_version200.py 文件源码

def to64(number):
    """Converts a number in the range of 0 to 63 into base 64 digit
    character in the range of '0'-'9', 'A'-'Z', 'a'-'z','-','_'.
    """

    if not (type(number) is types.LongType or type(number) is types.IntType):
        raise TypeError("You must pass a long or an int")

    if 0 <= number <= 9:            #00-09 translates to '0' - '9'
        return byte(number + 48)

    if 10 <= number <= 35:
        return byte(number + 55)     #10-35 translates to 'A' - 'Z'

    if 36 <= number <= 61:
        return byte(number + 61)     #36-61 translates to 'a' - 'z'

    if number == 62:                # 62   translates to '-' (minus)
        return byte(45)

    if number == 63:                # 63   translates to '_' (underscore)
        return byte(95)

    raise ValueError('Invalid Base64 value: %i' % number)