fpdi-cn/Fpdi/PdfParser/Type/PdfType.php

<?php

/**
 * This file is part of FPDI
 *
 * @package   Fpdi
 * @copyright Copyright (c) 2020 Setasign GmbH & Co. KG (https://www.setasign.com)
 * @license   http://opensource.org/licenses/mit-license The MIT License
 */

namespace Fpdi\PdfParser\Type;

use Fpdi\PdfParser\CrossReference\CrossReferenceException;
use Fpdi\PdfParser\PdfParser;
use Fpdi\PdfParser\PdfParserException;

/**
 * A class defining a PDF data type
 */
class PdfType
{
    /**
     * Resolves a PdfType value to its value.
     *
     * This method is used to evaluate indirect and direct object references until a final value is reached.
     *
     * @param PdfType $value
     * @param PdfParser $parser
     * @param bool $stopAtIndirectObject
     * @return PdfType
     * @throws CrossReferenceException
     * @throws PdfParserException
     */
    public static function resolve(PdfType $value, PdfParser $parser, $stopAtIndirectObject = false)
    {
        if ($value instanceof PdfIndirectObject) {
            if ($stopAtIndirectObject === true) {
                return $value;
            }

            return self::resolve($value->value, $parser, $stopAtIndirectObject);
        }

        if ($value instanceof PdfIndirectObjectReference) {
            return self::resolve($parser->getIndirectObject($value->value), $parser, $stopAtIndirectObject);
        }

        return $value;
    }

    /**
     * Ensure that a value is an instance of a specific PDF type.
     *
     * @param string $type
     * @param PdfType $value
     * @param string $errorMessage
     * @return mixed
     * @throws PdfTypeException
     */
    protected static function ensureType($type, $value, $errorMessage)
    {
        if (!($value instanceof $type)) {
            throw new PdfTypeException(
                $errorMessage,
                PdfTypeException::INVALID_DATA_TYPE
            );
        }

        return $value;
    }

    /**
     * The value of the PDF type.
     *
     * @var mixed
     */
    public $value;
}