Revamped QrCode.encodeSegments() to add parameters to make a much richer API, in all language versions; updated JavaScript demo script to handle new semantics.

cpp/QrCode.cpp

@@ -55,34 +55,34 @@ qrcodegen::QrCode qrcodegen::QrCode::encodeBinary(const std::vector<uint8_t> &da
 }
 
 
-qrcodegen::QrCode qrcodegen::QrCode::encodeSegments(const std::vector<QrSegment> &segs, const Ecc &ecl) {
+qrcodegen::QrCode qrcodegen::QrCode::encodeSegments(const std::vector<QrSegment> &segs, const Ecc &ecl,
+		int minVersion, int maxVersion, int mask, bool boostEcl) {
+	if (!(1 <= minVersion && minVersion <= maxVersion && maxVersion <= 40) || mask < -1 || mask > 7)
+		throw "Invalid value";
+	
 	// Find the minimal version number to use
-	int version, dataCapacityBits;
-	for (version = 1; ; version++) {  // Increment until the data fits in the QR Code
-		if (version > 40)  // All versions could not fit the given data
-			throw "Data too long";
-		dataCapacityBits = getNumDataCodewords(version, ecl) * 8;  // Number of data bits available
-		
-		// Calculate the total number of bits needed at this version number
-		// to encode all the segments (i.e. segment metadata and payloads)
-		int dataUsedBits = 0;
-		for (size_t i = 0; i < segs.size(); i++) {
-			const QrSegment &seg(segs.at(i));
-			if (seg.numChars < 0)
-				throw "Assertion error";
-			int ccbits = seg.mode.numCharCountBits(version);
-			if (seg.numChars >= (1 << ccbits)) {
-				// Segment length value doesn't fit in the length field's bit-width, so fail immediately
-				goto continueOuter;
-			}
-			dataUsedBits += 4 + ccbits + seg.bitLength;
-		}
-		if (dataUsedBits <= dataCapacityBits)
+	int version, dataUsedBits;
+	for (version = minVersion; ; version++) {
+		int dataCapacityBits = getNumDataCodewords(version, ecl) * 8;  // Number of data bits available
+		dataUsedBits = QrSegment::getTotalBits(segs, version);
+		if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits)
 			break;  // This version number is found to be suitable
-		continueOuter:;
+		if (version >= maxVersion)  // All versions in the range could not fit the given data
+			throw "Data too long";
+	}
+	if (dataUsedBits == -1)
+		throw "Assertion error";
+	
+	// Increase the error correction level while the data still fits in the current version number
+	const Ecc *newEcl = &ecl;
+	if (boostEcl) {
+		if (dataUsedBits <= getNumDataCodewords(version, Ecc::MEDIUM  ) * 8)  newEcl = &Ecc::MEDIUM  ;
+		if (dataUsedBits <= getNumDataCodewords(version, Ecc::QUARTILE) * 8)  newEcl = &Ecc::QUARTILE;
+		if (dataUsedBits <= getNumDataCodewords(version, Ecc::HIGH    ) * 8)  newEcl = &Ecc::HIGH    ;
 	}
 	
 	// Create the data bit string by concatenating all segments
+	int dataCapacityBits = getNumDataCodewords(version, *newEcl) * 8;
 	BitBuffer bb;
 	for (size_t i = 0; i < segs.size(); i++) {
 		const QrSegment &seg(segs.at(i));
@@ -102,7 +102,7 @@ qrcodegen::QrCode qrcodegen::QrCode::encodeSegments(const std::vector<QrSegment>
 		throw "Assertion error";
 	
 	// Create the QR Code symbol
-	return QrCode(version, ecl, bb.getBytes(), -1);
+	return QrCode(version, *newEcl, bb.getBytes(), mask);
 }
 
 

cpp/QrCode.hpp

@@ -83,13 +83,14 @@ public:
 	
 	
 	/* 
-	 * Returns a QR Code symbol representing the given data segments at the given error
-	 * correction level. The smallest possible QR Code version is automatically chosen for the output.
+	 * Returns a QR Code symbol representing the specified data segments with the specified encoding parameters.
+	 * The smallest possible QR Code version within the specified range is automatically chosen for the output.
 	 * This function allows the user to create a custom sequence of segments that switches
-	 * between modes (such as alphanumeric and binary) to encode text more efficiently. This
-	 * function is considered to be lower level than simply encoding text or binary data.
+	 * between modes (such as alphanumeric and binary) to encode text more efficiently.
+	 * This function is considered to be lower level than simply encoding text or binary data.
 	 */
-	static QrCode encodeSegments(const std::vector<QrSegment> &segs, const Ecc &ecl);
+	static QrCode encodeSegments(const std::vector<QrSegment> &segs, const Ecc &ecl,
+		int minVersion=1, int maxVersion=40, int mask=-1, bool boostEcl=true);  // All optional parameters
 	
 	
 	

cpp/QrSegment.cpp

@@ -22,6 +22,7 @@
  *   Software.
  */
 
+#include <cstddef>
 #include "BitBuffer.hpp"
 #include "QrSegment.hpp"
 
@@ -128,6 +129,22 @@ qrcodegen::QrSegment::QrSegment(const Mode &md, int numCh, const std::vector<uin
 }
 
 
+int qrcodegen::QrSegment::getTotalBits(const std::vector<QrSegment> &segs, int version) {
+	if (version < 1 || version > 40)
+		throw "Version number out of range";
+	int result = 0;
+	for (size_t i = 0; i < segs.size(); i++) {
+		const QrSegment &seg(segs.at(i));
+		int ccbits = seg.mode.numCharCountBits(version);
+		// Fail if segment length value doesn't fit in the length field's bit-width
+		if (seg.numChars >= (1 << ccbits))
+			return -1;
+		result += 4 + ccbits + seg.bitLength;
+	}
+	return result;
+}
+
+
 bool qrcodegen::QrSegment::isAlphanumeric(const char *text) {
 	for (; *text != '\0'; text++) {
 		char c = *text;

cpp/QrSegment.hpp

@@ -151,6 +151,10 @@ public:
 	QrSegment(const Mode &md, int numCh, const std::vector<uint8_t> &b, int bitLen);
 	
 	
+	// Package-private helper function.
+	static int getTotalBits(const std::vector<QrSegment> &segs, int version);
+	
+	
 	/*---- Constant ----*/
 private: