qidoublelist.pas

Iocomp Ultra Pack v3.0.2 Sources.For.Delphi 数据显示编程插件,可用于工业控制

{*******************************************************}
{                                                       }
{       TiDoubleList                                    }
{                                                       }
{       Copyright (c) 1997,2003 Iocomp Software         }
{                                                       }
{*******************************************************}
{$I iInclude.inc}

{$ifdef iVCL}unit  iDoubleList;{$endif}
{$ifdef iCLX}unit QiDoubleList;{$endif}

interface

uses
  {$I iIncludeUses.inc}
  {$IFDEF iVCL} iTypes;{$ENDIF}
  {$IFDEF iCLX}QiTypes;{$ENDIF}

type
  PDoubleList = ^TDoubleList;
  TDoubleList = array[0..MaxListSize - 1] of Double;

  TiDoubleList = class(TObject)
  private
    FList          : PDoubleList;
    FCount         : Integer;
    FCapacity      : Integer;
    FUseRingBuffer : Boolean;
    FTail          : Integer;
  protected
    procedure Grow;
    function  GetItem(Index: Integer): Double;
    procedure SetItem(Index: Integer; const Value: Double);
  public
    destructor Destroy; override;
    procedure Add(Item: Double);
    procedure SetCapacity(NewCapacity: Integer);
    procedure DeleteRange(Size : Integer);
    procedure Clear;
    property  Count: Integer read FCount;
    property  Item[Index: Integer]: Double  read GetItem        write SetItem;
    property  UseRingBuffer       : Boolean read FUseRingBuffer write FUseRingBuffer;
  end;
implementation

//****************************************************************************************************************************************************
destructor TiDoubleList.Destroy;
begin
  FreeMem(FList);
  inherited;
end;
//****************************************************************************************************************************************************
procedure TiDoubleList.Add(Item: Double);
var
  ActualIndex : Integer;
begin
  if FUseRingBuffer then
    begin
      if FCount < FCapacity then
        begin
          ActualIndex         := FCount;
          FList^[ActualIndex] := Item;
          Inc(FCount);
        end                      
      else
        begin
          Inc(FTail);
          if FTail = FCount then FTail := 0;

          if FTail <> 0 then ActualIndex := FTail-1 else ActualIndex := FCount-1;
          FList^[ActualIndex] := Item;
        end;
    end
  else
    begin
      ActualIndex := FCount;
      if ActualIndex = FCapacity then Grow;
      FList^[ActualIndex] := Item;
      Inc(FCount);
    end;
end;
//****************************************************************************************************************************************************
procedure TiDoubleList.Clear;
begin
  FCount := 0;
  FTail  := 0;
  if not FUseRingBuffer then SetCapacity(4);
end;
//****************************************************************************************************************************************************
procedure TiDoubleList.Grow;
var
  Delta: Integer;
begin
  if      FCapacity > 64 then Delta := FCapacity div 4
  else if FCapacity >  8 then Delta := 16
    else                      Delta := 4;
  SetCapacity(FCapacity + Delta);
end;
//****************************************************************************************************************************************************
function TiDoubleList.GetItem(Index: Integer): Double;
var
  ActualIndex : Integer;
begin
  if (Index < 0) or (Index >= FCount) then raise Exception.Create('Index out of Bounds');

  if FTail <> 0 then
    begin
      ActualIndex := Index + FTail;
      if ActualIndex > (FCount-1) then ActualIndex := ActualIndex - FCount;
    end
  else ActualIndex := Index;

  Result := FList^[ActualIndex];
end;
//****************************************************************************************************************************************************
procedure TiDoubleList.SetItem(Index: Integer; const Value: Double);
var
  ActualIndex : Integer;
begin
  if (Index < 0) or (Index >= FCount) then raise Exception.Create('Index out of Bounds');

  if FTail <> 0 then
    begin
      ActualIndex := Index + FTail;
      if ActualIndex > (FCount-1) then ActualIndex := ActualIndex - FCount;
    end
  else ActualIndex := Index;

  FList^[ActualIndex] := Value;
end;
//****************************************************************************************************************************************************
procedure TiDoubleList.SetCapacity(NewCapacity: Integer);
begin
  if (NewCapacity > MaxListSize) then Exception.Create('Exceed Maximum List Size');
  if NewCapacity <> FCapacity then
  begin
    ReallocMem(FList, NewCapacity * SizeOf(Double));
    try
      if NewCapacity <> 0 then FList^[NewCapacity-1] := 0;
    except
      on Exception do raise Exception.Create('Memory could not be allocated');
    end;
    FCapacity := NewCapacity;
  end;
end;
//****************************************************************************************************************************************************
procedure TiDoubleList.DeleteRange(Size: Integer);
begin
  if (Size < 0) or (Size >= FCount) then raise Exception.Create('Delete size out of Range');
  FCount := FCount - Size;
  if FCount > 0 then System.Move(FList^[Size], FList^[0], (FCount) * SizeOf(Double));
end;
//****************************************************************************************************************************************************
end.