Updated QrCode.encodeSegments() to throw DataTooLongException - in Java, C++, Python, Rust code. Rust code also changes return types from Option to Result. Updated Java and Rust documentation.

cpp/QrCode.cpp

@@ -74,8 +74,16 @@ QrCode QrCode::encodeSegments(const vector<QrSegment> &segs, Ecc ecl,
 		dataUsedBits = QrSegment::getTotalBits(segs, version);
 		if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits)
 			break;  // This version number is found to be suitable
-		if (version >= maxVersion)  // All versions in the range could not fit the given data
+		if (version >= maxVersion) {  // All versions in the range could not fit the given data
-			throw std::length_error("Data too long");
+			std::ostringstream sb;
+			if (dataUsedBits == -1)
+				sb << "Segment too long";
+			else {
+				sb << "Data length = " << dataUsedBits << " bits, ";
+				sb << "Max capacity = " << dataCapacityBits << " bits";
+			}
+			throw data_too_long(sb.str());
+		}
 	}
 	if (dataUsedBits == -1)
 		throw std::logic_error("Assertion error");

java/io/nayuki/qrcodegen/QrCode.java

@@ -64,7 +64,7 @@ public final class QrCode {
 	 * @param ecl the error correction level to use (not {@code null}) (boostable)
 	 * @return a QR Code (not {@code null}) representing the text
 	 * @throws NullPointerException if the text or error correction level is {@code null}
-	 * @throws IllegalArgumentException if the text fails to fit in the
+	 * @throws DataTooLongException if the text fails to fit in the
 	 * largest version QR Code at the ECL, which means it is too long
 	 */
 	public static QrCode encodeText(String text, Ecc ecl) {
@@ -84,7 +84,7 @@ public final class QrCode {
 	 * @param ecl the error correction level to use (not {@code null}) (boostable)
 	 * @return a QR Code (not {@code null}) representing the data
 	 * @throws NullPointerException if the data or error correction level is {@code null}
-	 * @throws IllegalArgumentException if the data fails to fit in the
+	 * @throws DataTooLongException if the data fails to fit in the
 	 * largest version QR Code at the ECL, which means it is too long
 	 */
 	public static QrCode encodeBinary(byte[] data, Ecc ecl) {
@@ -109,7 +109,7 @@ public final class QrCode {
 	 * @param ecl the error correction level to use (not {@code null}) (boostable)
 	 * @return a QR Code (not {@code null}) representing the segments
 	 * @throws NullPointerException if the list of segments, any segment, or the error correction level is {@code null}
-	 * @throws IllegalArgumentException if the segments fail to fit in the
+	 * @throws DataTooLongException if the segments fail to fit in the
 	 * largest version QR Code at the ECL, which means they are too long
 	 */
 	public static QrCode encodeSegments(List<QrSegment> segs, Ecc ecl) {
@@ -137,8 +137,9 @@ public final class QrCode {
 	 * @return a QR Code (not {@code null}) representing the segments
 	 * @throws NullPointerException if the list of segments, any segment, or the error correction level is {@code null}
 	 * @throws IllegalArgumentException if 1 &#x2264; minVersion &#x2264; maxVersion &#x2264; 40
-	 * or &#x2212;1 &#x2264; mask &#x2264; 7 is violated; or if the segments fail to
+	 * or &#x2212;1 &#x2264; mask &#x2264; 7 is violated
-	 * fit in the maxVersion QR Code at the ECL, which means they are too long
+	 * @throws DataTooLongException if the segments fail to fit in
+	 * the maxVersion QR Code at the ECL, which means they are too long
 	 */
 	public static QrCode encodeSegments(List<QrSegment> segs, Ecc ecl, int minVersion, int maxVersion, int mask, boolean boostEcl) {
 		Objects.requireNonNull(segs);
@@ -153,8 +154,12 @@ public final class QrCode {
 			dataUsedBits = QrSegment.getTotalBits(segs, version);
 			if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits)
 				break;  // This version number is found to be suitable
-			if (version >= maxVersion)  // All versions in the range could not fit the given data
+			if (version >= maxVersion) {  // All versions in the range could not fit the given data
-				throw new IllegalArgumentException("Data too long");
+				String msg = "Segment too long";
+				if (dataUsedBits != -1)
+					msg = String.format("Data length = %d bits, Max capacity = %d bits", dataUsedBits, dataCapacityBits);
+				throw new DataTooLongException(msg);
+			}
 		}
 		assert dataUsedBits != -1;
 		

python/qrcodegen.py

@@ -124,7 +124,10 @@ class QrCode(object):
 			if datausedbits is not None and datausedbits <= datacapacitybits:
 				break  # This version number is found to be suitable
 			if version >= maxversion:  # All versions in the range could not fit the given data
-				raise ValueError("Data too long")
+				msg = "Segment too long"
+				if datausedbits is not None:
+					msg = "Data length = {} bits, Max capacity = {} bits".format(datausedbits, datacapacitybits)
+				raise DataTooLongError(msg)
 		if datausedbits is None:
 			raise AssertionError()
 		

rust/src/lib.rs

@@ -146,9 +146,9 @@ impl QrCode {
 	/// QR Code version is automatically chosen for the output. The ECC level of the result may be higher than
 	/// the ecl argument if it can be done without increasing the version.
 	/// 
-	/// Returns a wrapped `QrCode` if successful, or `None` if the
+	/// Returns a wrapped `QrCode` if successful, or `Err` if the
 	/// data is too long to fit in any version at the given ECC level.
-	pub fn encode_text(text: &str, ecl: QrCodeEcc) -> Option<Self> {
+	pub fn encode_text(text: &str, ecl: QrCodeEcc) -> Result<Self,DataTooLong> {
 		let chrs: Vec<char> = text.chars().collect();
 		let segs: Vec<QrSegment> = QrSegment::make_segments(&chrs);
 		QrCode::encode_segments(&segs, ecl)
@@ -161,9 +161,9 @@ impl QrCode {
 	/// bytes allowed is 2953. The smallest possible QR Code version is automatically chosen for the output.
 	/// The ECC level of the result may be higher than the ecl argument if it can be done without increasing the version.
 	/// 
-	/// Returns a wrapped `QrCode` if successful, or `None` if the
+	/// Returns a wrapped `QrCode` if successful, or `Err` if the
 	/// data is too long to fit in any version at the given ECC level.
-	pub fn encode_binary(data: &[u8], ecl: QrCodeEcc) -> Option<Self> {
+	pub fn encode_binary(data: &[u8], ecl: QrCodeEcc) -> Result<Self,DataTooLong> {
 		let segs: Vec<QrSegment> = vec![QrSegment::make_bytes(data)];
 		QrCode::encode_segments(&segs, ecl)
 	}
@@ -180,9 +180,9 @@ impl QrCode {
 	/// between modes (such as alphanumeric and byte) to encode text in less space.
 	/// This is a mid-level API; the high-level API is `encode_text()` and `encode_binary()`.
 	/// 
-	/// Returns a wrapped `QrCode` if successful, or `None` if the
+	/// Returns a wrapped `QrCode` if successful, or `Err` if the
 	/// data is too long to fit in any version at the given ECC level.
-	pub fn encode_segments(segs: &[QrSegment], ecl: QrCodeEcc) -> Option<Self> {
+	pub fn encode_segments(segs: &[QrSegment], ecl: QrCodeEcc) -> Result<Self,DataTooLong> {
 		QrCode::encode_segments_advanced(segs, ecl, QrCode_MIN_VERSION, QrCode_MAX_VERSION, None, true)
 	}
 	
@@ -199,10 +199,10 @@ impl QrCode {
 	/// between modes (such as alphanumeric and byte) to encode text in less space.
 	/// This is a mid-level API; the high-level API is `encode_text()` and `encode_binary()`.
 	/// 
-	/// Returns a wrapped `QrCode` if successful, or `None` if the data is too
+	/// Returns a wrapped `QrCode` if successful, or `Err` if the data is too
 	/// long to fit in any version in the given range at the given ECC level.
 	pub fn encode_segments_advanced(segs: &[QrSegment], mut ecl: QrCodeEcc,
-			minversion: Version, maxversion: Version, mask: Option<Mask>, boostecl: bool) -> Option<Self> {
+			minversion: Version, maxversion: Version, mask: Option<Mask>, boostecl: bool) -> Result<Self,DataTooLong> {
 		assert!(minversion.value() <= maxversion.value(), "Invalid value");
 		
 		// Find the minimal version number to use
@@ -211,14 +211,20 @@ impl QrCode {
 		loop {
 			// Number of data bits available
 			let datacapacitybits: usize = QrCode::get_num_data_codewords(version, ecl) * 8;
-			if let Some(n) = QrSegment::get_total_bits(segs, version) {
+			let dataused: Option<usize> = QrSegment::get_total_bits(segs, version);
+			if let Some(n) = dataused {
 				if n <= datacapacitybits {
 					datausedbits = n;
 					break;  // This version number is found to be suitable
 				}
 			}
 			if version.value() >= maxversion.value() {  // All versions in the range could not fit the given data
-				return None;
+				let msg: String = match dataused {
+					None => String::from("Segment too long"),
+					Some(n) => format!("Data length = {} bits, Max capacity = {} bits",
+						n, datacapacitybits),
+				};
+				return Err(DataTooLong(msg));
 			}
 			version = Version::new(version.value() + 1);
 		}
@@ -263,7 +269,7 @@ impl QrCode {
 		}
 		
 		// Create the QR Code object
-		Some(QrCode::encode_codewords(version, ecl, &datacodewords, mask))
+		Ok(QrCode::encode_codewords(version, ecl, &datacodewords, mask))
 	}