github.com/zuoyebang/bitalosdb@v1.1.1-0.20240516111551-79a8c4d8ce20/internal/crc/crc.go (about)

     1  // Copyright 2021 The Bitalosdb author(hustxrb@163.com) and other contributors.
     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.Castagnoli)
    20  
    21  type CRC uint32
    22  
    23  func New(b []byte) CRC {
    24  	return CRC(0).Update(b)
    25  }
    26  
    27  func (c CRC) Update(b []byte) CRC {
    28  	return CRC(crc32.Update(uint32(c), table, b))
    29  }
    30  
    31  func (c CRC) Value() uint32 {
    32  	return uint32(c>>15|c<<17) + 0xa282ead8
    33  }