/**
* 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);
}
}
/**
* @dataProvider pregAddDelimiterProvider
*
* @param string $string
* @param string $expected
*/
public function testPregAddDelimiter($string, $expected)
{
$this->assertSame($expected, OperatorsUtils::pregAddDelimiter($string));
}
