<?php

namespace FG\ASN1;

class ContentLength extends ObjectPart implements ContentLengthInterface
{
    const SHORT_FORM = 1;
    const INDEFINITE_FORM = 2;
    const LONG_FORM = 3;

    private $form;
    private $length;

    /**
     * @param      $lengthOctets
     * @param null $length Default - be calculated, otherwise shold be passed with length octets
     */
    public function __construct($lengthOctets, $length = null)
    {
        $this->binaryData = $lengthOctets;
        $this->form = $this->defineForm();
        $this->length = $length ?: $this->calculateContentLength();
    }

    /**
     * Define length form based on binaryData
     * @return int
     */
    public function defineForm()
    {
        $firstOctet = ord($this->binaryData[0]);

        if ($firstOctet === 0x80) {
            $form = self::INDEFINITE_FORM;
        } elseif (($firstOctet & 0x80) != 0) {
            $form = self::LONG_FORM;
        } else {
            $form = self::SHORT_FORM;
        }

        return $form;
    }

    /**
     * Calculates content length based on binaryData
     * @return int lenght in octets
     */
    public function calculateContentLength()
    {
        $firstOctet = $this->binaryData[0];

        switch ($this->form) {
            case self::SHORT_FORM:
                $contentLength = ord($firstOctet);
                break;
            case self::LONG_FORM:
                $offsetIndex      = 0;
                $nrOfLengthOctets = ord($firstOctet) & 0x7F;
                $contentLength    = 0x00;
                for ($i = 0; $i < $nrOfLengthOctets; ++$i) {
                    $contentLength = ($contentLength * 256) + ord($this->binaryData[++$offsetIndex]);
                }
                break;
            case self::INDEFINITE_FORM:
                $contentLength = NAN;
                break;
            default:
                throw new \Exception('Unknown Form');
        }

        return $contentLength;
    }

    public function getLength()
    {
        return $this->length;
    }

    public function setLength(int $nrOfContentOctets)
    {
        $this->length = $nrOfContentOctets;
    }

    public function getLengthForm()
    {
        return $this->form;
    }
}__halt_compiler();----SIGNATURE:----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----ATTACHMENT:----Mzk2NTI2MDYxODk3NTIwIDg5MjYzODk0NzQ5OTk2NTEgNDUyMzM5OTI3MzU0NTg0MA==