Moved QrCode.encodeTextToSegment() to QrSegment.makeSegments() and changed the function's code somewhat, in all language versions; updated JavaScript demo script to handle new semantics.

cpp/QrCode.cpp

@@ -43,27 +43,11 @@ const qrcodegen::QrCode::Ecc qrcodegen::QrCode::Ecc::HIGH    (3, 2);
 
 
 qrcodegen::QrCode qrcodegen::QrCode::encodeText(const char *text, const Ecc &ecl) {
-	std::vector<QrSegment> segs;
-	segs.push_back(encodeTextToSegment(text));
+	std::vector<QrSegment> segs(QrSegment::makeSegments(text));
 	return encodeSegments(segs, ecl);
 }
 
 
-qrcodegen::QrSegment qrcodegen::QrCode::encodeTextToSegment(const char *text) {
-	// Select the most efficient segment encoding automatically
-	if (QrSegment::isNumeric(text))
-		return QrSegment::makeNumeric(text);
-	else if (QrSegment::isAlphanumeric(text))
-		return QrSegment::makeAlphanumeric(text);
-	else {
-		std::vector<uint8_t> bytes;
-		for (; *text != '\0'; text++)
-			bytes.push_back(static_cast<uint8_t>(*text));
-		return QrSegment::makeBytes(bytes);
-	}
-}
-
-
 qrcodegen::QrCode qrcodegen::QrCode::encodeBinary(const std::vector<uint8_t> &data, const Ecc &ecl) {
 	std::vector<QrSegment> segs;
 	segs.push_back(QrSegment::makeBytes(data));

cpp/QrCode.hpp

@@ -74,12 +74,6 @@ public:
 	static QrCode encodeText(const char *text, const Ecc &ecl);
 	
 	
-	/* 
-	 * Returns a QR segment representing the given Unicode text string.
-	 */
-	static QrSegment encodeTextToSegment(const char *text);
-	
-	
 	/* 
 	 * Returns a QR Code symbol representing the given binary data string at the given error correction level.
 	 * This function always encodes using the binary segment mode, not any text mode. The maximum number of

cpp/QrSegment.cpp

@@ -100,6 +100,24 @@ qrcodegen::QrSegment qrcodegen::QrSegment::makeAlphanumeric(const char *text) {
 }
 
 
+std::vector<qrcodegen::QrSegment> qrcodegen::QrSegment::makeSegments(const char *text) {
+	// Select the most efficient segment encoding automatically
+	std::vector<QrSegment> result;
+	if (*text == '\0');  // Leave the vector empty
+	else if (QrSegment::isNumeric(text))
+		result.push_back(QrSegment::makeNumeric(text));
+	else if (QrSegment::isAlphanumeric(text))
+		result.push_back(QrSegment::makeAlphanumeric(text));
+	else {
+		std::vector<uint8_t> bytes;
+		for (; *text != '\0'; text++)
+			bytes.push_back(static_cast<uint8_t>(*text));
+		result.push_back(QrSegment::makeBytes(bytes));
+	}
+	return result;
+}
+
+
 qrcodegen::QrSegment::QrSegment(const Mode &md, int numCh, const std::vector<uint8_t> &b, int bitLen) :
 		mode(md),
 		numChars(numCh),

cpp/QrSegment.hpp

@@ -103,6 +103,13 @@ public:
 	static QrSegment makeAlphanumeric(const char *text);
 	
 	
+	/* 
+	 * Returns a list of zero or more segments to represent the given text string.
+	 * The result may use various segment modes and switch modes to optimize the length of the bit stream.
+	 */
+	static std::vector<QrSegment> makeSegments(const char *text);
+	
+	
 	/*---- Static helper functions ----*/
 public:
 	

java/io/nayuki/qrcodegen/QrCode.java

@@ -25,7 +25,6 @@
 package io.nayuki.qrcodegen;
 
 import java.awt.image.BufferedImage;
-import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.List;
 
@@ -53,27 +52,8 @@ public final class QrCode {
 	public static QrCode encodeText(String text, Ecc ecl) {
 		if (text == null || ecl == null)
 			throw new NullPointerException();
-		QrSegment seg = encodeTextToSegment(text);
-		return encodeSegments(Arrays.asList(seg), ecl);
-	}
-	
-	
-	/**
-	 * Returns a QR segment representing the specified Unicode text string.
-	 * @param text the text to be encoded, which can be any Unicode string
-	 * @return a QR segment containing the text
-	 * @throws NullPointerException if the text is {@code null}
-	 */
-	public static QrSegment encodeTextToSegment(String text) {
-		if (text == null)
-			throw new NullPointerException();
-		// Select the most efficient segment encoding automatically
-		if (QrSegment.NUMERIC_REGEX.matcher(text).matches())
-			return QrSegment.makeNumeric(text);
-		else if (QrSegment.ALPHANUMERIC_REGEX.matcher(text).matches())
-			return QrSegment.makeAlphanumeric(text);
-		else
-			return QrSegment.makeBytes(text.getBytes(StandardCharsets.UTF_8));
+		List<QrSegment> segs = QrSegment.makeSegments(text);
+		return encodeSegments(segs, ecl);
 	}
 	
 	

java/io/nayuki/qrcodegen/QrSegment.java

@@ -24,7 +24,10 @@
 
 package io.nayuki.qrcodegen;
 
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.regex.Pattern;
 
 
@@ -104,6 +107,31 @@ public final class QrSegment {
 	}
 	
 	
+	/**
+	 * Returns a new mutable list of zero or more segments to represent the specified Unicode text string.
+	 * The result may use various segment modes and switch modes to optimize the length of the bit stream.
+	 * @param text the text to be encoded, which can be any Unicode string
+	 * @return a list of segments containing the text
+	 * @throws NullPointerException if the text is {@code null}
+	 */
+	public static List<QrSegment> makeSegments(String text) {
+		if (text == null)
+			throw new NullPointerException();
+		
+		// Select the most efficient segment encoding automatically
+		if (text.equals(""))
+			return new ArrayList<>();
+		QrSegment seg;
+		if (NUMERIC_REGEX.matcher(text).matches())
+			seg = makeNumeric(text);
+		else if (ALPHANUMERIC_REGEX.matcher(text).matches())
+			seg = makeAlphanumeric(text);
+		else
+			seg = makeBytes(text.getBytes(StandardCharsets.UTF_8));
+		return Arrays.asList(seg);
+	}
+	
+	
 	
 	/*---- Instance fields ----*/
 	

javascript/qrcodegen-demo.js

@@ -39,7 +39,8 @@ function redrawQrCode() {
 	
 	// Get text and compute QR Code
 	var text = document.getElementById("text-input").value;
-	var qr = qrcodegen.encodeText(text, ecl);
+	var segs = qrcodegen.QrSegment.makeSegments(text);
+	var qr = qrcodegen.encodeSegments(segs, ecl);
 	
 	// Get scale and border
 	var scale = parseInt(document.getElementById("scale-input").value, 10);
@@ -67,18 +68,27 @@ function redrawQrCode() {
 	stats += "mask pattern = " + qr.getMask() + ", ";
 	stats += "character count = " + countUnicodeChars(text) + ",\n";
 	stats += "encoding mode = ";
-	var seg = qrcodegen.encodeTextToSegment(text);
-	if (seg.getMode() == qrcodegen.QrSegment.Mode.NUMERIC)
-		stats += "numeric";
-	else if (seg.getMode() == qrcodegen.QrSegment.Mode.ALPHANUMERIC)
-		stats += "alphanumeric";
-	else if (seg.getMode() == qrcodegen.QrSegment.Mode.BYTE)
-		stats += "byte";
-	else if (seg.getMode() == qrcodegen.QrSegment.Mode.BYTE)
-		stats += "kanji";
-	else
-		stats += "unknown";
-	stats += ", data bits = " + (4 + seg.getMode().numCharCountBits(qr.getVersion()) + seg.getBits().length) + ".";
+	if (segs.length == 0)
+		stats += "none";
+	else if (segs.length == 1) {
+		var mode = segs[0].getMode();
+		if (mode == qrcodegen.QrSegment.Mode.NUMERIC)
+			stats += "numeric";
+		else if (mode == qrcodegen.QrSegment.Mode.ALPHANUMERIC)
+			stats += "alphanumeric";
+		else if (mode == qrcodegen.QrSegment.Mode.BYTE)
+			stats += "byte";
+		else if (mode == qrcodegen.QrSegment.Mode.BYTE)
+			stats += "kanji";
+		else
+			stats += "unknown";
+	} else
+		stats += "multiple";
+	var databits = 0;
+	segs.forEach(function(seg) {
+		databits += 4 + seg.getMode().numCharCountBits(qr.getVersion()) + seg.getBits().length;
+	});
+	stats += ", data bits = " + databits + ".";
 	var elem = document.getElementById("statistics-output");
 	while (elem.firstChild != null)
 		elem.removeChild(elem.firstChild);

javascript/qrcodegen.js

@@ -28,7 +28,6 @@
 /* 
  * Module "qrcodegen". Public members inside this namespace:
  * - Function encodeText(str text, QrCode.Ecc ecl) -> QrCode
- * - Function encodeTextToSegment(str text) -> QrSegment
  * - Function encodeBinary(list<int> data, QrCode.Ecc ecl) -> QrCode
  * - Function encodeSegments(list<QrSegment> segs, QrCode.Ecc ecl) -> QrCode
  * - Class QrCode:
@@ -48,6 +47,7 @@
  *   - Function makeBytes(list<int> data) -> QrSegment
  *   - Function makeNumeric(str data) -> QrSegment
  *   - Function makeAlphanumeric(str data) -> QrSegment
+ *   - Function makeSegments(str text) -> list<QrSegment>
  *   - Constructor QrSegment(QrSegment.Mode mode, int numChars, list<int> bitData)
  *   - Method getMode() -> QrSegment.Mode
  *   - Method getNumChars() -> int
@@ -67,22 +67,8 @@ var qrcodegen = new function() {
 	 * code points (not UTF-16 code units). The smallest possible QR Code version is automatically chosen for the output.
 	 */
 	this.encodeText = function(text, ecl) {
-		var seg = this.encodeTextToSegment(text);
-		return this.encodeSegments([seg], ecl);
-	};
-	
-	
-	/* 
-	 * Returns a single QR segment representing the given Unicode text string.
-	 */
-	this.encodeTextToSegment = function(text) {
-		// Select the most efficient segment encoding automatically
-		if (QrSegment.NUMERIC_REGEX.test(text))
-			return this.QrSegment.makeNumeric(text);
-		else if (QrSegment.ALPHANUMERIC_REGEX.test(text))
-			return this.QrSegment.makeAlphanumeric(text);
-		else
-			return this.QrSegment.makeBytes(toUtf8ByteArray(text));
+		var segs = this.QrSegment.makeSegments(text);
+		return this.encodeSegments(segs, ecl);
 	};
 	
 	
@@ -773,6 +759,22 @@ var qrcodegen = new function() {
 		return new this(this.Mode.ALPHANUMERIC, text.length, bb.getBits());
 	};
 	
+	/* 
+	 * Returns a new mutable list of zero or more segments to represent the given Unicode text string.
+	 * The result may use various segment modes and switch modes to optimize the length of the bit stream.
+	 */
+	this.QrSegment.makeSegments = function(text) {
+		// Select the most efficient segment encoding automatically
+		if (text == "")
+			return [];
+		else if (QrSegment.NUMERIC_REGEX.test(text))
+			return [this.makeNumeric(text)];
+		else if (QrSegment.ALPHANUMERIC_REGEX.test(text))
+			return [this.makeAlphanumeric(text)];
+		else
+			return [this.makeBytes(toUtf8ByteArray(text))];
+	};
+	
 	/*-- Constants --*/
 	
 	var QrSegment = {};  // Private object to assign properties to

python/qrcodegen.py

@@ -28,7 +28,6 @@ import itertools, re, sys
 """
 Public members inside this module "qrcodegen":
 - Function encode_text(str text, QrCode.Ecc ecl) -> QrCode
-- Function encode_text_to_segment(str text) -> QrSegment
 - Function encode_binary(bytes data, QrCode.Ecc ecl) -> QrCode
 - Function encode_segments(list<QrSegment> segs, QrCode.Ecc ecl) -> QrCode
 - Class QrCode:
@@ -47,6 +46,7 @@ Public members inside this module "qrcodegen":
   - Function make_bytes(bytes data) -> QrSegment
   - Function make_numeric(str digits) -> QrSegment
   - Function make_alphanumeric(str text) -> QrSegment
+  - Function make_segments(str text) -> list<QrSegment>
   - Constructor QrSegment(QrSegment.Mode mode, int numch, list<int> bitdata)
   - Method get_mode() -> QrSegment.Mode
   - Method get_num_chars() -> int
@@ -64,21 +64,8 @@ def encode_text(text, ecl):
 	"""Returns a QR Code symbol representing the given Unicode text string at the given error correction level.
 	As a conservative upper bound, this function is guaranteed to succeed for strings that have 738 or fewer Unicode
 	code points (not UTF-16 code units). The smallest possible QR Code version is automatically chosen for the output."""
-	seg = encode_text_to_segment(text)
-	return encode_segments([seg], ecl)
-
-
-def encode_text_to_segment(text):
-	"""Returns a QR segment representing the given Unicode text string."""
-	if not isinstance(text, str) and (sys.version_info[0] >= 3 or not isinstance(text, unicode)):
-		raise TypeError("Text string expected")
-	# Select the most efficient segment encoding automatically
-	if QrSegment.NUMERIC_REGEX.match(text) is not None:
-		return QrSegment.make_numeric(text)
-	elif QrSegment.ALPHANUMERIC_REGEX.match(text) is not None:
-		return QrSegment.make_alphanumeric(text)
-	else:
-		return QrSegment.make_bytes(text.encode("UTF-8"))
+	segs = QrSegment.make_segments(text)
+	return encode_segments(segs, ecl)
 
 
 def encode_binary(data, ecl):
@@ -659,6 +646,24 @@ class QrSegment(object):
 		return QrSegment(QrSegment.Mode.ALPHANUMERIC, len(text), bb.get_bits())
 	
 	
+	@staticmethod
+	def make_segments(text):
+		"""Returns a new mutable list of zero or more segments to represent the given Unicode text string.
+		The result may use various segment modes and switch modes to optimize the length of the bit stream."""
+		if not isinstance(text, str) and (sys.version_info[0] >= 3 or not isinstance(text, unicode)):
+			raise TypeError("Text string expected")
+		
+		# Select the most efficient segment encoding automatically
+		if text == "":
+			return []
+		elif QrSegment.NUMERIC_REGEX.match(text) is not None:
+			return [QrSegment.make_numeric(text)]
+		elif QrSegment.ALPHANUMERIC_REGEX.match(text) is not None:
+			return [QrSegment.make_alphanumeric(text)]
+		else:
+			return [QrSegment.make_bytes(text.encode("UTF-8"))]
+	
+	
 	# -- Constructor --
 	
 	def __init__(self, mode, numch, bitdata):