58 lines
1.3 KiB
Go
58 lines
1.3 KiB
Go
package atomics
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import (
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"sync/atomic"
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"unsafe"
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)
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// Bytes provides user-friendly means of performing atomic operations on []byte types.
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type Bytes struct{ ptr unsafe.Pointer }
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// NewBytes will return a new Bytes instance initialized with zero value.
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func NewBytes() *Bytes {
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var v []byte
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return &Bytes{
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ptr: unsafe.Pointer(&v),
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}
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}
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// Store will atomically store []byte value in address contained within v.
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func (v *Bytes) Store(val []byte) {
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atomic.StorePointer(&v.ptr, unsafe.Pointer(&val))
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}
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// Load will atomically load []byte value at address contained within v.
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func (v *Bytes) Load() []byte {
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return *(*[]byte)(atomic.LoadPointer(&v.ptr))
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}
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// CAS performs a compare-and-swap for a(n) []byte value at address contained within v.
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func (v *Bytes) CAS(cmp, swp []byte) bool {
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for {
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// Load current value at address
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ptr := atomic.LoadPointer(&v.ptr)
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cur := *(*[]byte)(ptr)
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// Perform comparison against current
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if !(string(cur) == string(cmp)) {
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return false
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}
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// Attempt to replace pointer
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if atomic.CompareAndSwapPointer(
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&v.ptr,
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ptr,
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unsafe.Pointer(&swp),
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) {
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return true
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}
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}
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}
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// Swap atomically stores new []byte value into address contained within v, and returns previous value.
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func (v *Bytes) Swap(swp []byte) []byte {
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ptr := unsafe.Pointer(&swp)
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ptr = atomic.SwapPointer(&v.ptr, ptr)
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return *(*[]byte)(ptr)
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}
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