Revamped C++ BitBuffer code to be based on std::vector<bool>, updated dependent code.

cpp/BitBuffer.cpp

@@ -27,44 +27,23 @@
 
 namespace qrcodegen {
 
-BitBuffer::BitBuffer() :
+BitBuffer::BitBuffer()
-	data(),
+	: std::vector<bool>() {}
-	bitLength(0) {}
-
-
-int BitBuffer::getBitLength() const {
-	return bitLength;
-}
 
 
 std::vector<std::uint8_t> BitBuffer::getBytes() const {
-	return data;
+	std::vector<std::uint8_t> result((size() + 7) / 8);
+	for (std::size_t i = 0; i < size(); i++)
+		result[i >> 3] |= (*this)[i] ? 1 << (7 - (i & 7)) : 0;
+	return result;
 }
 
 
 void BitBuffer::appendBits(std::uint32_t val, int len) {
 	if (len < 0 || len > 32 || (len < 32 && (val >> len) != 0))
 		throw "Value out of range";
-	if (len > INT_MAX - bitLength)
+	for (int i = len - 1; i >= 0; i--)  // Append bit by bit
-		throw "Buffer too long";
+		this->push_back(((val >> i) & 1) != 0);
-	unsigned int newByteLen = ((unsigned int)bitLength + len + 7) / 8;
-	while (data.size() < newByteLen)
-		data.push_back(0);
-	for (int i = len - 1; i >= 0; i--, bitLength++)  // Append bit by bit
-		data.at(bitLength >> 3) |= ((val >> i) & 1) << (7 - (bitLength & 7));
-}
-
-
-void BitBuffer::appendData(const QrSegment &seg) {
-	if (seg.bitLength > INT_MAX - bitLength)
-		throw "Buffer too long";
-	unsigned int newByteLen = ((unsigned int)bitLength + seg.bitLength + 7) / 8;
-	while (data.size() < newByteLen)
-		data.push_back(0);
-	for (int i = 0; i < seg.bitLength; i++, bitLength++) {  // Append bit by bit
-		int bit = (seg.data.at(i >> 3) >> (7 - (i & 7))) & 1;
-		data.at(bitLength >> 3) |= bit << (7 - (bitLength & 7));
-	}
 }
 
 }

cpp/BitBuffer.hpp

@@ -25,7 +25,6 @@
 
 #include <cstdint>
 #include <vector>
-#include "QrSegment.hpp"
 
 
 namespace qrcodegen {
@@ -33,14 +32,7 @@ namespace qrcodegen {
 /* 
  * An appendable sequence of bits. Bits are packed in big endian within a byte.
  */
-class BitBuffer final {
+class BitBuffer final : public std::vector<bool> {
-	
-	/*---- Fields ----*/
-	
-	private: std::vector<std::uint8_t> data;
-	private: int bitLength;
-	
-	
 	
 	/*---- Constructor ----*/
 	
@@ -51,11 +43,7 @@ class BitBuffer final {
 	
 	/*---- Methods ----*/
 	
-	// Returns the number of bits in the buffer, which is a non-negative value.
+	// Returns a copy of all bytes, padding up to the nearest byte. Bits are packed in big endian within a byte.
-	public: int getBitLength() const;
-	
-	
-	// Returns a copy of all bytes, padding up to the nearest byte.
 	public: std::vector<std::uint8_t> getBytes() const;
 	
 	
@@ -63,10 +51,6 @@ class BitBuffer final {
 	// If 0 <= len <= 31, then this requires 0 <= val < 2^len.
 	public: void appendBits(std::uint32_t val, int len);
 	
-	
-	// Appends the data of the given segment to this bit buffer.
-	public: void appendData(const QrSegment &seg);
-	
 };
 
 }

cpp/QrCode.cpp

@@ -88,22 +88,23 @@ QrCode QrCode::encodeSegments(const vector<QrSegment> &segs, const Ecc &ecl,
 	}
 	
 	// Create the data bit string by concatenating all segments
-	int dataCapacityBits = getNumDataCodewords(version, *newEcl) * 8;
+	size_t dataCapacityBits = getNumDataCodewords(version, *newEcl) * 8;
 	BitBuffer bb;
 	for (const QrSegment &seg : segs) {
 		bb.appendBits(seg.mode.modeBits, 4);
 		bb.appendBits(seg.numChars, seg.mode.numCharCountBits(version));
-		bb.appendData(seg);
+		for (int i = 0; i < seg.bitLength; i++)
+			bb.push_back(((seg.data.at(i >> 3) >> (7 - (i & 7))) & 1) != 0);
 	}
 	
 	// Add terminator and pad up to a byte if applicable
-	bb.appendBits(0, std::min(4, dataCapacityBits - bb.getBitLength()));
+	bb.appendBits(0, std::min(static_cast<size_t>(4), dataCapacityBits - bb.size()));
-	bb.appendBits(0, (8 - bb.getBitLength() % 8) % 8);
+	bb.appendBits(0, (8 - bb.size() % 8) % 8);
 	
 	// Pad with alternate bytes until data capacity is reached
-	for (uint8_t padByte = 0xEC; bb.getBitLength() < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
+	for (uint8_t padByte = 0xEC; bb.size() < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
 		bb.appendBits(padByte, 8);
-	if (bb.getBitLength() % 8 != 0)
+	if (bb.size() % 8 != 0)
 		throw "Assertion error";
 	
 	// Create the QR Code symbol

cpp/QrSegment.cpp

@@ -83,7 +83,7 @@ QrSegment QrSegment::makeNumeric(const char *digits) {
 	}
 	if (accumCount > 0)  // 1 or 2 digits remaining
 		bb.appendBits(accumData, accumCount * 3 + 1);
-	return QrSegment(Mode::NUMERIC, charCount, bb.getBytes(), bb.getBitLength());
+	return QrSegment(Mode::NUMERIC, charCount, bb.getBytes(), bb.size());
 }
 
 
@@ -106,7 +106,7 @@ QrSegment QrSegment::makeAlphanumeric(const char *text) {
 	}
 	if (accumCount > 0)  // 1 character remaining
 		bb.appendBits(accumData, 6);
-	return QrSegment(Mode::ALPHANUMERIC, charCount, bb.getBytes(), bb.getBitLength());
+	return QrSegment(Mode::ALPHANUMERIC, charCount, bb.getBytes(), bb.size());
 }