+		let alignpatpos: Vec<i32> = self.get_alignment_pattern_positions();
 		let numalign: usize = alignpatpos.len();
 		for i in 0 .. numalign {
 			for j in 0 .. numalign {
@@ -620,19 +620,19 @@ impl QrCode {
 	
 	/*---- Private static helper functions ----*/
 	
-	// Returns a set of positions of the alignment patterns in ascending order. These positions are
+	// Returns an ascending list of positions of alignment patterns for this version number.
-	// used on both the x and y axes. Each value in the resulting list is in the range [0, 177).
+	// Each position is in the range [0,177), and are used on both the x and y axes.
-	// This stateless pure function could be implemented as table of 40 variable-length lists of unsigned bytes.
+	// This could be implemented as lookup table of 40 variable-length lists of unsigned bytes.
-	fn get_alignment_pattern_positions(ver: Version) -> Vec<i32> {
+	fn get_alignment_pattern_positions(&self) -> Vec<i32> {
-		let ver = ver.value();
+		let ver = self.version.value();
 		if ver == 1 {
 			vec![]
 		} else {
 			let numalign: i32 = (ver as i32) / 7 + 2;
 			let step: i32 = if ver == 32 { 26 } else
 				{((ver as i32)*4 + numalign*2 + 1) / (numalign*2 - 2) * 2};
-			let start = (ver as i32) * 4 + 10;
+			let mut result: Vec<i32> = (0 .. numalign - 1).map(
-			let mut result: Vec<i32> = (0 .. numalign - 1).map(|i| start - i * step).collect();
+				|i| self.size - 7 - i * step).collect();
 			result.push(6);
 			result.reverse();
 			result

typescript/qrcodegen.ts

@@ -270,7 +270,7 @@ namespace qrcodegen {
 			this.drawFinderPattern(3, this.size - 4);
 			
 			// Draw numerous alignment patterns
-			let alignPatPos: Array<int> = QrCode.getAlignmentPatternPositions(this.version);
+			let alignPatPos: Array<int> = this.getAlignmentPatternPositions();
 			let numAlign: int = alignPatPos.length;
 			for (let i = 0; i < numAlign; i++) {
 				for (let j = 0; j < numAlign; j++) {
@@ -560,22 +560,18 @@ namespace qrcodegen {
 		
 		/*-- Private static helper functions QrCode --*/
 		
-		// Returns a sequence of positions of the alignment patterns in ascending order. These positions are
+		// Returns an ascending list of positions of alignment patterns for this version number.
-		// used on both the x and y axes. Each value in the resulting sequence is in the range [0, 177).
+		// Each position is in the range [0,177), and are used on both the x and y axes.
-		// This stateless pure function could be implemented as table of 40 variable-length lists of integers.
+		// This could be implemented as lookup table of 40 variable-length lists of integers.
-		private static getAlignmentPatternPositions(ver: int): Array<int> {
+		private getAlignmentPatternPositions(): Array<int> {
-			if (ver < QrCode.MIN_VERSION || ver > QrCode.MAX_VERSION)
+			if (this.version == 1)
-				throw "Version number out of range";
-			else if (ver == 1)
 				return [];
 			else {
-				let size: int = ver * 4 + 17;
+				let numAlign: int = Math.floor(this.version / 7) + 2;
-				let numAlign: int = Math.floor(ver / 7) + 2;
+				let step: int = (this.version == 32) ? 26 :
-				let step: int = (ver == 32) ? 26 :
+					Math.ceil((this.size - 13) / (numAlign*2 - 2)) * 2;
-					Math.ceil((size - 13) / (numAlign*2 - 2)) * 2;
-				
 				let result: Array<int> = [6];
-				for (let i = 0, pos = size - 7; i < numAlign - 1; i++, pos -= step)
+				for (let i = 0, pos = this.size - 7; i < numAlign - 1; i++, pos -= step)
 					result.splice(1, 0, pos);
 				return result;
 			}