/**
* Process the PatternMatch.
*
* @return boolean|null A single boolean with a value of true if the sub-expression matches the pattern and false if it does not. If the sub-expression is NULL, the the operator results in NULL.
* @throws \qtism\runtime\expressions\operators\OperatorProcessingException
*/
public function process()
{
$operands = $this->getOperands();
if ($operands->containsNull() === true) {
return null;
}
if ($operands->exclusivelySingle() === false) {
$msg = "The PatternMatch operator only accepts operands with a single cardinality.";
throw new OperatorProcessingException($msg, $this, OperatorProcessingException::WRONG_CARDINALITY);
}
if ($operands->exclusivelyString() === false) {
$msg = "The PatternMatch operator only accepts operands with a string baseType.";
throw new OperatorProcessingException($msg, $this, OperatorProcessingException::WRONG_BASETYPE);
}
// XML schema always implicitly anchors the entire regular expression
// because there is no carret (^) nor dollar ($) signs.
// see http://www.regular-expressions.info/xml.html
$rawPattern = $this->getExpression()->getPattern();
$pattern = OperatorUtils::escapeSymbols($rawPattern, array('$', '^'));
$pattern = OperatorUtils::pregAddDelimiter('^' . $pattern . '$');
// XSD regexp always case-sensitive (nothing to do), dot matches white-spaces (use PCRE_DOTALL).
$pattern .= 's';
$result = @preg_match($pattern, $operands[0]->getValue());
if ($result === 1) {
return new Boolean(true);
} elseif ($result === 0) {
return new Boolean(false);
} else {
$error = preg_last_error();
$errorType = 'PCRE Engine compilation error';
switch ($error) {
case PREG_INTERNAL_ERROR:
$errorType = "PCRE Engine internal error";
break;
case PREG_BACKTRACK_LIMIT_ERROR:
$errorType = "PCRE Engine backtrack limit exceeded";
break;
case PREG_RECURSION_LIMIT_ERROR:
$errorType = "PCRE Engine recursion limit exceeded";
break;
case PREG_BAD_UTF8_ERROR:
$errorType = "PCRE Engine malformed UTF-8";
break;
case PREG_BAD_UTF8_OFFSET_ERROR:
$errorType = "PCRE Engine UTF-8 offset error";
break;
}
$msg = "An internal error occured while processing the regular expression '{$rawPattern}': {$errorType}.";
throw new OperatorProcessingException($msg, $this, OperatorProcessingException::RUNTIME_ERROR);
}
}
/**
* Create the OperatorProcessor relevant to the given $expression.
*
* @param \qtism\data\expressions\Expression $expression The Operator object you want to get the processor.
* @param \qtism\runtime\expressions\operators\OperandsCollection $operands The operands to be involved in the Operator object.
* @return \qtism\runtime\expressions\operators\OperatorProcessor An OperatorProcessor object ready to process $expression.
* @throws \qtism\runtime\expressions\operators\OperatorProcessingException If the $operands count is not compliant with the Operator object to be processed.
* @throws \InvalidArgumentException If $expression is not an Operator object.
* @throws \RuntimeException If no relevant OperatorProcessor is found for the given $expression.
*/
public function createProcessor(QtiComponent $expression, OperandsCollection $operands = null)
{
if ($expression instanceof Operator) {
if ($expression instanceof CustomOperator) {
// QTI custom operator. Try to load an autoloaded class by using
// its class attribute value.
if ($expression->hasClass() === true) {
$className = Utils::customOperatorClassToPhpClass($expression->getClass());
if (class_exists($className) === true) {
return new $className($expression, $operands);
} else {
$msg = "No custom operator implementation found for class '" . $expression->getClass() . "'.";
throw new RuntimeException($msg);
}
} else {
$msg = "Only custom operators with a 'class' attribute value can be processed.";
throw new RuntimeException($msg);
}
} else {
// QTI built-in operator.
$qtiClassName = ucfirst($expression->getQtiClassName());
$nsPackage = 'qtism\\runtime\\expressions\\operators\\';
$className = $nsPackage . $qtiClassName . 'Processor';
if (class_exists($className)) {
if (is_null($operands) === true) {
$operands = new OperandsCollection();
}
return new $className($expression, $operands);
} else {
$msg = "No dedicated OperatorProcessor class found for QTI operator '{$qtiClassName}'.";
throw new RuntimeException($msg);
}
}
} else {
$msg = "The OperatorProcessorFactory only accepts to create processors for Operator objects.";
throw new InvalidArgumentException($msg);
}
}
/**
* Process the Gcd operator.
*
* @return integer The integer value equal in value to the greatest common divisor of the sub-expressions. If any of the sub-expressions is NULL, the result is NULL.
* @throws \qtism\runtime\expressions\operators\OperatorProcessingException
*/
public function process()
{
$operands = $this->getOperands();
if ($operands->containsNull() === true) {
return null;
}
if ($operands->anythingButRecord() === false) {
$msg = "The Gcd operator only accepts operands with a cardinality of single, multiple or ordered.";
throw new OperatorProcessingException($msg, $this, OperatorProcessingException::WRONG_CARDINALITY);
}
if ($operands->exclusivelyInteger() === false) {
$msg = "The Gcd operator only accepts operands with an integer baseType.";
throw new OperatorProcessingException($msg, $this, OperatorProcessingException::WRONG_BASETYPE);
}
// Make a flat collection first.
$flatCollection = new OperandsCollection();
$zeroCount = 0;
$valueCount = 0;
foreach ($operands as $operand) {
if ($operand instanceof QtiScalar) {
$valueCount++;
if ($operand->getValue() !== 0) {
$flatCollection[] = $operand;
} else {
$zeroCount++;
}
} elseif ($operand->contains(null)) {
// Container with at least one null value inside.
// -> If any of the sub-expressions is null or not numeric, returns null.
return null;
} else {
// Container with no null values.
foreach ($operand as $o) {
$valueCount++;
if ($o->getValue() !== 0) {
$flatCollection[] = $o;
} else {
$zeroCount++;
}
}
}
}
if ($zeroCount === $valueCount) {
// All arguments of gcd() are 0.
return new QtiInteger(0);
} else {
$g = $flatCollection[0];
$loopLimit = count($flatCollection) - 1;
$i = 0;
while ($i < $loopLimit) {
$g = new QtiInteger(Utils::gcd($g->getValue(), $flatCollection[$i + 1]->getValue()));
$i++;
}
return $g;
}
}
/**
* Process the Repeat operator.
*
* Note: NULL values are simply ignored. If all sub-expressions are NULL, NULL is
* returned.
*
* @return \qtism\runtime\common\OrderedContainer An ordered container filled sequentially by evaluating each sub-expressions, repeated a 'numberRepeats' of times. NULL is returned if all sub-expressions are NULL or numberRepeats < 1.
* @throws \qtism\runtime\expressions\operators\OperatorProcessingException
*/
public function process()
{
$operands = $this->getOperands();
// get the value of numberRepeats
$expression = $this->getExpression();
$numberRepeats = $expression->getNumberRepeats();
if (gettype($numberRepeats) === 'string') {
// Variable reference found.
$state = $this->getState();
$varName = Utils::sanitizeVariableRef($numberRepeats);
$varValue = $state[$varName];
if (is_null($varValue) === true) {
$msg = "The variable with name '{$varName}' could not be resolved.";
throw new OperatorProcessingException($msg, $this);
} elseif ($varValue instanceof Integer) {
$msg = "The variable with name '{$varName}' is not an integer value.";
throw new OperatorProcessingException($msg, $this);
}
$numberRepeats = $varValue->getValue();
}
if ($numberRepeats < 1) {
return null;
}
$result = null;
for ($i = 0; $i < $numberRepeats; $i++) {
$refType = null;
foreach ($operands as $operand) {
// If null, ignore
if (is_null($operand) || $operand instanceof Container && $operand->isNull()) {
continue;
}
// Check cardinality.
if ($operand->getCardinality() !== Cardinality::SINGLE && $operand->getCardinality() !== Cardinality::ORDERED) {
$msg = "The Repeat operator only accepts operands with a single or ordered cardinality.";
throw new OperatorProcessingException($msg, $this, OperatorProcessingException::WRONG_CARDINALITY);
}
// Check baseType.
$currentType = RuntimeUtils::inferBaseType($operand);
if ($refType !== null && $currentType !== $refType) {
$msg = "The Repeat operator only accepts operands with the same baseType.";
throw new OperatorProcessingException($msg, $this, OperatorProcessingException::WRONG_BASETYPE);
} elseif (is_null($result)) {
$refType = $currentType;
$result = new OrderedContainer($refType);
}
// Okay we are good...
$operandCardinality = RuntimeUtils::inferCardinality($operand);
if ($operandCardinality !== Cardinality::ORDERED) {
$operand = new OrderedContainer($currentType, array($operand));
}
foreach ($operand as $o) {
$result[] = $o instanceof QtiDatatype ? clone $o : $o;
}
}
}
if (isset($result) && $result->isNull() !== true) {
return $result;
} else {
return null;
}
}
/**
*
* @return null, \qtism\common\datatypes\Float
*/
protected function processPopSD()
{
$operands = $this->getOperands();
$operand = $operands[0];
$result = OperatorsUtils::standardDeviation(self::filterValues($operand->getArrayCopy()), false);
return $result !== false ? new QtiFloat(floatval($result)) : null;
}
/**
* @dataProvider invalidCustomOperatorClassToPhpClassProvider
*
* @param string $customClass
*/
public function testInvalidCustomOperatorClassToPhpClass($customClass)
{
$this->assertFalse(OperatorsUtils::customOperatorClassToPhpClass($customClass));
}
/**
* Process the RoundTo operator.
*
* An OperatorProcessingException will be thrown if:
*
* * The given operand is not a numeric value.
* * The cardinality of the operand is not single.
* * The value of the 'figures' attribute comes from a templateVariable which does not exist or is not numeric or null.
*
* @return null|float A single float with the value nearest to that of the expression's value or NULL if the sub-expression is NaN.
* @throws \qtism\runtime\expressions\operators\OperatorProcessingException
*/
public function process()
{
$operands = $this->getOperands();
$state = $this->getState();
$operand = $operands[0];
// If the value is null, return null.
if ($operands->containsNull()) {
return null;
}
if (!$operands->exclusivelySingle()) {
$msg = "The RoundTo operator accepts 1 operand with single cardinality.";
throw new OperatorProcessingException($msg, $this, OperatorProcessingException::WRONG_CARDINALITY);
}
// Accept only numerical operands.
if (!$operands->exclusivelyNumeric()) {
$msg = "The RoundTo operand accepts 1 operand with numerical baseType.";
throw new OperatorProcessingException($msg, $this, OperatorProcessingException::WRONG_BASETYPE);
}
// As per QTI 2.1 spec...
if (is_nan($operand->getValue())) {
return null;
} elseif (is_infinite($operand->getValue())) {
return $operand;
}
$roundingMode = $this->getExpression()->getRoundingMode();
$figures = $this->getExpression()->getFigures();
if (gettype($figures) === 'string') {
// try to recover the value from the state.
$figuresIdentifier = Utils::sanitizeVariableRef($figures);
$figures = $state[$figuresIdentifier];
if (is_null($figures)) {
$msg = "The variable '{$figuresIdentifier}' used to set up the 'figures' attribute is null or nonexisting.";
throw new OperatorProcessingException($msg, $this, OperatorProcessingException::NONEXISTENT_VARIABLE);
} elseif (!$figures instanceof Integer) {
$msg = "The variable '{$figuresIdentifier}' used to set up the 'figures' attribute is not an integer.";
throw new OperatorProcessingException($msg, $this, OperatorProcessingException::WRONG_VARIABLE_BASETYPE);
}
$figures = $figures->getValue();
}
if ($roundingMode === RoundingMode::SIGNIFICANT_FIGURES) {
if ($figures <= 0) {
// As per QTI 2.1 spec.
$msg = "The 'figures' attribute must be a non-zero positive integer when mode 'significantFigures' is used, '{$figures}' given.";
throw new OperatorProcessingException($msg, $this, OperatorProcessingException::LOGIC_ERROR);
}
if ($operand->getValue() == 0) {
return new Float(0.0);
}
$d = ceil(log10($operand->getValue() < 0 ? -$operand->getValue() : $operand->getValue()));
$power = $figures - intval($d);
$magnitude = pow(10, $power);
$shifted = round($operand->getValue() * $magnitude);
return new Float(floatval($shifted / $magnitude));
} else {
// As per QTI 2.1 spec.
if ($figures < 0) {
$msg = "The 'figures' attribute must be a integer greater than or equal to zero when mode 'decimalPlaces' is used, '{$figures}' given.";
throw new OperatorProcessingException($msg, $this);
}
return new Float(round($operand->getValue(), $figures));
}
}