VdZddlmZddlmZddlmZddlZddlZddlZ ej5ejdddl Z ddde jdvrdZ ne  d Zd Zgd Zdd ZdZdZdZdZdZdZdZdZdZy#1swYExYw#e $r ddlZd Z YAwxYw)z)Helpers for calculating CRC32C checksums.)absolute_import)division)unicode_literalsNignore)ccffiTFlAo= )iiAoivE:iWiPYlT/Ul?OiNi.%i'hinTi\Fib&l",iGWL;iglb !l<cl!lN,Ql2!l=X iD3iKS}i2=lmyixBctrtj}ntjj d}|r|j ||S)aReturns an instance of Hashlib-like helper for CRC32C operations. Args: initial_data (bytes): The CRC32C object will be initialized with the checksum of the data. Returns: The google_crc32c.Checksum instance if google-crc32c (https://github.com/googleapis/python-crc32c) is available. If not, returns the predefined.Crc instance from crcmod library. Usage: # Get the instance. crc = get_crc32c() # Update the instance with data. If your data is available in chunks, # you can update each chunk so that you don't have to keep everything in # memory. for chunk in chunks: crc.update(data) # Get the digest. crc_digest = crc.digest() zcrc-32c)IS_FAST_GOOGLE_CRC32C_AVAILABLE google_crc32cChecksumcrcmod predefinedCrcupdate) initial_datacrcs -lib/googlecloudsdk/command_lib/util/crc32c.py get_crc32cr@s?0%  "C      *CJJ| *cFt}tr ||_|S||_|S)a/Returns Hashlib-like CRC32C object with a starting checksum. Args: checksum (int): CRC32C checksum representing the hash of processed data. Returns: google_crc32c.Checksum if google-crc32c is available or predefined.Crc instance from crcmod library. Both set to use initial checksum. )rr_crccrcValue)checksumrs rget_crc32c_from_checksumrcs*  #$CH *CL *rc.t|}t|S)zReturns base64-encoded hash from the checksum. Args: checksum (int): CRC32C checksum representing the hash of processed data. Returns: A string representing the base64 encoded CRC32C hash. )rget_hash)r crc_objects r$get_crc32c_hash_string_from_checksumr#ws(1* * rc6t|jdS)zGets the hex checksum from a CRC32C object. Args: crc (google_crc32c.Checksum|predefined.Crc): CRC32C object from google-crc32c or crcmod package. Returns: An int representing the CRC32C checksum of the provided object. r )int hexdigestrs r get_checksumr(s S]]_b !!rcftj|jjdS)zGets the base64-encoded hash from a CRC32C object. Args: crc (google_crc32c.Checksum|predefined.Crc): CRC32C object from google-crc32c or crcmod package. Returns: A string representing the base64 encoded CRC32C hash. ascii)base64 b64encodedigestdecoder's rr!r!s&   #**, ' . .w 77rczt}|jtj|t ||k(S)aChecks if checksum for the data matches the supplied checksum. Args: data (bytes): Bytes over which the checksum should be calculated. crc32c_checksum (int): Checksum against which data's checksum will be compared. Returns: True iff both checksums match. )rrsix ensure_binaryr()datacrc32c_checksumrs rdoes_data_match_checksumr4s2  #**S  t $% c o --rcHtdj|dddddS)Nz{0:032b}r )widthr )r%format) crc_checksums r_reverse_32_bitsr:s( Z  |2  6tt ? rc4|s|Sd|z}t|||z S)aComputes CRC32C for concat(A, B) given crc(A), crc(B),and len(B). An explanation of the algorithm can be found at https://code.google.com/archive/p/crcutil/downloads. Args: crc_a (int): Represents the CRC32C checksum of object A. crc_b (int): Represents the CRC32C checksum of object B. b_byte_count (int): Length of data covered by crc_b in bytes. Returns: CRC32C checksum representing the data covered by crc_a and crc_b (int). )rI)rL)crc_acrc_b b_byte_count b_bit_counts rconcat_checksumsrSs(  LL + )%; G% OOr)r)__doc__ __future__rrrr+warningsr0catch_warnings simplefilterrimplementationr ImportError gcloud_crcmodrr?r=rGrrr#r(r!r4r:rErLrSrrr]s0&'  *x H(#!!!]2'+# $    F (  " 8 . A00PG! *!$)! *s(BB BBB B('B(