protected function doInput()
    {
        /* @var $result IReadResult */
        $this->resetInput();
        $this->inputAttemptsUsed++;
        $result = $this->playPrePromptMessages();
        if (!$this->acceptPrePromptInputAsInput) {
            $result = $this->playPromptMessages();
            if ($result !== null && !$result->isTimeout()) {
                $this->acceptInput($result->getDigits());
            }
        } elseif ($result !== null && !$result->isTimeout()) {
            $this->acceptInput($result->getDigits());
        } else {
            $result = $this->playPromptMessages();
            if ($result !== null) {
                $this->acceptInput($result->getDigits());
            }
        }
        if ($this->inputLengthIsAtLeast($this->maxInput) // max = 1
            || $this->wasCancelled()
            || ($this->isComplete() && !$this->hasInput()) // user pressed eoi
        ) {
            return;
        }
        $len = strlen($this->input);
        $start = time();
        for ($i = $len; $i < $this->maxInput; $i++) {
            if ($this->totalTimeForInput != -1) {
                $totalElapsedTime = (time() - $start) * 1000;
                if ($totalElapsedTime >= $this->totalTimeForInput) {
                    $this->logDebug("Expired total available time for input");
                    break;
                }
            }
            $this->logDebug($this->name . ": Reading Digit #: " . ($i + 1));
            $result = $this->callClientMethods(array(
                    array('waitDigit' => array($this->timeBetweenDigits))
            ));
            if ($result->isTimeout()) {
                $this->logDebug("Expired available time per digit");
                break;
            }
            $input = $result->getDigits();
            $this->acceptInput($input);
            if ($this->inputIsEnd($input) || $this->wasCancelled()) {
                break;
            }
        }
    }