Reads the bits in the {@link BitMatrix} representing the finder pattern in the * correct order in order to reconstruct the codewords bytes contained within the * QR Code.
* * @return bytes encoded within the QR Code * @throws FormatException if the exact number of bytes expected is not read */ public function readCodewords() { $formatInfo = $this->readFormatInformation(); $version = $this->readVersion(); // Get the data mask for the format used in this QR Code. This will exclude // some bits from reading as we wind through the bit matrix. $dataMask = DataMask::forReference($formatInfo->getDataMask()); $dimension = $this->bitMatrix->getHeight(); $dataMask->unmaskBitMatrix($this->bitMatrix, $dimension); $functionPattern = $version->buildFunctionPattern(); $readingUp = true; if ($version->getTotalCodewords()) { $result = fill_array(0, $version->getTotalCodewords(), 0); } else { $result = []; } $resultOffset = 0; $currentByte = 0; $bitsRead = 0; // Read columns in pairs, from right to left for ($j = $dimension - 1; $j > 0; $j -= 2) { if ($j == 6) { // Skip whole column with vertical alignment pattern; // saves time and makes the other code proceed more cleanly $j--; } // Read alternatingly from bottom to top then top to bottom for ($count = 0; $count < $dimension; $count++) { $i = $readingUp ? $dimension - 1 - $count : $count; for ($col = 0; $col < 2; $col++) { // Ignore bits covered by the function pattern if (!$functionPattern->get($j - $col, $i)) { // Read a bit $bitsRead++; $currentByte <<= 1; if ($this->bitMatrix->get($j - $col, $i)) { $currentByte |= 1; } // If we've made a whole byte, save it off if ($bitsRead == 8) { $result[$resultOffset++] = $currentByte; //(byte) $bitsRead = 0; $currentByte = 0; } } } } $readingUp ^= true; // readingUp = !readingUp; // switch directions } if ($resultOffset != $version->getTotalCodewords()) { throw FormatException::getFormatInstance(); } return $result; } /** *Reads format information from one of its two locations within the QR Code.
* * @return {@link FormatInformation} encapsulating the QR Code's format info * @throws FormatException if both format information locations cannot be parsed as * the valid encoding of format information */ public function readFormatInformation() { if ($this->parsedFormatInfo != null) { return $this->parsedFormatInfo; } // Read top-left format info bits $formatInfoBits1 = 0; for ($i = 0; $i < 6; $i++) { $formatInfoBits1 = $this->copyBit($i, 8, $formatInfoBits1); } // .. and skip a bit in the timing pattern ... $formatInfoBits1 = $this->copyBit(7, 8, $formatInfoBits1); $formatInfoBits1 = $this->copyBit(8, 8, $formatInfoBits1); $formatInfoBits1 = $this->copyBit(8, 7, $formatInfoBits1); // .. and skip a bit in the timing pattern ... for ($j = 5; $j >= 0; $j--) { $formatInfoBits1 = $this->copyBit(8, $j, $formatInfoBits1); } // Read the top-right/bottom-left pattern too $dimension = $this->bitMatrix->getHeight(); $formatInfoBits2 = 0; $jMin = $dimension - 7; for ($j = $dimension - 1; $j >= $jMin; $j--) { $formatInfoBits2 = $this->copyBit(8, $j, $formatInfoBits2); } for ($i = $dimension - 8; $i < $dimension; $i++) { $formatInfoBits2 = $this->copyBit($i, 8, $formatInfoBits2); } $parsedFormatInfo = FormatInformation::decodeFormatInformation($formatInfoBits1, $formatInfoBits2); if ($parsedFormatInfo != null) { return $parsedFormatInfo; } throw FormatException::getFormatInstance(); } private function copyBit($i, $j, $versionBits) { $bit = $this->mirror ? $this->bitMatrix->get($j, $i) : $this->bitMatrix->get($i, $j); return $bit ? ($versionBits << 1) | 0x1 : $versionBits << 1; } /** *Reads version information from one of its two locations within the QR Code.
* * @return {@link Version} encapsulating the QR Code's version * @throws FormatException if both version information locations cannot be parsed as * the valid encoding of version information */ public function readVersion() { if ($this->parsedVersion != null) { return $this->parsedVersion; } $dimension = $this->bitMatrix->getHeight(); $provisionalVersion = ($dimension - 17) / 4; if ($provisionalVersion <= 6) { return Version::getVersionForNumber($provisionalVersion); } // Read top-right version info: 3 wide by 6 tall $versionBits = 0; $ijMin = $dimension - 11; for ($j = 5; $j >= 0; $j--) { for ($i = $dimension - 9; $i >= $ijMin; $i--) { $versionBits = $this->copyBit($i, $j, $versionBits); } } $theParsedVersion = Version::decodeVersionInformation($versionBits); if ($theParsedVersion != null && $theParsedVersion->getDimensionForVersion() == $dimension) { $this->parsedVersion = $theParsedVersion; return $theParsedVersion; } // Hmm, failed. Try bottom left: 6 wide by 3 tall $versionBits = 0; for ($i = 5; $i >= 0; $i--) { for ($j = $dimension - 9; $j >= $ijMin; $j--) { $versionBits = $this->copyBit($i, $j, $versionBits); } } $theParsedVersion = Version::decodeVersionInformation($versionBits); if ($theParsedVersion != null && $theParsedVersion->getDimensionForVersion() == $dimension) { $this->parsedVersion = $theParsedVersion; return $theParsedVersion; } throw FormatException::getFormatInstance(); } /** * Revert the mask removal done while reading the code words. The bit matrix should revert to its original state. */ public function remask(): void { if ($this->parsedFormatInfo == null) { return; // We have no format information, and have no data mask } $dataMask = DataMask::forReference($this->parsedFormatInfo->getDataMask()); $dimension = $this->bitMatrix->getHeight(); $dataMask->unmaskBitMatrix($this->bitMatrix, $dimension); } /** * Prepare the parser for a mirrored operation. * This flag has effect only on the {@link #readFormatInformation()} and the * {@link #readVersion()}. Before proceeding with {@link #readCodewords()} the * {@link #mirror()} method should be called. * * @param Whether $mirror to read version and format information mirrored. */ public function setMirror($mirror): void { $parsedVersion = null; $parsedFormatInfo = null; $this->mirror = $mirror; } /** Mirror the bit matrix in order to attempt a second reading. */ public function mirror(): void { for ($x = 0; $x < $this->bitMatrix->getWidth(); $x++) { for ($y = $x + 1; $y < $this->bitMatrix->getHeight(); $y++) { if ($this->bitMatrix->get($x, $y) != $this->bitMatrix->get($y, $x)) { $this->bitMatrix->flip($y, $x); $this->bitMatrix->flip($x, $y); } } } } }