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<?php
/**
* This file is part of FPDI
*
* @package setasign\Fpdi
* @copyright Copyright (c) 2024 Setasign GmbH & Co. KG (https://www.setasign.com)
* @license http://opensource.org/licenses/mit-license The MIT License
*/
namespace setasign\Fpdi\PdfReader;
use setasign\Fpdi\PdfParser\CrossReference\CrossReferenceException;
use setasign\Fpdi\PdfParser\PdfParser;
use setasign\Fpdi\PdfParser\PdfParserException;
use setasign\Fpdi\PdfParser\Type\PdfArray;
use setasign\Fpdi\PdfParser\Type\PdfDictionary;
use setasign\Fpdi\PdfParser\Type\PdfIndirectObject;
use setasign\Fpdi\PdfParser\Type\PdfIndirectObjectReference;
use setasign\Fpdi\PdfParser\Type\PdfNumeric;
use setasign\Fpdi\PdfParser\Type\PdfType;
use setasign\Fpdi\PdfParser\Type\PdfTypeException;
/**
* A PDF reader class
*/
class PdfReader
{
/**
* @var PdfParser
*/
protected $parser;
/**
* @var int
*/
protected $pageCount;
/**
* Indirect objects of resolved pages.
*
* @var PdfIndirectObjectReference[]|PdfIndirectObject[]
*/
protected $pages = [];
/**
* PdfReader constructor.
*
* @param PdfParser $parser
*/
public function __construct(PdfParser $parser)
{
$this->parser = $parser;
}
/**
* PdfReader destructor.
*/
public function __destruct()
{
if ($this->parser !== null) {
$this->parser->cleanUp();
}
}
/**
* Get the pdf parser instance.
*
* @return PdfParser
*/
public function getParser()
{
return $this->parser;
}
/**
* Get the PDF version.
*
* @return string
* @throws PdfParserException
*/
public function getPdfVersion()
{
return \implode('.', $this->parser->getPdfVersion());
}
/**
* Get the page count.
*
* @return int
* @throws PdfTypeException
* @throws CrossReferenceException
* @throws PdfParserException
*/
public function getPageCount()
{
if ($this->pageCount === null) {
$catalog = $this->parser->getCatalog();
$pages = PdfType::resolve(PdfDictionary::get($catalog, 'Pages'), $this->parser);
$count = PdfType::resolve(PdfDictionary::get($pages, 'Count'), $this->parser);
$this->pageCount = PdfNumeric::ensure($count)->value;
}
return $this->pageCount;
}
/**
* Get a page instance.
*
* @param int|numeric-string $pageNumber
* @return Page
* @throws PdfTypeException
* @throws CrossReferenceException
* @throws PdfParserException
* @throws \InvalidArgumentException
*/
public function getPage($pageNumber)
{
if (!\is_numeric($pageNumber)) {
throw new \InvalidArgumentException(
'Page number needs to be a number.'
);
}
if ($pageNumber < 1 || $pageNumber > $this->getPageCount()) {
throw new \InvalidArgumentException(
\sprintf(
'Page number "%s" out of available page range (1 - %s)',
$pageNumber,
$this->getPageCount()
)
);
}
$this->readPages();
$page = $this->pages[$pageNumber - 1];
if ($page instanceof PdfIndirectObjectReference) {
$alreadyReadKids = [];
$readPages = function ($kids) use (&$readPages, &$alreadyReadKids) {
$kids = PdfArray::ensure($kids);
/** @noinspection LoopWhichDoesNotLoopInspection */
foreach ($kids->value as $reference) {
$reference = PdfIndirectObjectReference::ensure($reference);
if (\in_array($reference->value, $alreadyReadKids, true)) {
throw new PdfReaderException('Recursive pages dictionary detected.');
}
$alreadyReadKids[] = $reference->value;
$object = $this->parser->getIndirectObject($reference->value);
$type = PdfDictionary::get($object->value, 'Type');
if ($type->value === 'Pages') {
return $readPages(PdfDictionary::get($object->value, 'Kids'));
}
return $object;
}
throw new PdfReaderException(
'Kids array cannot be empty.',
PdfReaderException::KIDS_EMPTY
);
};
$page = $this->parser->getIndirectObject($page->value);
$dict = PdfType::resolve($page, $this->parser);
$type = PdfDictionary::get($dict, 'Type');
if ($type->value === 'Pages') {
$kids = PdfType::resolve(PdfDictionary::get($dict, 'Kids'), $this->parser);
try {
$alreadyReadKids[] = $page->objectNumber;
$page = $this->pages[$pageNumber - 1] = $readPages($kids);
} catch (PdfReaderException $e) {
if ($e->getCode() !== PdfReaderException::KIDS_EMPTY) {
throw $e;
}
// let's reset the pages array and read all page objects
$this->pages = [];
$this->readPages(true);
// @phpstan-ignore-next-line
$page = $this->pages[$pageNumber - 1];
}
} else {
$this->pages[$pageNumber - 1] = $page;
}
}
return new Page($page, $this->parser);
}
/**
* Walk the page tree and resolve all indirect objects of all pages.
*
* @param bool $readAll
* @throws CrossReferenceException
* @throws PdfParserException
* @throws PdfTypeException
*/
protected function readPages($readAll = false)
{
if (\count($this->pages) > 0) {
return;
}
$expectedPageCount = $this->getPageCount();
$alreadyReadKids = [];
$readPages = function ($kids, $count) use (&$readPages, &$alreadyReadKids, $readAll, $expectedPageCount) {
$kids = PdfArray::ensure($kids);
$isLeaf = ($count->value === \count($kids->value));
foreach ($kids->value as $reference) {
$reference = PdfIndirectObjectReference::ensure($reference);
if (!$readAll && $isLeaf) {
$this->pages[] = $reference;
continue;
}
if (\in_array($reference->value, $alreadyReadKids, true)) {
throw new PdfReaderException('Recursive pages dictionary detected.');
}
$alreadyReadKids[] = $reference->value;
$object = $this->parser->getIndirectObject($reference->value);
$type = PdfDictionary::get($object->value, 'Type');
if ($type->value === 'Pages') {
$readPages(
PdfType::resolve(PdfDictionary::get($object->value, 'Kids'), $this->parser),
PdfType::resolve(PdfDictionary::get($object->value, 'Count'), $this->parser)
);
} else {
$this->pages[] = $object;
}
// stop if all pages are read - faulty documents exists with additional entries with invalid data.
if (count($this->pages) === $expectedPageCount) {
break;
}
}
};
$catalog = $this->parser->getCatalog();
$pages = PdfType::resolve(PdfDictionary::get($catalog, 'Pages'), $this->parser);
$count = PdfType::resolve(PdfDictionary::get($pages, 'Count'), $this->parser);
$kids = PdfType::resolve(PdfDictionary::get($pages, 'Kids'), $this->parser);
$readPages($kids, $count);
}
}
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