| /* |
| * QR Code generator library (C++) |
| * |
| * Copyright (c) Project Nayuki. (MIT License) |
| * https://www.nayuki.io/page/qr-code-generator-library |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy of |
| * this software and associated documentation files (the "Software"), to deal in |
| * the Software without restriction, including without limitation the rights to |
| * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of |
| * the Software, and to permit persons to whom the Software is furnished to do so, |
| * subject to the following conditions: |
| * - The above copyright notice and this permission notice shall be included in |
| * all copies or substantial portions of the Software. |
| * - The Software is provided "as is", without warranty of any kind, express or |
| * implied, including but not limited to the warranties of merchantability, |
| * fitness for a particular purpose and noninfringement. In no event shall the |
| * authors or copyright holders be liable for any claim, damages or other |
| * liability, whether in an action of contract, tort or otherwise, arising from, |
| * out of or in connection with the Software or the use or other dealings in the |
| * Software. |
| */ |
| |
| #include <algorithm> |
| #include <climits> |
| #include <cstddef> |
| #include <cstdlib> |
| #include <sstream> |
| #include <utility> |
| #include "BitBuffer.hpp" |
| #include "QrCode.hpp" |
| |
| #include "starboard/log.h" |
| |
| #define throw SB_CHECK(false) << |
| |
| using std::int8_t; |
| using std::uint8_t; |
| using std::size_t; |
| using std::vector; |
| |
| |
| namespace qrcodegen { |
| |
| int QrCode::getFormatBits(Ecc ecl) { |
| switch (ecl) { |
| case Ecc::LOW : return 1; |
| case Ecc::MEDIUM : return 0; |
| case Ecc::QUARTILE: return 3; |
| case Ecc::HIGH : return 2; |
| default: throw "Assertion error"; |
| } |
| return 0; |
| } |
| |
| |
| QrCode QrCode::encodeText(const char *text, Ecc ecl) { |
| vector<QrSegment> segs = QrSegment::makeSegments(text); |
| return encodeSegments(segs, ecl); |
| } |
| |
| |
| QrCode QrCode::encodeBinary(const vector<uint8_t> &data, Ecc ecl) { |
| vector<QrSegment> segs{QrSegment::makeBytes(data)}; |
| return encodeSegments(segs, ecl); |
| } |
| |
| |
| QrCode QrCode::encodeSegments(const vector<QrSegment> &segs, Ecc ecl, |
| int minVersion, int maxVersion, int mask, bool boostEcl) { |
| if (!(MIN_VERSION <= minVersion && minVersion <= maxVersion && maxVersion <= MAX_VERSION) || mask < -1 || mask > 7) |
| throw "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); |
| 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 |
| 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 |
| for (Ecc newEcl : vector<Ecc>{Ecc::MEDIUM, Ecc::QUARTILE, Ecc::HIGH}) { |
| if (boostEcl && dataUsedBits <= getNumDataCodewords(version, newEcl) * 8) |
| ecl = newEcl; |
| } |
| |
| // Create the data bit string by concatenating all segments |
| size_t dataCapacityBits = getNumDataCodewords(version, ecl) * 8; |
| BitBuffer bb; |
| for (const QrSegment &seg : segs) { |
| bb.appendBits(seg.getMode().getModeBits(), 4); |
| bb.appendBits(seg.getNumChars(), seg.getMode().numCharCountBits(version)); |
| bb.insert(bb.end(), seg.getData().begin(), seg.getData().end()); |
| } |
| |
| // Add terminator and pad up to a byte if applicable |
| bb.appendBits(0, std::min<size_t>(4, dataCapacityBits - bb.size())); |
| bb.appendBits(0, (8 - bb.size() % 8) % 8); |
| |
| // Pad with alternate bytes until data capacity is reached |
| for (uint8_t padByte = 0xEC; bb.size() < dataCapacityBits; padByte ^= 0xEC ^ 0x11) |
| bb.appendBits(padByte, 8); |
| if (bb.size() % 8 != 0) |
| throw "Assertion error"; |
| |
| // Create the QR Code symbol |
| return QrCode(version, ecl, bb.getBytes(), mask); |
| } |
| |
| |
| QrCode::QrCode(int ver, Ecc ecl, const vector<uint8_t> &dataCodewords, int mask) : |
| // Initialize fields |
| version(ver), |
| size(MIN_VERSION <= ver && ver <= MAX_VERSION ? ver * 4 + 17 : -1), // Avoid signed overflow undefined behavior |
| errorCorrectionLevel(ecl), |
| modules(size, vector<bool>(size)), // Entirely white grid |
| isFunction(size, vector<bool>(size)) { |
| |
| // Check arguments |
| if (ver < MIN_VERSION || ver > MAX_VERSION || mask < -1 || mask > 7) |
| throw "Value out of range"; |
| |
| // Draw function patterns, draw all codewords, do masking |
| drawFunctionPatterns(); |
| const vector<uint8_t> allCodewords = appendErrorCorrection(dataCodewords); |
| drawCodewords(allCodewords); |
| this->mask = handleConstructorMasking(mask); |
| } |
| |
| |
| int QrCode::getVersion() const { |
| return version; |
| } |
| |
| |
| int QrCode::getSize() const { |
| return size; |
| } |
| |
| |
| QrCode::Ecc QrCode::getErrorCorrectionLevel() const { |
| return errorCorrectionLevel; |
| } |
| |
| |
| int QrCode::getMask() const { |
| return mask; |
| } |
| |
| |
| bool QrCode::getModule(int x, int y) const { |
| return 0 <= x && x < size && 0 <= y && y < size && module(x, y); |
| } |
| |
| |
| std::string QrCode::toSvgString(int border) const { |
| if (border < 0) |
| throw "Border must be non-negative"; |
| if (border > INT_MAX / 2 || border * 2 > INT_MAX - size) |
| throw "Border too large"; |
| |
| std::ostringstream sb; |
| sb << "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"; |
| sb << "<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\" \"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\">\n"; |
| sb << "<svg xmlns=\"http://www.w3.org/2000/svg\" version=\"1.1\" viewBox=\"0 0 "; |
| sb << (size + border * 2) << " " << (size + border * 2) << "\" stroke=\"none\">\n"; |
| sb << "\t<rect width=\"100%\" height=\"100%\" fill=\"#FFFFFF\"/>\n"; |
| sb << "\t<path d=\""; |
| bool head = true; |
| for (int y = -border; y < size + border; y++) { |
| for (int x = -border; x < size + border; x++) { |
| if (getModule(x, y)) { |
| if (head) |
| head = false; |
| else |
| sb << " "; |
| sb << "M" << (x + border) << "," << (y + border) << "h1v1h-1z"; |
| } |
| } |
| } |
| sb << "\" fill=\"#000000\"/>\n"; |
| sb << "</svg>\n"; |
| return sb.str(); |
| } |
| |
| |
| void QrCode::drawFunctionPatterns() { |
| // Draw horizontal and vertical timing patterns |
| for (int i = 0; i < size; i++) { |
| setFunctionModule(6, i, i % 2 == 0); |
| setFunctionModule(i, 6, i % 2 == 0); |
| } |
| |
| // Draw 3 finder patterns (all corners except bottom right; overwrites some timing modules) |
| drawFinderPattern(3, 3); |
| drawFinderPattern(size - 4, 3); |
| drawFinderPattern(3, size - 4); |
| |
| // Draw numerous alignment patterns |
| const vector<int> alignPatPos = getAlignmentPatternPositions(version); |
| int numAlign = alignPatPos.size(); |
| for (int i = 0; i < numAlign; i++) { |
| for (int j = 0; j < numAlign; j++) { |
| if ((i == 0 && j == 0) || (i == 0 && j == numAlign - 1) || (i == numAlign - 1 && j == 0)) |
| continue; // Skip the three finder corners |
| else |
| drawAlignmentPattern(alignPatPos.at(i), alignPatPos.at(j)); |
| } |
| } |
| |
| // Draw configuration data |
| drawFormatBits(0); // Dummy mask value; overwritten later in the constructor |
| drawVersion(); |
| } |
| |
| |
| void QrCode::drawFormatBits(int mask) { |
| // Calculate error correction code and pack bits |
| int data = getFormatBits(errorCorrectionLevel) << 3 | mask; // errCorrLvl is uint2, mask is uint3 |
| int rem = data; |
| for (int i = 0; i < 10; i++) |
| rem = (rem << 1) ^ ((rem >> 9) * 0x537); |
| data = data << 10 | rem; |
| data ^= 0x5412; // uint15 |
| if (data >> 15 != 0) |
| throw "Assertion error"; |
| |
| // Draw first copy |
| for (int i = 0; i <= 5; i++) |
| setFunctionModule(8, i, ((data >> i) & 1) != 0); |
| setFunctionModule(8, 7, ((data >> 6) & 1) != 0); |
| setFunctionModule(8, 8, ((data >> 7) & 1) != 0); |
| setFunctionModule(7, 8, ((data >> 8) & 1) != 0); |
| for (int i = 9; i < 15; i++) |
| setFunctionModule(14 - i, 8, ((data >> i) & 1) != 0); |
| |
| // Draw second copy |
| for (int i = 0; i <= 7; i++) |
| setFunctionModule(size - 1 - i, 8, ((data >> i) & 1) != 0); |
| for (int i = 8; i < 15; i++) |
| setFunctionModule(8, size - 15 + i, ((data >> i) & 1) != 0); |
| setFunctionModule(8, size - 8, true); |
| } |
| |
| |
| void QrCode::drawVersion() { |
| if (version < 7) |
| return; |
| |
| // Calculate error correction code and pack bits |
| int rem = version; // version is uint6, in the range [7, 40] |
| for (int i = 0; i < 12; i++) |
| rem = (rem << 1) ^ ((rem >> 11) * 0x1F25); |
| long data = (long)version << 12 | rem; // uint18 |
| if (data >> 18 != 0) |
| throw "Assertion error"; |
| |
| // Draw two copies |
| for (int i = 0; i < 18; i++) { |
| bool bit = ((data >> i) & 1) != 0; |
| int a = size - 11 + i % 3, b = i / 3; |
| setFunctionModule(a, b, bit); |
| setFunctionModule(b, a, bit); |
| } |
| } |
| |
| |
| void QrCode::drawFinderPattern(int x, int y) { |
| for (int i = -4; i <= 4; i++) { |
| for (int j = -4; j <= 4; j++) { |
| int dist = std::max(std::abs(i), std::abs(j)); // Chebyshev/infinity norm |
| int xx = x + j, yy = y + i; |
| if (0 <= xx && xx < size && 0 <= yy && yy < size) |
| setFunctionModule(xx, yy, dist != 2 && dist != 4); |
| } |
| } |
| } |
| |
| |
| void QrCode::drawAlignmentPattern(int x, int y) { |
| for (int i = -2; i <= 2; i++) { |
| for (int j = -2; j <= 2; j++) |
| setFunctionModule(x + j, y + i, std::max(std::abs(i), std::abs(j)) != 1); |
| } |
| } |
| |
| |
| void QrCode::setFunctionModule(int x, int y, bool isBlack) { |
| modules.at(y).at(x) = isBlack; |
| isFunction.at(y).at(x) = true; |
| } |
| |
| |
| bool QrCode::module(int x, int y) const { |
| return modules.at(y).at(x); |
| } |
| |
| |
| vector<uint8_t> QrCode::appendErrorCorrection(const vector<uint8_t> &data) const { |
| if (data.size() != static_cast<unsigned int>(getNumDataCodewords(version, errorCorrectionLevel))) |
| throw "Invalid argument"; |
| |
| // Calculate parameter numbers |
| int numBlocks = NUM_ERROR_CORRECTION_BLOCKS[static_cast<int>(errorCorrectionLevel)][version]; |
| int blockEccLen = ECC_CODEWORDS_PER_BLOCK[static_cast<int>(errorCorrectionLevel)][version]; |
| int rawCodewords = getNumRawDataModules(version) / 8; |
| int numShortBlocks = numBlocks - rawCodewords % numBlocks; |
| int shortBlockLen = rawCodewords / numBlocks; |
| |
| // Split data into blocks and append ECC to each block |
| vector<vector<uint8_t> > blocks; |
| const ReedSolomonGenerator rs(blockEccLen); |
| for (int i = 0, k = 0; i < numBlocks; i++) { |
| vector<uint8_t> dat(data.cbegin() + k, data.cbegin() + (k + shortBlockLen - blockEccLen + (i < numShortBlocks ? 0 : 1))); |
| k += dat.size(); |
| const vector<uint8_t> ecc = rs.getRemainder(dat); |
| if (i < numShortBlocks) |
| dat.push_back(0); |
| dat.insert(dat.end(), ecc.cbegin(), ecc.cend()); |
| blocks.push_back(std::move(dat)); |
| } |
| |
| // Interleave (not concatenate) the bytes from every block into a single sequence |
| vector<uint8_t> result; |
| for (int i = 0; static_cast<unsigned int>(i) < blocks.at(0).size(); i++) { |
| for (int j = 0; static_cast<unsigned int>(j) < blocks.size(); j++) { |
| // Skip the padding byte in short blocks |
| if (i != shortBlockLen - blockEccLen || j >= numShortBlocks) |
| result.push_back(blocks.at(j).at(i)); |
| } |
| } |
| if (result.size() != static_cast<unsigned int>(rawCodewords)) |
| throw "Assertion error"; |
| return result; |
| } |
| |
| |
| void QrCode::drawCodewords(const vector<uint8_t> &data) { |
| if (data.size() != static_cast<unsigned int>(getNumRawDataModules(version) / 8)) |
| throw "Invalid argument"; |
| |
| size_t i = 0; // Bit index into the data |
| // Do the funny zigzag scan |
| for (int right = size - 1; right >= 1; right -= 2) { // Index of right column in each column pair |
| if (right == 6) |
| right = 5; |
| for (int vert = 0; vert < size; vert++) { // Vertical counter |
| for (int j = 0; j < 2; j++) { |
| int x = right - j; // Actual x coordinate |
| bool upward = ((right + 1) & 2) == 0; |
| int y = upward ? size - 1 - vert : vert; // Actual y coordinate |
| if (!isFunction.at(y).at(x) && i < data.size() * 8) { |
| modules.at(y).at(x) = ((data.at(i >> 3) >> (7 - (i & 7))) & 1) != 0; |
| i++; |
| } |
| // If there are any remainder bits (0 to 7), they are already |
| // set to 0/false/white when the grid of modules was initialized |
| } |
| } |
| } |
| if (static_cast<unsigned int>(i) != data.size() * 8) |
| throw "Assertion error"; |
| } |
| |
| |
| void QrCode::applyMask(int mask) { |
| if (mask < 0 || mask > 7) |
| throw "Mask value out of range"; |
| for (int y = 0; y < size; y++) { |
| for (int x = 0; x < size; x++) { |
| bool invert; |
| switch (mask) { |
| case 0: invert = (x + y) % 2 == 0; break; |
| case 1: invert = y % 2 == 0; break; |
| case 2: invert = x % 3 == 0; break; |
| case 3: invert = (x + y) % 3 == 0; break; |
| case 4: invert = (x / 3 + y / 2) % 2 == 0; break; |
| case 5: invert = x * y % 2 + x * y % 3 == 0; break; |
| case 6: invert = (x * y % 2 + x * y % 3) % 2 == 0; break; |
| case 7: invert = ((x + y) % 2 + x * y % 3) % 2 == 0; break; |
| default: throw "Assertion error"; |
| } |
| modules.at(y).at(x) = modules.at(y).at(x) ^ (invert & !isFunction.at(y).at(x)); |
| } |
| } |
| } |
| |
| |
| int QrCode::handleConstructorMasking(int mask) { |
| if (mask == -1) { // Automatically choose best mask |
| long minPenalty = LONG_MAX; |
| for (int i = 0; i < 8; i++) { |
| drawFormatBits(i); |
| applyMask(i); |
| long penalty = getPenaltyScore(); |
| if (penalty < minPenalty) { |
| mask = i; |
| minPenalty = penalty; |
| } |
| applyMask(i); // Undoes the mask due to XOR |
| } |
| } |
| if (mask < 0 || mask > 7) |
| throw "Assertion error"; |
| drawFormatBits(mask); // Overwrite old format bits |
| applyMask(mask); // Apply the final choice of mask |
| return mask; // The caller shall assign this value to the final-declared field |
| } |
| |
| |
| long QrCode::getPenaltyScore() const { |
| long result = 0; |
| |
| // Adjacent modules in row having same color |
| for (int y = 0; y < size; y++) { |
| bool colorX = false; |
| for (int x = 0, runX = -1; x < size; x++) { |
| if (x == 0 || module(x, y) != colorX) { |
| colorX = module(x, y); |
| runX = 1; |
| } else { |
| runX++; |
| if (runX == 5) |
| result += PENALTY_N1; |
| else if (runX > 5) |
| result++; |
| } |
| } |
| } |
| // Adjacent modules in column having same color |
| for (int x = 0; x < size; x++) { |
| bool colorY = false; |
| for (int y = 0, runY = -1; y < size; y++) { |
| if (y == 0 || module(x, y) != colorY) { |
| colorY = module(x, y); |
| runY = 1; |
| } else { |
| runY++; |
| if (runY == 5) |
| result += PENALTY_N1; |
| else if (runY > 5) |
| result++; |
| } |
| } |
| } |
| |
| // 2*2 blocks of modules having same color |
| for (int y = 0; y < size - 1; y++) { |
| for (int x = 0; x < size - 1; x++) { |
| bool color = module(x, y); |
| if ( color == module(x + 1, y) && |
| color == module(x, y + 1) && |
| color == module(x + 1, y + 1)) |
| result += PENALTY_N2; |
| } |
| } |
| |
| // Finder-like pattern in rows |
| for (int y = 0; y < size; y++) { |
| for (int x = 0, bits = 0; x < size; x++) { |
| bits = ((bits << 1) & 0x7FF) | (module(x, y) ? 1 : 0); |
| if (x >= 10 && (bits == 0x05D || bits == 0x5D0)) // Needs 11 bits accumulated |
| result += PENALTY_N3; |
| } |
| } |
| // Finder-like pattern in columns |
| for (int x = 0; x < size; x++) { |
| for (int y = 0, bits = 0; y < size; y++) { |
| bits = ((bits << 1) & 0x7FF) | (module(x, y) ? 1 : 0); |
| if (y >= 10 && (bits == 0x05D || bits == 0x5D0)) // Needs 11 bits accumulated |
| result += PENALTY_N3; |
| } |
| } |
| |
| // Balance of black and white modules |
| int black = 0; |
| for (const vector<bool> &row : modules) { |
| for (bool color : row) { |
| if (color) |
| black++; |
| } |
| } |
| int total = size * size; |
| // Find smallest k such that (45-5k)% <= dark/total <= (55+5k)% |
| for (int k = 0; black*20L < (9L-k)*total || black*20L > (11L+k)*total; k++) |
| result += PENALTY_N4; |
| return result; |
| } |
| |
| |
| vector<int> QrCode::getAlignmentPatternPositions(int ver) { |
| if (ver < MIN_VERSION || ver > MAX_VERSION) { |
| throw "Version number out of range"; |
| return vector<int>(); |
| } else if (ver == 1) { |
| return vector<int>(); |
| } else { |
| int numAlign = ver / 7 + 2; |
| int step; |
| if (ver != 32) { |
| // ceil((size - 13) / (2*numAlign - 2)) * 2 |
| step = (ver * 4 + numAlign * 2 + 1) / (2 * numAlign - 2) * 2; |
| } else // C-C-C-Combo breaker! |
| step = 26; |
| |
| vector<int> result; |
| for (int i = 0, pos = ver * 4 + 10; i < numAlign - 1; i++, pos -= step) |
| result.insert(result.begin(), pos); |
| result.insert(result.begin(), 6); |
| return result; |
| } |
| } |
| |
| |
| int QrCode::getNumRawDataModules(int ver) { |
| if (ver < MIN_VERSION || ver > MAX_VERSION) |
| throw "Version number out of range"; |
| int result = (16 * ver + 128) * ver + 64; |
| if (ver >= 2) { |
| int numAlign = ver / 7 + 2; |
| result -= (25 * numAlign - 10) * numAlign - 55; |
| if (ver >= 7) |
| result -= 18 * 2; // Subtract version information |
| } |
| return result; |
| } |
| |
| |
| int QrCode::getNumDataCodewords(int ver, Ecc ecl) { |
| if (ver < MIN_VERSION || ver > MAX_VERSION) |
| throw "Version number out of range"; |
| return getNumRawDataModules(ver) / 8 |
| - ECC_CODEWORDS_PER_BLOCK[static_cast<int>(ecl)][ver] |
| * NUM_ERROR_CORRECTION_BLOCKS[static_cast<int>(ecl)][ver]; |
| } |
| |
| |
| /*---- Tables of constants ----*/ |
| |
| const int QrCode::PENALTY_N1 = 3; |
| const int QrCode::PENALTY_N2 = 3; |
| const int QrCode::PENALTY_N3 = 40; |
| const int QrCode::PENALTY_N4 = 10; |
| |
| |
| const int8_t QrCode::ECC_CODEWORDS_PER_BLOCK[4][41] = { |
| // Version: (note that index 0 is for padding, and is set to an illegal value) |
| //0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 Error correction level |
| {-1, 7, 10, 15, 20, 26, 18, 20, 24, 30, 18, 20, 24, 26, 30, 22, 24, 28, 30, 28, 28, 28, 28, 30, 30, 26, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30}, // Low |
| {-1, 10, 16, 26, 18, 24, 16, 18, 22, 22, 26, 30, 22, 22, 24, 24, 28, 28, 26, 26, 26, 26, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28}, // Medium |
| {-1, 13, 22, 18, 26, 18, 24, 18, 22, 20, 24, 28, 26, 24, 20, 30, 24, 28, 28, 26, 30, 28, 30, 30, 30, 30, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30}, // Quartile |
| {-1, 17, 28, 22, 16, 22, 28, 26, 26, 24, 28, 24, 28, 22, 24, 24, 30, 28, 28, 26, 28, 30, 24, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30}, // High |
| }; |
| |
| const int8_t QrCode::NUM_ERROR_CORRECTION_BLOCKS[4][41] = { |
| // Version: (note that index 0 is for padding, and is set to an illegal value) |
| //0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 Error correction level |
| {-1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 4, 4, 4, 4, 4, 6, 6, 6, 6, 7, 8, 8, 9, 9, 10, 12, 12, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 21, 22, 24, 25}, // Low |
| {-1, 1, 1, 1, 2, 2, 4, 4, 4, 5, 5, 5, 8, 9, 9, 10, 10, 11, 13, 14, 16, 17, 17, 18, 20, 21, 23, 25, 26, 28, 29, 31, 33, 35, 37, 38, 40, 43, 45, 47, 49}, // Medium |
| {-1, 1, 1, 2, 2, 4, 4, 6, 6, 8, 8, 8, 10, 12, 16, 12, 17, 16, 18, 21, 20, 23, 23, 25, 27, 29, 34, 34, 35, 38, 40, 43, 45, 48, 51, 53, 56, 59, 62, 65, 68}, // Quartile |
| {-1, 1, 1, 2, 4, 4, 4, 5, 6, 8, 8, 11, 11, 16, 16, 18, 16, 19, 21, 25, 25, 25, 34, 30, 32, 35, 37, 40, 42, 45, 48, 51, 54, 57, 60, 63, 66, 70, 74, 77, 81}, // High |
| }; |
| |
| |
| QrCode::ReedSolomonGenerator::ReedSolomonGenerator(int degree) : |
| coefficients() { |
| if (degree < 1 || degree > 255) |
| throw "Degree out of range"; |
| |
| // Start with the monomial x^0 |
| coefficients.resize(degree); |
| coefficients.at(degree - 1) = 1; |
| |
| // Compute the product polynomial (x - r^0) * (x - r^1) * (x - r^2) * ... * (x - r^{degree-1}), |
| // drop the highest term, and store the rest of the coefficients in order of descending powers. |
| // Note that r = 0x02, which is a generator element of this field GF(2^8/0x11D). |
| uint8_t root = 1; |
| for (int i = 0; i < degree; i++) { |
| // Multiply the current product by (x - r^i) |
| for (size_t j = 0; j < coefficients.size(); j++) { |
| coefficients.at(j) = multiply(coefficients.at(j), root); |
| if (j + 1 < coefficients.size()) |
| coefficients.at(j) ^= coefficients.at(j + 1); |
| } |
| root = multiply(root, 0x02); |
| } |
| } |
| |
| |
| vector<uint8_t> QrCode::ReedSolomonGenerator::getRemainder(const vector<uint8_t> &data) const { |
| // Compute the remainder by performing polynomial division |
| vector<uint8_t> result(coefficients.size()); |
| for (uint8_t b : data) { |
| uint8_t factor = b ^ result.at(0); |
| result.erase(result.begin()); |
| result.push_back(0); |
| for (size_t j = 0; j < result.size(); j++) |
| result.at(j) ^= multiply(coefficients.at(j), factor); |
| } |
| return result; |
| } |
| |
| |
| uint8_t QrCode::ReedSolomonGenerator::multiply(uint8_t x, uint8_t y) { |
| // Russian peasant multiplication |
| int z = 0; |
| for (int i = 7; i >= 0; i--) { |
| z = (z << 1) ^ ((z >> 7) * 0x11D); |
| z ^= ((y >> i) & 1) * x; |
| } |
| if (z >> 8 != 0) |
| throw "Assertion error"; |
| return static_cast<uint8_t>(z); |
| } |
| |
| } |