]BSrSSKrSSKrSSKr\R"5 \R "S5 SSKrSSS5 \RS;aSrO\ eSr Sr /S QrSS jrS rS rS rSrSrSrSrSrSrg!,(df  NL=f!\ a SSK r SrNHf=f)z)Helpers for calculating CRC32C checksums.Nignore)ccffiTFlAo= )iiAoivE:iWiPYlT/Ul?OiNi.%i'hinTi\Fib&l",iGWL;iglb !l<cl!lN,Ql2!l=X iD3iKS}i2=lmyixBc[(a[R"5nO[RR S5nU(aUR U5 U$)aReturns an instance of Hashlib-like helper for CRC32C operations. Args: initial_data (bytes): The CRC32C object will be initialized with the checksum of the data. Returns: The google_crc32c.Checksum instance if google-crc32c (https://github.com/googleapis/python-crc32c) is available. If not, returns the predefined.Crc instance from crcmod library. Usage: # Get the instance. crc = get_crc32c() # Update the instance with data. If your data is available in chunks, # you can update each chunk so that you don't have to keep everything in # memory. for chunk in chunks: crc.update(data) # Get the digest. crc_digest = crc.digest() zcrc-32c)IS_FAST_GOOGLE_CRC32C_AVAILABLE google_crc32cChecksumcrcmod predefinedCrcupdate) initial_datacrcs -lib/googlecloudsdk/command_lib/util/crc32c.py get_crc32cr=sB0%$  "C      *CJJ| *cL[5n[(aXlU$XlU$)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_checksumr`s)  #$$H *L *rc.[U5n[U5$)zReturns base64-encoded hash from the checksum. Args: checksum (int): CRC32C checksum representing the hash of processed data. Returns: A string representing the base64 encoded CRC32C hash. )rget_hash)r crc_objects r$get_crc32c_hash_string_from_checksumr ts(1* * rc6[UR5S5$)zGets the hex checksum from a CRC32C object. Args: crc (google_crc32c.Checksum|predefined.Crc): CRC32C object from google-crc32c or crcmod package. Returns: An int representing the CRC32C checksum of the provided object. r )int hexdigestrs r get_checksumr%s S]]_b !!rch[R"UR55RS5$)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$s rrrs&   #**, ' . .w 77rc|[5nUR[R"U55 [ U5U:H$)a Checks 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_checksumr1s2  #**S  t $% c o --rcB[SRUSS9SSS2S5$)Nz{0:032b}r)widthr)r"format) crc_checksums r_reverse_32_bitsr7s( Z  |2  6tt ? rc6U(dU$SU-n[XS9U- $)aComputes CRC32C for concat(A, B) given crc(A), crc(B),and len(B). An explanation of the algorithm can be found at https://code.google.com/archive/p/crcutil/downloads. Args: crc_a (int): Represents the CRC32C checksum of object A. crc_b (int): Represents the CRC32C checksum of object B. b_byte_count (int): Length of data covered by crc_b in bytes. Returns: CRC32C checksum representing the data covered by crc_a and crc_b (int). )rF)rI)crc_acrc_b b_byte_count b_bit_counts rconcat_checksumsrPs&  LL + )% G% OOr)r)__doc__r(warningsr-catch_warnings simplefilterr implementationr ImportError gcloud_crcmodrr<r:rDrrr r%rr1r7rBrIrPrrrYs0 *  (#!!!]2'+#     F (  " 8 . A00PG! *!$)! *s-BA>BB> B B BB