1/* 2 * QR Code generator library (C++) 3 * 4 * Copyright (c) Project Nayuki. (MIT License) 5 * https://www.nayuki.io/page/qr-code-generator-library 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a copy of 8 * this software and associated documentation files (the "Software"), to deal in 9 * the Software without restriction, including without limitation the rights to 10 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of 11 * the Software, and to permit persons to whom the Software is furnished to do so, 12 * subject to the following conditions: 13 * - The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * - The Software is provided "as is", without warranty of any kind, express or 16 * implied, including but not limited to the warranties of merchantability, 17 * fitness for a particular purpose and noninfringement. In no event shall the 18 * authors or copyright holders be liable for any claim, damages or other 19 * liability, whether in an action of contract, tort or otherwise, arising from, 20 * out of or in connection with the Software or the use or other dealings in the 21 * Software. 22 */ 23 24#include <algorithm> 25#include <cassert> 26#include <climits> 27#include <cstddef> 28#include <cstdlib> 29#include <cstring> 30#include <sstream> 31#include <utility> 32#include "qrcodegen.hpp" 33 34using std::int8_t; 35using std::uint8_t; 36using std::size_t; 37using std::vector; 38 39 40namespace qrcodegen { 41 42/*---- Class QrSegment ----*/ 43 44QrSegment::Mode::Mode(int mode, int cc0, int cc1, int cc2) : 45 modeBits(mode) { 46 numBitsCharCount[0] = cc0; 47 numBitsCharCount[1] = cc1; 48 numBitsCharCount[2] = cc2; 49} 50 51 52int QrSegment::Mode::getModeBits() const { 53 return modeBits; 54} 55 56 57int QrSegment::Mode::numCharCountBits(int ver) const { 58 return numBitsCharCount[(ver + 7) / 17]; 59} 60 61 62const QrSegment::Mode QrSegment::Mode::NUMERIC (0x1, 10, 12, 14); 63const QrSegment::Mode QrSegment::Mode::ALPHANUMERIC(0x2, 9, 11, 13); 64const QrSegment::Mode QrSegment::Mode::BYTE (0x4, 8, 16, 16); 65const QrSegment::Mode QrSegment::Mode::KANJI (0x8, 8, 10, 12); 66const QrSegment::Mode QrSegment::Mode::ECI (0x7, 0, 0, 0); 67 68 69QrSegment QrSegment::makeBytes(const vector<uint8_t> &data) { 70 if (data.size() > static_cast<unsigned int>(INT_MAX)) 71 throw std::length_error("Data too long"); 72 BitBuffer bb; 73 for (uint8_t b : data) 74 bb.appendBits(b, 8); 75 return QrSegment(Mode::BYTE, static_cast<int>(data.size()), std::move(bb)); 76} 77 78 79QrSegment QrSegment::makeNumeric(const char *digits) { 80 BitBuffer bb; 81 int accumData = 0; 82 int accumCount = 0; 83 int charCount = 0; 84 for (; *digits != '\0'; digits++, charCount++) { 85 char c = *digits; 86 if (c < '0' || c > '9') 87 throw std::domain_error("String contains non-numeric characters"); 88 accumData = accumData * 10 + (c - '0'); 89 accumCount++; 90 if (accumCount == 3) { 91 bb.appendBits(static_cast<uint32_t>(accumData), 10); 92 accumData = 0; 93 accumCount = 0; 94 } 95 } 96 if (accumCount > 0) // 1 or 2 digits remaining 97 bb.appendBits(static_cast<uint32_t>(accumData), accumCount * 3 + 1); 98 return QrSegment(Mode::NUMERIC, charCount, std::move(bb)); 99} 100 101 102QrSegment QrSegment::makeAlphanumeric(const char *text) { 103 BitBuffer bb; 104 int accumData = 0; 105 int accumCount = 0; 106 int charCount = 0; 107 for (; *text != '\0'; text++, charCount++) { 108 const char *temp = std::strchr(ALPHANUMERIC_CHARSET, *text); 109 if (temp == nullptr) 110 throw std::domain_error("String contains unencodable characters in alphanumeric mode"); 111 accumData = accumData * 45 + static_cast<int>(temp - ALPHANUMERIC_CHARSET); 112 accumCount++; 113 if (accumCount == 2) { 114 bb.appendBits(static_cast<uint32_t>(accumData), 11); 115 accumData = 0; 116 accumCount = 0; 117 } 118 } 119 if (accumCount > 0) // 1 character remaining 120 bb.appendBits(static_cast<uint32_t>(accumData), 6); 121 return QrSegment(Mode::ALPHANUMERIC, charCount, std::move(bb)); 122} 123 124 125vector<QrSegment> QrSegment::makeSegments(const char *text) { 126 // Select the most efficient segment encoding automatically 127 vector<QrSegment> result; 128 if (*text == '\0'); // Leave result empty 129 else if (isNumeric(text)) 130 result.push_back(makeNumeric(text)); 131 else if (isAlphanumeric(text)) 132 result.push_back(makeAlphanumeric(text)); 133 else { 134 vector<uint8_t> bytes; 135 for (; *text != '\0'; text++) 136 bytes.push_back(static_cast<uint8_t>(*text)); 137 result.push_back(makeBytes(bytes)); 138 } 139 return result; 140} 141 142 143QrSegment QrSegment::makeEci(long assignVal) { 144 BitBuffer bb; 145 if (assignVal < 0) 146 throw std::domain_error("ECI assignment value out of range"); 147 else if (assignVal < (1 << 7)) 148 bb.appendBits(static_cast<uint32_t>(assignVal), 8); 149 else if (assignVal < (1 << 14)) { 150 bb.appendBits(2, 2); 151 bb.appendBits(static_cast<uint32_t>(assignVal), 14); 152 } else if (assignVal < 1000000L) { 153 bb.appendBits(6, 3); 154 bb.appendBits(static_cast<uint32_t>(assignVal), 21); 155 } else 156 throw std::domain_error("ECI assignment value out of range"); 157 return QrSegment(Mode::ECI, 0, std::move(bb)); 158} 159 160 161QrSegment::QrSegment(const Mode &md, int numCh, const std::vector<bool> &dt) : 162 mode(&md), 163 numChars(numCh), 164 data(dt) { 165 if (numCh < 0) 166 throw std::domain_error("Invalid value"); 167} 168 169 170QrSegment::QrSegment(const Mode &md, int numCh, std::vector<bool> &&dt) : 171 mode(&md), 172 numChars(numCh), 173 data(std::move(dt)) { 174 if (numCh < 0) 175 throw std::domain_error("Invalid value"); 176} 177 178 179int QrSegment::getTotalBits(const vector<QrSegment> &segs, int version) { 180 int result = 0; 181 for (const QrSegment &seg : segs) { 182 int ccbits = seg.mode->numCharCountBits(version); 183 if (seg.numChars >= (1L << ccbits)) 184 return -1; // The segment's length doesn't fit the field's bit width 185 if (4 + ccbits > INT_MAX - result) 186 return -1; // The sum will overflow an int type 187 result += 4 + ccbits; 188 if (seg.data.size() > static_cast<unsigned int>(INT_MAX - result)) 189 return -1; // The sum will overflow an int type 190 result += static_cast<int>(seg.data.size()); 191 } 192 return result; 193} 194 195 196bool QrSegment::isNumeric(const char *text) { 197 for (; *text != '\0'; text++) { 198 char c = *text; 199 if (c < '0' || c > '9') 200 return false; 201 } 202 return true; 203} 204 205 206bool QrSegment::isAlphanumeric(const char *text) { 207 for (; *text != '\0'; text++) { 208 if (std::strchr(ALPHANUMERIC_CHARSET, *text) == nullptr) 209 return false; 210 } 211 return true; 212} 213 214 215const QrSegment::Mode &QrSegment::getMode() const { 216 return *mode; 217} 218 219 220int QrSegment::getNumChars() const { 221 return numChars; 222} 223 224 225const std::vector<bool> &QrSegment::getData() const { 226 return data; 227} 228 229 230const char *QrSegment::ALPHANUMERIC_CHARSET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:"; 231 232 233 234/*---- Class QrCode ----*/ 235 236int QrCode::getFormatBits(Ecc ecl) { 237 switch (ecl) { 238 case Ecc::LOW : return 1; 239 case Ecc::MEDIUM : return 0; 240 case Ecc::QUARTILE: return 3; 241 case Ecc::HIGH : return 2; 242 default: throw std::logic_error("Unreachable"); 243 } 244} 245 246 247QrCode QrCode::encodeText(const char *text, Ecc ecl) { 248 vector<QrSegment> segs = QrSegment::makeSegments(text); 249 return encodeSegments(segs, ecl); 250} 251 252 253QrCode QrCode::encodeBinary(const vector<uint8_t> &data, Ecc ecl) { 254 vector<QrSegment> segs{QrSegment::makeBytes(data)}; 255 return encodeSegments(segs, ecl); 256} 257 258 259QrCode QrCode::encodeSegments(const vector<QrSegment> &segs, Ecc ecl, 260 int minVersion, int maxVersion, int mask, bool boostEcl) { 261 if (!(MIN_VERSION <= minVersion && minVersion <= maxVersion && maxVersion <= MAX_VERSION) || mask < -1 || mask > 7) 262 throw std::invalid_argument("Invalid value"); 263 264 // Find the minimal version number to use 265 int version, dataUsedBits; 266 for (version = minVersion; ; version++) { 267 int dataCapacityBits = getNumDataCodewords(version, ecl) * 8; // Number of data bits available 268 dataUsedBits = QrSegment::getTotalBits(segs, version); 269 if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits) 270 break; // This version number is found to be suitable 271 if (version >= maxVersion) { // All versions in the range could not fit the given data 272 std::ostringstream sb; 273 if (dataUsedBits == -1) 274 sb << "Segment too long"; 275 else { 276 sb << "Data length = " << dataUsedBits << " bits, "; 277 sb << "Max capacity = " << dataCapacityBits << " bits"; 278 } 279 throw data_too_long(sb.str()); 280 } 281 } 282 assert(dataUsedBits != -1); 283 284 // Increase the error correction level while the data still fits in the current version number 285 for (Ecc newEcl : {Ecc::MEDIUM, Ecc::QUARTILE, Ecc::HIGH}) { // From low to high 286 if (boostEcl && dataUsedBits <= getNumDataCodewords(version, newEcl) * 8) 287 ecl = newEcl; 288 } 289 290 // Concatenate all segments to create the data bit string 291 BitBuffer bb; 292 for (const QrSegment &seg : segs) { 293 bb.appendBits(static_cast<uint32_t>(seg.getMode().getModeBits()), 4); 294 bb.appendBits(static_cast<uint32_t>(seg.getNumChars()), seg.getMode().numCharCountBits(version)); 295 bb.insert(bb.end(), seg.getData().begin(), seg.getData().end()); 296 } 297 assert(bb.size() == static_cast<unsigned int>(dataUsedBits)); 298 299 // Add terminator and pad up to a byte if applicable 300 size_t dataCapacityBits = static_cast<size_t>(getNumDataCodewords(version, ecl)) * 8; 301 assert(bb.size() <= dataCapacityBits); 302 bb.appendBits(0, std::min(4, static_cast<int>(dataCapacityBits - bb.size()))); 303 bb.appendBits(0, (8 - static_cast<int>(bb.size() % 8)) % 8); 304 assert(bb.size() % 8 == 0); 305 306 // Pad with alternating bytes until data capacity is reached 307 for (uint8_t padByte = 0xEC; bb.size() < dataCapacityBits; padByte ^= 0xEC ^ 0x11) 308 bb.appendBits(padByte, 8); 309 310 // Pack bits into bytes in big endian 311 vector<uint8_t> dataCodewords(bb.size() / 8); 312 for (size_t i = 0; i < bb.size(); i++) 313 dataCodewords.at(i >> 3) |= (bb.at(i) ? 1 : 0) << (7 - (i & 7)); 314 315 // Create the QR Code object 316 return QrCode(version, ecl, dataCodewords, mask); 317} 318 319 320QrCode::QrCode(int ver, Ecc ecl, const vector<uint8_t> &dataCodewords, int msk) : 321 // Initialize fields and check arguments 322 version(ver), 323 errorCorrectionLevel(ecl) { 324 if (ver < MIN_VERSION || ver > MAX_VERSION) 325 throw std::domain_error("Version value out of range"); 326 if (msk < -1 || msk > 7) 327 throw std::domain_error("Mask value out of range"); 328 size = ver * 4 + 17; 329 size_t sz = static_cast<size_t>(size); 330 modules = vector<vector<bool> >(sz, vector<bool>(sz)); // Initially all light 331 isFunction = vector<vector<bool> >(sz, vector<bool>(sz)); 332 333 // Compute ECC, draw modules 334 drawFunctionPatterns(); 335 const vector<uint8_t> allCodewords = addEccAndInterleave(dataCodewords); 336 drawCodewords(allCodewords); 337 338 // Do masking 339 if (msk == -1) { // Automatically choose best mask 340 long minPenalty = LONG_MAX; 341 for (int i = 0; i < 8; i++) { 342 applyMask(i); 343 drawFormatBits(i); 344 long penalty = getPenaltyScore(); 345 if (penalty < minPenalty) { 346 msk = i; 347 minPenalty = penalty; 348 } 349 applyMask(i); // Undoes the mask due to XOR 350 } 351 } 352 assert(0 <= msk && msk <= 7); 353 mask = msk; 354 applyMask(msk); // Apply the final choice of mask 355 drawFormatBits(msk); // Overwrite old format bits 356 357 isFunction.clear(); 358 isFunction.shrink_to_fit(); 359} 360 361 362int QrCode::getVersion() const { 363 return version; 364} 365 366 367int QrCode::getSize() const { 368 return size; 369} 370 371 372QrCode::Ecc QrCode::getErrorCorrectionLevel() const { 373 return errorCorrectionLevel; 374} 375 376 377int QrCode::getMask() const { 378 return mask; 379} 380 381 382bool QrCode::getModule(int x, int y) const { 383 return 0 <= x && x < size && 0 <= y && y < size && module(x, y); 384} 385 386 387void QrCode::drawFunctionPatterns() { 388 // Draw horizontal and vertical timing patterns 389 for (int i = 0; i < size; i++) { 390 setFunctionModule(6, i, i % 2 == 0); 391 setFunctionModule(i, 6, i % 2 == 0); 392 } 393 394 // Draw 3 finder patterns (all corners except bottom right; overwrites some timing modules) 395 drawFinderPattern(3, 3); 396 drawFinderPattern(size - 4, 3); 397 drawFinderPattern(3, size - 4); 398 399 // Draw numerous alignment patterns 400 const vector<int> alignPatPos = getAlignmentPatternPositions(); 401 size_t numAlign = alignPatPos.size(); 402 for (size_t i = 0; i < numAlign; i++) { 403 for (size_t j = 0; j < numAlign; j++) { 404 // Don't draw on the three finder corners 405 if (!((i == 0 && j == 0) || (i == 0 && j == numAlign - 1) || (i == numAlign - 1 && j == 0))) 406 drawAlignmentPattern(alignPatPos.at(i), alignPatPos.at(j)); 407 } 408 } 409 410 // Draw configuration data 411 drawFormatBits(0); // Dummy mask value; overwritten later in the constructor 412 drawVersion(); 413} 414 415 416void QrCode::drawFormatBits(int msk) { 417 // Calculate error correction code and pack bits 418 int data = getFormatBits(errorCorrectionLevel) << 3 | msk; // errCorrLvl is uint2, msk is uint3 419 int rem = data; 420 for (int i = 0; i < 10; i++) 421 rem = (rem << 1) ^ ((rem >> 9) * 0x537); 422 int bits = (data << 10 | rem) ^ 0x5412; // uint15 423 assert(bits >> 15 == 0); 424 425 // Draw first copy 426 for (int i = 0; i <= 5; i++) 427 setFunctionModule(8, i, getBit(bits, i)); 428 setFunctionModule(8, 7, getBit(bits, 6)); 429 setFunctionModule(8, 8, getBit(bits, 7)); 430 setFunctionModule(7, 8, getBit(bits, 8)); 431 for (int i = 9; i < 15; i++) 432 setFunctionModule(14 - i, 8, getBit(bits, i)); 433 434 // Draw second copy 435 for (int i = 0; i < 8; i++) 436 setFunctionModule(size - 1 - i, 8, getBit(bits, i)); 437 for (int i = 8; i < 15; i++) 438 setFunctionModule(8, size - 15 + i, getBit(bits, i)); 439 setFunctionModule(8, size - 8, true); // Always dark 440} 441 442 443void QrCode::drawVersion() { 444 if (version < 7) 445 return; 446 447 // Calculate error correction code and pack bits 448 int rem = version; // version is uint6, in the range [7, 40] 449 for (int i = 0; i < 12; i++) 450 rem = (rem << 1) ^ ((rem >> 11) * 0x1F25); 451 long bits = static_cast<long>(version) << 12 | rem; // uint18 452 assert(bits >> 18 == 0); 453 454 // Draw two copies 455 for (int i = 0; i < 18; i++) { 456 bool bit = getBit(bits, i); 457 int a = size - 11 + i % 3; 458 int b = i / 3; 459 setFunctionModule(a, b, bit); 460 setFunctionModule(b, a, bit); 461 } 462} 463 464 465void QrCode::drawFinderPattern(int x, int y) { 466 for (int dy = -4; dy <= 4; dy++) { 467 for (int dx = -4; dx <= 4; dx++) { 468 int dist = std::max(std::abs(dx), std::abs(dy)); // Chebyshev/infinity norm 469 int xx = x + dx, yy = y + dy; 470 if (0 <= xx && xx < size && 0 <= yy && yy < size) 471 setFunctionModule(xx, yy, dist != 2 && dist != 4); 472 } 473 } 474} 475 476 477void QrCode::drawAlignmentPattern(int x, int y) { 478 for (int dy = -2; dy <= 2; dy++) { 479 for (int dx = -2; dx <= 2; dx++) 480 setFunctionModule(x + dx, y + dy, std::max(std::abs(dx), std::abs(dy)) != 1); 481 } 482} 483 484 485void QrCode::setFunctionModule(int x, int y, bool isDark) { 486 size_t ux = static_cast<size_t>(x); 487 size_t uy = static_cast<size_t>(y); 488 modules .at(uy).at(ux) = isDark; 489 isFunction.at(uy).at(ux) = true; 490} 491 492 493bool QrCode::module(int x, int y) const { 494 return modules.at(static_cast<size_t>(y)).at(static_cast<size_t>(x)); 495} 496 497 498vector<uint8_t> QrCode::addEccAndInterleave(const vector<uint8_t> &data) const { 499 if (data.size() != static_cast<unsigned int>(getNumDataCodewords(version, errorCorrectionLevel))) 500 throw std::invalid_argument("Invalid argument"); 501 502 // Calculate parameter numbers 503 int numBlocks = NUM_ERROR_CORRECTION_BLOCKS[static_cast<int>(errorCorrectionLevel)][version]; 504 int blockEccLen = ECC_CODEWORDS_PER_BLOCK [static_cast<int>(errorCorrectionLevel)][version]; 505 int rawCodewords = getNumRawDataModules(version) / 8; 506 int numShortBlocks = numBlocks - rawCodewords % numBlocks; 507 int shortBlockLen = rawCodewords / numBlocks; 508 509 // Split data into blocks and append ECC to each block 510 vector<vector<uint8_t> > blocks; 511 const vector<uint8_t> rsDiv = reedSolomonComputeDivisor(blockEccLen); 512 for (int i = 0, k = 0; i < numBlocks; i++) { 513 vector<uint8_t> dat(data.cbegin() + k, data.cbegin() + (k + shortBlockLen - blockEccLen + (i < numShortBlocks ? 0 : 1))); 514 k += static_cast<int>(dat.size()); 515 const vector<uint8_t> ecc = reedSolomonComputeRemainder(dat, rsDiv); 516 if (i < numShortBlocks) 517 dat.push_back(0); 518 dat.insert(dat.end(), ecc.cbegin(), ecc.cend()); 519 blocks.push_back(std::move(dat)); 520 } 521 522 // Interleave (not concatenate) the bytes from every block into a single sequence 523 vector<uint8_t> result; 524 for (size_t i = 0; i < blocks.at(0).size(); i++) { 525 for (size_t j = 0; j < blocks.size(); j++) { 526 // Skip the padding byte in short blocks 527 if (i != static_cast<unsigned int>(shortBlockLen - blockEccLen) || j >= static_cast<unsigned int>(numShortBlocks)) 528 result.push_back(blocks.at(j).at(i)); 529 } 530 } 531 assert(result.size() == static_cast<unsigned int>(rawCodewords)); 532 return result; 533} 534 535 536void QrCode::drawCodewords(const vector<uint8_t> &data) { 537 if (data.size() != static_cast<unsigned int>(getNumRawDataModules(version) / 8)) 538 throw std::invalid_argument("Invalid argument"); 539 540 size_t i = 0; // Bit index into the data 541 // Do the funny zigzag scan 542 for (int right = size - 1; right >= 1; right -= 2) { // Index of right column in each column pair 543 if (right == 6) 544 right = 5; 545 for (int vert = 0; vert < size; vert++) { // Vertical counter 546 for (int j = 0; j < 2; j++) { 547 size_t x = static_cast<size_t>(right - j); // Actual x coordinate 548 bool upward = ((right + 1) & 2) == 0; 549 size_t y = static_cast<size_t>(upward ? size - 1 - vert : vert); // Actual y coordinate 550 if (!isFunction.at(y).at(x) && i < data.size() * 8) { 551 modules.at(y).at(x) = getBit(data.at(i >> 3), 7 - static_cast<int>(i & 7)); 552 i++; 553 } 554 // If this QR Code has any remainder bits (0 to 7), they were assigned as 555 // 0/false/light by the constructor and are left unchanged by this method 556 } 557 } 558 } 559 assert(i == data.size() * 8); 560} 561 562 563void QrCode::applyMask(int msk) { 564 if (msk < 0 || msk > 7) 565 throw std::domain_error("Mask value out of range"); 566 size_t sz = static_cast<size_t>(size); 567 for (size_t y = 0; y < sz; y++) { 568 for (size_t x = 0; x < sz; x++) { 569 bool invert; 570 switch (msk) { 571 case 0: invert = (x + y) % 2 == 0; break; 572 case 1: invert = y % 2 == 0; break; 573 case 2: invert = x % 3 == 0; break; 574 case 3: invert = (x + y) % 3 == 0; break; 575 case 4: invert = (x / 3 + y / 2) % 2 == 0; break; 576 case 5: invert = x * y % 2 + x * y % 3 == 0; break; 577 case 6: invert = (x * y % 2 + x * y % 3) % 2 == 0; break; 578 case 7: invert = ((x + y) % 2 + x * y % 3) % 2 == 0; break; 579 default: throw std::logic_error("Unreachable"); 580 } 581 modules.at(y).at(x) = modules.at(y).at(x) ^ (invert & !isFunction.at(y).at(x)); 582 } 583 } 584} 585 586 587long QrCode::getPenaltyScore() const { 588 long result = 0; 589 590 // Adjacent modules in row having same color, and finder-like patterns 591 for (int y = 0; y < size; y++) { 592 bool runColor = false; 593 int runX = 0; 594 std::array<int,7> runHistory = {}; 595 for (int x = 0; x < size; x++) { 596 if (module(x, y) == runColor) { 597 runX++; 598 if (runX == 5) 599 result += PENALTY_N1; 600 else if (runX > 5) 601 result++; 602 } else { 603 finderPenaltyAddHistory(runX, runHistory); 604 if (!runColor) 605 result += finderPenaltyCountPatterns(runHistory) * PENALTY_N3; 606 runColor = module(x, y); 607 runX = 1; 608 } 609 } 610 result += finderPenaltyTerminateAndCount(runColor, runX, runHistory) * PENALTY_N3; 611 } 612 // Adjacent modules in column having same color, and finder-like patterns 613 for (int x = 0; x < size; x++) { 614 bool runColor = false; 615 int runY = 0; 616 std::array<int,7> runHistory = {}; 617 for (int y = 0; y < size; y++) { 618 if (module(x, y) == runColor) { 619 runY++; 620 if (runY == 5) 621 result += PENALTY_N1; 622 else if (runY > 5) 623 result++; 624 } else { 625 finderPenaltyAddHistory(runY, runHistory); 626 if (!runColor) 627 result += finderPenaltyCountPatterns(runHistory) * PENALTY_N3; 628 runColor = module(x, y); 629 runY = 1; 630 } 631 } 632 result += finderPenaltyTerminateAndCount(runColor, runY, runHistory) * PENALTY_N3; 633 } 634 635 // 2*2 blocks of modules having same color 636 for (int y = 0; y < size - 1; y++) { 637 for (int x = 0; x < size - 1; x++) { 638 bool color = module(x, y); 639 if ( color == module(x + 1, y) && 640 color == module(x, y + 1) && 641 color == module(x + 1, y + 1)) 642 result += PENALTY_N2; 643 } 644 } 645 646 // Balance of dark and light modules 647 int dark = 0; 648 for (const vector<bool> &row : modules) { 649 for (bool color : row) { 650 if (color) 651 dark++; 652 } 653 } 654 int total = size * size; // Note that size is odd, so dark/total != 1/2 655 // Compute the smallest integer k >= 0 such that (45-5k)% <= dark/total <= (55+5k)% 656 int k = static_cast<int>((std::abs(dark * 20L - total * 10L) + total - 1) / total) - 1; 657 assert(0 <= k && k <= 9); 658 result += k * PENALTY_N4; 659 assert(0 <= result && result <= 2568888L); // Non-tight upper bound based on default values of PENALTY_N1, ..., N4 660 return result; 661} 662 663 664vector<int> QrCode::getAlignmentPatternPositions() const { 665 if (version == 1) 666 return vector<int>(); 667 else { 668 int numAlign = version / 7 + 2; 669 int step = (version == 32) ? 26 : 670 (version * 4 + numAlign * 2 + 1) / (numAlign * 2 - 2) * 2; 671 vector<int> result; 672 for (int i = 0, pos = size - 7; i < numAlign - 1; i++, pos -= step) 673 result.insert(result.begin(), pos); 674 result.insert(result.begin(), 6); 675 return result; 676 } 677} 678 679 680int QrCode::getNumRawDataModules(int ver) { 681 if (ver < MIN_VERSION || ver > MAX_VERSION) 682 throw std::domain_error("Version number out of range"); 683 int result = (16 * ver + 128) * ver + 64; 684 if (ver >= 2) { 685 int numAlign = ver / 7 + 2; 686 result -= (25 * numAlign - 10) * numAlign - 55; 687 if (ver >= 7) 688 result -= 36; 689 } 690 assert(208 <= result && result <= 29648); 691 return result; 692} 693 694 695int QrCode::getNumDataCodewords(int ver, Ecc ecl) { 696 return getNumRawDataModules(ver) / 8 697 - ECC_CODEWORDS_PER_BLOCK [static_cast<int>(ecl)][ver] 698 * NUM_ERROR_CORRECTION_BLOCKS[static_cast<int>(ecl)][ver]; 699} 700 701 702vector<uint8_t> QrCode::reedSolomonComputeDivisor(int degree) { 703 if (degree < 1 || degree > 255) 704 throw std::domain_error("Degree out of range"); 705 // Polynomial coefficients are stored from highest to lowest power, excluding the leading term which is always 1. 706 // For example the polynomial x^3 + 255x^2 + 8x + 93 is stored as the uint8 array {255, 8, 93}. 707 vector<uint8_t> result(static_cast<size_t>(degree)); 708 result.at(result.size() - 1) = 1; // Start off with the monomial x^0 709 710 // Compute the product polynomial (x - r^0) * (x - r^1) * (x - r^2) * ... * (x - r^{degree-1}), 711 // and drop the highest monomial term which is always 1x^degree. 712 // Note that r = 0x02, which is a generator element of this field GF(2^8/0x11D). 713 uint8_t root = 1; 714 for (int i = 0; i < degree; i++) { 715 // Multiply the current product by (x - r^i) 716 for (size_t j = 0; j < result.size(); j++) { 717 result.at(j) = reedSolomonMultiply(result.at(j), root); 718 if (j + 1 < result.size()) 719 result.at(j) ^= result.at(j + 1); 720 } 721 root = reedSolomonMultiply(root, 0x02); 722 } 723 return result; 724} 725 726 727vector<uint8_t> QrCode::reedSolomonComputeRemainder(const vector<uint8_t> &data, const vector<uint8_t> &divisor) { 728 vector<uint8_t> result(divisor.size()); 729 for (uint8_t b : data) { // Polynomial division 730 uint8_t factor = b ^ result.at(0); 731 result.erase(result.begin()); 732 result.push_back(0); 733 for (size_t i = 0; i < result.size(); i++) 734 result.at(i) ^= reedSolomonMultiply(divisor.at(i), factor); 735 } 736 return result; 737} 738 739 740uint8_t QrCode::reedSolomonMultiply(uint8_t x, uint8_t y) { 741 // Russian peasant multiplication 742 int z = 0; 743 for (int i = 7; i >= 0; i--) { 744 z = (z << 1) ^ ((z >> 7) * 0x11D); 745 z ^= ((y >> i) & 1) * x; 746 } 747 assert(z >> 8 == 0); 748 return static_cast<uint8_t>(z); 749} 750 751 752int QrCode::finderPenaltyCountPatterns(const std::array<int,7> &runHistory) const { 753 int n = runHistory.at(1); 754 assert(n <= size * 3); 755 bool core = n > 0 && runHistory.at(2) == n && runHistory.at(3) == n * 3 && runHistory.at(4) == n && runHistory.at(5) == n; 756 return (core && runHistory.at(0) >= n * 4 && runHistory.at(6) >= n ? 1 : 0) 757 + (core && runHistory.at(6) >= n * 4 && runHistory.at(0) >= n ? 1 : 0); 758} 759 760 761int QrCode::finderPenaltyTerminateAndCount(bool currentRunColor, int currentRunLength, std::array<int,7> &runHistory) const { 762 if (currentRunColor) { // Terminate dark run 763 finderPenaltyAddHistory(currentRunLength, runHistory); 764 currentRunLength = 0; 765 } 766 currentRunLength += size; // Add light border to final run 767 finderPenaltyAddHistory(currentRunLength, runHistory); 768 return finderPenaltyCountPatterns(runHistory); 769} 770 771 772void QrCode::finderPenaltyAddHistory(int currentRunLength, std::array<int,7> &runHistory) const { 773 if (runHistory.at(0) == 0) 774 currentRunLength += size; // Add light border to initial run 775 std::copy_backward(runHistory.cbegin(), runHistory.cend() - 1, runHistory.end()); 776 runHistory.at(0) = currentRunLength; 777} 778 779 780bool QrCode::getBit(long x, int i) { 781 return ((x >> i) & 1) != 0; 782} 783 784 785/*---- Tables of constants ----*/ 786 787const int QrCode::PENALTY_N1 = 3; 788const int QrCode::PENALTY_N2 = 3; 789const int QrCode::PENALTY_N3 = 40; 790const int QrCode::PENALTY_N4 = 10; 791 792 793const int8_t QrCode::ECC_CODEWORDS_PER_BLOCK[4][41] = { 794 // Version: (note that index 0 is for padding, and is set to an illegal value) 795 //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 796 {-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 797 {-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 798 {-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 799 {-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 800}; 801 802const int8_t QrCode::NUM_ERROR_CORRECTION_BLOCKS[4][41] = { 803 // Version: (note that index 0 is for padding, and is set to an illegal value) 804 //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 805 {-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 806 {-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 807 {-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 808 {-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 809}; 810 811 812data_too_long::data_too_long(const std::string &msg) : 813 std::length_error(msg) {} 814 815 816 817/*---- Class BitBuffer ----*/ 818 819BitBuffer::BitBuffer() 820 : std::vector<bool>() {} 821 822 823void BitBuffer::appendBits(std::uint32_t val, int len) { 824 if (len < 0 || len > 31 || val >> len != 0) 825 throw std::domain_error("Value out of range"); 826 for (int i = len - 1; i >= 0; i--) // Append bit by bit 827 this->push_back(((val >> i) & 1) != 0); 828} 829 830} 831