100 lines
1.9 KiB
Go
100 lines
1.9 KiB
Go
package mempool
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import (
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"unsafe"
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)
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const DefaultDirtyFactor = 128
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// Pool provides a type-safe form
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// of UnsafePool using generics.
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//
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// Note it is NOT safe for concurrent
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// use, you must protect it yourself!
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type Pool[T any] struct {
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// New is an optionally provided
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// allocator used when no value
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// is available for use in pool.
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New func() T
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// Reset is an optionally provided
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// value resetting function called
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// on passed value to Put().
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Reset func(T)
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UnsafePool
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}
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func (p *Pool[T]) Get() T {
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if ptr := p.UnsafePool.Get(); ptr != nil {
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return *(*T)(ptr)
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} else if p.New != nil {
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return p.New()
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}
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var z T
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return z
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}
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func (p *Pool[T]) Put(t T) {
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if p.Reset != nil {
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p.Reset(t)
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}
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ptr := unsafe.Pointer(&t)
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p.UnsafePool.Put(ptr)
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}
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// UnsafePool provides an incredibly
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// simple memory pool implementation
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// that stores ptrs to memory values,
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// and regularly flushes internal pool
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// structures according to DirtyFactor.
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//
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// Note it is NOT safe for concurrent
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// use, you must protect it yourself!
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type UnsafePool struct {
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// DirtyFactor determines the max
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// number of $dirty count before
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// pool is garbage collected. Where:
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// $dirty = len(current) - len(victim)
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DirtyFactor int
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current []unsafe.Pointer
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victim []unsafe.Pointer
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}
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func (p *UnsafePool) Get() unsafe.Pointer {
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// First try current list.
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if len(p.current) > 0 {
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ptr := p.current[len(p.current)-1]
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p.current = p.current[:len(p.current)-1]
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return ptr
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}
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// Fallback to victim.
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if len(p.victim) > 0 {
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ptr := p.victim[len(p.victim)-1]
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p.victim = p.victim[:len(p.victim)-1]
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return ptr
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}
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return nil
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}
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func (p *UnsafePool) Put(ptr unsafe.Pointer) {
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p.current = append(p.current, ptr)
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// Get dirty factor.
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df := p.DirtyFactor
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if df == 0 {
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df = DefaultDirtyFactor
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}
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if len(p.current)-len(p.victim) > df {
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// Garbage collection!
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p.victim = p.current
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p.current = nil
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}
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}
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