github.com/datastax/go-cassandra-native-protocol@v0.0.0-20220706104457-5e8aad05cf90/crc/crc32.go (about)

     1  // Copyright 2021 DataStax
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package crc
    16  
    17  import "hash/crc32"
    18  
    19  var table = crc32.MakeTable(crc32.IEEE)
    20  var initialBytes = []byte{0xFA, 0x2D, 0x55, 0xCA}
    21  var initialChecksum = crc32.Update(0, table, initialBytes)
    22  
    23  // ChecksumIEEE returns the CRC-32 checksum of the given data. The algorithm is the one expected by Cassandra:
    24  // the actual checksum is computed over the combination of 4 fixed initial bytes and the given byte slice.
    25  func ChecksumIEEE(data []byte) uint32 {
    26  	return crc32.Update(initialChecksum, table, data)
    27  }