437 lines
13 KiB
ObjectPascal
437 lines
13 KiB
ObjectPascal
{ ex_rx_xml_datapacket unit
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Copyright (C) 2005-2017 Lagunov Aleksey alexs@yandex.ru and Lazarus team
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original conception from rx library for Delphi (c)
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This library is free software; you can redistribute it and/or modify it
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under the terms of the GNU Library General Public License as published by
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the Free Software Foundation; either version 2 of the License, or (at your
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option) any later version with the following modification:
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent modules,and
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to copy and distribute the resulting executable under terms of your choice,
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provided that you also meet, for each linked independent module, the terms
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and conditions of the license of that module. An independent module is a
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module which is not derived from or based on this library. If you modify
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this library, you may extend this exception to your version of the library,
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but you are not obligated to do so. If you do not wish to do so, delete this
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exception statement from your version.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License
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for more details.
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You should have received a copy of the GNU Library General Public License
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along with this library; if not, write to the Free Software Foundation,
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Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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}
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{
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TXMLRxDatapacketReader implementation
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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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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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unit ex_rx_xml_datapacket;
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{$mode objfpc}{$H+}
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interface
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uses
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Classes, SysUtils, dom, db, ex_rx_datapacket;
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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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type
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{ TXMLRxDatapacketReader }
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TXMLRxDatapacketReader = class(TRxDataPacketReader)
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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 : TDataset; 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 : TDataset); 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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implementation
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uses xmlwrite, xmlread, rxdconst;
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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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{ TXMLRxDatapacketReader }
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destructor TXMLRxDatapacketReader.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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// Actually does a lot more than just loading the field defs...
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procedure TXMLRxDatapacketReader.LoadFieldDefs(AFieldDefs : TFieldDefs);
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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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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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bLoadFieldDefs : Boolean;
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begin
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// if we already have field defs then don't reload from the file
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bLoadFieldDefs := (AFieldDefs.Count = 0);
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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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MetaDataNode := DataPacketNode.FindNode('METADATA');
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if not assigned(MetaDataNode) then DatabaseError(sUnknownXMLDatasetFormat);
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FieldsNode := MetaDataNode.FindNode('FIELDS');
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if not assigned(FieldsNode) then DatabaseError(sUnknownXMLDatasetFormat);
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if bLoadFieldDefs then
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begin
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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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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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end;
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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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FRowDataNode := DataPacketNode.FindNode('ROWDATA');
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FRecordNode := nil;
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end;
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procedure TXMLRxDatapacketReader.StoreFieldDefs(AFieldDefs: TFieldDefs);
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var i : integer;
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AFieldNode : TDOMElement;
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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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MetaDataNode := XMLDocument.CreateElement('METADATA');
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FieldsNode := XMLDocument.CreateElement('FIELDS');
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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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FieldsNode.AppendChild(AFieldNode);
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end;
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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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procedure TXMLRxDatapacketReader.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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if ChangeLogStr<>'' then
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(FParamsNode as TDomElement).SetAttribute('CHANGE_LOG',Trim(ChangeLogStr));
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DataPacketNode.AppendChild(FRowDataNode);
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XMLDocument.AppendChild(DataPacketNode);
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WriteXML(XMLDocument,Stream);
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end;
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function TXMLRxDatapacketReader.GetCurrentRecord: boolean;
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begin
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Result := assigned(FRecordNode);
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end;
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function TXMLRxDatapacketReader.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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procedure TXMLRxDatapacketReader.InitLoadRecords;
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var ChangeLogStr : String;
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i,cp : integer;
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ps : string;
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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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procedure TXMLRxDatapacketReader.RestoreRecord(ADataset : TDataset);
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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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procedure TXMLRxDatapacketReader.StoreRecord(ADataset : TDataset; 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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class function TXMLRxDatapacketReader.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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procedure TXMLRxDatapacketReader.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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initialization
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RegisterDatapacketReader(TXMLRxDatapacketReader,dfXML);
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end.
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end.
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