msb-public
/
QR-Code-generator
mirror of https://github.com/nayuki/QR-Code-generator
4
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Code Issues Projects Releases Wiki Activity

1. Rename, Extract Variable

Browse Source 
2. encodSegments() in QrCode
3. To improve readability of conditional expressions and variable names
pull/90/head
gerzees 5 years ago
parent 093bed5205
commit 580485c189
1 changed files with 33 additions and 30 deletions
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63
java/src/main/java/io/nayuki/qrcodegen/QrCode.java
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@ -134,8 +134,8 @@ public final class 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 {@link #encodeText(String,Ecc)}
* and {@link #encodeBinary(byte[],Ecc)}.</p>
* @param segs the segments to encode
* @param ecl the error correction level to use (not {@code null}) (boostable)
* @param segments the segments to encode
* @param errorCorrectionLevel the error correction level to use (not {@code null}) (boostable)
* @param minVersion the minimum allowed version of the QR Code (at least 1)
* @param maxVersion the maximum allowed version of the QR Code (at most 40)
* @param mask the mask number to use (between 0 and 7 (inclusive)), or &#x2212;1 for automatic mask
@ -147,61 +147,64 @@ public final class QrCode {
* @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);
Objects.requireNonNull(ecl);
if (!(MIN_VERSION <= minVersion && minVersion <= maxVersion && maxVersion <= MAX_VERSION) || mask < -1 || mask > 7)
public static QrCode encodeSegments(List<QrSegment> segments, Ecc errorCorrectionLevel, int minVersion, int maxVersion, int mask, boolean boostEcl) {
Objects.requireNonNull(segments);
Objects.requireNonNull(errorCorrectionLevel);
final boolean isVersionInRange = MIN_VERSION <= minVersion && minVersion <= maxVersion && maxVersion <= MAX_VERSION;
final boolean isMaskValid = mask < -1 || mask > 7;
if (!isVersionInRange || isMaskValid)
throw new IllegalArgumentException("Invalid value");
// Find the minimal version number to use
int version, dataUsedBits;
for (version = minVersion; ; version++) {
int dataCapacityBits = getNumDataCodewords(version, ecl) * 8; // Number of data bits available
dataUsedBits = QrSegment.getTotalBits(segs, version);
int dataCapacityBits = getNumDataCodewords(version, errorCorrectionLevel) * 8; // Number of data bits available
dataUsedBits = QrSegment.getTotalBits(segments, 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
String msg = "Segment too long";
String message = "Segment too long";
if (dataUsedBits != -1)
msg = String.format("Data length = %d bits, Max capacity = %d bits", dataUsedBits, dataCapacityBits);
throw new DataTooLongException(msg);
message = String.format("Data length = %d bits, Max capacity = %d bits", dataUsedBits, dataCapacityBits);
throw new DataTooLongException(message);
}
}
assert dataUsedBits != -1;
// Increase the error correction level while the data still fits in the current version number
for (Ecc newEcl : Ecc.values()) { // From low to high
if (boostEcl && dataUsedBits <= getNumDataCodewords(version, newEcl) * 8)
ecl = newEcl;
final boolean canIncreaseErrorCorrectionLevel = dataUsedBits <= getNumDataCodewords(version, newEcl) * 8;
if (boostEcl && canIncreaseErrorCorrectionLevel)
errorCorrectionLevel = newEcl;
}
// Concatenate all segments to create the data bit string
BitBuffer bb = new BitBuffer();
for (QrSegment seg : segs) {
bb.appendBits(seg.mode.modeBits, 4);
bb.appendBits(seg.numChars, seg.mode.numCharCountBits(version));
bb.appendData(seg.data);
BitBuffer bitBuffer = new BitBuffer();
for (QrSegment segment : segments) {
bitBuffer.appendBits(segment.mode.modeBits, 4);
bitBuffer.appendBits(segment.numChars, segment.mode.numCharCountBits(version));
bitBuffer.appendData(segment.data);
}
assert bb.bitLength() == dataUsedBits;
assert bitBuffer.bitLength() == dataUsedBits;
// Add terminator and pad up to a byte if applicable
int dataCapacityBits = getNumDataCodewords(version, ecl) * 8;
assert bb.bitLength() <= dataCapacityBits;
bb.appendBits(0, Math.min(4, dataCapacityBits - bb.bitLength()));
bb.appendBits(0, (8 - bb.bitLength() % 8) % 8);
assert bb.bitLength() % 8 == 0;
int dataCapacityBits = getNumDataCodewords(version, errorCorrectionLevel) * 8;
assert bitBuffer.bitLength() <= dataCapacityBits;
bitBuffer.appendBits(0, Math.min(4, dataCapacityBits - bitBuffer.bitLength()));
bitBuffer.appendBits(0, (8 - bitBuffer.bitLength() % 8) % 8);
assert bitBuffer.bitLength() % 8 == 0;
// Pad with alternating bytes until data capacity is reached
for (int padByte = 0xEC; bb.bitLength() < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
bb.appendBits(padByte, 8);
for (int padByte = 0xEC; bitBuffer.bitLength() < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
bitBuffer.appendBits(padByte, 8);
// Pack bits into bytes in big endian
byte[] dataCodewords = new byte[bb.bitLength() / 8];
for (int i = 0; i < bb.bitLength(); i++)
dataCodewords[i >>> 3] |= bb.getBit(i) << (7 - (i & 7));
byte[] dataCodewords = new byte[bitBuffer.bitLength() / 8];
for (int i = 0; i < bitBuffer.bitLength(); i++)
dataCodewords[i >>> 3] |= bitBuffer.getBit(i) << (7 - (i & 7));
// Create the QR Code object
return new QrCode(version, ecl, dataCodewords, mask);
return new QrCode(version, errorCorrectionLevel, dataCodewords, mask);
}
/*---- Instance fields ----*/

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