<?php

/**
 * This file is based on code of tecnickcom/TCPDF PDF library.
 *
 * Original author Nicola Asuni (info@tecnick.com) and
 * contributors (https://github.com/tecnickcom/TCPDF/graphs/contributors).
 *
 * @see https://github.com/tecnickcom/TCPDF
 *
 * Original code was licensed on the terms of the LGPL v3.
 *
 * ------------------------------------------------------------------------------
 *
 * @file This file is part of the PdfParser library.
 *
 * @author  Konrad Abicht <k.abicht@gmail.com>
 *
 * @date    2020-01-06
 *
 * @license LGPLv3
 *
 * @url     <https://github.com/smalot/pdfparser>
 *
 *  PdfParser is a pdf library written in PHP, extraction oriented.
 *  Copyright (C) 2017 - Sébastien MALOT <sebastien@malot.fr>
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program.
 *  If not, see <http://www.pdfparser.org/sites/default/LICENSE.txt>.
 */
namespace SearchWP\Dependencies\Smalot\PdfParser\RawData;

use SearchWP\Dependencies\Smalot\PdfParser\Config;
class RawDataParser
{
    /**
     * @var \Smalot\PdfParser\Config
     */
    private $config;
    /**
     * Configuration array.
     */
    protected $cfg = [
        // if `true` ignore filter decoding errors
        'ignore_filter_decoding_errors' => \true,
        // if `true` ignore missing filter decoding errors
        'ignore_missing_filter_decoders' => \true,
    ];
    protected $filterHelper;
    protected $objects;
    /**
     * @param array $cfg Configuration array, default is []
     */
    public function __construct($cfg = [], Config $config = null)
    {
        // merge given array with default values
        $this->cfg = \array_merge($this->cfg, $cfg);
        $this->filterHelper = new FilterHelper();
        $this->config = $config ?: new Config();
    }
    /**
     * Decode the specified stream.
     *
     * @param string $pdfData PDF data
     * @param array  $sdic    Stream's dictionary array
     * @param string $stream  Stream to decode
     *
     * @return array containing decoded stream data and remaining filters
     *
     * @throws \Exception
     */
    protected function decodeStream(string $pdfData, array $xref, array $sdic, string $stream) : array
    {
        // get stream length and filters
        $slength = \strlen($stream);
        if ($slength <= 0) {
            return ['', []];
        }
        $filters = [];
        foreach ($sdic as $k => $v) {
            if ('/' == $v[0]) {
                if ('Length' == $v[1] && isset($sdic[$k + 1]) && 'numeric' == $sdic[$k + 1][0]) {
                    // get declared stream length
                    $declength = (int) $sdic[$k + 1][1];
                    if ($declength < $slength) {
                        $stream = \substr($stream, 0, $declength);
                        $slength = $declength;
                    }
                } elseif ('Filter' == $v[1] && isset($sdic[$k + 1])) {
                    // resolve indirect object
                    $objval = $this->getObjectVal($pdfData, $xref, $sdic[$k + 1]);
                    if ('/' == $objval[0]) {
                        // single filter
                        $filters[] = $objval[1];
                    } elseif ('[' == $objval[0]) {
                        // array of filters
                        foreach ($objval[1] as $flt) {
                            if ('/' == $flt[0]) {
                                $filters[] = $flt[1];
                            }
                        }
                    }
                }
            }
        }
        // decode the stream
        $remaining_filters = [];
        foreach ($filters as $filter) {
            if (\in_array($filter, $this->filterHelper->getAvailableFilters())) {
                try {
                    $stream = $this->filterHelper->decodeFilter($filter, $stream, $this->config->getDecodeMemoryLimit());
                } catch (\Exception $e) {
                    $emsg = $e->getMessage();
                    if ('~' == $emsg[0] && !$this->cfg['ignore_missing_filter_decoders'] || '~' != $emsg[0] && !$this->cfg['ignore_filter_decoding_errors']) {
                        throw new \Exception($e->getMessage());
                    }
                }
            } else {
                // add missing filter to array
                $remaining_filters[] = $filter;
            }
        }
        return [$stream, $remaining_filters];
    }
    /**
     * Decode the Cross-Reference section
     *
     * @param string $pdfData   PDF data
     * @param int    $startxref Offset at which the xref section starts (position of the 'xref' keyword)
     * @param array  $xref      Previous xref array (if any)
     *
     * @return array containing xref and trailer data
     *
     * @throws \Exception
     */
    protected function decodeXref(string $pdfData, int $startxref, array $xref = []) : array
    {
        $startxref += 4;
        // 4 is the length of the word 'xref'
        // skip initial white space chars
        $offset = $startxref + \strspn($pdfData, $this->config->getPdfWhitespaces(), $startxref);
        // initialize object number
        $obj_num = 0;
        // search for cross-reference entries or subsection
        while (\preg_match('/([0-9]+)[\\x20]([0-9]+)[\\x20]?([nf]?)(\\r\\n|[\\x20]?[\\r\\n])/', $pdfData, $matches, \PREG_OFFSET_CAPTURE, $offset) > 0) {
            if ($matches[0][1] != $offset) {
                // we are on another section
                break;
            }
            $offset += \strlen($matches[0][0]);
            if ('n' == $matches[3][0]) {
                // create unique object index: [object number]_[generation number]
                $index = $obj_num . '_' . (int) $matches[2][0];
                // check if object already exist
                if (!isset($xref['xref'][$index])) {
                    // store object offset position
                    $xref['xref'][$index] = (int) $matches[1][0];
                }
                ++$obj_num;
            } elseif ('f' == $matches[3][0]) {
                ++$obj_num;
            } else {
                // object number (index)
                $obj_num = (int) $matches[1][0];
            }
        }
        // get trailer data
        if (\preg_match('/trailer[\\s]*<<(.*)>>/isU', $pdfData, $matches, \PREG_OFFSET_CAPTURE, $offset) > 0) {
            $trailer_data = $matches[1][0];
            if (!isset($xref['trailer']) || empty($xref['trailer'])) {
                // get only the last updated version
                $xref['trailer'] = [];
                // parse trailer_data
                if (\preg_match('/Size[\\s]+([0-9]+)/i', $trailer_data, $matches) > 0) {
                    $xref['trailer']['size'] = (int) $matches[1];
                }
                if (\preg_match('/Root[\\s]+([0-9]+)[\\s]+([0-9]+)[\\s]+R/i', $trailer_data, $matches) > 0) {
                    $xref['trailer']['root'] = (int) $matches[1] . '_' . (int) $matches[2];
                }
                if (\preg_match('/Encrypt[\\s]+([0-9]+)[\\s]+([0-9]+)[\\s]+R/i', $trailer_data, $matches) > 0) {
                    $xref['trailer']['encrypt'] = (int) $matches[1] . '_' . (int) $matches[2];
                }
                if (\preg_match('/Info[\\s]+([0-9]+)[\\s]+([0-9]+)[\\s]+R/i', $trailer_data, $matches) > 0) {
                    $xref['trailer']['info'] = (int) $matches[1] . '_' . (int) $matches[2];
                }
                if (\preg_match('/ID[\\s]*[\\[][\\s]*[<]([^>]*)[>][\\s]*[<]([^>]*)[>]/i', $trailer_data, $matches) > 0) {
                    $xref['trailer']['id'] = [];
                    $xref['trailer']['id'][0] = $matches[1];
                    $xref['trailer']['id'][1] = $matches[2];
                }
            }
            if (\preg_match('/Prev[\\s]+([0-9]+)/i', $trailer_data, $matches) > 0) {
                // get previous xref
                $xref = $this->getXrefData($pdfData, (int) $matches[1], $xref);
            }
        } else {
            throw new \Exception('Unable to find trailer');
        }
        return $xref;
    }
    /**
     * Decode the Cross-Reference Stream section
     *
     * @param string $pdfData   PDF data
     * @param int    $startxref Offset at which the xref section starts
     * @param array  $xref      Previous xref array (if any)
     *
     * @return array containing xref and trailer data
     *
     * @throws \Exception if unknown PNG predictor detected
     */
    protected function decodeXrefStream(string $pdfData, int $startxref, array $xref = []) : array
    {
        // try to read Cross-Reference Stream
        $xrefobj = $this->getRawObject($pdfData, $startxref);
        $xrefcrs = $this->getIndirectObject($pdfData, $xref, $xrefobj[1], $startxref, \true);
        if (!isset($xref['trailer']) || empty($xref['trailer'])) {
            // get only the last updated version
            $xref['trailer'] = [];
            $filltrailer = \true;
        } else {
            $filltrailer = \false;
        }
        if (!isset($xref['xref'])) {
            $xref['xref'] = [];
        }
        $valid_crs = \false;
        $columns = 0;
        $predictor = null;
        $sarr = $xrefcrs[0][1];
        if (!\is_array($sarr)) {
            $sarr = [];
        }
        $wb = [];
        foreach ($sarr as $k => $v) {
            if ('/' == $v[0] && 'Type' == $v[1] && (isset($sarr[$k + 1]) && '/' == $sarr[$k + 1][0] && 'XRef' == $sarr[$k + 1][1])) {
                $valid_crs = \true;
            } elseif ('/' == $v[0] && 'Index' == $v[1] && isset($sarr[$k + 1])) {
                // initialize list for: first object number in the subsection / number of objects
                $index_blocks = [];
                for ($m = 0; $m < \count($sarr[$k + 1][1]); $m += 2) {
                    $index_blocks[] = [$sarr[$k + 1][1][$m][1], $sarr[$k + 1][1][$m + 1][1]];
                }
            } elseif ('/' == $v[0] && 'Prev' == $v[1] && (isset($sarr[$k + 1]) && 'numeric' == $sarr[$k + 1][0])) {
                // get previous xref offset
                $prevxref = (int) $sarr[$k + 1][1];
            } elseif ('/' == $v[0] && 'W' == $v[1] && isset($sarr[$k + 1])) {
                // number of bytes (in the decoded stream) of the corresponding field
                $wb[0] = (int) $sarr[$k + 1][1][0][1];
                $wb[1] = (int) $sarr[$k + 1][1][1][1];
                $wb[2] = (int) $sarr[$k + 1][1][2][1];
            } elseif ('/' == $v[0] && 'DecodeParms' == $v[1] && isset($sarr[$k + 1][1])) {
                $decpar = $sarr[$k + 1][1];
                foreach ($decpar as $kdc => $vdc) {
                    if ('/' == $vdc[0] && 'Columns' == $vdc[1] && (isset($decpar[$kdc + 1]) && 'numeric' == $decpar[$kdc + 1][0])) {
                        $columns = (int) $decpar[$kdc + 1][1];
                    } elseif ('/' == $vdc[0] && 'Predictor' == $vdc[1] && (isset($decpar[$kdc + 1]) && 'numeric' == $decpar[$kdc + 1][0])) {
                        $predictor = (int) $decpar[$kdc + 1][1];
                    }
                }
            } elseif ($filltrailer) {
                if ('/' == $v[0] && 'Size' == $v[1] && (isset($sarr[$k + 1]) && 'numeric' == $sarr[$k + 1][0])) {
                    $xref['trailer']['size'] = $sarr[$k + 1][1];
                } elseif ('/' == $v[0] && 'Root' == $v[1] && (isset($sarr[$k + 1]) && 'objref' == $sarr[$k + 1][0])) {
                    $xref['trailer']['root'] = $sarr[$k + 1][1];
                } elseif ('/' == $v[0] && 'Info' == $v[1] && (isset($sarr[$k + 1]) && 'objref' == $sarr[$k + 1][0])) {
                    $xref['trailer']['info'] = $sarr[$k + 1][1];
                } elseif ('/' == $v[0] && 'Encrypt' == $v[1] && (isset($sarr[$k + 1]) && 'objref' == $sarr[$k + 1][0])) {
                    $xref['trailer']['encrypt'] = $sarr[$k + 1][1];
                } elseif ('/' == $v[0] && 'ID' == $v[1] && isset($sarr[$k + 1])) {
                    $xref['trailer']['id'] = [];
                    $xref['trailer']['id'][0] = $sarr[$k + 1][1][0][1];
                    $xref['trailer']['id'][1] = $sarr[$k + 1][1][1][1];
                }
            }
        }
        // decode data
        if ($valid_crs && isset($xrefcrs[1][3][0])) {
            if (null !== $predictor) {
                // number of bytes in a row
                $rowlen = $columns + 1;
                // convert the stream into an array of integers
                /** @var array<int> */
                $sdata = \unpack('C*', $xrefcrs[1][3][0]);
                // TODO: Handle the case when unpack returns false
                // split the rows
                $sdata = \array_chunk($sdata, $rowlen);
                // initialize decoded array
                $ddata = [];
                // initialize first row with zeros
                $prev_row = \array_fill(0, $rowlen, 0);
                // for each row apply PNG unpredictor
                foreach ($sdata as $k => $row) {
                    // initialize new row
                    $ddata[$k] = [];
                    // get PNG predictor value
                    $predictor = 10 + $row[0];
                    // for each byte on the row
                    for ($i = 1; $i <= $columns; ++$i) {
                        // new index
                        $j = $i - 1;
                        $row_up = $prev_row[$j];
                        if (1 == $i) {
                            $row_left = 0;
                            $row_upleft = 0;
                        } else {
                            $row_left = $row[$i - 1];
                            $row_upleft = $prev_row[$j - 1];
                        }
                        switch ($predictor) {
                            case 10:
                                // PNG prediction (on encoding, PNG None on all rows)
                                $ddata[$k][$j] = $row[$i];
                                break;
                            case 11:
                                // PNG prediction (on encoding, PNG Sub on all rows)
                                $ddata[$k][$j] = $row[$i] + $row_left & 0xff;
                                break;
                            case 12:
                                // PNG prediction (on encoding, PNG Up on all rows)
                                $ddata[$k][$j] = $row[$i] + $row_up & 0xff;
                                break;
                            case 13:
                                // PNG prediction (on encoding, PNG Average on all rows)
                                $ddata[$k][$j] = $row[$i] + ($row_left + $row_up) / 2 & 0xff;
                                break;
                            case 14:
                                // PNG prediction (on encoding, PNG Paeth on all rows)
                                // initial estimate
                                $p = $row_left + $row_up - $row_upleft;
                                // distances
                                $pa = \abs($p - $row_left);
                                $pb = \abs($p - $row_up);
                                $pc = \abs($p - $row_upleft);
                                $pmin = \min($pa, $pb, $pc);
                                // return minimum distance
                                switch ($pmin) {
                                    case $pa:
                                        $ddata[$k][$j] = $row[$i] + $row_left & 0xff;
                                        break;
                                    case $pb:
                                        $ddata[$k][$j] = $row[$i] + $row_up & 0xff;
                                        break;
                                    case $pc:
                                        $ddata[$k][$j] = $row[$i] + $row_upleft & 0xff;
                                        break;
                                }
                                break;
                            default:
                                // PNG prediction (on encoding, PNG optimum)
                                throw new \Exception('Unknown PNG predictor: ' . $predictor);
                        }
                    }
                    $prev_row = $ddata[$k];
                }
                // end for each row
                // complete decoding
            } else {
                // number of bytes in a row
                $rowlen = \array_sum($wb);
                // convert the stream into an array of integers
                $sdata = \unpack('C*', $xrefcrs[1][3][0]);
                // split the rows
                $ddata = \array_chunk($sdata, $rowlen);
            }
            $sdata = [];
            // for every row
            foreach ($ddata as $k => $row) {
                // initialize new row
                $sdata[$k] = [0, 0, 0];
                if (0 == $wb[0]) {
                    // default type field
                    $sdata[$k][0] = 1;
                }
                $i = 0;
                // count bytes in the row
                // for every column
                for ($c = 0; $c < 3; ++$c) {
                    // for every byte on the column
                    for ($b = 0; $b < $wb[$c]; ++$b) {
                        if (isset($row[$i])) {
                            $sdata[$k][$c] += $row[$i] << ($wb[$c] - 1 - $b) * 8;
                        }
                        ++$i;
                    }
                }
            }
            // fill xref
            if (isset($index_blocks)) {
                // load the first object number of the first /Index entry
                $obj_num = $index_blocks[0][0];
            } else {
                $obj_num = 0;
            }
            foreach ($sdata as $k => $row) {
                switch ($row[0]) {
                    case 0:
                        // (f) linked list of free objects
                        break;
                    case 1:
                        // (n) objects that are in use but are not compressed
                        // create unique object index: [object number]_[generation number]
                        $index = $obj_num . '_' . $row[2];
                        // check if object already exist
                        if (!isset($xref['xref'][$index])) {
                            // store object offset position
                            $xref['xref'][$index] = $row[1];
                        }
                        break;
                    case 2:
                        // compressed objects
                        // $row[1] = object number of the object stream in which this object is stored
                        // $row[2] = index of this object within the object stream
                        $index = $row[1] . '_0_' . $row[2];
                        $xref['xref'][$index] = -1;
                        break;
                    default:
                        // null objects
                        break;
                }
                ++$obj_num;
                if (isset($index_blocks)) {
                    // reduce the number of remaining objects
                    --$index_blocks[0][1];
                    if (0 == $index_blocks[0][1]) {
                        // remove the actual used /Index entry
                        \array_shift($index_blocks);
                        if (0 < \count($index_blocks)) {
                            // load the first object number of the following /Index entry
                            $obj_num = $index_blocks[0][0];
                        } else {
                            // if there are no more entries, remove $index_blocks to avoid actions on an empty array
                            unset($index_blocks);
                        }
                    }
                }
            }
        }
        // end decoding data
        if (isset($prevxref)) {
            // get previous xref
            $xref = $this->getXrefData($pdfData, $prevxref, $xref);
        }
        return $xref;
    }
    protected function getObjectHeaderPattern(array $objRefs) : string
    {
        // consider all whitespace character (PDF specifications)
        return '/' . $objRefs[0] . $this->config->getPdfWhitespacesRegex() . $objRefs[1] . $this->config->getPdfWhitespacesRegex() . 'obj/';
    }
    protected function getObjectHeaderLen(array $objRefs) : int
    {
        // "4 0 obj"
        // 2 whitespaces + strlen("obj") = 5
        return 5 + \strlen($objRefs[0]) + \strlen($objRefs[1]);
    }
    /**
     * Get content of indirect object.
     *
     * @param string $pdfData  PDF data
     * @param string $objRef   Object number and generation number separated by underscore character
     * @param int    $offset   Object offset
     * @param bool   $decoding If true decode streams
     *
     * @return array containing object data
     *
     * @throws \Exception if invalid object reference found
     */
    protected function getIndirectObject(string $pdfData, array $xref, string $objRef, int $offset = 0, bool $decoding = \true) : array
    {
        /*
         * build indirect object header
         */
        // $objHeader = "[object number] [generation number] obj"
        $objRefArr = \explode('_', $objRef);
        if (2 !== \count($objRefArr)) {
            throw new \Exception('Invalid object reference for $obj.');
        }
        $objHeaderLen = $this->getObjectHeaderLen($objRefArr);
        /*
         * check if we are in position
         */
        // ignore whitespace characters at offset
        $offset += \strspn($pdfData, $this->config->getPdfWhitespaces(), $offset);
        // ignore leading zeros for object number
        $offset += \strspn($pdfData, '0', $offset);
        if (0 == \preg_match($this->getObjectHeaderPattern($objRefArr), \substr($pdfData, $offset, $objHeaderLen))) {
            // an indirect reference to an undefined object shall be considered a reference to the null object
            return ['null', 'null', $offset];
        }
        /*
         * get content
         */
        // starting position of object content
        $offset += $objHeaderLen;
        $objContentArr = [];
        $i = 0;
        // object main index
        do {
            $oldOffset = $offset;
            // get element
            $element = $this->getRawObject($pdfData, $offset);
            $offset = $element[2];
            // decode stream using stream's dictionary information
            if ($decoding && 'stream' === $element[0] && isset($objContentArr[$i - 1][0]) && '<<' === $objContentArr[$i - 1][0]) {
                $element[3] = $this->decodeStream($pdfData, $xref, $objContentArr[$i - 1][1], $element[1]);
            }
            $objContentArr[$i] = $element;
            ++$i;
        } while ('endobj' !== $element[0] && $offset !== $oldOffset);
        // remove closing delimiter
        \array_pop($objContentArr);
        /*
         * return raw object content
         */
        return $objContentArr;
    }
    /**
     * Get the content of object, resolving indirect object reference if necessary.
     *
     * @param string $pdfData PDF data
     * @param array  $obj     Object value
     *
     * @return array containing object data
     *
     * @throws \Exception
     */
    protected function getObjectVal(string $pdfData, $xref, array $obj) : array
    {
        if ('objref' == $obj[0]) {
            // reference to indirect object
            if (isset($this->objects[$obj[1]])) {
                // this object has been already parsed
                return $this->objects[$obj[1]];
            } elseif (isset($xref[$obj[1]])) {
                // parse new object
                $this->objects[$obj[1]] = $this->getIndirectObject($pdfData, $xref, $obj[1], $xref[$obj[1]], \false);
                return $this->objects[$obj[1]];
            }
        }
        return $obj;
    }
    /**
     * Get object type, raw value and offset to next object
     *
     * @param int $offset Object offset
     *
     * @return array containing object type, raw value and offset to next object
     */
    protected function getRawObject(string $pdfData, int $offset = 0) : array
    {
        $objtype = '';
        // object type to be returned
        $objval = '';
        // object value to be returned
        // skip initial white space chars
        $offset += \strspn($pdfData, $this->config->getPdfWhitespaces(), $offset);
        // get first char
        $char = $pdfData[$offset];
        // get object type
        switch ($char) {
            case '%':
                // \x25 PERCENT SIGN
                // skip comment and search for next token
                $next = \strcspn($pdfData, "\r\n", $offset);
                if ($next > 0) {
                    $offset += $next;
                    return $this->getRawObject($pdfData, $offset);
                }
                break;
            case '/':
                // \x2F SOLIDUS
                // name object
                $objtype = $char;
                ++$offset;
                $pregResult = \preg_match('/^([^\\x00\\x09\\x0a\\x0c\\x0d\\x20\\s\\x28\\x29\\x3c\\x3e\\x5b\\x5d\\x7b\\x7d\\x2f\\x25]+)/', \substr($pdfData, $offset, 256), $matches);
                if (1 == $pregResult) {
                    $objval = $matches[1];
                    // unescaped value
                    $offset += \strlen($objval);
                }
                break;
            case '(':
            // \x28 LEFT PARENTHESIS
            case ')':
                // \x29 RIGHT PARENTHESIS
                // literal string object
                $objtype = $char;
                ++$offset;
                $strpos = $offset;
                if ('(' == $char) {
                    $open_bracket = 1;
                    while ($open_bracket > 0) {
                        if (!isset($pdfData[$strpos])) {
                            break;
                        }
                        $ch = $pdfData[$strpos];
                        switch ($ch) {
                            case '\\':
                                // REVERSE SOLIDUS (5Ch) (Backslash)
                                // skip next character
                                ++$strpos;
                                break;
                            case '(':
                                // LEFT PARENHESIS (28h)
                                ++$open_bracket;
                                break;
                            case ')':
                                // RIGHT PARENTHESIS (29h)
                                --$open_bracket;
                                break;
                        }
                        ++$strpos;
                    }
                    $objval = \substr($pdfData, $offset, $strpos - $offset - 1);
                    $offset = $strpos;
                }
                break;
            case '[':
            // \x5B LEFT SQUARE BRACKET
            case ']':
                // \x5D RIGHT SQUARE BRACKET
                // array object
                $objtype = $char;
                ++$offset;
                if ('[' == $char) {
                    // get array content
                    $objval = [];
                    do {
                        $oldOffset = $offset;
                        // get element
                        $element = $this->getRawObject($pdfData, $offset);
                        $offset = $element[2];
                        $objval[] = $element;
                    } while (']' != $element[0] && $offset != $oldOffset);
                    // remove closing delimiter
                    \array_pop($objval);
                }
                break;
            case '<':
            // \x3C LESS-THAN SIGN
            case '>':
                // \x3E GREATER-THAN SIGN
                if (isset($pdfData[$offset + 1]) && $pdfData[$offset + 1] == $char) {
                    // dictionary object
                    $objtype = $char . $char;
                    $offset += 2;
                    if ('<' == $char) {
                        // get array content
                        $objval = [];
                        do {
                            $oldOffset = $offset;
                            // get element
                            $element = $this->getRawObject($pdfData, $offset);
                            $offset = $element[2];
                            $objval[] = $element;
                        } while ('>>' != $element[0] && $offset != $oldOffset);
                        // remove closing delimiter
                        \array_pop($objval);
                    }
                } else {
                    // hexadecimal string object
                    $objtype = $char;
                    ++$offset;
                    $pregResult = \preg_match('/^([0-9A-Fa-f\\x09\\x0a\\x0c\\x0d\\x20]+)>/iU', \substr($pdfData, $offset), $matches);
                    if ('<' == $char && 1 == $pregResult) {
                        // remove white space characters
                        $objval = \strtr($matches[1], $this->config->getPdfWhitespaces(), '');
                        $offset += \strlen($matches[0]);
                    } elseif (\false !== ($endpos = \strpos($pdfData, '>', $offset))) {
                        $offset = $endpos + 1;
                    }
                }
                break;
            default:
                if ('endobj' == \substr($pdfData, $offset, 6)) {
                    // indirect object
                    $objtype = 'endobj';
                    $offset += 6;
                } elseif ('null' == \substr($pdfData, $offset, 4)) {
                    // null object
                    $objtype = 'null';
                    $offset += 4;
                    $objval = 'null';
                } elseif ('true' == \substr($pdfData, $offset, 4)) {
                    // boolean true object
                    $objtype = 'boolean';
                    $offset += 4;
                    $objval = 'true';
                } elseif ('false' == \substr($pdfData, $offset, 5)) {
                    // boolean false object
                    $objtype = 'boolean';
                    $offset += 5;
                    $objval = 'false';
                } elseif ('stream' == \substr($pdfData, $offset, 6)) {
                    // start stream object
                    $objtype = 'stream';
                    $offset += 6;
                    if (1 == \preg_match('/^([\\r]?[\\n])/isU', \substr($pdfData, $offset), $matches)) {
                        $offset += \strlen($matches[0]);
                        $pregResult = \preg_match('/(endstream)[\\x09\\x0a\\x0c\\x0d\\x20]/isU', \substr($pdfData, $offset), $matches, \PREG_OFFSET_CAPTURE);
                        if (1 == $pregResult) {
                            $objval = \substr($pdfData, $offset, $matches[0][1]);
                            $offset += $matches[1][1];
                        }
                    }
                } elseif ('endstream' == \substr($pdfData, $offset, 9)) {
                    // end stream object
                    $objtype = 'endstream';
                    $offset += 9;
                } elseif (1 == \preg_match('/^([0-9]+)[\\s]+([0-9]+)[\\s]+R/iU', \substr($pdfData, $offset, 33), $matches)) {
                    // indirect object reference
                    $objtype = 'objref';
                    $offset += \strlen($matches[0]);
                    $objval = (int) $matches[1] . '_' . (int) $matches[2];
                } elseif (1 == \preg_match('/^([0-9]+)[\\s]+([0-9]+)[\\s]+obj/iU', \substr($pdfData, $offset, 33), $matches)) {
                    // object start
                    $objtype = 'obj';
                    $objval = (int) $matches[1] . '_' . (int) $matches[2];
                    $offset += \strlen($matches[0]);
                } elseif (($numlen = \strspn($pdfData, '+-.0123456789', $offset)) > 0) {
                    // numeric object
                    $objtype = 'numeric';
                    $objval = \substr($pdfData, $offset, $numlen);
                    $offset += $numlen;
                }
                break;
        }
        return [$objtype, $objval, $offset];
    }
    /**
     * Get Cross-Reference (xref) table and trailer data from PDF document data.
     *
     * @param int   $offset xref offset (if known)
     * @param array $xref   previous xref array (if any)
     *
     * @return array containing xref and trailer data
     *
     * @throws \Exception if it was unable to find startxref
     * @throws \Exception if it was unable to find xref
     */
    protected function getXrefData(string $pdfData, int $offset = 0, array $xref = []) : array
    {
        $startxrefPreg = \preg_match('/[\\r\\n]startxref[\\s]*[\\r\\n]+([0-9]+)[\\s]*[\\r\\n]+%%EOF/i', $pdfData, $matches, \PREG_OFFSET_CAPTURE, $offset);
        if (0 == $offset) {
            // find last startxref
            $pregResult = \preg_match_all('/[\\r\\n]startxref[\\s]*[\\r\\n]+([0-9]+)[\\s]*[\\r\\n]+%%EOF/i', $pdfData, $matches, \PREG_SET_ORDER, $offset);
            if (0 == $pregResult) {
                throw new \Exception('Unable to find startxref');
            }
            $matches = \array_pop($matches);
            $startxref = $matches[1];
        } elseif (\strpos($pdfData, 'xref', $offset) == $offset) {
            // Already pointing at the xref table
            $startxref = $offset;
        } elseif (\preg_match('/([0-9]+[\\s][0-9]+[\\s]obj)/i', $pdfData, $matches, \PREG_OFFSET_CAPTURE, $offset)) {
            // Cross-Reference Stream object
            $startxref = $offset;
        } elseif ($startxrefPreg) {
            // startxref found
            $startxref = $matches[1][0];
        } else {
            throw new \Exception('Unable to find startxref');
        }
        if ($startxref > \strlen($pdfData)) {
            throw new \Exception('Unable to find xref (PDF corrupted?)');
        }
        // check xref position
        if (\strpos($pdfData, 'xref', $startxref) == $startxref) {
            // Cross-Reference
            $xref = $this->decodeXref($pdfData, $startxref, $xref);
        } else {
            // Cross-Reference Stream
            $xref = $this->decodeXrefStream($pdfData, $startxref, $xref);
        }
        if (empty($xref)) {
            throw new \Exception('Unable to find xref');
        }
        return $xref;
    }
    /**
     * Parses PDF data and returns extracted data as array.
     *
     * @param string $data PDF data to parse
     *
     * @return array array of parsed PDF document objects
     *
     * @throws \Exception if empty PDF data given
     * @throws \Exception if PDF data missing %PDF header
     */
    public function parseData(string $data) : array
    {
        if (empty($data)) {
            throw new \Exception('Empty PDF data given.');
        }
        // find the pdf header starting position
        if (\false === ($trimpos = \strpos($data, '%PDF-'))) {
            throw new \Exception('Invalid PDF data: missing %PDF header.');
        }
        // get PDF content string
        $pdfData = \substr($data, $trimpos);
        // get xref and trailer data
        $xref = $this->getXrefData($pdfData);
        // parse all document objects
        $objects = [];
        foreach ($xref['xref'] as $obj => $offset) {
            if (!isset($objects[$obj]) && $offset > 0) {
                // decode objects with positive offset
                $objects[$obj] = $this->getIndirectObject($pdfData, $xref, $obj, $offset, \true);
            }
        }
        return [$xref, $objects];
    }
}
