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|
{
This file is part of the Free Component Library (FCL)
Copyright (c) 1999-2007 by the Free Pascal development team
Some modifications (c) 2007 by Martin Schreiber
See the file COPYING.FPC, included in this distribution,
for details about the copyright.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
**********************************************************************}
{$IFDEF FPC}
{$mode objfpc}
{$H+}
{$ENDIF}
{
TMemDataset : In-memory dataset.
- Has possibility to copy Structure/Data from other dataset.
- Can load/save to/from stream.
Ideas taken from THKMemTab Component by Harri Kasulke - Hamburg/Germany
E-mail: harri.kasulke@okay.net
}
unit memds;
interface
uses
sysutils, classes, db, types;
const
// Stream Markers.
MarkerSize = SizeOf(Integer);
smEOF = 0;
smFieldDefs = 1;
smData = 2;
type
{$IFNDEF FPC}
ptrint = Integer;
{$ENDIF}
MDSError=class(Exception);
PRecInfo=^TMTRecInfo;
TMTRecInfo=record
Bookmark: Longint;
BookmarkFlag: TBookmarkFlag;
end;
{ TMemDataset }
TMemDataset=class(TDataSet)
private
FOpenStream : TStream;
FFileName : String;
FFileModified : Boolean;
FStream: TMemoryStream;
FRecInfoOffset: integer;
FRecCount: integer;
FRecSize: integer;
FRecBufferSize: integer;
FCurrRecNo: integer;
FIsOpen: boolean;
FTableIsCreated: boolean;
FFilterBuffer: PChar;
ffieldoffsets: PInteger;
ffieldsizes: PInteger;
function GetCharPointer(p:PChar; Pos:Integer):PChar;
function GetIntegerPointer(p:PInteger; Pos:Integer):PInteger;
procedure calcrecordlayout;
function MDSGetRecordOffset(ARecNo: integer): longint;
function MDSGetFieldOffset(FieldNo: integer): integer;
function MDSGetBufferSize(FieldNo: integer): integer;
function MDSGetActiveBuffer(var Buffer: PChar): Boolean;
procedure MDSReadRecord(Buffer:PChar;ARecNo:Integer);
procedure MDSWriteRecord(Buffer:PChar;ARecNo:Integer);
procedure MDSAppendRecord(Buffer:PChar);
function MDSFilterRecord(Buffer: PChar): Boolean;
protected
// Mandatory
function AllocRecordBuffer: PChar; override;
procedure FreeRecordBuffer(var Buffer: PChar); override;
procedure GetBookmarkData(Buffer: PChar; Data: Pointer); override;
function GetBookmarkFlag(Buffer: PChar): TBookmarkFlag; override;
function GetFieldData(Field: TField; Buffer: Pointer): Boolean; override;
function GetRecord(Buffer: PChar; GetMode: TGetMode; DoCheck: Boolean): TGetResult; override;
function GetRecordSize: Word; override;
procedure InternalAddRecord(Buffer: Pointer; DoAppend: Boolean); override;
procedure InternalClose; override;
procedure InternalDelete; override;
procedure InternalFirst; override;
procedure InternalGotoBookmark(ABookmark: Pointer); override;
procedure InternalInitFieldDefs; override;
procedure InternalInitRecord(Buffer: PChar); override;
procedure InternalLast; override;
procedure InternalOpen; override;
procedure InternalPost; override;
procedure InternalSetToRecord(Buffer: PChar); override;
function IsCursorOpen: Boolean; override;
procedure SetBookmarkFlag(Buffer: PChar; Value: TBookmarkFlag); override;
procedure SetBookmarkData(Buffer: PChar; Data: Pointer); override;
procedure SetFieldData(Field: TField; Buffer: Pointer); override;
// Optional.
function GetRecordCount: Integer; override;
procedure SetRecNo(Value: Integer); override;
function GetRecNo: Integer; override;
// Own.
Procedure RaiseError(Fmt : String; Args : Array of const);
Procedure CheckMarker(F : TStream; Marker : Integer);
Procedure WriteMarker(F : TStream; Marker : Integer);
procedure ReadFieldDefsFromStream(F : TStream);
procedure SaveFieldDefsToStream(F : TStream);
// These should be overridden if you want to load more data.
// E.g. index defs.
Procedure LoadDataFromStream(F : TStream); virtual;
// If SaveData=False, a size 0 block should be written.
Procedure SaveDataToStream(F : TStream; SaveData : Boolean); virtual;
public
constructor Create(AOwner:tComponent); override;
destructor Destroy; override;
function BookmarkValid(ABookmark: TBookmark): Boolean; override;
procedure CreateTable;
Function DataSize : Integer;
procedure Clear(ClearDefs : Boolean);{$IFNDEF FPC} overload; {$ENDIF}
procedure Clear;{$IFNDEF FPC} overload; {$ENDIF}
Procedure SaveToFile(AFileName : String);{$IFNDEF FPC} overload; {$ENDIF}
Procedure SaveToFile(AFileName : String; SaveData : Boolean);{$IFNDEF FPC} overload; {$ENDIF}
Procedure SaveToStream(F : TStream); {$IFNDEF FPC} overload; {$ENDIF}
Procedure SaveToStream(F : TStream; SaveData : Boolean);{$IFNDEF FPC} overload; {$ENDIF}
Procedure LoadFromStream(F : TStream);
Procedure LoadFromFile(AFileName : String);
Procedure CopyFromDataset(DataSet : TDataSet); {$IFNDEF FPC} overload; {$ENDIF}
Procedure CopyFromDataset(DataSet : TDataSet; CopyData : Boolean); {$IFNDEF FPC} overload; {$ENDIF}
Property FileModified : Boolean Read FFileModified;
published
Property FileName : String Read FFileName Write FFileName;
property Filtered;
Property Active;
Property FieldDefs;
property BeforeOpen;
property AfterOpen;
property BeforeClose;
property AfterClose;
property BeforeInsert;
property AfterInsert;
property BeforeEdit;
property AfterEdit;
property BeforePost;
property AfterPost;
property BeforeCancel;
property AfterCancel;
property BeforeDelete;
property AfterDelete;
property BeforeScroll;
property AfterScroll;
property OnDeleteError;
property OnEditError;
property OnNewRecord;
property OnPostError;
property OnFilterRecord;
end;
implementation
ResourceString
SErrFieldTypeNotSupported = 'Fieldtype of Field "%s" not supported.';
SErrBookMarkNotFound = 'Bookmark %d not found.';
SErrInvalidDataStream = 'Error in data stream at position %d';
SErrInvalidMarkerAtPos = 'Wrong data stream marker at position %d. Got %d, expected %d';
SErrNoFileName = 'Filename must not be empty.';
Const
SizeRecInfo = SizeOf(TMTRecInfo);
procedure unsetfieldisnull(nullmask: pbyte; const x: integer);
begin
inc(nullmask,(x shr 3));
nullmask^:= nullmask^ or (1 shl (x and 7));
end;
procedure setfieldisnull(nullmask: pbyte; const x: integer);
begin
inc(nullmask,(x shr 3));
nullmask^:= nullmask^ and Not (1 shl (x and 7));
end;
function getfieldisnull(nullmask: pbyte; const x: integer): boolean;
begin
inc(nullmask,(x shr 3));
result:= nullmask^ and (1 shl (x and 7)) = 0;
end;
{ ---------------------------------------------------------------------
Stream functions
---------------------------------------------------------------------}
Function ReadInteger(S : TStream) : Integer;
begin
S.ReadBuffer(Result,SizeOf(Result));
end;
Function ReadString(S : TStream) : String;
Var
L : Integer;
begin
L:=ReadInteger(S);
Setlength(Result,L);
If (L<>0) then
S.ReadBuffer(Result[1],L);
end;
Procedure WriteInteger(S : TStream; Value : Integer);
begin
S.WriteBuffer(Value,SizeOf(Value));
end;
Procedure WriteString(S : TStream; Value : String);
Var
L : Integer;
begin
L:=Length(Value);
WriteInteger(S,Length(Value));
If (L<>0) then
S.WriteBuffer(Value[1],L);
end;
{ ---------------------------------------------------------------------
TMemDataset
---------------------------------------------------------------------}
constructor TMemDataset.Create(AOwner:tComponent);
begin
inherited create(aOwner);
FStream:=TMemoryStream.Create;
FRecCount:=0;
FRecSize:=0;
FRecBufferSize:=0;
FRecInfoOffset:=0;
FCurrRecNo:=-1;
BookmarkSize := sizeof(TMTRecInfo);
FIsOpen:=False;
end;
Destructor TMemDataset.Destroy;
begin
FStream.Free;
FreeMem(FFieldOffsets);
FreeMem(FFieldSizes);
inherited Destroy;
end;
function TMemDataset.BookmarkValid(ABookmark: TBookmark): Boolean;
var
ReqBookmark: integer;
begin
Result := False;
if ABookMark=nil then exit;
ReqBookmark:=PInteger(ABookmark)^;
Result := (ReqBookmark>=0) and (ReqBookmark<FRecCount);
end;
function TMemDataset.MDSGetRecordOffset(ARecNo: integer): longint;
begin
Result:=FRecSize*ARecNo
end;
function TMemDataset.MDSGetFieldOffset(FieldNo: integer): integer;
begin
result:= getIntegerpointer(ffieldoffsets, fieldno-1)^;
end;
Procedure TMemDataset.RaiseError(Fmt : String; Args : Array of const);
begin
Raise MDSError.CreateFmt(Fmt,Args);
end;
function TMemDataset.MDSGetBufferSize(FieldNo: integer): integer;
var
dt1: tfieldtype;
begin
dt1:= FieldDefs.Items[FieldNo-1].Datatype;
case dt1 of
ftString: result:=FieldDefs.Items[FieldNo-1].Size+1;
ftFixedChar:result:=FieldDefs.Items[FieldNo-1].Size+1;
ftBoolean: result:=SizeOf(Wordbool);
ftFloat: result:=SizeOf(Double);
ftLargeInt: result:=SizeOf(int64);
ftSmallInt: result:=SizeOf(SmallInt);
ftInteger: result:=SizeOf(longint);
ftDateTime,
ftTime,
ftDate: result:=SizeOf(TDateTime);
else
RaiseError(SErrFieldTypeNotSupported,[FieldDefs.Items[FieldNo-1].Name]);
end;
{$IFDEF FPC_REQUIRES_PROPER_ALIGNMENT}
Result:=Align(Result,4);
{$ENDIF}
end;
function TMemDataset.MDSGetActiveBuffer(var Buffer: PChar): Boolean;
begin
case State of
dsBrowse:
if IsEmpty then
Buffer:=nil
else
Buffer:=ActiveBuffer;
dsEdit,
dsInsert:
Buffer:=ActiveBuffer;
dsFilter:
Buffer:=FFilterBuffer;
else
Buffer:=nil;
end;
Result:=(Buffer<>nil);
end;
procedure TMemDataset.MDSReadRecord(Buffer:PChar;ARecNo:Integer); //Reads a Rec from Stream in Buffer
begin
FStream.Position:=MDSGetRecordOffset(ARecNo);
FStream.ReadBuffer(Buffer^, FRecSize);
end;
procedure TMemDataset.MDSWriteRecord(Buffer:PChar;ARecNo:Integer); //Writes a Rec from Buffer to Stream
begin
FStream.Position:=MDSGetRecordOffset(ARecNo);
FStream.WriteBuffer(Buffer^, FRecSize);
FFileModified:=True;
end;
procedure TMemDataset.MDSAppendRecord(Buffer:PChar); //Appends a Rec (from Buffer) to Stream
begin
FStream.Position:=MDSGetRecordOffset(FRecCount);
FStream.WriteBuffer(Buffer^, FRecSize);
FFileModified:=True;
end;
//Abstract Overrides
function TMemDataset.AllocRecordBuffer: PChar;
begin
GetMem(Result,FRecBufferSize);
end;
procedure TMemDataset.FreeRecordBuffer (var Buffer: PChar);
begin
FreeMem(Buffer);
end;
procedure TMemDataset.InternalInitRecord(Buffer: PChar);
var
I : integer;
begin
fillchar(buffer^,frecsize,0);
end;
procedure TMemDataset.InternalDelete;
Var
TS : TMemoryStream;
OldPos,NewPos,CopySize1,CopySize2 : Cardinal;
begin
if (FCurrRecNo<0) or (FCurrRecNo>=FRecCount) then
Exit;
// Very inefficient. We should simply move the last part closer to the beginning in
// The FStream.
TS:=TMemoryStream.Create;
Try
if FCurrRecNo>0 then
begin
FStream.Position:=MDSGetRecordOffset(0); //Delete Rec
if FCurrRecNo<FRecCount-1 then
begin
TS.CopyFrom(FStream, MDSGetRecordOffset(FCurrRecNo)-MDSGetRecordOffset(0));
FStream.Position:=MDSGetRecordOffset(FCurrRecNo+1);
TS.CopyFrom(FStream,(MDSGetRecordOffset(FRecCount))-MDSGetRecordOffset(FCurrRecNo+1));
end
else
TS.CopyFrom(FStream,MDSGetRecordOffset(FRecCount-1));
end
else
begin //Delete first Rec
FStream.Position:=MDSGetRecordOffset(FCurrRecNo+1);
TS.CopyFrom(FStream,(MDSGetRecordOffset(FRecCount))-MDSGetRecordOffset(FCurrRecNo+1));
end;
FStream.loadFromStream(TS);
Dec(FRecCount);
if FRecCount=0 then
FCurrRecNo:=-1
else
if FCurrRecNo>=FRecCount then FCurrRecNo:=FRecCount-1;
Finally
TS.Free;
end;
FFileModified:=True;
end;
procedure TMemDataset.InternalInitFieldDefs;
begin
If (FOpenStream<>Nil) then
ReadFieldDefsFromStream(FOpenStream);
end;
Procedure TMemDataset.CheckMarker(F : TStream; Marker : Integer);
Var
I,P : Integer;
begin
P:=F.Position;
If F.Read(I,MarkerSize)<>MarkerSize then
RaiseError(SErrInvalidDataStream,[P])
else
if (I<>Marker) then
RaiseError(SErrInvalidMarkerAtPos,[P,I,Marker]);
end;
procedure TMemDataset.ReadFieldDefsFromStream(F : TStream);
Var
I,ACount : Integer;
FN : String;
FS : Integer;
B : Boolean;
FT : TFieldType;
begin
CheckMarker(F,smFieldDefs);
FieldDefs.Clear;
ACount:=ReadInteger(F);
For I:=1 to ACount do
begin
FN:=ReadString(F);
FS:=ReadInteger(F);
FT:=TFieldType(ReadInteger(F));
B:=ReadInteger(F)<>0;
TFieldDef.Create(FieldDefs,FN,ft,FS,B,I);
end;
CreateTable;
end;
procedure TMemDataset.InternalFirst;
begin
FCurrRecNo:=-1;
end;
procedure TMemDataset.InternalLast;
begin
FCurrRecNo:=FRecCount;
end;
procedure TMemDataset.InternalOpen;
begin
if not FTableIsCreated then CreateTable;
If (FFileName<>'') then
FOpenStream:=TFileStream.Create(FFileName,fmOpenRead);
Try
InternalInitFieldDefs;
if DefaultFields then
CreateFields;
BindFields(True);
FCurrRecNo:=-1;
If (FOpenStream<>Nil) then
begin
LoadDataFromStream(FOpenStream);
CheckMarker(FOpenStream,smEOF);
end;
Finally
FreeAndNil(FOpenStream);
end;
FIsOpen:=True;
end;
Procedure TMemDataSet.LoadDataFromStream(F : TStream);
Var
Size : Integer;
begin
CheckMarker(F,smData);
Size:=ReadInteger(F);
FStream.Clear;
FStream.CopyFrom(F,Size);
FRecCount:=Size div FRecSize;
FCurrRecNo:=-1;
end;
Procedure TMemDataSet.LoadFromStream(F : TStream);
begin
Close;
ReadFieldDefsFromStream(F);
LoadDataFromStream(F);
CheckMarker(F,smEOF);
FFileModified:=False;
end;
Procedure TMemDataSet.LoadFromFile(AFileName : String);
Var
F : TFileStream;
begin
F:=TFileStream.Create(AFileName,fmOpenRead);
Try
LoadFromStream(F);
Finally
F.Free;
end;
end;
Procedure TMemDataset.SaveToFile(AFileName : String);
begin
SaveToFile(AFileName,True);
end;
Procedure TMemDataset.SaveToFile(AFileName : String; SaveData : Boolean);
Var
F : TFileStream;
begin
If (AFileName='') then
RaiseError(SErrNoFileName,[]);
F:=TFileStream.Create(AFileName,fmCreate);
try
SaveToStream(F,SaveData);
Finally
F.Free;
end;
end;
Procedure TMemDataset.WriteMarker(F : TStream; Marker : Integer);
begin
Writeinteger(F,Marker);
end;
Procedure TMemDataset.SaveToStream(F : TStream);
begin
SaveToStream(F,True);
end;
Procedure TMemDataset.SaveToStream(F : TStream; SaveData : Boolean);
begin
SaveFieldDefsToStream(F);
If SaveData then
SaveDataToStream(F,SaveData);
WriteMarker(F,smEOF);
end;
Procedure TMemDataset.SaveFieldDefsToStream(F : TStream);
Var
I,ACount : Integer;
FN : String;
FS : Integer;
B : Boolean;
FT : TFieldType;
FD : TFieldDef;
begin
WriteMarker(F,smFieldDefs);
WriteInteger(F,FieldDefs.Count);
For I:=1 to FieldDefs.Count do
begin
FD:=FieldDefs[I-1];
WriteString(F,FD.Name);
WriteInteger(F,FD.Size);
WriteInteger(F,Ord(FD.DataType));
WriteInteger(F,Ord(FD.Required));
end;
end;
Procedure TMemDataset.SaveDataToStream(F : TStream; SaveData : Boolean);
begin
if SaveData then
begin
WriteMarker(F,smData);
WriteInteger(F,FStream.Size);
FStream.Position:=0;
F.CopyFrom(FStream,FStream.Size);
FFileModified:=False;
end
else
begin
WriteMarker(F,smData);
WriteInteger(F,0);
end;
end;
procedure TMemDataset.InternalClose;
begin
if (FFileModified) and (FFileName<>'') then begin
SaveToFile(FFileName,True);
end;
FIsOpen:=False;
FFileModified:=False;
// BindFields(False);
if DefaultFields then begin
DestroyFields;
end;
end;
procedure TMemDataset.InternalPost;
begin
CheckActive;
if ((State<>dsEdit) and (State<>dsInsert)) then
Exit;
if (State=dsEdit) then
MDSWriteRecord(ActiveBuffer, FCurrRecNo)
else
InternalAddRecord(ActiveBuffer,True);
end;
function TMemDataset.IsCursorOpen: Boolean;
begin
Result:=FIsOpen;
end;
function TMemDataset.GetRecord(Buffer: PChar; GetMode: TGetMode; DoCheck: Boolean): TGetResult;
var
Accepted: Boolean;
begin
Result:=grOk;
Accepted:=False;
if (FRecCount<1) then
begin
Result:=grEOF;
exit;
end;
repeat
case GetMode of
gmCurrent:
if (FCurrRecNo>=FRecCount) or (FCurrRecNo<0) then
Result:=grError;
gmNext:
if (FCurrRecNo<FRecCount-1) then
Inc(FCurrRecNo)
else
Result:=grEOF;
gmPrior:
if (FCurrRecNo>0) then
Dec(FCurrRecNo)
else
result:=grBOF;
end;
if result=grOK then
begin
MDSReadRecord(Buffer, FCurrRecNo);
PRecInfo(Buffer+FRecInfoOffset)^.Bookmark:=FCurrRecNo;
PRecInfo(Buffer+FRecInfoOffset)^.BookmarkFlag:=bfCurrent;
if (Filtered) then
Accepted:=MDSFilterRecord(Buffer) //Filtering
else
Accepted:=True;
if (GetMode=gmCurrent) and not Accepted then
result:=grError;
end;
until (result<>grOK) or Accepted;
end;
function TMemDataset.GetFieldData(Field: TField; Buffer: Pointer): Boolean;
var
SrcBuffer: PChar;
I: integer;
begin
I:= Field.FieldNo - 1;
result:= (I >= 0) and MDSGetActiveBuffer(SrcBuffer) and
not getfieldisnull(pointer(srcbuffer),I);
if result and (buffer <> nil) then
begin
Move(getcharpointer(SrcBuffer,getintegerpointer(ffieldoffsets,I)^)^, Buffer^,GetIntegerPointer(FFieldSizes, I)^);
end;
end;
procedure TMemDataset.SetFieldData(Field: TField; Buffer: Pointer);
var
DestBuffer: PChar;
I,J: integer;
begin
I:= Field.FieldNo - 1;
if (I >= 0) and MDSGetActiveBuffer(DestBuffer) then
begin
if buffer = nil then
setfieldisnull(pointer(destbuffer),I)
else
begin
unsetfieldisnull(pointer(destbuffer),I);
J:=GetIntegerPointer(FFieldSizes, I)^;
if Field.DataType=ftString then
Dec(J); // Do not move terminating 0, which is in the size.
Move(Buffer^,GetCharPointer(DestBuffer, getIntegerPointer(FFieldOffsets, I)^)^,J);
dataevent(defieldchange,ptrint(field));
end;
end;
end;
function TMemDataset.GetRecordSize: Word;
begin
Result:= FRecSize;
end;
procedure TMemDataset.InternalGotoBookmark(ABookmark: Pointer);
var
ReqBookmark: integer;
begin
ReqBookmark:=PInteger(ABookmark)^;
if (ReqBookmark>=0) and (ReqBookmark<FRecCount) then
FCurrRecNo:=ReqBookmark
else
RaiseError(SErrBookMarkNotFound,[ReqBookmark]);
end;
procedure TMemDataset.InternalSetToRecord(Buffer: PChar);
var
ReqBookmark: integer;
begin
ReqBookmark:=PRecInfo(Buffer+FRecInfoOffset)^.Bookmark;
InternalGotoBookmark (@ReqBookmark);
end;
function TMemDataset.GetBookmarkFlag(Buffer: PChar): TBookmarkFlag;
begin
Result:=PRecInfo(Buffer+FRecInfoOffset)^.BookmarkFlag;
end;
procedure TMemDataset.SetBookmarkFlag(Buffer: PChar; Value: TBookmarkFlag);
begin
PRecInfo(Buffer+FRecInfoOffset)^.BookmarkFlag := Value;
end;
procedure TMemDataset.GetBookmarkData(Buffer: PChar; Data: Pointer);
begin
if Data<>nil then
PInteger(Data)^:=PRecInfo(Buffer+FRecInfoOffset)^.Bookmark;
end;
procedure TMemDataset.SetBookmarkData(Buffer: PChar; Data: Pointer);
begin
if Data<>nil then
PRecInfo(Buffer+FRecInfoOffset)^.Bookmark:=PInteger(Data)^
else
PRecInfo(Buffer+FRecInfoOffset)^.Bookmark:=0;
end;
function TMemDataset.MDSFilterRecord(Buffer: PChar): Boolean;
var
SaveState: TDatasetState;
begin
Result:=True;
if not Assigned(OnFilterRecord) then
Exit;
SaveState:=SetTempState(dsFilter);
Try
FFilterBuffer:=Buffer;
OnFilterRecord(Self,Result);
Finally
RestoreState(SaveState);
end;
end;
Function TMemDataset.DataSize : Integer;
begin
Result:=FStream.Size;
end;
procedure TMemDataset.Clear;
begin
Clear(True);
end;
procedure TMemDataset.Clear(ClearDefs : Boolean);
begin
FStream.Clear;
FRecCount:=0;
FCurrRecNo:=-1;
if Active then
Resync([]);
If ClearDefs then
begin
Close;
FieldDefs.Clear;
end;
end;
procedure tmemdataset.calcrecordlayout;
var
i,count : integer;
begin
Count := fielddefs.count;
// Avoid mem-leak if CreateTable is called twice
FreeMem(ffieldoffsets);
Freemem(ffieldsizes);
{$IFDEF FPC}
FFieldOffsets:=getmem(Count*sizeof(integer));
FFieldSizes:=getmem(Count*sizeof(integer));
{$ELSE}
getmem(FFieldOffsets, Count*sizeof(integer));
getmem(FFieldSizes, Count*sizeof(integer));
{$ENDIF}
FRecSize:= (Count+7) div 8; //null mask
{$IFDEF FPC_REQUIRES_PROPER_ALIGNMENT}
FRecSize:=Align(FRecSize,4);
{$ENDIF}
for i:= 0 to Count-1 do
begin
GetIntegerPointer(ffieldoffsets, i)^ := frecsize;
GetIntegerPointer(ffieldsizes, i)^ := MDSGetbufferSize(i+1);
FRecSize:= FRecSize+GetIntegerPointeR(FFieldSizes, i)^;
end;
end;
procedure TMemDataset.CreateTable;
begin
CheckInactive;
FStream.Clear;
FRecCount:=0;
FCurrRecNo:=-1;
FIsOpen:=False;
calcrecordlayout;
FRecInfoOffset:=FRecSize;
FRecSize:=FRecSize+SizeRecInfo;
FRecBufferSize:=FRecSize;
FTableIsCreated:=True;
end;
procedure TMemDataset.InternalAddRecord(Buffer: Pointer; DoAppend: Boolean);
begin
MDSAppendRecord(ActiveBuffer);
InternalLast;
Inc(FRecCount);
end;
procedure TMemDataset.SetRecNo(Value: Integer);
begin
CheckBrowseMode;
if (Value>=1) and (Value<=FRecCount) then
begin
FCurrRecNo:=Value-1;
Resync([]);
end;
end;
Function TMemDataset.GetRecNo: Longint;
begin
UpdateCursorPos;
if (FCurrRecNo<0) then
Result:=1
else
Result:=FCurrRecNo+1;
end;
Function TMemDataset.GetRecordCount: Longint;
begin
CheckActive;
Result:=FRecCount;
end;
Procedure TMemDataset.CopyFromDataset(DataSet : TDataSet);
begin
CopyFromDataset(Dataset,True);
end;
Procedure TMemDataset.CopyFromDataset(DataSet : TDataSet; CopyData : Boolean);
Var
I : Integer;
F,F1,F2 : TField;
L1,L2 : TList;
N : String;
begin
Clear(True);
// NOT from fielddefs. The data may not be available in buffers !!
For I:=0 to Dataset.FieldCount-1 do
begin
F:=Dataset.Fields[I];
TFieldDef.Create(FieldDefs,F.FieldName,F.DataType,F.Size,F.Required,F.FieldNo);
end;
CreateTable;
If CopyData then
begin
Open;
L1:=TList.Create;
Try
L2:=TList.Create;
Try
For I:=0 to FieldDefs.Count-1 do
begin
N:=FieldDefs[I].Name;
F1:=FieldByName(N);
F2:=DataSet.FieldByName(N);
L1.Add(F1);
L2.Add(F2);
end;
Dataset.DisableControls;
Try
Dataset.Open;
While not Dataset.EOF do
begin
Append;
For I:=0 to L1.Count-1 do
begin
F1:=TField(L1[i]);
F2:=TField(L2[I]);
Case F1.DataType of
ftString : F1.AsString:=F2.AsString;
ftBoolean : F1.AsBoolean:=F2.AsBoolean;
ftFloat : F1.AsFloat:=F2.AsFloat;
ftLargeInt : F1.AsInteger:=F2.AsInteger;
ftSmallInt : F1.AsInteger:=F2.AsInteger;
ftInteger : F1.AsInteger:=F2.AsInteger;
ftDate : F1.AsDateTime:=F2.AsDateTime;
ftTime : F1.AsDateTime:=F2.AsDateTime;
ftDateTime : F1.AsDateTime:=F2.AsDateTime;
end;
end;
Try
Post;
except
Cancel;
Raise;
end;
Dataset.Next;
end;
Finally
Dataset.EnableControls;
end;
finally
L2.Free;
end;
finally
l1.Free;
end;
end;
end;
function TMemDataset.GetCharPointer(p:PChar; Pos:Integer):PChar;
begin
Result:=p;
inc(Result, Pos);
end;
function TMemDataset.GetIntegerPointer(p:PInteger; Pos:Integer):PInteger;
begin
Result:=p;
inc(Result, Pos);
end;
end.
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