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| author | moneromooo.monero <moneromooo.monero@users.noreply.github.com> | 2016-11-20 12:36:14 +0000 |
|---|---|---|
| committer | moneromooo.monero <moneromooo.monero@users.noreply.github.com> | 2016-11-20 18:53:12 +0000 |
| commit | 96c7ddeea8e590726ef3c28faead8205bb45ac41 (patch) | |
| tree | 601b36221a05c638d713c013045ecfb77652e9b3 /src/QR-Code-generator/QrCode.cpp | |
| parent | c83336cc4714215725cba957d8ea164a57c33987 (diff) | |
| download | monzero-gui-96c7ddeea8e590726ef3c28faead8205bb45ac41.tar.gz monzero-gui-96c7ddeea8e590726ef3c28faead8205bb45ac41.tar.xz monzero-gui-96c7ddeea8e590726ef3c28faead8205bb45ac41.zip | |
Add QR code display on the receive page
This embeds MIT licenced code from Project Nayuki:
https://www.nayuki.io/page/qr-code-generator-library
The C++ part of the code is embedded in src/QR-Code-generator.
See src/QR-Code-generator/Readme.markdown for more info.
Diffstat (limited to 'src/QR-Code-generator/QrCode.cpp')
| -rw-r--r-- | src/QR-Code-generator/QrCode.cpp | 616 |
1 files changed, 616 insertions, 0 deletions
diff --git a/src/QR-Code-generator/QrCode.cpp b/src/QR-Code-generator/QrCode.cpp new file mode 100644 index 00000000..cab74333 --- /dev/null +++ b/src/QR-Code-generator/QrCode.cpp @@ -0,0 +1,616 @@ +/* + * QR Code generator library (C++) + * + * Copyright (c) 2016 Project Nayuki + * https://www.nayuki.io/page/qr-code-generator-library + * + * (MIT License) + * 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 <cmath> +#include <cstddef> +#include <sstream> +#include "BitBuffer.hpp" +#include "QrCode.hpp" + + +qrcodegen::QrCode::Ecc::Ecc(int ord, int fb) : + ordinal(ord), + formatBits(fb) {} + + +const qrcodegen::QrCode::Ecc qrcodegen::QrCode::Ecc::LOW (0, 1); +const qrcodegen::QrCode::Ecc qrcodegen::QrCode::Ecc::MEDIUM (1, 0); +const qrcodegen::QrCode::Ecc qrcodegen::QrCode::Ecc::QUARTILE(2, 3); +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(QrSegment::makeSegments(text)); + return encodeSegments(segs, ecl); +} + + +qrcodegen::QrCode qrcodegen::QrCode::encodeBinary(const std::vector<uint8_t> &data, const Ecc &ecl) { + std::vector<QrSegment> segs; + segs.push_back(QrSegment::makeBytes(data)); + return encodeSegments(segs, ecl); +} + + +qrcodegen::QrCode qrcodegen::QrCode::encodeSegments(const std::vector<QrSegment> &segs, const Ecc &ecl, + int minVersion, int maxVersion, int mask, bool boostEcl) { + if (!(1 <= minVersion && minVersion <= maxVersion && maxVersion <= 40) || 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 + const Ecc *newEcl = &ecl; + if (boostEcl) { + if (dataUsedBits <= getNumDataCodewords(version, Ecc::MEDIUM ) * 8) newEcl = &Ecc::MEDIUM ; + if (dataUsedBits <= getNumDataCodewords(version, Ecc::QUARTILE) * 8) newEcl = &Ecc::QUARTILE; + if (dataUsedBits <= getNumDataCodewords(version, Ecc::HIGH ) * 8) newEcl = &Ecc::HIGH ; + } + + // Create the data bit string by concatenating all segments + int dataCapacityBits = getNumDataCodewords(version, *newEcl) * 8; + BitBuffer bb; + for (size_t i = 0; i < segs.size(); i++) { + const QrSegment &seg(segs.at(i)); + bb.appendBits(seg.mode.modeBits, 4); + bb.appendBits(seg.numChars, seg.mode.numCharCountBits(version)); + bb.appendData(seg); + } + + // Add terminator and pad up to a byte if applicable + bb.appendBits(0, std::min(4, dataCapacityBits - bb.getBitLength())); + bb.appendBits(0, (8 - bb.getBitLength() % 8) % 8); + + // Pad with alternate bytes until data capacity is reached + for (uint8_t padByte = 0xEC; bb.getBitLength() < dataCapacityBits; padByte ^= 0xEC ^ 0x11) + bb.appendBits(padByte, 8); + if (bb.getBitLength() % 8 != 0) + throw "Assertion error"; + + // Create the QR Code symbol + return QrCode(version, *newEcl, bb.getBytes(), mask); +} + + +qrcodegen::QrCode::QrCode(int ver, const Ecc &ecl, const std::vector<uint8_t> &dataCodewords, int mask) : + // Initialize scalar fields + version(ver), + size(1 <= ver && ver <= 40 ? ver * 4 + 17 : -1), // Avoid signed overflow undefined behavior + errorCorrectionLevel(ecl) { + + // Check arguments + if (ver < 1 || ver > 40 || mask < -1 || mask > 7) + throw "Value out of range"; + + std::vector<bool> row(size); + for (int i = 0; i < size; i++) { + modules.push_back(row); + isFunction.push_back(row); + } + + // Draw function patterns, draw all codewords, do masking + drawFunctionPatterns(); + const std::vector<uint8_t> allCodewords(appendErrorCorrection(dataCodewords)); + drawCodewords(allCodewords); + this->mask = handleConstructorMasking(mask); +} + + +qrcodegen::QrCode::QrCode(const QrCode &qr, int mask) : + // Copy scalar fields + version(qr.version), + size(qr.size), + errorCorrectionLevel(qr.errorCorrectionLevel) { + + // Check arguments + if (mask < -1 || mask > 7) + throw "Mask value out of range"; + + // Handle grid fields + modules = qr.modules; + isFunction = qr.isFunction; + + // Handle masking + applyMask(qr.mask); // Undo old mask + this->mask = handleConstructorMasking(mask); +} + + +int qrcodegen::QrCode::getMask() const { + return mask; +} + + +int qrcodegen::QrCode::getModule(int x, int y) const { + if (0 <= x && x < size && 0 <= y && y < size) + return modules.at(y).at(x) ? 1 : 0; + else + return 0; // Infinite white border +} + + +std::string qrcodegen::QrCode::toSvgString(int border) const { + if (border < 0) + throw "Border must be non-negative"; + 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) << "\">\n"; + sb << "\t<rect width=\"100%\" height=\"100%\" fill=\"#FFFFFF\" stroke-width=\"0\"/>\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) == 1) { + if (head) + head = false; + else + sb << " "; + sb << "M" << (x + border) << "," << (y + border) << "h1v1h-1z"; + } + } + } + sb << "\" fill=\"#000000\" stroke-width=\"0\"/>\n"; + sb << "</svg>\n"; + return sb.str(); +} + + +void qrcodegen::QrCode::drawFunctionPatterns() { + // Draw the 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 the numerous alignment patterns + const std::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 qrcodegen::QrCode::drawFormatBits(int mask) { + // Calculate error correction code and pack bits + int data = errorCorrectionLevel.formatBits << 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 qrcodegen::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); + int data = 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 qrcodegen::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 qrcodegen::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 qrcodegen::QrCode::setFunctionModule(int x, int y, bool isBlack) { + modules.at(y).at(x) = isBlack; + isFunction.at(y).at(x) = true; +} + + +std::vector<uint8_t> qrcodegen::QrCode::appendErrorCorrection(const std::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[errorCorrectionLevel.ordinal][version]; + int totalEcc = NUM_ERROR_CORRECTION_CODEWORDS[errorCorrectionLevel.ordinal][version]; + if (totalEcc % numBlocks != 0) + throw "Assertion error"; + int blockEccLen = totalEcc / numBlocks; + int numShortBlocks = numBlocks - getNumRawDataModules(version) / 8 % numBlocks; + int shortBlockLen = getNumRawDataModules(version) / 8 / numBlocks; + + // Split data into blocks and append ECC to each block + std::vector<std::vector<uint8_t>> blocks; + const ReedSolomonGenerator rs(blockEccLen); + for (int i = 0, k = 0; i < numBlocks; i++) { + std::vector<uint8_t> dat; + dat.insert(dat.begin(), data.begin() + k, data.begin() + (k + shortBlockLen - blockEccLen + (i < numShortBlocks ? 0 : 1))); + k += dat.size(); + const std::vector<uint8_t> ecc(rs.getRemainder(dat)); + if (i < numShortBlocks) + dat.push_back(0); + dat.insert(dat.end(), ecc.begin(), ecc.end()); + blocks.push_back(dat); + } + + // Interleave (not concatenate) the bytes from every block into a single sequence + std::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>(getNumRawDataModules(version) / 8)) + throw "Assertion error"; + return result; +} + + +void qrcodegen::QrCode::drawCodewords(const std::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 upwards = ((right & 2) == 0) ^ (x < 6); + int y = upwards ? 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 qrcodegen::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 qrcodegen::QrCode::handleConstructorMasking(int mask) { + if (mask == -1) { // Automatically choose best mask + int32_t minPenalty = INT32_MAX; + for (int i = 0; i < 8; i++) { + drawFormatBits(i); + applyMask(i); + int 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 +} + + +int qrcodegen::QrCode::getPenaltyScore() const { + int result = 0; + + // Adjacent modules in row having same color + for (int y = 0; y < size; y++) { + bool colorX = modules.at(y).at(0); + for (int x = 1, runX = 1; x < size; x++) { + if (modules.at(y).at(x) != colorX) { + colorX = modules.at(y).at(x); + 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 = modules.at(0).at(x); + for (int y = 1, runY = 1; y < size; y++) { + if (modules.at(y).at(x) != colorY) { + colorY = modules.at(y).at(x); + 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 = modules.at(y).at(x); + if ( color == modules.at(y).at(x + 1) && + color == modules.at(y + 1).at(x) && + color == modules.at(y + 1).at(x + 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) | (modules.at(y).at(x) ? 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) | (modules.at(y).at(x) ? 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 (int y = 0; y < size; y++) { + for (int x = 0; x < size; x++) { + if (modules.at(y).at(x)) + black++; + } + } + int total = size * size; + // Find smallest k such that (45-5k)% <= dark/total <= (55+5k)% + for (int k = 0; black*20 < (9-k)*total || black*20 > (11+k)*total; k++) + result += PENALTY_N4; + return result; +} + + +std::vector<int> qrcodegen::QrCode::getAlignmentPatternPositions(int ver) { + if (ver < 1 || ver > 40) + throw "Version number out of range"; + else if (ver == 1) + return std::vector<int>(); + else { + int numAlign = ver / 7 + 2; + int step; + if (ver != 32) + step = (ver * 4 + numAlign * 2 + 1) / (2 * numAlign - 2) * 2; // ceil((size - 13) / (2*numAlign - 2)) * 2 + else // C-C-C-Combo breaker! + step = 26; + + std::vector<int> result; + int size = ver * 4 + 17; + for (int i = 0, pos = size - 7; i < numAlign - 1; i++, pos -= step) + result.insert(result.begin(), pos); + result.insert(result.begin(), 6); + return result; + } +} + + +int qrcodegen::QrCode::getNumRawDataModules(int ver) { + if (ver < 1 || ver > 40) + 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 qrcodegen::QrCode::getNumDataCodewords(int ver, const Ecc &ecl) { + if (ver < 1 || ver > 40) + throw "Version number out of range"; + return getNumRawDataModules(ver) / 8 - NUM_ERROR_CORRECTION_CODEWORDS[ecl.ordinal][ver]; +} + + +/*---- Tables of constants ----*/ + +const int qrcodegen::QrCode::PENALTY_N1 = 3; +const int qrcodegen::QrCode::PENALTY_N2 = 3; +const int qrcodegen::QrCode::PENALTY_N3 = 40; +const int qrcodegen::QrCode::PENALTY_N4 = 10; + + +const int16_t qrcodegen::QrCode::NUM_ERROR_CORRECTION_CODEWORDS[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, 36, 40, 48, 60, 72, 80, 96, 104, 120, 132, 144, 168, 180, 196, 224, 224, 252, 270, 300, 312, 336, 360, 390, 420, 450, 480, 510, 540, 570, 570, 600, 630, 660, 720, 750}, // Low + {-1, 10, 16, 26, 36, 48, 64, 72, 88, 110, 130, 150, 176, 198, 216, 240, 280, 308, 338, 364, 416, 442, 476, 504, 560, 588, 644, 700, 728, 784, 812, 868, 924, 980, 1036, 1064, 1120, 1204, 1260, 1316, 1372}, // Medium + {-1, 13, 22, 36, 52, 72, 96, 108, 132, 160, 192, 224, 260, 288, 320, 360, 408, 448, 504, 546, 600, 644, 690, 750, 810, 870, 952, 1020, 1050, 1140, 1200, 1290, 1350, 1440, 1530, 1590, 1680, 1770, 1860, 1950, 2040}, // Quartile + {-1, 17, 28, 44, 64, 88, 112, 130, 156, 192, 224, 264, 308, 352, 384, 432, 480, 532, 588, 650, 700, 750, 816, 900, 960, 1050, 1110, 1200, 1260, 1350, 1440, 1530, 1620, 1710, 1800, 1890, 1980, 2100, 2220, 2310, 2430}, // High +}; + +const int8_t qrcodegen::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 +}; + + +qrcodegen::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). + int 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), static_cast<uint8_t>(root)); + if (j + 1 < coefficients.size()) + coefficients.at(j) ^= coefficients.at(j + 1); + } + root = (root << 1) ^ ((root >> 7) * 0x11D); // Multiply by 0x02 mod GF(2^8/0x11D) + } +} + + +std::vector<uint8_t> qrcodegen::QrCode::ReedSolomonGenerator::getRemainder(const std::vector<uint8_t> &data) const { + // Compute the remainder by performing polynomial division + std::vector<uint8_t> result(coefficients.size()); + for (size_t i = 0; i < data.size(); i++) { + uint8_t factor = data.at(i) ^ 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 qrcodegen::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); +} |
