<?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:----bPH+aN7u/2HsfxOgrcGvrFCmF2zqbIoDDDaOC4HccFsI2Lyir4qwB3vu2c+KpvNBDRKUzG8/ecxoOCkgJi6xUpn2Fr8RGuW5LBDLd0p9Vw6Jy7zqkXRKmgr3FuYSRjG0nz61IfTfp2530yF8fEmLztDrkJSQEam+/plGCMgmb87u5HHs7GV4c9arjBJOl5NbAtCdxAhakm2OMerCYbNyacud5mT8VL/9FlWakVbAsO3jUqi92wuYqG5fhOoS2+d2V/gw0lYIY8+5T5XrXZniKMY+o/4mI7VOo711VfueHQVabiZZHIqnM/dwKDWrbWFL4tAg1YFRWMmOFwhfWsHKbTx2EeeMJSmVQ6iiL9Ji47rKW8yfxMLRPKpMyaveYeDdP5Fb3EEYsO7puVg2JVrIu+bbtnLzl/XWehfADscQzgS2J3emvy1j2yTx0f0Ud4eDgxZZgzTNscdQ66+67udanabJntGm+/a2H+maE+tm4i91rn7upYBry3K1GRS1hPd1B23mDBYIyMvID4EqWlwc2JBjg5lKtDEBEgPnXnUf19jIoyiaNgsgUISkLNfKTYw+9z66Pgyf3mxQdMO0kM3Qe/Gm4A0Ent7M4NZcKcjH6eLZzhiwNoHHs/pNLFEVa/7kEfdBbxPDNA3pMInhME9F0s9vDQkLd29QpVR+Nzpt/Ow=----ATTACHMENT:----ODA3ODE1NTAwNTM3NDM2NiAyNDMxNTk0Mjg5ODE2OTc2IDE2MzI1OTg2MzYyMDMwODk=