101 lines
2.1 KiB
Go
101 lines
2.1 KiB
Go
|
package main
|
||
|
|
|
||
|
|
import (
|
||
|
|
"errors"
|
||
|
|
"fmt"
|
||
|
|
"unsafe"
|
||
|
|
)
|
||
|
|
|
||
|
|
type PoolAllocator struct {
|
||
|
|
objectPool []byte
|
||
|
|
freeObjects map[unsafe.Pointer]struct{}
|
||
|
|
objectSize int
|
||
|
|
}
|
||
|
|
|
||
|
|
func NewPoolAllocator(capacity int, objectSize int) (PoolAllocator, error) {
|
||
|
|
if capacity <= 0 || objectSize <= 0 || capacity%objectSize != 0 {
|
||
|
|
return PoolAllocator{}, errors.New("incorrect argumnets")
|
||
|
|
}
|
||
|
|
|
||
|
|
allocator := PoolAllocator{
|
||
|
|
objectPool: make([]byte, capacity),
|
||
|
|
freeObjects: make(map[unsafe.Pointer]struct{}, capacity/objectSize),
|
||
|
|
objectSize: objectSize,
|
||
|
|
}
|
||
|
|
|
||
|
|
allocator.resetMemoryState()
|
||
|
|
return allocator, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func (a *PoolAllocator) Allocate() (unsafe.Pointer, error) {
|
||
|
|
if len(a.freeObjects) == 0 {
|
||
|
|
// can increase capacity
|
||
|
|
return nil, errors.New("not enough memory")
|
||
|
|
}
|
||
|
|
|
||
|
|
var pointer unsafe.Pointer
|
||
|
|
for freePointer := range a.freeObjects {
|
||
|
|
pointer = freePointer
|
||
|
|
break
|
||
|
|
}
|
||
|
|
|
||
|
|
delete(a.freeObjects, pointer)
|
||
|
|
return pointer, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func (a *PoolAllocator) Deallocate(pointer unsafe.Pointer) error {
|
||
|
|
if pointer == nil {
|
||
|
|
return errors.New("incorrect pointer")
|
||
|
|
}
|
||
|
|
|
||
|
|
// potentionally incorrect pointer
|
||
|
|
a.freeObjects[pointer] = struct{}{}
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func (a *PoolAllocator) Free() {
|
||
|
|
a.resetMemoryState()
|
||
|
|
}
|
||
|
|
|
||
|
|
func (a *PoolAllocator) resetMemoryState() {
|
||
|
|
for offset := 0; offset < len(a.objectPool); offset += a.objectSize {
|
||
|
|
pointer := unsafe.Pointer(&a.objectPool[offset])
|
||
|
|
a.freeObjects[pointer] = struct{}{}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func store[T any](pointer unsafe.Pointer, value T) {
|
||
|
|
*(*T)(pointer) = value
|
||
|
|
}
|
||
|
|
|
||
|
|
func load[T any](pointer unsafe.Pointer) T {
|
||
|
|
return *(*T)(pointer)
|
||
|
|
}
|
||
|
|
|
||
|
|
func main() {
|
||
|
|
const KB = 1 << 10
|
||
|
|
allocator, err := NewPoolAllocator(KB, 4)
|
||
|
|
if err != nil {
|
||
|
|
// handling...
|
||
|
|
}
|
||
|
|
|
||
|
|
defer allocator.Free()
|
||
|
|
|
||
|
|
pointer1, _ := allocator.Allocate()
|
||
|
|
pointer2, _ := allocator.Allocate()
|
||
|
|
|
||
|
|
store[int32](pointer1, 100)
|
||
|
|
store[int32](pointer2, 200)
|
||
|
|
|
||
|
|
value1 := load[int32](pointer1)
|
||
|
|
value2 := load[int32](pointer2)
|
||
|
|
fmt.Println("value1:", value1)
|
||
|
|
fmt.Println("value2:", value2)
|
||
|
|
|
||
|
|
fmt.Println("address1:", pointer1)
|
||
|
|
fmt.Println("address2:", pointer2)
|
||
|
|
|
||
|
|
allocator.Deallocate(pointer1)
|
||
|
|
allocator.Deallocate(pointer2)
|
||
|
|
}
|