一个队列类的实现 转

Posted 2021-03-15 面朝大海，春暖花开。

一个队列类的实现(比delphi自带的速度快70倍)

测试结果

 

实现的代码

 

unit sfContnrs;

interface

{$DEFINE MULTI_THREAD_QUEUE} //线程安全版本，如果不需要线程安全，请注释掉此行代码

{$IFDEF MULTI_THREAD_QUEUE}
uses
    Windows;
{$ENDIF}

type
  TsfQueue=class
  private
    FCapacity:Integer;
    FTmpBuff:Pointer;
    FBuff:Pointer;
    FPosition:Integer;
  {$IFDEF MULTI_THREAD_QUEUE}
    FCS:TRTLCriticalSection;
  {$ENDIF}
    //\\\\
    FPushIndex:Integer;
    FPopIndex:Integer;

    procedure Lock();
    procedure UnLock();
    procedure Inernal_SetCapacity(const Value:Integer);
    //\\\\
    procedure setCapacity(const Value: Integer);
    function getCapacity: Integer;
  public
    constructor Create(InitCapacity: Integer=1024);
    destructor  Destroy();override;
    //\\\\
    function Push(AItem: Pointer): Pointer;
    function Pop(): Pointer;
  public
    property Capacity:Integer read getCapacity write setCapacity;
  end;

implementation

{ TsfQueue }

constructor TsfQueue.Create(InitCapacity:Integer);
begin
  {$IFDEF MULTI_THREAD_QUEUE}
     InitializeCriticalSection(FCS);
  {$ENDIF}

  if InitCapacity < 1024 then InitCapacity := 1024;

  Inernal_SetCapacity(InitCapacity);

end;

destructor TsfQueue.Destroy;
begin
  FreeMem(FBuff);
  if FTmpBuff <> nil then
    FreeMem(FTmpBuff);
  //\\\\
  {$IFDEF MULTI_THREAD_QUEUE}
     DeleteCriticalSection(FCS);
  {$ENDIF}

  inherited;
end;

procedure TsfQueue.Lock;
begin
  {$IFDEF MULTI_THREAD_QUEUE}
     EnterCriticalSection(FCS);
  {$ENDIF}
end;

procedure TsfQueue.UnLock;
begin
  {$IFDEF MULTI_THREAD_QUEUE}
      LeaveCriticalSection(FCS);
  {$ENDIF}
end;

procedure TsfQueue.Inernal_SetCapacity(const Value: Integer);
var
  PageCount,ASize:Integer;
begin
    if Value > FCapacity then
    begin
      if FTmpBuff <> nil then
        FreeMem(FTmpBuff);

      //扩容
      ASize := Value * 4;//计算出所需要的字节数量
      Pagecount := ASize div 4096;
      if (ASize mod 4096) > 0 then Inc(PageCount);

      //转移数据
      GetMem(FTmpBuff,PageCount * 4096);
      FillChar(FTmpBuff^,PageCount * 4096,#0);

      if FBuff <> nil then
      begin
        Move(FBuff^,FTmpBuff^,FCapacity * 4);
        FreeMem(FBuff);
      end;

      FBuff := FTmpBuff;

      //计算新的容量
      FCapacity := (PageCount * 4096) div 4;

      if FCapacity >= 2048 then
      begin
         //FTmpBuff 分配用于Pop时候，移动内存用
         GetMem(FTmpBuff,PageCount * 4096);
      end
      else
        FTmpBuff := nil;
    end;
end;

 

function TsfQueue.Pop: Pointer;
  procedure AdjuestMem();
  var
    pSrc:PInteger;
    pTmp:Pointer;
  begin
    FillChar(FTmpBuff^,FCapacity * 4,#0);
    pSrc := PInteger(FBuff);
    Inc(pSrc,FPopIndex);
    Move(pSrc^,FTmpBuff^,(FCapacity - FPopIndex) * 4);
    //\\\\
    //交换指针
    pTmp    := FBuff;
    FBuff   := FTmpBuff;
    FTmpBuff := pTmp;
    //\\\\
  end;

const
    _MoveRange_ = 2048;

var
  P:PInteger;
begin
  Lock();
  try
    Result := nil;
    if (FPopIndex = FPushIndex) then
      Exit;
    P := PInteger(FBuff);
    Inc(P,FPopIndex);
    Result := Pointer(P^);
    Inc(FPopIndex);
    //队列底部空余内存达到 8192 整体搬迁
    if FPopIndex = _MoveRange_ then
    begin
      AdjuestMem();
      FPopIndex := 0;
      Dec(FPushIndex,_MoveRange_);
    end;
  finally
    UnLock();
  end;
end;

function TsfQueue.Push(AItem: Pointer): Pointer;
var
  P:PInteger;
begin
  Lock();
  try
    P := PInteger(FBuff);
    Inc(P,FPushIndex);
    P^ := Integer(AItem);
    Inc(FPushIndex);
    if FPushIndex >= FCapacity then
    begin
      //扩容加 1024 个位置
      Inernal_SetCapacity(FCapacity + 1024);
    end;
  finally
    UnLock();
  end;
end;

procedure TsfQueue.setCapacity(const Value: Integer);
begin
  Lock();
  try
    Inernal_SetCapacity(Value);
  finally
    UnLock();
  end;
end;

function TsfQueue.getCapacity: Integer;
begin
  Lock();
  try
    Result := Self.FCapacity;
  finally
    UnLock();
  end;
end;

end.

 

 

 

//测试函数

procedure TfrmMain.btnQueueClick(Sender: TObject);
var
  A:TsfQueue; //优化后的高速队类实现（线程安全）
  B:TQueue;
  Index:Integer;
begin
  A := TsfQueue.Create();
  B := TQueue.Create();
  SW.Start();
  for Index := 1 to 10000 * 2 do
  begin
    b.Push(0);
  end;
  for Index := 1 to 10000 * 2 do
  begin
    b.Pop();
  end;

  SW.Stop();

  showMessage(IntToStr(SW.ElapsedMiliseconds));

end;