github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/pkg/tcpip/link/sharedmem/pipe/pipe_unsafe.go (about)

     1  // Copyright 2018 The gVisor Authors.
     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 pipe
    16  
    17  import (
    18  	"sync/atomic"
    19  	"unsafe"
    20  )
    21  
    22  func (p *pipe) write(idx uint64, v uint64) {
    23  	ptr := (*uint64)(unsafe.Pointer(&p.buffer[idx&offsetMask:][:8][0]))
    24  	*ptr = v
    25  }
    26  
    27  func (p *pipe) writeAtomic(idx uint64, v uint64) {
    28  	ptr := (*uint64)(unsafe.Pointer(&p.buffer[idx&offsetMask:][:8][0]))
    29  	atomic.StoreUint64(ptr, v)
    30  }
    31  
    32  func (p *pipe) readAtomic(idx uint64) uint64 {
    33  	ptr := (*uint64)(unsafe.Pointer(&p.buffer[idx&offsetMask:][:8][0]))
    34  	return atomic.LoadUint64(ptr)
    35  }