HeadFilter::read PHP Method

    function read($len = null)
    {
        if (!$this->getInitialized()) {
            $this->_initialize();
            $this->setInitialized(true);
        }
        // note, if buffer contains fewer lines than
        // $this->_lines this code will not work.
        if ($this->_linesRead < $this->_lines) {
            $buffer = $this->in->read($len);
            if ($buffer === -1) {
                return -1;
            }
            // now grab first X lines from buffer
            $lines = explode("\n", $buffer);
            $linesCount = count($lines);
            // must account for possibility that the num lines requested could
            // involve more than one buffer read.
            $len = $linesCount > $this->_lines ? $this->_lines - $this->_linesRead : $linesCount;
            $filtered_buffer = implode("\n", array_slice($lines, 0, $len));
            $this->_linesRead += $len;
            return $filtered_buffer;
        }
        return -1;
        // EOF, since the file is "finished" as far as subsequent filters are concerned.
    }