Is the position valid ?

@return bool
763879
public function valid() {
		if ($this->string === null) {
			$this->string = fgets($this->file);
		}
		
		return $this->string === false ? false : true;
	}
915388
public function isValid(): bool
    {
        $segments = explode('.', $this->value, self::NUM_SEGMENTS);

        if (count($segments) !== self::NUM_SEGMENTS) {
            return false;
        }

        for ($i = 0; $i < self::NUM_SEGMENTS; $i++) {
            $value = (int) $segments[$i];

            if ($value < self::MIN_VALUE || $value > self::MAX_VALUE) {
                return false;
            }
        }

        return true;
    }
515564
public function valid()
    {

        if (!preg_match("/^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=)?$/", $this->container['picture'])) {
            return false;
        }
        if ($this->container['section'] === null) {
            return false;
        }
        return true;
    }
875091
public function is_valid() {
        $ret = false;

        if (is_null($this->maxRecipients) === false && is_null($this->priority) === false &&
            is_null($this->compileBeforeDeliveryStart) === false && is_null($this->allowMultipleDeliveries) === false &&
            is_null($this->deliverImmediately) === false && is_null($this->obeyDeliveryLimits) === false
        ) {
            if ($this->deliverImmediately === true || is_null($this->deliveryStartDateTime) === false) {
                if ($this->compileBeforeDeliveryStart === false ||
                    (is_null($this->compileStartDateTime) === false && is_null($this->deliveryStartDateTime) === false &&
                        $this->compileStartDateTime <= $this->deliveryStartDateTime)
                ) {
                    // TODO: deliveryFrequency
                    $ret = true;
                }
            }
        }

        return $ret;
    }
267513
final public function valid()
    {
        /**
         * Fetching is the most reliable way to check if we have a valid row.
         * Other methods were attempted, such as checking the current position against the result set count,
         * but sqlite lets us down here as the driver doesn't support count, so we have to fetch which screws everything up
         */
        $current = $this->getNextRow();

        # If we found a record, then seek back so that it can be fetched
        if (is_array($current)) {
            $this->seek($this->position - 1);
            return true;

        # If we didn't find a record then just return false
        } else {
            return false;
        }
    }
290711
public function valid()
    {

        $allowed_values = $this->getStateAllowableValues();
        if (!in_array($this->container['state'], $allowed_values)) {
            return false;
        }
        return true;
    }
1233578
public function valid()
    {
        $fieldCount = count($this->record);
        return ($this->at >= 0 && $this->at < $fieldCount);
    }
948369
public function valid()
    {
        $valid = $this->current();

        // stop the loop I want to get off.
        if ((($this->position + 1) > $this->displayLimit)) {
            $valid = false;
        }

        return $valid;
    }
975841
public function valid()
    {
        if($this->folderList == null){
            $this->folderList = $this->listFolder();
        }
        return is_array($this->folderList) && isset($this->folderList[$this->key]);
    }
1203061
public function valid()
    {
        if (!isset($this->resources[$this->position])) {
            $this->fetchBatch();
        }

        return isset($this->resources[$this->position]);
    }
693555
public function valid()
    {
        echo "\n", __METHOD__, "\n";
        $key = key($this->values);
        var_export($key);

        return ($key !== null && $key !== false);
    }
7
public function valid() : bool
    {
        if ($this->pointer >= 0 && $this->pointer < count($this->members)) {
            return true;
        }
        return false;
    }
806078
public function isPaymentValid()
    {
        $isValid = $this->isPaymentActive();

        if ($isValid && !is_null($this->getPrice())) {
            $isValid = $this->checkPriceRange() && $this->checkMinOrderPrice();
        }

        $user = $this->getUser();
        if ($isValid && $user && $user->hasAccount()) {
            $isValid = $this->checkUserGroup();
        }

        if ($isValid && $user && $this->getCheckCountry()) {
            $isValid = $this->checkUserCountry();
        }

        return $isValid;
    }
1138809
public function valid()
    {
        return isset($this->base['value'][$this->position]) && is_array($this->base['value'][$this->position]);
    }
151138
public function valid()
    {

        $allowed_values = $this->getInputAllowableValues();
        if (!in_array($this->container['input'], $allowed_values)) {
            return false;
        }
        return true;
    }
1098226
public function isValid()
    {
        $valid = $this->prefix != '';
        $valid = $valid && $this->startMultiLine != '';
        $valid = $valid && $this->endMultiLine != '';
        $valid = $valid && $this->simpleDirective != '';

        return $valid;
    }
194443
public function valid()
    {
        if ($this->_buffer->offsetExists($this->_index)) {
            $current = $this->_buffer->offsetGet($this->_index);
            $this->_current = $current['value'];
            $this->_key = $current['key'];

            return true;
        }

        $valid = parent::valid();

        if ($valid) {
            $this->_current = parent::current();
            $this->_key = parent::key();
            $this->_buffer->push([
                'key' => $this->_key,
                'value' => $this->_current
            ]);
        }

        $this->_finished = !$valid;

        return $valid;
    }