U
    k]e                     @   s:   d Z ddlZejZG dd dejZG dd dejZdS )z7Internal classes used by the gzip, lzma and bz2 modules    Nc                   @   s0   e Zd ZdZdd Zdd Zdd Zdd	 Zd
S )
BaseStreamzMode-checking helper functions.c                 C   s   | j rtdd S )NzI/O operation on closed file)closed
ValueErrorself r   "/usr/lib/python3.8/_compression.py_check_not_closed   s    zBaseStream._check_not_closedc                 C   s   |   stdd S )NzFile not open for reading)readableioUnsupportedOperationr   r   r   r   _check_can_read   s    zBaseStream._check_can_readc                 C   s   |   stdd S )NzFile not open for writing)writabler   r   r   r   r   r   _check_can_write   s    zBaseStream._check_can_writec                 C   s(   |   std|  s$tdd S )Nz3Seeking is only supported on files open for readingz3The underlying file object does not support seeking)r
   r   r   seekabler   r   r   r   _check_can_seek   s    
zBaseStream._check_can_seekN)__name__
__module____qualname____doc__r	   r   r   r   r   r   r   r   r   	   s
   r   c                       sj   e Zd ZdZdd ZdddZ fddZd	d
 Zdd ZdddZ	dd Z
ejfddZdd Z  ZS )DecompressReaderz5Adapts the decompressor API to a RawIOBase reader APIc                 C   s   dS )NTr   r   r   r   r   r
   $   s    zDecompressReader.readabler   c                 K   s>   || _ d| _d| _d| _|| _|| _| jf | j| _|| _d S )NFr   )_fp_eof_pos_size_decomp_factory_decomp_args_decompressor_trailing_error)r   fpZdecomp_factoryZtrailing_errorZdecomp_argsr   r   r   __init__'   s    zDecompressReader.__init__c                    s   d | _ t  S N)r   supercloser   	__class__r   r   r$   ;   s    zDecompressReader.closec                 C   s
   | j  S r"   )r   r   r   r   r   r   r   ?   s    zDecompressReader.seekablec              
   C   sP   t |:}|d$}| t|}||d t|< W 5 Q R X W 5 Q R X t|S )NB)
memoryviewcastreadlen)r   bZviewZ	byte_viewdatar   r   r   readintoB   s    $zDecompressReader.readintor   c                 C   s   |dk r|   S |r| jrdS d }| jjr| jjp<| jt}|sDq| jf | j	| _z| j
||}W q | jk
r   Y qY qX n4| jjr| jt}|stdnd}| j
||}|r"qq"|sd| _| j| _dS |  jt|7  _|S )Nr       zACompressed file ended before the end-of-stream marker was reachedT)readallr   r   ZeofZunused_datar   r*   BUFFER_SIZEr   r   
decompressr   Zneeds_inputEOFErrorr   r   r+   )r   sizer-   Zrawblockr   r   r   r*   H   s@    


zDecompressReader.readc                 C   s,   | j d d| _d| _| jf | j| _d S )Nr   F)r   seekr   r   r   r   r   r   r   r   r   _rewindr   s    zDecompressReader._rewindc                 C   s   |t jkrnR|t jkr"| j| }n<|t jkrP| jdk rD| t jrDq6| j| }ntd	||| jk rr| 
  n
|| j8 }|dkr| tt j|}|sq|t|8 }q|| jS )Nr   zInvalid value for whence: {})r   SEEK_SETSEEK_CURr   SEEK_ENDr   r*   DEFAULT_BUFFER_SIZEr   formatr6   minr+   )r   offsetwhencer-   r   r   r   r5   x   s&    






zDecompressReader.seekc                 C   s   | j S )z!Return the current file position.)r   r   r   r   r   tell   s    zDecompressReader.tell)r   )r   )r   r   r   r   r
   r!   r$   r   r.   r*   r6   r   r7   r5   r?   __classcell__r   r   r%   r   r   !   s   

*r   )r   r   r:   r1   BufferedIOBaser   	RawIOBaser   r   r   r   r   <module>   s   