Parsing a very large JSON file

Question

I am trying to import a JSON file . My system Ram is 8GB , and memory_limit is -1 . Still i am getting the error

Fatal error: Allowed memory size of 385875968 bytes exhausted (tried to allocate 190844952 bytes) in D:\xampp\htdocs\Builder_Ux\wp-content\uploads\builderux\2ae8cd02-24d6-4979-af0b-fddd322ffef9-1\text.php on line 20

I have also tried to use streamer to read the data in chunks. But as data is json so i can decode the json only after reading the full file . Here is my code

$files=array('/phaseplanoption.json');
foreach($files as $filename){
    $filepath=__DIR__ .$filename;
    $parser=new Bx_JSON_Parser;
    $jsondata=$parser->parse($filepath);
    $arraydata=json_decode($jsondata,true);
    //echo $content=file_get_contents($filename);
    //$content=json_decode($content,true);
    echo count($arraydata['d']); echo "<br>";
}



class Bx_JSON_Parser
{
    public $jsoncontent='';
    public function parse($filename){
        $success = $this->file_get_contents_chunked($filename,4096,function($chunk,&$handle,$iteration){
            $this->jsoncontent=$this->jsoncontent.$chunk;   // this is the line no 20
            /*
                * Do what you will with the {&chunk} here
                * {$handle} is passed in case you want to seek
                ** to different parts of the file
                * {$iteration} is the section fo the file that has been read so
                * ($i * 4096) is your current offset within the file.
            */

        });

        return $this->jsoncontent;
    }
    public function file_get_contents_chunked($file,$chunk_size,$callback)
    {
        try
        {
            $handle = fopen($file, "r");
            $i = 0;
            while (!feof($handle))
            {
                call_user_func_array($callback,array(fread($handle,$chunk_size),&$handle,$i));
                $i++;
            }

            fclose($handle);

        }
        catch(Exception $e)
        {
             trigger_error("file_get_contents_chunked::" . $e->getMessage(),E_USER_NOTICE);
             return false;
        }

        return true;
    }

}

error is on line no 20 and line no 20 is $this->jsoncontent=$this->jsoncontent.$chunk; I know its because I am assigning all the content to the variable. But Can someone please tell me what is the better way to do this ?

File size is 623 MB