public function testNullOrEmpty()
{
$str = new MString('一二三四五');
$this->assertFalse($str->isNullOrEmpty());
$str = new MString('');
$this->assertTrue($str->isNullOrEmpty());
$str = new MString(' ');
$this->assertFalse($str->isNullOrEmpty());
}
/**
* Whether this string starts with a given string
* @link http://stackoverflow.com/a/3282864/570787
* @param self $str
* @param MStringComparison $cmp optional comparision option, default is null (case sensitive)
* @return bool
*/
public function startsWith(self $str, MStringComparison $cmp = null)
{
if ($str->isNullOrEmpty()) {
throw new \InvalidArgumentException('$str is empty');
}
if ($str->count() > $this->count()) {
throw new \InvalidArgumentException('$str is longer than $this');
}
if ($cmp === null || $cmp->getValue() === MStringComparison::CASE_SENSITIVE) {
return $this->substring(0, $str->count())->_Value === $str->_Value;
} else {
return $this->substring(0, $str->count())->toLower()->_Value === $str->toLower()->_Value;
}
}
