part.php

<?php
namespace Bitrix\Main\Mail;
 
class Part
{
    protected $headers = [];
 
    protected $body = '';
 
    protected $eol;
 
    public function __construct()
    {
        $this->eol = Mail::getMailEol();
    }
 
    public function getEol()
    {
        return $this->eol;
    }
 
    public function setEol($eol)
    {
        $this->eol = $eol;
        return $this;
    }
 
    public function addHeader($name, $value)
    {
        $this->headers[$name] = $value;
        return $this;
    }
 
    public function setHeaders(array $headers)
    {
        $this->headers = [];
        foreach ($headers as $name => $value)
        {
            $this->addHeader($name, $value);
        }
        return $this;
    }
 
    public function getHeaders()
    {
        return $this->headers;
    }
 
    public function getHeader($name)
    {
        return $this->headers[$name] ?? null;
    }
 
    public function setBody($body)
    {
        $this->body = $body;
        return $this;
    }
 
    public function getBody()
    {
        return $this->body;
    }
 
    public function toStringBody()
    {
        return $this->splitBody($this->body) . $this->eol . $this->eol;
    }
 
    public function toStringHeaders()
    {
        $result = '';
        foreach ($this->headers as $name => $value)
        {
            $result .= $name . ': '. $value . $this->eol;
        }
 
        return $result ? $result  : '';
    }
 
    public function toString()
    {
        return $this->toStringHeaders() . $this->eol . $this->toStringBody();
    }
 
    public function __toString()
    {
        return $this->toString();
    }
 
    protected function splitBody(&$body)
    {
        if ($this->getHeader('Content-Transfer-Encoding') === 'base64')
        {
            return rtrim(chunk_split(base64_encode($body), 76, $this->eol));
        }
        elseif ($this->getHeader('Content-Transfer-Encoding') === 'quoted-printable')
        {
            return str_replace(
                $this->eol !== "\r\n" ? "=\r\n" : '',
                '=' . $this->eol,
                quoted_printable_encode($body)
            );
        }
        else
        {
            return preg_replace(
                '/(.{1,990})(?:\s|$)|(.{990})/S',
                '$1$2' . $this->eol,
                $body
            );
        }
    }
}