nizika_broadcast/common_module.py

import unicodedata


class CommonModule:
    @staticmethod
    def is_wide (c: str) -> bool:
        return unicodedata.east_asian_width (c) in ['F', 'W', 'A']

    @classmethod
    def len_by_full (cls, string: str) -> float:
        return sum ([1 if cls.is_wide (c) else .5
                     for c in string.decode ('utf-8')])

    @classmethod
    def index_by_f2c (cls, string: str, index: float) -> int:
        i = 0
        work = ''
        for c in string.decode ('utf-8'):
            work += c
            if cls.len_by_full (work) > index:
                break
            else:
                i += 1

        return i

    @classmethod
    def mid_by_full (cls, string: str, start: float, length: float) -> str:
        trimmed_left = string[cls.index_by_f2c (string, start):]

        return trimmed_left[:cls.index_by_f2c (trimmed_left, length)]