U
    ڲg                     @   s   d Z ddlZG dd deZeedddZeedd	d
ZeeedddZeeejeeef dddZ	eeedddZ
eje eje edddZedkrddlZe  dS )z/Common functionality shared by several modules.    Nc                       s,   e Zd Zdeeeedd fddZ  ZS )NotRelativePrimeError N)abdmsgreturnc                    s0   t  |pd|||f  || _|| _|| _d S )Nz.%d and %d are not relatively prime, divider=%i)super__init__r   r   r   )selfr   r   r   r   	__class__ ./tmp/pip-unpacked-wheel-1z1vrokf/rsa/common.pyr
      s    zNotRelativePrimeError.__init__)r   )__name__
__module____qualname__intstrr
   __classcell__r   r   r   r   r      s   r   )numr   c              
   C   sD   z
|   W S  tk
r> } ztdt|  |W 5 d}~X Y nX dS )a  
    Number of bits needed to represent a integer excluding any prefix
    0 bits.

    Usage::

        >>> bit_size(1023)
        10
        >>> bit_size(1024)
        11
        >>> bit_size(1025)
        11

    :param num:
        Integer value. If num is 0, returns 0. Only the absolute value of the
        number is considered. Therefore, signed integers will be abs(num)
        before the number's bit length is determined.
    :returns:
        Returns the number of bits in the integer.
    z,bit_size(num) only supports integers, not %rN)
bit_lengthAttributeError	TypeErrortype)r   exr   r   r   bit_size   s    
r   )numberr   c                 C   s   | dkrdS t t| dS )a  
    Returns the number of bytes required to hold a specific long number.

    The number of bytes is rounded up.

    Usage::

        >>> byte_size(1 << 1023)
        128
        >>> byte_size((1 << 1024) - 1)
        128
        >>> byte_size(1 << 1024)
        129

    :param number:
        An unsigned integer
    :returns:
        The number of bytes required to hold a specific long number.
    r         )ceil_divr   )r   r   r   r   	byte_size8   s    r!   )r   divr   c                 C   s   t | |\}}|r|d7 }|S )av  
    Returns the ceiling function of a division between `num` and `div`.

    Usage::

        >>> ceil_div(100, 7)
        15
        >>> ceil_div(100, 10)
        10
        >>> ceil_div(1, 4)
        1

    :param num: Division's numerator, a number
    :param div: Division's divisor, a number

    :return: Rounded up result of the division between the parameters.
    r   )divmod)r   r"   quantamodr   r   r   r    Q   s    r    )r   r   r   c           	      C   s   d}d}d}d}| }|}|dkr\| | }|| |  } }|||  | }}|||  | }}q|dk rl||7 }|dk r|||7 }| ||fS )z;Returns a tuple (r, i, j) such that r = gcd(a, b) = ia + jbr   r   r   )	r   r   xyZlxZlyZoaobqr   r   r   extended_gcdi   s     r*   )r&   nr   c                 C   s(   t | |\}}}|dkr$t| |||S )zReturns the inverse of x % n under multiplication, a.k.a x^-1 (mod n)

    >>> inverse(7, 4)
    3
    >>> (inverse(143, 4) * 143) % 4
    1
    r   )r*   r   )r&   r+   dividerinv_r   r   r   inverse   s    	r/   )a_valuesmodulo_valuesr   c           	      C   sX   d}d}|D ]}||9 }qt || D ].\}}|| }t||}||| |  | }q$|S )a  Chinese Remainder Theorem.

    Calculates x such that x = a[i] (mod m[i]) for each i.

    :param a_values: the a-values of the above equation
    :param modulo_values: the m-values of the above equation
    :returns: x such that x = a[i] (mod m[i]) for each i


    >>> crt([2, 3], [3, 5])
    8

    >>> crt([2, 3, 2], [3, 5, 7])
    23

    >>> crt([2, 3, 0], [7, 11, 15])
    135
    r   r   )zipr/   )	r0   r1   mr&   ZmoduloZm_iZa_iZM_ir-   r   r   r   crt   s    

r4   __main__)__doc__typing
ValueErrorr   r   r   r!   r    Tupler*   r/   Iterabler4   r   doctesttestmodr   r   r   r   <module>   s   #