Updated all language versions to add getBit() helper function and refactor existing arithmetic code to use it.

c/qrcodegen.c

@@ -82,6 +82,7 @@ static long getPenaltyScore(const uint8_t qrcode[]);
 testable bool getModule(const uint8_t qrcode[], int x, int y);
 testable void setModule(uint8_t qrcode[], int x, int y, bool isBlack);
 testable void setModuleBounded(uint8_t qrcode[], int x, int y, bool isBlack);
+static bool getBit(int x, int i);
 
 testable int calcSegmentBitLength(enum qrcodegen_Mode mode, size_t numChars);
 testable int getTotalBits(const struct qrcodegen_Segment segs[], size_t len, int version);
@@ -442,19 +443,19 @@ static void drawFormatBits(enum qrcodegen_Ecc ecl, enum qrcodegen_Mask mask, uin
 	
 	// Draw first copy
 	for (int i = 0; i <= 5; i++)
-		setModule(qrcode, 8, i, ((data >> i) & 1) != 0);
-	setModule(qrcode, 8, 7, ((data >> 6) & 1) != 0);
-	setModule(qrcode, 8, 8, ((data >> 7) & 1) != 0);
-	setModule(qrcode, 7, 8, ((data >> 8) & 1) != 0);
+		setModule(qrcode, 8, i, getBit(data, i));
+	setModule(qrcode, 8, 7, getBit(data, 6));
+	setModule(qrcode, 8, 8, getBit(data, 7));
+	setModule(qrcode, 7, 8, getBit(data, 8));
 	for (int i = 9; i < 15; i++)
-		setModule(qrcode, 14 - i, 8, ((data >> i) & 1) != 0);
+		setModule(qrcode, 14 - i, 8, getBit(data, i));
 	
 	// Draw second copy
 	int qrsize = qrcodegen_getSize(qrcode);
 	for (int i = 0; i <= 7; i++)
-		setModule(qrcode, qrsize - 1 - i, 8, ((data >> i) & 1) != 0);
+		setModule(qrcode, qrsize - 1 - i, 8, getBit(data, i));
 	for (int i = 8; i < 15; i++)
-		setModule(qrcode, 8, qrsize - 15 + i, ((data >> i) & 1) != 0);
+		setModule(qrcode, 8, qrsize - 15 + i, getBit(data, i));
 	setModule(qrcode, 8, qrsize - 8, true);
 }
 
@@ -505,7 +506,7 @@ static void drawCodewords(const uint8_t data[], int dataLen, uint8_t qrcode[]) {
 				bool upward = ((right + 1) & 2) == 0;
 				int y = upward ? qrsize - 1 - vert : vert;  // Actual y coordinate
 				if (!getModule(qrcode, x, y) && i < dataLen * 8) {
-					bool black = ((data[i >> 3] >> (7 - (i & 7))) & 1) != 0;
+					bool black = getBit(data[i >> 3], 7 - (i & 7));
 					setModule(qrcode, x, y, black);
 					i++;
 				}
@@ -657,9 +658,7 @@ testable bool getModule(const uint8_t qrcode[], int x, int y) {
 	int qrsize = qrcode[0];
 	assert(21 <= qrsize && qrsize <= 177 && 0 <= x && x < qrsize && 0 <= y && y < qrsize);
 	int index = y * qrsize + x;
-	int bitIndex = index & 7;
-	int byteIndex = (index >> 3) + 1;
-	return ((qrcode[byteIndex] >> bitIndex) & 1) != 0;
+	return getBit(qrcode[(index >> 3) + 1], index & 7);
 }
 
 
@@ -685,6 +684,12 @@ testable void setModuleBounded(uint8_t qrcode[], int x, int y, bool isBlack) {
 }
 
 
+// Returns true iff the i'th bit of x is set to 1.
+static bool getBit(int x, int i) {
+	return ((x >> i) & 1) != 0;
+}
+
+
 
 /*---- Segment handling ----*/
 

cpp/QrCode.cpp

@@ -228,18 +228,18 @@ void QrCode::drawFormatBits(int mask) {
 	
 	// Draw first copy
 	for (int i = 0; i <= 5; i++)
-		setFunctionModule(8, i, ((data >> i) & 1) != 0);
-	setFunctionModule(8, 7, ((data >> 6) & 1) != 0);
-	setFunctionModule(8, 8, ((data >> 7) & 1) != 0);
-	setFunctionModule(7, 8, ((data >> 8) & 1) != 0);
+		setFunctionModule(8, i, getBit(data, i));
+	setFunctionModule(8, 7, getBit(data, 6));
+	setFunctionModule(8, 8, getBit(data, 7));
+	setFunctionModule(7, 8, getBit(data, 8));
 	for (int i = 9; i < 15; i++)
-		setFunctionModule(14 - i, 8, ((data >> i) & 1) != 0);
+		setFunctionModule(14 - i, 8, getBit(data, i));
 	
 	// Draw second copy
 	for (int i = 0; i <= 7; i++)
-		setFunctionModule(size - 1 - i, 8, ((data >> i) & 1) != 0);
+		setFunctionModule(size - 1 - i, 8, getBit(data, i));
 	for (int i = 8; i < 15; i++)
-		setFunctionModule(8, size - 15 + i, ((data >> i) & 1) != 0);
+		setFunctionModule(8, size - 15 + i, getBit(data, i));
 	setFunctionModule(8, size - 8, true);
 }
 
@@ -258,7 +258,7 @@ void QrCode::drawVersion() {
 	
 	// Draw two copies
 	for (int i = 0; i < 18; i++) {
-		bool bit = ((data >> i) & 1) != 0;
+		bool bit = getBit(data, i);
 		int a = size - 11 + i % 3, b = i / 3;
 		setFunctionModule(a, b, bit);
 		setFunctionModule(b, a, bit);
@@ -351,7 +351,7 @@ void QrCode::drawCodewords(const vector<uint8_t> &data) {
 				bool upward = ((right + 1) & 2) == 0;
 				int y = upward ? size - 1 - vert : vert;  // Actual y coordinate
 				if (!isFunction.at(y).at(x) && i < data.size() * 8) {
-					modules.at(y).at(x) = ((data.at(i >> 3) >> (7 - (i & 7))) & 1) != 0;
+					modules.at(y).at(x) = getBit(data.at(i >> 3), 7 - static_cast<int>(i & 7));
 					i++;
 				}
 				// If there are any remainder bits (0 to 7), they are already
@@ -535,6 +535,11 @@ int QrCode::getNumDataCodewords(int ver, Ecc ecl) {
 }
 
 
+bool QrCode::getBit(long x, int i) {
+	return ((x >> i) & 1) != 0;
+}
+
+
 /*---- Tables of constants ----*/
 
 const int QrCode::PENALTY_N1 = 3;

cpp/QrCode.hpp

@@ -245,6 +245,10 @@ class QrCode final {
 	private: static int getNumDataCodewords(int ver, Ecc ecl);
 	
 	
+	// Returns true iff the i'th bit of x is set to 1.
+	private: static bool getBit(long x, int i);
+	
+	
 	/*---- Private tables of constants ----*/
 	
 	// For use in getPenaltyScore(), when evaluating which mask is best.

java/io/nayuki/qrcodegen/BitBuffer.java

@@ -99,7 +99,7 @@ public final class BitBuffer implements Cloneable {
 		if (len < 0 || len > 31 || val >>> len != 0)
 			throw new IllegalArgumentException("Value out of range");
 		for (int i = len - 1; i >= 0; i--, bitLength++)  // Append bit by bit
-			data.set(bitLength, ((val >>> i) & 1) != 0);
+			data.set(bitLength, QrCode.getBit(val, i));
 	}
 	
 	

java/io/nayuki/qrcodegen/QrCode.java

@@ -359,18 +359,18 @@ public final class QrCode {
 		
 		// Draw first copy
 		for (int i = 0; i <= 5; i++)
-			setFunctionModule(8, i, ((data >>> i) & 1) != 0);
-		setFunctionModule(8, 7, ((data >>> 6) & 1) != 0);
-		setFunctionModule(8, 8, ((data >>> 7) & 1) != 0);
-		setFunctionModule(7, 8, ((data >>> 8) & 1) != 0);
+			setFunctionModule(8, i, getBit(data, i));
+		setFunctionModule(8, 7, getBit(data, 6));
+		setFunctionModule(8, 8, getBit(data, 7));
+		setFunctionModule(7, 8, getBit(data, 8));
 		for (int i = 9; i < 15; i++)
-			setFunctionModule(14 - i, 8, ((data >>> i) & 1) != 0);
+			setFunctionModule(14 - i, 8, getBit(data, i));
 		
 		// Draw second copy
 		for (int i = 0; i <= 7; i++)
-			setFunctionModule(size - 1 - i, 8, ((data >>> i) & 1) != 0);
+			setFunctionModule(size - 1 - i, 8, getBit(data, i));
 		for (int i = 8; i < 15; i++)
-			setFunctionModule(8, size - 15 + i, ((data >>> i) & 1) != 0);
+			setFunctionModule(8, size - 15 + i, getBit(data, i));
 		setFunctionModule(8, size - 8, true);
 	}
 	
@@ -391,7 +391,7 @@ public final class QrCode {
 		
 		// Draw two copies
 		for (int i = 0; i < 18; i++) {
-			boolean bit = ((data >>> i) & 1) != 0;
+			boolean bit = getBit(data, i);
 			int a = size - 11 + i % 3, b = i / 3;
 			setFunctionModule(a, b, bit);
 			setFunctionModule(b, a, bit);
@@ -489,7 +489,7 @@ public final class QrCode {
 					boolean upward = ((right + 1) & 2) == 0;
 					int y = upward ? size - 1 - vert : vert;  // Actual y coordinate
 					if (!isFunction[y][x] && i < data.length * 8) {
-						modules[y][x] = ((data[i >>> 3] >>> (7 - (i & 7))) & 1) != 0;
+						modules[y][x] = getBit(data[i >>> 3], 7 - (i & 7));
 						i++;
 					}
 					// If there are any remainder bits (0 to 7), they are already
@@ -702,6 +702,12 @@ public final class QrCode {
 	}
 	
 	
+	// Returns true iff the i'th bit of x is set to 1.
+	static boolean getBit(int x, int i) {
+		return ((x >>> i) & 1) != 0;
+	}
+	
+	
 	/*---- Private tables of constants ----*/
 	
 	// For use in getPenaltyScore(), when evaluating which mask is best.

javascript/qrcodegen.js

@@ -250,18 +250,18 @@ var qrcodegen = new function() {
 			
 			// Draw first copy
 			for (var i = 0; i <= 5; i++)
-				setFunctionModule(8, i, ((data >>> i) & 1) != 0);
-			setFunctionModule(8, 7, ((data >>> 6) & 1) != 0);
-			setFunctionModule(8, 8, ((data >>> 7) & 1) != 0);
-			setFunctionModule(7, 8, ((data >>> 8) & 1) != 0);
+				setFunctionModule(8, i, getBit(data, i));
+			setFunctionModule(8, 7, getBit(data, 6));
+			setFunctionModule(8, 8, getBit(data, 7));
+			setFunctionModule(7, 8, getBit(data, 8));
 			for (var i = 9; i < 15; i++)
-				setFunctionModule(14 - i, 8, ((data >>> i) & 1) != 0);
+				setFunctionModule(14 - i, 8, getBit(data, i));
 			
 			// Draw second copy
 			for (var i = 0; i <= 7; i++)
-				setFunctionModule(size - 1 - i, 8, ((data >>> i) & 1) != 0);
+				setFunctionModule(size - 1 - i, 8, getBit(data, i));
 			for (var i = 8; i < 15; i++)
-				setFunctionModule(8, size - 15 + i, ((data >>> i) & 1) != 0);
+				setFunctionModule(8, size - 15 + i, getBit(data, i));
 			setFunctionModule(8, size - 8, true);
 		}
 		
@@ -282,7 +282,7 @@ var qrcodegen = new function() {
 			
 			// Draw two copies
 			for (var i = 0; i < 18; i++) {
-				var bit = ((data >>> i) & 1) != 0;
+				var bit = getBit(data, i);
 				var a = size - 11 + i % 3, b = Math.floor(i / 3);
 				setFunctionModule(a, b, bit);
 				setFunctionModule(b, a, bit);
@@ -381,7 +381,7 @@ var qrcodegen = new function() {
 						var upward = ((right + 1) & 2) == 0;
 						var y = upward ? size - 1 - vert : vert;  // Actual y coordinate
 						if (!isFunction[y][x] && i < data.length * 8) {
-							modules[y][x] = ((data[i >>> 3] >>> (7 - (i & 7))) & 1) != 0;
+							modules[y][x] = getBit(data[i >>> 3], 7 - (i & 7));
 							i++;
 						}
 						// If there are any remainder bits (0 to 7), they are already
@@ -499,6 +499,12 @@ var qrcodegen = new function() {
 				result += QrCode.PENALTY_N4;
 			return result;
 		}
+		
+		
+		// Returns true iff the i'th bit of x is set to 1.
+		function getBit(x, i) {
+			return ((x >>> i) & 1) != 0;
+		}
 	};
 	
 	

python/qrcodegen.py

@@ -279,18 +279,18 @@ class QrCode(object):
 		
 		# Draw first copy
 		for i in range(0, 6):
-			self._set_function_module(8, i, (data >> i) & 1 != 0)
-		self._set_function_module(8, 7, (data >> 6) & 1 != 0)
-		self._set_function_module(8, 8, (data >> 7) & 1 != 0)
-		self._set_function_module(7, 8, (data >> 8) & 1 != 0)
+			self._set_function_module(8, i, _get_bit(data, i))
+		self._set_function_module(8, 7, _get_bit(data, 6))
+		self._set_function_module(8, 8, _get_bit(data, 7))
+		self._set_function_module(7, 8, _get_bit(data, 8))
 		for i in range(9, 15):
-			self._set_function_module(14 - i, 8, (data >> i) & 1 != 0)
+			self._set_function_module(14 - i, 8, _get_bit(data, i))
 		
 		# Draw second copy
 		for i in range(0, 8):
-			self._set_function_module(self._size - 1 - i, 8, (data >> i) & 1 != 0)
+			self._set_function_module(self._size - 1 - i, 8, _get_bit(data, i))
 		for i in range(8, 15):
-			self._set_function_module(8, self._size - 15 + i, (data >> i) & 1 != 0)
+			self._set_function_module(8, self._size - 15 + i, _get_bit(data, i))
 		self._set_function_module(8, self._size - 8, True)
 	
 	
@@ -309,7 +309,7 @@ class QrCode(object):
 		
 		# Draw two copies
 		for i in range(18):
-			bit = (data >> i) & 1 != 0
+			bit = _get_bit(data, i)
 			a, b = self._size - 11 + i % 3, i // 3
 			self._set_function_module(a, b, bit)
 			self._set_function_module(b, a, bit)
@@ -396,7 +396,7 @@ class QrCode(object):
 					upward = (right + 1) & 2 == 0
 					y = (self._size - 1 - vert) if upward else vert  # Actual y coordinate
 					if not self._isfunction[y][x] and i < len(data) * 8:
-						self._modules[y][x] = (data[i >> 3] >> (7 - (i & 7))) & 1 != 0
+						self._modules[y][x] = _get_bit(data[i >> 3], 7 - (i & 7))
 						i += 1
 					# If there are any remainder bits (0 to 7), they are already
 					# set to 0/false/white when the grid of modules was initialized
@@ -834,3 +834,8 @@ class _BitBuffer(list):
 		if n < 0 or val >> n != 0:
 			raise ValueError("Value out of range")
 		self.extend(((val >> i) & 1) for i in reversed(range(n)))
+
+
+def _get_bit(x, i):
+	"""Returns true iff the i'th bit of x is set to 1."""
+	return (x >> i) & 1 != 0

rust/src/lib.rs

@@ -315,21 +315,21 @@ impl QrCode {
 		
 		// Draw first copy
 		for i in 0 .. 6 {
-			self.set_function_module(8, i, (data >> i) & 1 != 0);
+			self.set_function_module(8, i, get_bit(data, i));
 		}
-		self.set_function_module(8, 7, (data >> 6) & 1 != 0);
-		self.set_function_module(8, 8, (data >> 7) & 1 != 0);
-		self.set_function_module(7, 8, (data >> 8) & 1 != 0);
+		self.set_function_module(8, 7, get_bit(data, 6));
+		self.set_function_module(8, 8, get_bit(data, 7));
+		self.set_function_module(7, 8, get_bit(data, 8));
 		for i in 9 .. 15 {
-			self.set_function_module(14 - i, 8, (data >> i) & 1 != 0);
+			self.set_function_module(14 - i, 8, get_bit(data, i));
 		}
 		
 		// Draw second copy
 		for i in 0 .. 8 {
-			self.set_function_module(size - 1 - i, 8, (data >> i) & 1 != 0);
+			self.set_function_module(size - 1 - i, 8, get_bit(data, i));
 		}
 		for i in 8 .. 15 {
-			self.set_function_module(8, size - 15 + i, (data >> i) & 1 != 0);
+			self.set_function_module(8, size - 15 + i, get_bit(data, i));
 		}
 		self.set_function_module(8, size - 8, true);
 	}
@@ -352,7 +352,7 @@ impl QrCode {
 		
 		// Draw two copies
 		for i in 0 .. 18 {
-			let bit: bool = (data >> i) & 1 != 0;
+			let bit: bool = get_bit(data, i);
 			let a: i32 = self.size - 11 + i % 3;
 			let b: i32 = i / 3;
 			self.set_function_module(a, b, bit);
@@ -458,7 +458,7 @@ impl QrCode {
 					let upward: bool = (right + 1) & 2 == 0;
 					let y: i32 = if upward { self.size - 1 - vert } else { vert };  // Actual y coordinate
 					if !self.isfunction[(y * self.size + x) as usize] && i < data.len() * 8 {
-						*self.module_mut(x, y) = (data[i >> 3] >> (7 - (i & 7))) & 1 != 0;
+						*self.module_mut(x, y) = get_bit(data[i >> 3] as u32, 7 - ((i & 7) as i32));
 						i += 1;
 					}
 					// If there are any remainder bits (0 to 7), they are already
@@ -1081,8 +1081,8 @@ impl BitBuffer {
 	// to this sequence. Requires 0 <= val < 2^len.
 	pub fn append_bits(&mut self, val: u32, len: u8) {
 		assert!(len < 32 && (val >> len) == 0 || len == 32, "Value out of range");
-		for i in (0 .. len).rev() {  // Append bit by bit
-			self.0.push((val >> i) & 1 != 0);
+		for i in (0 .. len as i32).rev() {  // Append bit by bit
+			self.0.push(get_bit(val, i));
 		}
 	}
 }
@@ -1119,3 +1119,9 @@ impl Mask {
 		self.0
 	}
 }
+
+
+// Returns true iff the i'th bit of x is set to 1.
+fn get_bit(x: u32, i: i32) -> bool {
+	(x >> i) & 1 != 0
+}