Convenience method that can decode a QR Code represented as a 2D array of booleans. * "true" is taken to mean a black module.
* * @param array $image booleans representing white/black QR Code modules * @param decoding $hints hints that should be used to influence decoding * * @return text and bytes encoded within the QR Code * @throws FormatException if the QR Code cannot be decoded * @throws ChecksumException if error correction fails */ public function decodeImage($image, $hints = null) { $dimension = count($image); $bits = new BitMatrix($dimension); for ($i = 0; $i < $dimension; $i++) { for ($j = 0; $j < $dimension; $j++) { if ($image[$i][$j]) { $bits->set($j, $i); } } } return $this->decode($bits, $hints); } /** *Decodes a QR Code represented as a {@link BitMatrix}. A 1 or "true" is taken to mean a black module.
* * @param BitMatrix $bits booleans representing white/black QR Code modules * @param decoding $hints hints that should be used to influence decoding * * @return text and bytes encoded within the QR Code * @throws FormatException if the QR Code cannot be decoded * @throws ChecksumException if error correction fails */ public function decodeBits($bits, $hints = null) { // Construct a parser and read version, error-correction level $parser = new BitMatrixParser($bits); $fe = null; $ce = null; try { return $this->decode($parser, $hints); } catch (FormatException $e) { $fe = $e; } catch (ChecksumException $e) { $ce = $e; } try { // Revert the bit matrix $parser->remask(); // Will be attempting a mirrored reading of the version and format info. $parser->setMirror(true); // Preemptively read the version. $parser->readVersion(); // Preemptively read the format information. $parser->readFormatInformation(); /* * Since we're here, this means we have successfully detected some kind * of version and format information when mirrored. This is a good sign, * that the QR code may be mirrored, and we should try once more with a * mirrored content. */ // Prepare for a mirrored reading. $parser->mirror(); $result = $this->decode($parser, $hints); // Success! Notify the caller that the code was mirrored. $result->setOther(new QRCodeDecoderMetaData(true)); return $result; } catch (FormatException $e) {// catch (FormatException | ChecksumException e) { // Throw the exception from the original reading if ($fe != null) { throw $fe; } if ($ce != null) { throw $ce; } throw $e; } } private function decodeParser($parser, $hints = null) { $version = $parser->readVersion(); $ecLevel = $parser->readFormatInformation()->getErrorCorrectionLevel(); // Read codewords $codewords = $parser->readCodewords(); // Separate into data blocks $dataBlocks = DataBlock::getDataBlocks($codewords, $version, $ecLevel); // Count total number of data bytes $totalBytes = 0; foreach ($dataBlocks as $dataBlock) { $totalBytes += $dataBlock->getNumDataCodewords(); } $resultBytes = fill_array(0, $totalBytes, 0); $resultOffset = 0; // Error-correct and copy data blocks together into a stream of bytes foreach ($dataBlocks as $dataBlock) { $codewordBytes = $dataBlock->getCodewords(); $numDataCodewords = $dataBlock->getNumDataCodewords(); $this->correctErrors($codewordBytes, $numDataCodewords); for ($i = 0; $i < $numDataCodewords; $i++) { $resultBytes[$resultOffset++] = $codewordBytes[$i]; } } // Decode the contents of that stream of bytes return DecodedBitStreamParser::decode($resultBytes, $version, $ecLevel, $hints); } /** *Given data and error-correction codewords received, possibly corrupted by errors, attempts to * correct the errors in-place using Reed-Solomon error correction.
* * @param data $codewordBytes and error correction codewords * @param number $numDataCodewords of codewords that are data bytes * * @throws ChecksumException if error correction fails */ private function correctErrors(&$codewordBytes, $numDataCodewords) { $numCodewords = is_countable($codewordBytes) ? count($codewordBytes) : 0; // First read into an array of ints $codewordsInts = fill_array(0, $numCodewords, 0); for ($i = 0; $i < $numCodewords; $i++) { $codewordsInts[$i] = $codewordBytes[$i] & 0xFF; } $numECCodewords = (is_countable($codewordBytes) ? count($codewordBytes) : 0) - $numDataCodewords; try { $this->rsDecoder->decode($codewordsInts, $numECCodewords); } catch (ReedSolomonException) { throw ChecksumException::getChecksumInstance(); } // Copy back into array of bytes -- only need to worry about the bytes that were data // We don't care about errors in the error-correction codewords for ($i = 0; $i < $numDataCodewords; $i++) { $codewordBytes[$i] = $codewordsInts[$i]; } } }