diff options
Diffstat (limited to 'pkg/atomicbitops/atomic_bitops_common.go')
-rw-r--r-- | pkg/atomicbitops/atomic_bitops_common.go | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/pkg/atomicbitops/atomic_bitops_common.go b/pkg/atomicbitops/atomic_bitops_common.go new file mode 100644 index 000000000..542ff4e83 --- /dev/null +++ b/pkg/atomicbitops/atomic_bitops_common.go @@ -0,0 +1,147 @@ +// Copyright 2018 Google Inc. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// +build !amd64 + +package atomicbitops + +import ( + "sync/atomic" +) + +// AndUint32 atomically applies bitwise and operation to *addr with val. +func AndUint32(addr *uint32, val uint32) { + for { + o := atomic.LoadUint32(addr) + n := o & val + if atomic.CompareAndSwapUint32(addr, o, n) { + break + } + } +} + +// OrUint32 atomically applies bitwise or operation to *addr with val. +func OrUint32(addr *uint32, val uint32) { + for { + o := atomic.LoadUint32(addr) + n := o | val + if atomic.CompareAndSwapUint32(addr, o, n) { + break + } + } +} + +// XorUint32 atomically applies bitwise xor operation to *addr with val. +func XorUint32(addr *uint32, val uint32) { + for { + o := atomic.LoadUint32(addr) + n := o ^ val + if atomic.CompareAndSwapUint32(addr, o, n) { + break + } + } +} + +// CompareAndSwapUint32 is like sync/atomic.CompareAndSwapUint32, but returns +// the value previously stored at addr. +func CompareAndSwapUint32(addr *uint32, old, new uint32) (prev uint32) { + for { + prev = atomic.LoadUint32(addr) + if prev != old { + return + } + if atomic.CompareAndSwapUint32(addr, old, new) { + return + } + } +} + +// AndUint64 atomically applies bitwise and operation to *addr with val. +func AndUint64(addr *uint64, val uint64) { + for { + o := atomic.LoadUint64(addr) + n := o & val + if atomic.CompareAndSwapUint64(addr, o, n) { + break + } + } +} + +// OrUint64 atomically applies bitwise or operation to *addr with val. +func OrUint64(addr *uint64, val uint64) { + for { + o := atomic.LoadUint64(addr) + n := o | val + if atomic.CompareAndSwapUint64(addr, o, n) { + break + } + } +} + +// XorUint64 atomically applies bitwise xor operation to *addr with val. +func XorUint64(addr *uint64, val uint64) { + for { + o := atomic.LoadUint64(addr) + n := o ^ val + if atomic.CompareAndSwapUint64(addr, o, n) { + break + } + } +} + +// CompareAndSwapUint64 is like sync/atomic.CompareAndSwapUint64, but returns +// the value previously stored at addr. +func CompareAndSwapUint64(addr *uint64, old, new uint64) (prev uint64) { + for { + prev = atomic.LoadUint64(addr) + if prev != old { + return + } + if atomic.CompareAndSwapUint64(addr, old, new) { + return + } + } +} + +// IncUnlessZeroInt32 increments the value stored at the given address and +// returns true; unless the value stored in the pointer is zero, in which case +// it is left unmodified and false is returned. +func IncUnlessZeroInt32(addr *int32) bool { + for { + v := atomic.LoadInt32(addr) + if v == 0 { + return false + } + + if atomic.CompareAndSwapInt32(addr, v, v+1) { + return true + } + } +} + +// DecUnlessOneInt32 decrements the value stored at the given address and +// returns true; unless the value stored in the pointer is 1, in which case it +// is left unmodified and false is returned. +func DecUnlessOneInt32(addr *int32) bool { + for { + v := atomic.LoadInt32(addr) + if v == 1 { + return false + } + + if atomic.CompareAndSwapInt32(addr, v, v-1) { + return true + } + } +} |