github.com/zuoyebang/bitalosdb@v1.1.1-0.20240516111551-79a8c4d8ce20/internal/bindex/bits_amd64.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  //go:build amd64 && !nosimd
    16  
    17  package bindex
    18  
    19  import (
    20  	"math/bits"
    21  	_ "unsafe"
    22  )
    23  
    24  const (
    25  	groupSize       = 16
    26  	maxAvgGroupLoad = 14
    27  )
    28  
    29  type bitset uint16
    30  
    31  func metaMatchH2(m *metadata, h h2) bitset {
    32  	b := MatchMetadata((*[16]int8)(m), int8(h))
    33  	return bitset(b)
    34  }
    35  
    36  func metaMatchEmpty(m *metadata) bitset {
    37  	b := MatchMetadata((*[16]int8)(m), empty)
    38  	return bitset(b)
    39  }
    40  
    41  func nextMatch(b *bitset) (s uint32) {
    42  	s = uint32(bits.TrailingZeros16(uint16(*b)))
    43  	*b &= ^(1 << s) // clear bit |s|
    44  	return
    45  }