com.itextpdf.barcodes.qrcode.Encoder Maven / Gradle / Ivy
/*
This file is part of the iText (R) project.
Copyright (c) 1998-2024 Apryse Group NV
Authors: Apryse Software.
This program is offered under a commercial and under the AGPL license.
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AGPL licensing:
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see
* We recommend you to use QRCode.EC_LEVEL_L (the lowest level) for
* "getECLevel" since our primary use is to show QR code on desktop screens. We don't need very
* strong error correction for this purpose.
*
* Note that there is no way to encode bytes in MODE_KANJI. We might want to add EncodeWithMode()
* with which clients can specify the encoding mode. For now, we don't need the functionality.
*
* @param content String to encode
* @param ecLevel Error-correction level to use
* @param qrCode QR code to store the result in
* @throws WriterException
*/
public static void encode(String content, ErrorCorrectionLevel ecLevel, QRCode qrCode)
throws WriterException {
encode(content, ecLevel, null, qrCode);
}
/**
* Encode "bytes" with the error correction level "ecLevel". The encoding mode will be chosen
* internally by chooseMode(). On success, store the result in "qrCode".
*
* We recommend you to use QRCode.EC_LEVEL_L (the lowest level) for
* "getECLevel" since our primary use is to show QR code on desktop screens. We don't need very
* strong error correction for this purpose.
*
* Note that there is no way to encode bytes in MODE_KANJI. We might want to add EncodeWithMode()
* with which clients can specify the encoding mode. For now, we don't need the functionality.
*
* @param content String to encode
* @param ecLevel Error-correction level to use
* @param hints Optional Map containing encoding and suggested minimum version to use
* @param qrCode QR code to store the result in
* @throws WriterException
*/
public static void encode(String content, ErrorCorrectionLevel ecLevel, Map hints,
QRCode qrCode) throws WriterException {
String encoding = hints == null ? null : (String) hints.get(EncodeHintType.CHARACTER_SET);
if (encoding == null) {
encoding = DEFAULT_BYTE_MODE_ENCODING;
}
int desiredMinVersion = (hints == null || hints.get(EncodeHintType.MIN_VERSION_NR) == null) ? 1 : (int) hints.get(EncodeHintType.MIN_VERSION_NR);
//Check if desired level is within bounds of [1,40]
if (desiredMinVersion < 1) desiredMinVersion = 1;
if (desiredMinVersion > 40) desiredMinVersion = 40;
// Step 1: Choose the mode (encoding).
Mode mode = chooseMode(content, encoding);
// Step 2: Append "bytes" into "dataBits" in appropriate encoding.
BitVector dataBits = new BitVector();
appendBytes(content, mode, dataBits, encoding);
// Step 3: Initialize QR code that can contain "dataBits".
int numInputBytes = dataBits.sizeInBytes();
initQRCode(numInputBytes, ecLevel, desiredMinVersion, mode, qrCode);
// Step 4: Build another bit vector that contains header and data.
BitVector headerAndDataBits = new BitVector();
// Step 4.5: Append ECI message if applicable
if (mode == Mode.BYTE && !DEFAULT_BYTE_MODE_ENCODING.equals(encoding)) {
CharacterSetECI eci = CharacterSetECI.getCharacterSetECIByName(encoding);
if (eci != null) {
appendECI(eci, headerAndDataBits);
}
}
appendModeInfo(mode, headerAndDataBits);
int numLetters = mode.equals(Mode.BYTE) ? dataBits.sizeInBytes() : content.length();
appendLengthInfo(numLetters, qrCode.getVersion(), mode, headerAndDataBits);
headerAndDataBits.appendBitVector(dataBits);
// Step 5: Terminate the bits properly.
terminateBits(qrCode.getNumDataBytes(), headerAndDataBits);
// Step 6: Interleave data bits with error correction code.
BitVector finalBits = new BitVector();
interleaveWithECBytes(headerAndDataBits, qrCode.getNumTotalBytes(), qrCode.getNumDataBytes(),
qrCode.getNumRSBlocks(), finalBits);
// Step 7: Choose the mask pattern and set to "qrCode".
ByteMatrix matrix = new ByteMatrix(qrCode.getMatrixWidth(), qrCode.getMatrixWidth());
qrCode.setMaskPattern(chooseMaskPattern(finalBits, qrCode.getECLevel(), qrCode.getVersion(),
matrix));
// Step 8. Build the matrix and set it to "qrCode".
MatrixUtil.buildMatrix(finalBits, qrCode.getECLevel(), qrCode.getVersion(),
qrCode.getMaskPattern(), matrix);
qrCode.setMatrix(matrix);
// Step 9. Make sure we have a valid QR Code.
if (!qrCode.isValid()) {
throw new WriterException("Invalid QR code: " + qrCode.toString());
}
}
/**
* @return the code point of the table used in alphanumeric mode or
* -1 if there is no corresponding code in the table.
*/
static int getAlphanumericCode(int code) {
if (code < ALPHANUMERIC_TABLE.length) {
return ALPHANUMERIC_TABLE[code];
}
return -1;
}
/**
* Choose the best mode by examining the content.
*
* @param content content to examine
* @return mode to use
*/
public static Mode chooseMode(String content) {
return chooseMode(content, null);
}
/**
* Choose the best mode by examining the content. Note that 'encoding' is used as a hint;
* if it is Shift_JIS, and the input is only double-byte Kanji, then we return {@link Mode#KANJI}
*
* @param content content to examine
* @param encoding hint for the encoding to use
* @return mode to use
*/
public static Mode chooseMode(String content, String encoding) {
if ("Shift_JIS".equals(encoding)) {
// Choose Kanji mode if all input are double-byte characters
return isOnlyDoubleByteKanji(content) ? Mode.KANJI : Mode.BYTE;
}
boolean hasNumeric = false;
boolean hasAlphanumeric = false;
for (int i = 0; i < content.length(); ++i) {
char c = content.charAt(i);
if (c >= '0' && c <= '9') {
hasNumeric = true;
} else if (getAlphanumericCode(c) != -1) {
hasAlphanumeric = true;
} else {
return Mode.BYTE;
}
}
if (hasAlphanumeric) {
return Mode.ALPHANUMERIC;
} else if (hasNumeric) {
return Mode.NUMERIC;
}
return Mode.BYTE;
}
private static boolean isOnlyDoubleByteKanji(String content) {
byte[] bytes;
try {
bytes = content.getBytes("Shift_JIS");
} catch (UnsupportedEncodingException uee) {
return false;
}
int length = bytes.length;
if (length % 2 != 0) {
return false;
}
for (int i = 0; i < length; i += 2) {
int byte1 = bytes[i] & 0xFF;
if ((byte1 < 0x81 || byte1 > 0x9F) && (byte1 < 0xE0 || byte1 > 0xEB)) {
return false;
}
}
return true;
}
private static int chooseMaskPattern(BitVector bits, ErrorCorrectionLevel ecLevel, int version,
ByteMatrix matrix) throws WriterException {
// Lower penalty is better.
int minPenalty = Integer.MAX_VALUE;
int bestMaskPattern = -1;
// We try all mask patterns to choose the best one.
for (int maskPattern = 0; maskPattern < QRCode.NUM_MASK_PATTERNS; maskPattern++) {
MatrixUtil.buildMatrix(bits, ecLevel, version, maskPattern, matrix);
int penalty = calculateMaskPenalty(matrix);
if (penalty < minPenalty) {
minPenalty = penalty;
bestMaskPattern = maskPattern;
}
}
return bestMaskPattern;
}
/**
* Initialize "qrCode" according to "numInputBytes", "ecLevel", and "mode". On success,
* modify "qrCode".
*/
private static void initQRCode(int numInputBytes, ErrorCorrectionLevel ecLevel, int desiredMinVersion, Mode mode,
QRCode qrCode) throws WriterException {
qrCode.setECLevel(ecLevel);
qrCode.setMode(mode);
// In the following comments, we use numbers of Version 7-H.
for (int versionNum = desiredMinVersion; versionNum <= 40; versionNum++) {
Version version = Version.getVersionForNumber(versionNum);
// numBytes = 196
int numBytes = version.getTotalCodewords();
// getNumECBytes = 130
Version.ECBlocks ecBlocks = version.getECBlocksForLevel(ecLevel);
int numEcBytes = ecBlocks.getTotalECCodewords();
// getNumRSBlocks = 5
int numRSBlocks = ecBlocks.getNumBlocks();
// getNumDataBytes = 196 - 130 = 66
int numDataBytes = numBytes - numEcBytes;
// We want to choose the smallest version which can contain data of "numInputBytes" + some
// extra bits for the header (mode info and length info). The header can be three bytes
// (precisely 4 + 16 bits) at most. Hence we do +3 here.
if (numDataBytes >= numInputBytes + 3) {
// Yay, we found the proper rs block info!
qrCode.setVersion(versionNum);
qrCode.setNumTotalBytes(numBytes);
qrCode.setNumDataBytes(numDataBytes);
qrCode.setNumRSBlocks(numRSBlocks);
// getNumECBytes = 196 - 66 = 130
qrCode.setNumECBytes(numEcBytes);
// matrix width = 21 + 6 * 4 = 45
qrCode.setMatrixWidth(version.getDimensionForVersion());
return;
}
}
throw new WriterException("Cannot find proper rs block info (input data too big?)");
}
/**
* Terminate bits as described in 8.4.8 and 8.4.9 of JISX0510:2004 (p.24).
*/
static void terminateBits(int numDataBytes, BitVector bits) throws WriterException {
int capacity = numDataBytes << 3;
if (bits.size() > capacity) {
throw new WriterException("data bits cannot fit in the QR Code" + bits.size() + " > " +
capacity);
}
// Append termination bits. See 8.4.8 of JISX0510:2004 (p.24) for details.
for (int i = 0; i < 4 && bits.size() < capacity; ++i) {
bits.appendBit(0);
}
int numBitsInLastByte = bits.size() % 8;
// If the last byte isn't 8-bit aligned, we'll add padding bits.
if (numBitsInLastByte > 0) {
int numPaddingBits = 8 - numBitsInLastByte;
for (int i = 0; i < numPaddingBits; ++i) {
bits.appendBit(0);
}
}
// Should be 8-bit aligned here.
if (bits.size() % 8 != 0) {
throw new WriterException("Number of bits is not a multiple of 8");
}
// If we have more space, we'll fill the space with padding patterns defined in 8.4.9 (p.24).
int numPaddingBytes = numDataBytes - bits.sizeInBytes();
for (int i = 0; i < numPaddingBytes; ++i) {
if (i % 2 == 0) {
bits.appendBits(0xec, 8);
} else {
bits.appendBits(0x11, 8);
}
}
if (bits.size() != capacity) {
throw new WriterException("Bits size does not equal capacity");
}
}
/**
* Get number of data bytes and number of error correction bytes for block id "blockID". Store
* the result in "numDataBytesInBlock", and "numECBytesInBlock". See table 12 in 8.5.1 of
* JISX0510:2004 (p.30)
*/
static void getNumDataBytesAndNumECBytesForBlockID(int numTotalBytes, int numDataBytes,
int numRSBlocks, int blockID, int[] numDataBytesInBlock,
int[] numECBytesInBlock) throws WriterException {
if (blockID >= numRSBlocks) {
throw new WriterException("Block ID too large");
}
// numRsBlocksInGroup2 = 196 % 5 = 1
int numRsBlocksInGroup2 = numTotalBytes % numRSBlocks;
// numRsBlocksInGroup1 = 5 - 1 = 4
int numRsBlocksInGroup1 = numRSBlocks - numRsBlocksInGroup2;
// numTotalBytesInGroup1 = 196 / 5 = 39
int numTotalBytesInGroup1 = numTotalBytes / numRSBlocks;
// numTotalBytesInGroup2 = 39 + 1 = 40
int numTotalBytesInGroup2 = numTotalBytesInGroup1 + 1;
// numDataBytesInGroup1 = 66 / 5 = 13
int numDataBytesInGroup1 = numDataBytes / numRSBlocks;
// numDataBytesInGroup2 = 13 + 1 = 14
int numDataBytesInGroup2 = numDataBytesInGroup1 + 1;
// numEcBytesInGroup1 = 39 - 13 = 26
int numEcBytesInGroup1 = numTotalBytesInGroup1 - numDataBytesInGroup1;
// numEcBytesInGroup2 = 40 - 14 = 26
int numEcBytesInGroup2 = numTotalBytesInGroup2 - numDataBytesInGroup2;
// Sanity checks.
// 26 = 26
if (numEcBytesInGroup1 != numEcBytesInGroup2) {
throw new WriterException("EC bytes mismatch");
}
// 5 = 4 + 1.
if (numRSBlocks != numRsBlocksInGroup1 + numRsBlocksInGroup2) {
throw new WriterException("RS blocks mismatch");
}
// 196 = (13 + 26) * 4 + (14 + 26) * 1
if (numTotalBytes !=
((numDataBytesInGroup1 + numEcBytesInGroup1) *
numRsBlocksInGroup1) +
((numDataBytesInGroup2 + numEcBytesInGroup2) *
numRsBlocksInGroup2)) {
throw new WriterException("Total bytes mismatch");
}
if (blockID < numRsBlocksInGroup1) {
numDataBytesInBlock[0] = numDataBytesInGroup1;
numECBytesInBlock[0] = numEcBytesInGroup1;
} else {
numDataBytesInBlock[0] = numDataBytesInGroup2;
numECBytesInBlock[0] = numEcBytesInGroup2;
}
}
/**
* Interleave "bits" with corresponding error correction bytes. On success, store the result in
* "result". The interleave rule is complicated. See 8.6 of JISX0510:2004 (p.37) for details.
*/
static void interleaveWithECBytes(BitVector bits, int numTotalBytes,
int numDataBytes, int numRSBlocks, BitVector result) throws WriterException {
// "bits" must have "getNumDataBytes" bytes of data.
if (bits.sizeInBytes() != numDataBytes) {
throw new WriterException("Number of bits and data bytes does not match");
}
// Step 1. Divide data bytes into blocks and generate error correction bytes for them. We'll
// store the divided data bytes blocks and error correction bytes blocks into "blocks".
int dataBytesOffset = 0;
int maxNumDataBytes = 0;
int maxNumEcBytes = 0;
// Since, we know the number of reedsolmon blocks, we can initialize the vector with the number.
List blocks = new ArrayList<>(numRSBlocks);
for (int i = 0; i < numRSBlocks; ++i) {
int[] numDataBytesInBlock = new int[1];
int[] numEcBytesInBlock = new int[1];
getNumDataBytesAndNumECBytesForBlockID(
numTotalBytes, numDataBytes, numRSBlocks, i,
numDataBytesInBlock, numEcBytesInBlock);
ByteArray dataBytes = new ByteArray();
dataBytes.set(bits.getArray(), dataBytesOffset, numDataBytesInBlock[0]);
ByteArray ecBytes = generateECBytes(dataBytes, numEcBytesInBlock[0]);
blocks.add(new BlockPair(dataBytes, ecBytes));
maxNumDataBytes = Math.max(maxNumDataBytes, dataBytes.size());
maxNumEcBytes = Math.max(maxNumEcBytes, ecBytes.size());
dataBytesOffset += numDataBytesInBlock[0];
}
if (numDataBytes != dataBytesOffset) {
throw new WriterException("Data bytes does not match offset");
}
// First, place data blocks.
for (int i = 0; i < maxNumDataBytes; ++i) {
for (int j = 0; j < blocks.size(); ++j) {
ByteArray dataBytes = blocks.get(j).getDataBytes();
if (i < dataBytes.size()) {
result.appendBits(dataBytes.at(i), 8);
}
}
}
// Then, place error correction blocks.
for (int i = 0; i < maxNumEcBytes; ++i) {
for (int j = 0; j < blocks.size(); ++j) {
ByteArray ecBytes = blocks.get(j).getErrorCorrectionBytes();
if (i < ecBytes.size()) {
result.appendBits(ecBytes.at(i), 8);
}
}
}
// Should be same.
if (numTotalBytes != result.sizeInBytes()) {
throw new WriterException("Interleaving error: " + numTotalBytes + " and " +
result.sizeInBytes() + " differ.");
}
}
static ByteArray generateECBytes(ByteArray dataBytes, int numEcBytesInBlock) {
int numDataBytes = dataBytes.size();
int[] toEncode = new int[numDataBytes + numEcBytesInBlock];
for (int i = 0; i < numDataBytes; i++) {
toEncode[i] = dataBytes.at(i);
}
new ReedSolomonEncoder(GF256.QR_CODE_FIELD).encode(toEncode, numEcBytesInBlock);
ByteArray ecBytes = new ByteArray(numEcBytesInBlock);
for (int i = 0; i < numEcBytesInBlock; i++) {
ecBytes.set(i, toEncode[numDataBytes + i]);
}
return ecBytes;
}
/**
* Append mode info. On success, store the result in "bits".
*/
static void appendModeInfo(Mode mode, BitVector bits) {
bits.appendBits(mode.getBits(), 4);
}
/**
* Append length info. On success, store the result in "bits".
*/
static void appendLengthInfo(int numLetters, int version, Mode mode, BitVector bits)
throws WriterException {
int numBits = mode.getCharacterCountBits(Version.getVersionForNumber(version));
if (numLetters > ((1 << numBits) - 1)) {
throw new WriterException(numLetters + "is bigger than" + ((1 << numBits) - 1));
}
bits.appendBits(numLetters, numBits);
}
/**
* Append "bytes" in "mode" mode (encoding) into "bits". On success, store the result in "bits".
*/
static void appendBytes(String content, Mode mode, BitVector bits, String encoding)
throws WriterException {
if (mode.equals(Mode.NUMERIC)) {
appendNumericBytes(content, bits);
} else if (mode.equals(Mode.ALPHANUMERIC)) {
appendAlphanumericBytes(content, bits);
} else if (mode.equals(Mode.BYTE)) {
append8BitBytes(content, bits, encoding);
} else if (mode.equals(Mode.KANJI)) {
appendKanjiBytes(content, bits);
} else {
throw new WriterException("Invalid mode: " + mode);
}
}
static void appendNumericBytes(String content, BitVector bits) {
int length = content.length();
int i = 0;
while (i < length) {
int num1 = content.charAt(i) - '0';
if (i + 2 < length) {
// Encode three numeric letters in ten bits.
int num2 = content.charAt(i + 1) - '0';
int num3 = content.charAt(i + 2) - '0';
bits.appendBits(num1 * 100 + num2 * 10 + num3, 10);
i += 3;
} else if (i + 1 < length) {
// Encode two numeric letters in seven bits.
int num2 = content.charAt(i + 1) - '0';
bits.appendBits(num1 * 10 + num2, 7);
i += 2;
} else {
// Encode one numeric letter in four bits.
bits.appendBits(num1, 4);
i++;
}
}
}
static void appendAlphanumericBytes(String content, BitVector bits) throws WriterException {
int length = content.length();
int i = 0;
while (i < length) {
int code1 = getAlphanumericCode(content.charAt(i));
if (code1 == -1) {
throw new WriterException();
}
if (i + 1 < length) {
int code2 = getAlphanumericCode(content.charAt(i + 1));
if (code2 == -1) {
throw new WriterException();
}
// Encode two alphanumeric letters in 11 bits.
bits.appendBits(code1 * 45 + code2, 11);
i += 2;
} else {
// Encode one alphanumeric letter in six bits.
bits.appendBits(code1, 6);
i++;
}
}
}
static void append8BitBytes(String content, BitVector bits, String encoding)
throws WriterException {
byte[] bytes;
try {
bytes = content.getBytes(encoding);
} catch (UnsupportedEncodingException uee) {
throw new WriterException(uee.toString());
}
for (int i = 0; i < bytes.length; ++i) {
bits.appendBits(bytes[i], 8);
}
}
static void appendKanjiBytes(String content, BitVector bits) throws WriterException {
byte[] bytes;
try {
bytes = content.getBytes("Shift_JIS");
} catch (UnsupportedEncodingException uee) {
throw new WriterException(uee.toString());
}
int length = bytes.length;
for (int i = 0; i < length; i += 2) {
int byte1 = bytes[i] & 0xFF;
int byte2 = bytes[i + 1] & 0xFF;
int code = (byte1 << 8) | byte2;
int subtracted = -1;
if (code >= 0x8140 && code <= 0x9ffc) {
subtracted = code - 0x8140;
} else if (code >= 0xe040 && code <= 0xebbf) {
subtracted = code - 0xc140;
}
if (subtracted == -1) {
throw new WriterException("Invalid byte sequence");
}
int encoded = ((subtracted >> 8) * 0xc0) + (subtracted & 0xff);
bits.appendBits(encoded, 13);
}
}
private static void appendECI(CharacterSetECI eci, BitVector bits) {
bits.appendBits(Mode.ECI.getBits(), 4);
// This is correct for values up to 127, which is all we need now.
bits.appendBits(eci.getValue(), 8);
}
}