Arena storage pool: Difference between revisions

=={{header|Delphi}}==

{{libheader| Winapi.Windows}}

{{libheader| System.SysUtils}}

{{libheader| system.generics.collections}}

<lang Delphi>

program Arena_storage_pool;

{$APPTYPE CONSOLE}

uses

Winapi.Windows,

System.SysUtils,

system.generics.collections;

type

TPool = class

private

FStorage: TList<Pointer>;

public

constructor Create;

destructor Destroy; override;

function Allocate(aSize: Integer): Pointer;

function Release(P: Pointer): Integer;

end;

{ TPool }

function TPool.Allocate(aSize: Integer): Pointer;

begin

Result := GetMemory(aSize);

if Assigned(Result) then

FStorage.Add(Result);

end;

constructor TPool.Create;

begin

FStorage := TList<Pointer>.Create;

end;

destructor TPool.Destroy;

var

p: Pointer;

begin

while FStorage.Count > 0 do

begin

p := FStorage[0];

Release(p);

end;

FStorage.Free;

inherited;

end;

function TPool.Release(P: Pointer): Integer;

var

index: Integer;

begin

index := FStorage.IndexOf(P);

if index > -1 then

FStorage.Delete(index);

FreeMemory(P)

end;

var

Manager: TPool;

int1, int2: PInteger;

str: PChar;

begin

Manager := TPool.Create;

int1 := Manager.Allocate(sizeof(Integer));

int1^ := 5;

int2 := Manager.Allocate(sizeof(Integer));

int2^ := 3;

writeln('Allocate at addres ', cardinal(int1).ToHexString, ' with value of ', int1^);

writeln('Allocate at addres ', cardinal(int2).ToHexString, ' with value of ', int2^);

Manager.Free;

readln;

end.</lang>

{{out}}

<pre>Allocate at addres 026788D0 with value of 5

Allocate at addres 026788E0 with value of 3</pre>