Encapsulates a block of data within a QR Code. QR Codes may split their data into * multiple blocks, each of which is a unit of data and error-correction codewords. Each * is represented by an instance of this class.

* * @author Sean Owen */ final class DataBlock { //byte[] private function __construct(private $numDataCodewords, private $codewords) { } /** *

When QR Codes use multiple data blocks, they are actually interleaved. * That is, the first byte of data block 1 to n is written, then the second bytes, and so on. This * method will separate the data into original blocks.

* * @param bytes $rawCodewords as read directly from the QR Code * @param version $version of the QR Code * @param error $ecLevel-correction level of the QR Code * * @return array DataBlocks containing original bytes, "de-interleaved" from representation in the * QR Code */ public static function getDataBlocks( $rawCodewords, $version, $ecLevel ) { if ((is_countable($rawCodewords) ? count($rawCodewords) : 0) != $version->getTotalCodewords()) { throw new \InvalidArgumentException(); } // Figure out the number and size of data blocks used by this version and // error correction level $ecBlocks = $version->getECBlocksForLevel($ecLevel); // First count the total number of data blocks $totalBlocks = 0; $ecBlockArray = $ecBlocks->getECBlocks(); foreach ($ecBlockArray as $ecBlock) { $totalBlocks += $ecBlock->getCount(); } // Now establish DataBlocks of the appropriate size and number of data codewords $result = [];//new DataBlock[$totalBlocks]; $numResultBlocks = 0; foreach ($ecBlockArray as $ecBlock) { $ecBlockCount = $ecBlock->getCount(); for ($i = 0; $i < $ecBlockCount; $i++) { $numDataCodewords = $ecBlock->getDataCodewords(); $numBlockCodewords = $ecBlocks->getECCodewordsPerBlock() + $numDataCodewords; $result[$numResultBlocks++] = new DataBlock($numDataCodewords, fill_array(0, $numBlockCodewords, 0)); } } // All blocks have the same amount of data, except that the last n // (where n may be 0) have 1 more byte. Figure out where these start. $shorterBlocksTotalCodewords = is_countable($result[0]->codewords) ? count($result[0]->codewords) : 0; $longerBlocksStartAt = count($result) - 1; while ($longerBlocksStartAt >= 0) { $numCodewords = is_countable($result[$longerBlocksStartAt]->codewords) ? count($result[$longerBlocksStartAt]->codewords) : 0; if ($numCodewords == $shorterBlocksTotalCodewords) { break; } $longerBlocksStartAt--; } $longerBlocksStartAt++; $shorterBlocksNumDataCodewords = $shorterBlocksTotalCodewords - $ecBlocks->getECCodewordsPerBlock(); // The last elements of result may be 1 element longer; // first fill out as many elements as all of them have $rawCodewordsOffset = 0; for ($i = 0; $i < $shorterBlocksNumDataCodewords; $i++) { for ($j = 0; $j < $numResultBlocks; $j++) { $result[$j]->codewords[$i] = $rawCodewords[$rawCodewordsOffset++]; } } // Fill out the last data block in the longer ones for ($j = $longerBlocksStartAt; $j < $numResultBlocks; $j++) { $result[$j]->codewords[$shorterBlocksNumDataCodewords] = $rawCodewords[$rawCodewordsOffset++]; } // Now add in error correction blocks $max = is_countable($result[0]->codewords) ? count($result[0]->codewords) : 0; for ($i = $shorterBlocksNumDataCodewords; $i < $max; $i++) { for ($j = 0; $j < $numResultBlocks; $j++) { $iOffset = $j < $longerBlocksStartAt ? $i : $i + 1; $result[$j]->codewords[$iOffset] = $rawCodewords[$rawCodewordsOffset++]; } } return $result; } public function getNumDataCodewords() { return $this->numDataCodewords; } public function getCodewords() { return $this->codewords; } }