options.py 文件源码

def _generate_case_table(case_mapping: str) -> Dict[int, str]:
    case_mapping = case_mapping.lower()
    if case_mapping not in ('ascii', 'rfc1459', 'strict-rfc1459'):
        # TODO log warning
        case_mapping = DEFAULT_CASE_MAPPING

    upper_str = string.ascii_uppercase
    lower_str = string.ascii_lowercase

    if case_mapping == 'rfc1459':
        upper_str += "[]\\^"
        lower_str += "{}|~"
    elif case_mapping == 'strict-rfc1459':
        upper_str += "[]\\"
        lower_str += "{}|"

    return str.maketrans(upper_str, lower_str)