Method _decode_lower_special

python/pyfory/meta/metastring.py:126–149

Decodes data encoded with LOWER_SPECIAL encoding. Args: data (bytes): The encoded data. Returns: str: The decoded string.

(self, data: bytes)

            raise ValueError(f"Unexpected encoding flag: {encoding}")

    def _decode_lower_special(self, data: bytes) -> str:
        """
        Decodes data encoded with LOWER_SPECIAL encoding.

        Args:
            data (bytes): The encoded data.

        Returns:
            str: The decoded string.
        """
        decoded = []
        num_bits = len(data) * 8  # Total number of bits in the data
        strip_last_char = (data[0] & 0x80) != 0  # Check the first bit of the first byte
        bit_index = 1
        bit_mask = 0b11111
        while bit_index + 5 <= num_bits and not (strip_last_char and (bit_index + 2 * 5 > num_bits)):
            byte_index = bit_index // 8
            intra_byte_index = bit_index % 8
            # Extract the 5-bit character value across byte boundaries if needed
            char_value = ((data[byte_index] << 8) | (data[byte_index + 1] if byte_index + 1 < len(data) else 0)) >> (11 - intra_byte_index) & bit_mask
            bit_index += 5
            decoded.append(self._decode_lower_special_char(char_value))

        return "".join(decoded)

    def _decode_lower_upper_digit_special(self, data: bytes) -> str:
        """