_version200.py 文件源码

def from64(number):
    """Converts an ordinal character value in the range of
    0-9,A-Z,a-z,-,_ to a number in the range of 0-63.
    """

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

    if 48 <= number <= 57:         #ord('0') - ord('9') translates to 0-9
        return(number - 48)

    if 65 <= number <= 90:         #ord('A') - ord('Z') translates to 10-35
        return(number - 55)

    if 97 <= number <= 122:        #ord('a') - ord('z') translates to 36-61
        return(number - 61)

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

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

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