TAChart: Add TChartSourceBuffer utility class

git-svn-id: trunk@28800 -

components/tachart/tacustomsource.pas

@@ -25,6 +25,7 @@ uses
   Classes, Types, TAChartUtils;
 
 type
+  EBufferError = class(EChartError);
   EEditableSourceRequired = class(EChartError);
   EYCountError = class(EChartError);
 
@@ -87,6 +88,26 @@ type
     property YCount: Cardinal read FYCount write SetYCount default 1;
   end;
 
+  { TChartSourceBuffer }
+
+  TChartSourceBuffer = class
+  private
+    FBuf: array of TChartDataItem;
+    FCount: Cardinal;
+    FStart: Cardinal;
+    FSum: TChartDataItem;
+    function GetCapacity: Cardinal; inline;
+    procedure Put(AIndex: Integer; const AItem: TChartDataItem);
+    procedure Remove(AIndex: Integer);
+    procedure SetCapacity(AValue: Cardinal); inline;
+  public
+    procedure AddFirst(const AItem: TChartDataItem);
+    procedure AddLast(const AItem: TChartDataItem);
+    procedure Clear; inline;
+    procedure GetSum(var AItem: TChartDataItem);
+    property Capacity: Cardinal read GetCapacity write SetCapacity;
+  end;
+
 procedure SetDataItemDefaults(var AItem: TChartDataItem);
 
 implementation
@@ -106,6 +127,89 @@ begin
     AItem.YList[i] := 0;
 end;
 
+{ TChartSourceBuffer }
+
+procedure TChartSourceBuffer.AddFirst(const AItem: TChartDataItem);
+begin
+  if Capacity = 0 then
+    raise EBufferError.Create('');
+  FStart := (FStart + Cardinal(High(FBuf))) mod Capacity;
+  if FCount = Capacity then
+    Remove(FStart)
+  else
+    FCount += 1;
+  Put(FStart, AItem);
+end;
+
+procedure TChartSourceBuffer.AddLast(const AItem: TChartDataItem);
+begin
+  if Capacity = 0 then
+    raise EBufferError.Create('');
+  if FCount = Capacity then begin
+    Remove(FStart);
+    Put(FStart, AItem);
+    FStart += 1;
+  end
+  else begin
+    Put((FStart + FCount) mod Capacity, AItem);
+    FCount += 1;
+  end;
+end;
+
+procedure TChartSourceBuffer.Clear;
+begin
+  FCount := 0;
+  FSum.Y := 0;
+  FSum.YList := nil;
+end;
+
+function TChartSourceBuffer.GetCapacity: Cardinal;
+begin
+  Result := Length(FBuf);
+end;
+
+procedure TChartSourceBuffer.GetSum(var AItem: TChartDataItem);
+begin
+  if FCount = 0 then
+    raise EBufferError.Create('Empty');
+  AItem.Y := FSum.Y;
+  AItem.YList := Copy(FSum.YList);
+end;
+
+procedure TChartSourceBuffer.Put(AIndex: Integer; const AItem: TChartDataItem);
+var
+  i, oldLen: Integer;
+begin
+  FBuf[AIndex] := AItem;
+  with FSum do begin
+    Y += AItem.Y;
+    oldLen := Length(YList);
+    SetLength(YList, Max(Length(AItem.YList), oldLen));
+    for i := oldLen to High(YList) do
+      YList[i] := 0;
+    for i := 0 to Min(High(YList), High(AItem.YList)) do
+      YList[i] += AItem.YList[i];
+  end;
+end;
+
+procedure TChartSourceBuffer.Remove(AIndex: Integer);
+var
+  i: Integer;
+begin
+  with FBuf[AIndex] do begin
+    FSum.Y -= Y;
+    for i := 0 to Min(High(FSum.YList), High(YList)) do
+      FSum.YList[i] -= YList[i];
+  end;
+end;
+
+procedure TChartSourceBuffer.SetCapacity(AValue: Cardinal);
+begin
+  if AValue = Capacity then exit;
+  SetLength(FBuf, AValue);
+  Clear;
+end;
+
 { TCustomChartSource }
 
 procedure TCustomChartSource.AfterDraw;

components/tachart/tasources.pas

@@ -205,7 +205,7 @@ type
   private
     FAccumulationMethod: TChartAccumulationMethod;
     FAccumulationRange: Integer;
-    FHistory: array of TChartDataItem;
+    FHistory: TChartSourceBuffer;
     FIndex: Integer;
     FItem: TChartDataItem;
     FListener: TListener;
@@ -218,7 +218,7 @@ type
     procedure CalcAccumulation(AIndex: Integer);
     procedure CalcPercentage;
     procedure Changed(ASender: TObject); inline;
-    procedure ExtractItem(var AItem: TChartDataItem; AIndex: Integer);
+    procedure ExtractItem(out AItem: TChartDataItem; AIndex: Integer);
     procedure SetAccumulationMethod(AValue: TChartAccumulationMethod);
     procedure SetAccumulationRange(AValue: Integer);
     procedure SetOrigin(AValue: TCustomChartSource);
@@ -999,28 +999,25 @@ end;
 
 procedure TCalculatedChartSource.CalcAccumulation(AIndex: Integer);
 var
-  i, j: Integer;
+  i: Integer;
 begin
-  SetLength(FHistory, AccumulationRange);
+  FHistory.Capacity := AccumulationRange;
   if FIndex = AIndex - 1 then begin
-    for i := High(FHistory) downto 1 do
-      FHistory[i] := FHistory[i - 1];
-    ExtractItem(FHistory[0], AIndex);
+    ExtractItem(FItem, AIndex);
+    FHistory.AddLast(FItem);
   end
-  else
-    for i := 0 to Min(High(FHistory), AIndex) do
-      ExtractItem(FHistory[i], AIndex - i);
-  SetDataItemDefaults(FItem);
-  for i := 0 to Min(High(FHistory), AIndex) do begin
-    FItem.Y += FHistory[i].Y;
-    for j := 0 to High(FItem.YList) do
-      FItem.YList[j] += FHistory[i].YList[j];
+  else begin
+    FHistory.Clear;
+    for i := Max(AIndex - AccumulationRange + 1, 0) to AIndex do begin
+      ExtractItem(FItem, i);
+      FHistory.AddLast(FItem);
+    end;
   end;
-  FItem.X := FHistory[0].X;
+  FHistory.GetSum(FItem);
   if AccumulationMethod = camAverage then begin
     FItem.Y /= Min(AccumulationRange, AIndex + 1);
-    for j := 0 to High(FItem.YList) do
-      FItem.YList[j] /= Min(AccumulationRange, AIndex + 1);
+    for i := 0 to High(FItem.YList) do
+      FItem.YList[i] /= Min(AccumulationRange, AIndex + 1);
   end;
 end;
 
@@ -1051,17 +1048,19 @@ constructor TCalculatedChartSource.Create(AOwner: TComponent);
 begin
   inherited Create(AOwner);
   FIndex := -1;
+  FHistory := TChartSourceBuffer.Create;
   FListener := TListener.Create(@FOrigin, @Changed);
 end;
 
 destructor TCalculatedChartSource.Destroy;
 begin
+  FreeAndNil(FHistory);
   FreeAndNil(FListener);
   inherited Destroy;
 end;
 
 procedure TCalculatedChartSource.ExtractItem(
-  var AItem: TChartDataItem; AIndex: Integer);
+  out AItem: TChartDataItem; AIndex: Integer);
 var
   t: TDoubleDynArray;
   i: Integer;

components/tachart/test/SourcesTest.pas

@@ -74,11 +74,14 @@ begin
   FSource.AccumulationMethod := camSum;
   FSource.AccumulationRange := 2;
   AssertEquals(3, FSource.YCount);
+  AssertEquals(1, FSource[0]^.X);
   AssertEquals(102, FSource[0]^.Y);
+  AssertEquals(2, FSource[1]^.X);
   AssertEquals(102 + 202, FSource[1]^.Y);
   AssertEquals(202 + 302, FSource[2]^.Y);
   FSource.AccumulationMethod := camAverage;
-  AssertEquals((202 + 302) / 2, FSource[2]^.Y);
+  AssertEquals((2002 + 2102) / 2, FSource[20]^.Y);
+  AssertEquals(1, FSource[0]^.X);
   AssertEquals(102, FSource[0]^.Y);
   AssertEquals((102 + 202) / 2, FSource[1]^.Y);
 end;
@@ -114,15 +117,16 @@ begin
 end;
 
 procedure TCalculatedSourceTest.SetUp;
+var
+  i: Integer;
 begin
   inherited SetUp;
   FOrigin := TListChartSource.Create(nil);
   FSource := TCalculatedChartSource.Create(nil);
   FSource.Origin := FOrigin;
   FOrigin.YCount := 3;
-  FOrigin.SetYList(FOrigin.Add(1, 102), [103, 104]);
-  FOrigin.SetYList(FOrigin.Add(2, 202), [203, 204]);
-  FOrigin.SetYList(FOrigin.Add(3, 302), [303, 304]);
+  for i := 1 to 100 do
+    FOrigin.SetYList(FOrigin.Add(i, i * 100 + 2), [i * 100 + 3, i * 100 + 4]);
 end;
 
 procedure TCalculatedSourceTest.TearDown;