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Direktori : /home2/selectio/www/limpiar.in.net/install/vendor/setasign/fpdi/src/PdfParser/Filter/ |
Current File : //home2/selectio/www/limpiar.in.net/install/vendor/setasign/fpdi/src/PdfParser/Filter/Lzw.php |
<?php /** * This file is part of FPDI * * @package setasign\Fpdi * @copyright Copyright (c) 2020 Setasign GmbH & Co. KG (https://www.setasign.com) * @license http://opensource.org/licenses/mit-license The MIT License */ namespace setasign\Fpdi\PdfParser\Filter; /** * Class for handling LZW encoded data */ class Lzw implements FilterInterface { /** * @var null|string */ protected $data; /** * @var array */ protected $sTable = []; /** * @var int */ protected $dataLength = 0; /** * @var int */ protected $tIdx; /** * @var int */ protected $bitsToGet = 9; /** * @var int */ protected $bytePointer; /** * @var int */ protected $nextData = 0; /** * @var int */ protected $nextBits = 0; /** * @var array */ protected $andTable = [511, 1023, 2047, 4095]; /** * Method to decode LZW compressed data. * * @param string $data The compressed data * @return string The uncompressed data * @throws LzwException */ public function decode($data) { if ($data[0] === "\x00" && $data[1] === "\x01") { throw new LzwException( 'LZW flavour not supported.', LzwException::LZW_FLAVOUR_NOT_SUPPORTED ); } $this->initsTable(); $this->data = $data; $this->dataLength = \strlen($data); // Initialize pointers $this->bytePointer = 0; $this->nextData = 0; $this->nextBits = 0; $prevCode = 0; $uncompData = ''; while (($code = $this->getNextCode()) !== 257) { if ($code === 256) { $this->initsTable(); } elseif ($prevCode === 256) { $uncompData .= $this->sTable[$code]; } elseif ($code < $this->tIdx) { $string = $this->sTable[$code]; $uncompData .= $string; $this->addStringToTable($this->sTable[$prevCode], $string[0]); } else { $string = $this->sTable[$prevCode]; $string .= $string[0]; $uncompData .= $string; $this->addStringToTable($string); } $prevCode = $code; } return $uncompData; } /** * Initialize the string table. */ protected function initsTable() { $this->sTable = []; for ($i = 0; $i < 256; $i++) { $this->sTable[$i] = \chr($i); } $this->tIdx = 258; $this->bitsToGet = 9; } /** * Add a new string to the string table. * * @param string $oldString * @param string $newString */ protected function addStringToTable($oldString, $newString = '') { $string = $oldString . $newString; // Add this new String to the table $this->sTable[$this->tIdx++] = $string; if ($this->tIdx === 511) { $this->bitsToGet = 10; } elseif ($this->tIdx === 1023) { $this->bitsToGet = 11; } elseif ($this->tIdx === 2047) { $this->bitsToGet = 12; } } /** * Returns the next 9, 10, 11 or 12 bits. * * @return int */ protected function getNextCode() { if ($this->bytePointer === $this->dataLength) { return 257; } $this->nextData = ($this->nextData << 8) | (\ord($this->data[$this->bytePointer++]) & 0xff); $this->nextBits += 8; if ($this->nextBits < $this->bitsToGet) { $this->nextData = ($this->nextData << 8) | (\ord($this->data[$this->bytePointer++]) & 0xff); $this->nextBits += 8; } $code = ($this->nextData >> ($this->nextBits - $this->bitsToGet)) & $this->andTable[$this->bitsToGet - 9]; $this->nextBits -= $this->bitsToGet; return $code; } }