Body::matchFieldNames

static function matchFieldNames($content)
{
	$names = [];
	if(preg_match_all(static::$valuesPattern, $content, $fieldMatches, PREG_SET_ORDER))
	{
		foreach($fieldMatches as $fieldMatch)
		{
			if (
				mb_strpos($fieldMatch[2], static::BLOCK_START_PLACEHOLDER) === false
				&& mb_strpos($fieldMatch[2], static::BLOCK_END_PLACEHOLDER) === false
			)
			{
				$names[$fieldMatch[2]] = $fieldMatch[2];
			}
		}
	}

	return $names;
}