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+{
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+ This file is part of the Free Pascal run time library.
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+ Copyright (c) 1999-2008 by Joost van der Sluis, member of the
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+ Free Pascal development team
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+
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+ TXMLDatapacketReader implementation
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+
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+ See the file COPYING.FPC, included in this distribution,
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+ for details about the copyright.
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+
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+ This program is distributed in the hope that it will be useful,
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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+
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+ **********************************************************************}
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+
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+unit XMLDatapacketReader;
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+
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+{$mode objfpc}{$H+}
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+
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+interface
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+
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+uses
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+ Classes, SysUtils, Bufdataset, dom, db;
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+
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+type
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+ TChangeLogEntry = record
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+ UpdateKind : TUpdateKind;
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+ OrigEntry : integer;
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+ NewEntry : integer;
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+ end;
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+ TChangeLogEntryArr = array of TChangeLogEntry;
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+
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+type
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+ { TXMLDatapacketReader }
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+
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+ TXMLDatapacketReader = class(TDataPacketReader)
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+ XMLDocument : TXMLDocument;
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+ DataPacketNode : TDOMElement;
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+ MetaDataNode : TDOMNode;
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+ FieldsNode : TDOMNode;
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+ FChangeLogNode,
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+ FParamsNode,
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+ FRowDataNode,
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+ FRecordNode : TDOMNode;
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+ FChangeLog : TChangeLogEntryArr;
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+ FEntryNr : integer;
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+ FLastChange : integer;
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+ public
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+ destructor destroy; override;
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+ procedure StoreFieldDefs(AFieldDefs : TFieldDefs); override;
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+ procedure StoreRecord(ADataset : TBufDataset; ARowState : TRowState; AUpdOrder : integer = 0); override;
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+ procedure FinalizeStoreRecords; override;
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+ procedure LoadFieldDefs(AFieldDefs : TFieldDefs); override;
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+ procedure InitLoadRecords; override;
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+ function GetCurrentRecord : boolean; override;
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+ function GetRecordRowState(out AUpdOrder : Integer) : TRowState; override;
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+ procedure RestoreRecord(ADataset : TBufDataset); override;
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+ procedure GotoNextRecord; override;
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+ class function RecognizeStream(AStream : TStream) : boolean; override;
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+ end;
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+
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+implementation
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+
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+uses xmlwrite, xmlread;
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+
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+const
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+ XMLFieldtypenames : Array [TFieldType] of String[15] =
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+ (
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+ 'Unknown',
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+ 'string',
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+ 'i2',
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+ 'i4',
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+ 'i4',
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+ 'boolean',
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+ 'r8',
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+ 'r8',
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+ 'fixed',
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+ 'date',
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+ 'time',
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+ 'datetime',
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+ 'bin.hex',
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+ 'bin.hex',
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+ 'i4',
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+ 'bin.hex',
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+ 'bin.hex',
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+ 'bin.hex',
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+ 'bin.hex',
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+ 'bin.hex',
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+ 'bin.hex',
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+ 'bin.hex',
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+ '',
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+ 'string',
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+ 'string',
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+ 'i8',
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+ '',
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+ '',
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+ '',
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+ '',
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+ '',
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+ '',
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+ '',
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+ '',
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+ '',
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+ '',
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+ '',
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+ '',
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+ '',
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+ ''
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+ );
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+
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+resourcestring
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+ sUnknownXMLDatasetFormat = 'Unknown XML Dataset format';
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+
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+{ TXMLDatapacketReader }
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+
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+destructor TXMLDatapacketReader.destroy;
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+begin
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+ FieldsNode.Free;
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+ MetaDataNode.Free;
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+ DataPacketNode.Free;
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+ XMLDocument.Free;
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+ inherited destroy;
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+end;
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+
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+procedure TXMLDatapacketReader.LoadFieldDefs(AFieldDefs : TFieldDefs);
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+
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+ function GetNodeAttribute(const aNode : TDOMNode; AttName : String) : string;
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+ var AnAttr : TDomNode;
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+ begin
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+ AnAttr := ANode.Attributes.GetNamedItem(AttName);
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+ if assigned(AnAttr) then result := AnAttr.NodeValue
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+ else result := '';
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+ end;
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+
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+var i : integer;
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+ AFieldDef : TFieldDef;
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+ iFieldType : TFieldType;
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+ FTString : string;
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+ AFieldNode : TDOMNode;
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+
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+begin
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+ ReadXMLFile(XMLDocument,Stream);
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+ DataPacketNode := XMLDocument.FindNode('DATAPACKET') as TDOMElement;
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+ if not assigned(DataPacketNode) then DatabaseError(sUnknownXMLDatasetFormat);
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+
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+ MetaDataNode := DataPacketNode.FindNode('METADATA');
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+ if not assigned(MetaDataNode) then DatabaseError(sUnknownXMLDatasetFormat);
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+
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+ FieldsNode := MetaDataNode.FindNode('FIELDS');
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+ if not assigned(FieldsNode) then DatabaseError(sUnknownXMLDatasetFormat);
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+
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+ with FieldsNode.ChildNodes do for i := 0 to Count - 1 do
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+ begin
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+ AFieldNode := item[i];
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+ if AFieldNode.CompareName('FIELD')=0 then
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+ begin
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+ AFieldDef := TFieldDef.create(AFieldDefs);
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+ AFieldDef.DisplayName:=GetNodeAttribute(AFieldNode,'fieldname');
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+ AFieldDef.Name:=GetNodeAttribute(AFieldNode,'attrname');
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+ AFieldDef.Size:=StrToIntDef(GetNodeAttribute(AFieldNode,'width'),0);
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+ FTString:=GetNodeAttribute(AFieldNode,'fieldtype');
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+
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+ AFieldDef.DataType:=ftUnknown;
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+ for iFieldType:=low(TFieldType) to high(TFieldType) do
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+ if SameText(XMLFieldtypenames[iFieldType],FTString) then
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+ begin
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+ AFieldDef.DataType:=iFieldType;
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+ break;
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+ end;
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+ end;
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+ end;
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+
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+ FChangeLogNode := MetaDataNode.FindNode('PARAMS');
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+ if assigned(FChangeLogNode) then
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+ FChangeLogNode := FChangeLogNode.Attributes.GetNamedItem('CHANGE_LOG');
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+
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+ FRowDataNode := DataPacketNode.FindNode('ROWDATA');
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+ FRecordNode := nil;
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+end;
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+
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+procedure TXMLDatapacketReader.StoreFieldDefs(AFieldDefs: TFieldDefs);
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+
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+var i : integer;
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+ AFieldNode : TDOMElement;
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+
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+begin
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+ XMLDocument := TXMLDocument.Create;
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+ DataPacketNode := XMLDocument.CreateElement('DATAPACKET');
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+ DataPacketNode.SetAttribute('Version','2.0');
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+
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+ MetaDataNode := XMLDocument.CreateElement('METADATA');
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+ FieldsNode := XMLDocument.CreateElement('FIELDS');
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+
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+ for i := 0 to AFieldDefs.Count -1 do with AFieldDefs[i] do
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+ begin
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+ AFieldNode := XMLDocument.CreateElement('FIELD');
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+ if Name <> '' then AFieldNode.SetAttribute('fieldname',Name);
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+ AFieldNode.SetAttribute('attrname',DisplayName);
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+ if size <> 0 then AFieldNode.SetAttribute('width',IntToStr(Size));
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+ AFieldNode.SetAttribute('fieldtype',XMLFieldtypenames[DataType]);
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+ case DataType of
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+ ftAutoInc : begin
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+ AFieldNode.SetAttribute('readonly','true');
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+ AFieldNode.SetAttribute('subtype','Autoinc');
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+ end;
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+ ftCurrency: AFieldNode.SetAttribute('subtype','Money');
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+ ftVarBytes,
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+ ftBlob : AFieldNode.SetAttribute('subtype','Binary');
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+ ftMemo : AFieldNode.SetAttribute('subtype','Text');
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+ ftTypedBinary,
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+ ftGraphic: AFieldNode.SetAttribute('subtype','Graphics');
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+ ftFmtMemo : AFieldNode.SetAttribute('subtype','Formatted');
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+ ftParadoxOle,
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+ ftDBaseOle : AFieldNode.SetAttribute('subtype','Ole');
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+ end; {case}
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+ if faReadonly in Attributes then AFieldNode.SetAttribute('readonly','true');
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+
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+ FieldsNode.AppendChild(AFieldNode);
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+ end;
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+
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+ MetaDataNode.AppendChild(FieldsNode);
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+ FParamsNode := XMLDocument.CreateElement('PARAMS');
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+ MetaDataNode.AppendChild(FParamsNode);
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+ DataPacketNode.AppendChild(MetaDataNode);
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+ FRowDataNode := XMLDocument.CreateElement('ROWDATA');
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+ setlength(FChangeLog,0);
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+ FEntryNr:=0;
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+ FLastChange:=-1;
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+end;
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+
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+procedure TXMLDatapacketReader.FinalizeStoreRecords;
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+var ChangeLogStr : String;
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+ i : integer;
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+begin
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+ ChangeLogStr:='';
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+ for i := 0 to length(FChangeLog)-1 do with FChangeLog[i] do
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+ begin
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+ ChangeLogStr:=ChangeLogStr+' '+inttostr(NewEntry)+' '+inttostr(OrigEntry)+' ';
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+ if UpdateKind=ukModify then ChangeLogStr := ChangeLogStr+'8';
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+ if UpdateKind=ukInsert then ChangeLogStr := ChangeLogStr+'4';
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+ if UpdateKind=ukDelete then ChangeLogStr := ChangeLogStr+'2';
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+ end;
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+ setlength(FChangeLog,0);
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+
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+ if ChangeLogStr<>'' then
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+ (FParamsNode as TDomElement).SetAttribute('CHANGE_LOG',Trim(ChangeLogStr));
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+
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+ DataPacketNode.AppendChild(FRowDataNode);
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+ XMLDocument.AppendChild(DataPacketNode);
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+
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+ WriteXML(XMLDocument,Stream);
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+end;
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+
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+function TXMLDatapacketReader.GetCurrentRecord: boolean;
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+begin
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+ Result := assigned(FRecordNode);
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+end;
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+
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+function TXMLDatapacketReader.GetRecordRowState(out AUpdOrder: Integer
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+ ): TRowState;
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+var ARowStateNode : TDOmNode;
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+ ARowState : integer;
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+ i : integer;
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+begin
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+ ARowStateNode := FRecordNode.Attributes.GetNamedItem('RowState');
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+ if ARowStateNode = nil then // This item is not edited
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+ Result := []
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+ else
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+ begin
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+ Result := ByteToRowState(StrToIntDef(ARowStateNode.NodeValue,0));
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+ if Result = [rsvOriginal] then
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+ begin
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+ for i := 0 to length(FChangeLog)-1 do
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+ if FChangeLog[i].NewEntry=FEntryNr then break;
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+ assert(FChangeLog[i].NewEntry=FEntryNr);
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+ end
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+ else
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+ begin
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+ for i := 0 to length(FChangeLog)-1 do
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+ if FChangeLog[i].OrigEntry=FEntryNr then break;
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+ assert(FChangeLog[i].OrigEntry=FEntryNr);
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+ end;
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+ AUpdOrder:=i;
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+ end;
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+end;
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+
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+procedure TXMLDatapacketReader.InitLoadRecords;
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+
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+var ChangeLogStr : String;
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+ i,cp : integer;
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+ ps : string;
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+
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+begin
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+ FRecordNode := FRowDataNode.FirstChild;
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+ FEntryNr := 1;
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+ setlength(FChangeLog,0);
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+ if assigned(FChangeLogNode) then
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+ ChangeLogStr:=FChangeLogNode.NodeValue
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+ else
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+ ChangeLogStr:='';
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+ ps := '';
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+ cp := 0;
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+ if ChangeLogStr<>'' then for i := 1 to length(ChangeLogStr)+1 do
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+ begin
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+ if not (ChangeLogStr[i] in [' ',#0]) then
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+ ps := ps + ChangeLogStr[i]
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+ else
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+ begin
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+ case (cp mod 3) of
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+ 0 : begin
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+ SetLength(FChangeLog,length(FChangeLog)+1);
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+ FChangeLog[cp div 3].OrigEntry:=StrToIntDef(ps,0);
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+ end;
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+ 1 : FChangeLog[cp div 3].NewEntry:=StrToIntDef(ps,0);
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+ 2 : begin
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+ if ps = '2' then
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+ FChangeLog[cp div 3].UpdateKind:=ukDelete
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+ else if ps = '4' then
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+ FChangeLog[cp div 3].UpdateKind:=ukInsert
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+ else if ps = '8' then
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+ FChangeLog[cp div 3].UpdateKind:=ukModify;
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+ end;
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+ end; {case}
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+ ps := '';
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+ inc(cp);
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+ end;
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+ end;
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+end;
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+
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+procedure TXMLDatapacketReader.RestoreRecord(ADataset : TBufDataset);
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+var FieldNr : integer;
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+ AFieldNode : TDomNode;
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+begin
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+ with ADataset do for FieldNr:=0 to FieldCount-1 do
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+ begin
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+ AFieldNode := FRecordNode.Attributes.GetNamedItem(Fields[FieldNr].FieldName);
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+ if assigned(AFieldNode) then
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+ begin
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+ Fields[FieldNr].AsString := AFieldNode.NodeValue; // set it to the filterbuffer
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+ end
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+ end;
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+end;
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+
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+procedure TXMLDatapacketReader.StoreRecord(ADataset : TBufDataset; ARowState : TRowState; AUpdOrder : integer = 0);
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+var FieldNr : Integer;
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+ ARecordNode : TDOMElement;
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+begin
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+ inc(FEntryNr);
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+ ARecordNode := XMLDocument.CreateElement('ROW');
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+ for FieldNr := 0 to ADataset.Fields.Count-1 do
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+ begin
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+ ARecordNode.SetAttribute(ADataset.fields[FieldNr].FieldName,ADataset.fields[FieldNr].AsString);
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+ end;
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+ if ARowState<>[] then
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+ begin
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+ ARecordNode.SetAttribute('RowState',inttostr(RowStateToByte(ARowState)));
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+ if AUpdOrder>=length(FChangeLog) then
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+ setlength(FChangeLog,AUpdOrder+1);
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+ if (rsvOriginal in ARowState) or (rsvDeleted in ARowState) then
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+ FChangeLog[AUpdOrder].OrigEntry:=FEntryNr;
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+ if (rsvDeleted in ARowState) or (rsvUpdated in ARowState) or (rsvInserted in ARowState) then
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+ FChangeLog[AUpdOrder].NewEntry:=FEntryNr;
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+ if ARowState=[rsvUpdated] then
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+ FChangeLog[AUpdOrder].UpdateKind := ukModify;
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+ if ARowState=[rsvInserted] then
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+ FChangeLog[AUpdOrder].UpdateKind := ukInsert;
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+ if ARowState=[rsvDeleted] then
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+ FChangeLog[AUpdOrder].UpdateKind := ukDelete;
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+ end;
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+ FRowDataNode.AppendChild(ARecordNode);
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+end;
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+
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+class function TXMLDatapacketReader.RecognizeStream(AStream: TStream): boolean;
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+const XmlStart = '<?xml';
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+var s : string;
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+ len : integer;
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+begin
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+ Len := length(XmlStart);
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+ setlength(s,len);
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+ if (AStream.Read (s[1],len) = len)
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+ and (s=XmlStart) then
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+ Result := True
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+ else
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+ Result := False;
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+end;
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+
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+procedure TXMLDatapacketReader.GotoNextRecord;
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+begin
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+ FRecordNode := FRecordNode.NextSibling;
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+ inc(FEntryNr);
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+ while assigned(FRecordNode) and (FRecordNode.CompareName('ROW')<>0) do
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+ FRecordNode := FRecordNode.NextSibling;
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+end;
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+
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+initialization
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+ RegisterDatapacketReader(TXMLDatapacketReader,dfXML);
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+end.
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