75 lines
1.4 KiB
Go
75 lines
1.4 KiB
Go
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package main
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import (
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"errors"
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"fmt"
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"unsafe"
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)
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type LinearAllocator struct {
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data []byte
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}
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func NewLinearAllocator(capacity int) (LinearAllocator, error) {
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if capacity <= 0 {
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return LinearAllocator{}, errors.New("incorrect capacity")
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}
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return LinearAllocator{
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data: make([]byte, 0, capacity),
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}, nil
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}
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func (a *LinearAllocator) Allocate(size int) (unsafe.Pointer, error) {
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previousLength := len(a.data)
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newLength := previousLength + size
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if newLength > cap(a.data) {
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// can increase capacity
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return nil, errors.New("not enough memory")
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}
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a.data = a.data[:newLength]
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pointer := unsafe.Pointer(&a.data[previousLength])
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return pointer, nil
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}
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// not supported by this kind of allocator
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// func (a *LinearAllocator) Deallocate(pointer unsafe.Pointer) error {}
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func (a *LinearAllocator) Free() {
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a.data = a.data[:0]
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}
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func store[T any](pointer unsafe.Pointer, value T) {
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*(*T)(pointer) = value
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}
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func load[T any](pointer unsafe.Pointer) T {
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return *(*T)(pointer)
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}
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func main() {
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const MB = 1 << 20
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allocator, err := NewLinearAllocator(MB)
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if err != nil {
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// handling...
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}
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defer allocator.Free()
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pointer1, _ := allocator.Allocate(2)
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pointer2, _ := allocator.Allocate(4)
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store[int16](pointer1, 100)
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store[int32](pointer2, 200)
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value1 := load[int16](pointer1)
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value2 := load[int32](pointer2)
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fmt.Println("value1:", value1)
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fmt.Println("value2:", value2)
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fmt.Println("address1:", pointer1)
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fmt.Println("address2:", pointer2)
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}
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