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RXLib/.svn/pristine/75/75f10dbee667c690afefbacd15bf69d0b5906fa2.svn-base

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+{ ex_rx_bin_datapacket unit
+
+  Copyright (C) 2005-2017 Lagunov Aleksey alexs@yandex.ru and Lazarus team
+  original conception from rx library for Delphi (c)
+
+  This library is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Library General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or (at your
+  option) any later version with the following modification:
+
+  As a special exception, the copyright holders of this library give you
+  permission to link this library with independent modules to produce an
+  executable, regardless of the license terms of these independent modules,and
+  to copy and distribute the resulting executable under terms of your choice,
+  provided that you also meet, for each linked independent module, the terms
+  and conditions of the license of that module. An independent module is a
+  module which is not derived from or based on this library. If you modify
+  this library, you may extend this exception to your version of the library,
+  but you are not obligated to do so. If you do not wish to do so, delete this
+  exception statement from your version.
+
+  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. See the GNU Library General Public License
+  for more details.
+
+  You should have received a copy of the GNU Library General Public License
+  along with this library; if not, write to the Free Software Foundation,
+  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+}
+
+
+{
+    TBinaryRxDatapacketReader implementation
+
+    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.
+
+ **********************************************************************}
+
+unit ex_rx_bin_datapacket;
+
+{$mode objfpc}{$H+}
+
+interface
+
+uses
+  Classes, SysUtils, dom, db, ex_rx_datapacket;
+
+type
+  TChangeLogEntry = record
+       UpdateKind : TUpdateKind;
+       OrigEntry  : integer;
+       NewEntry   : integer;
+  end;
+  TChangeLogEntryArr = array of TChangeLogEntry;
+
+type
+  { TBinaryRxDatapacketReader }
+
+  TBinaryRxDatapacketReader = class(TRxDataPacketReader)
+  public
+    procedure LoadFieldDefs(AFieldDefs : TFieldDefs); override;
+    procedure StoreFieldDefs(AFieldDefs : TFieldDefs); override;
+    function GetRecordRowState(out AUpdOrder : Integer) : TRowState; override;
+    procedure FinalizeStoreRecords; override;
+    function GetCurrentRecord : boolean; override;
+    procedure GotoNextRecord; override;
+    procedure InitLoadRecords; override;
+    procedure RestoreRecord(ADataset : TDataset); override;
+    procedure StoreRecord(ADataset : TDataset; ARowState : TRowState; AUpdOrder : integer = 0); override;
+    class function RecognizeStream(AStream : TStream) : boolean; override;
+  end;
+
+implementation
+
+uses
+  dbconst;
+
+{ TBinaryRxDatapacketReader }
+
+const
+  RxBinaryIdent = 'BinRxDataset';
+
+procedure TBinaryRxDatapacketReader.LoadFieldDefs(AFieldDefs: TFieldDefs);
+var
+  FldCount : word;
+  i : integer;
+begin
+
+  if not RecognizeStream(Stream) then
+    DatabaseError(SStreamNotRecognised);
+
+  FldCount:=Stream.ReadWord;
+  AFieldDefs.Clear;
+  for i := 0 to FldCount -1 do with TFieldDef.create(AFieldDefs) do
+    begin
+    Name := Stream.ReadAnsiString;
+    Displayname := Stream.ReadAnsiString;
+    Size := Stream.ReadWord;
+    DataType := TFieldType(Stream.ReadWord);
+
+    if Stream.ReadByte = 1 then
+      Attributes := Attributes + [faReadonly];
+    end;
+
+end;
+
+procedure TBinaryRxDatapacketReader.StoreFieldDefs(AFieldDefs: TFieldDefs);
+var i : integer;
+begin
+  Stream.Write(RxBinaryIdent[1],length(RxBinaryIdent));
+
+  Stream.WriteWord(AFieldDefs.Count);
+  for i := 0 to AFieldDefs.Count -1 do with AFieldDefs[i] do
+    begin
+    Stream.WriteAnsiString(Name);
+    Stream.WriteAnsiString(DisplayName);
+    Stream.WriteWord(size);
+    Stream.WriteWord(ord(DataType));
+
+    if faReadonly in Attributes then
+      Stream.WriteByte(1)
+    else
+      Stream.WriteByte(0);
+    end;
+
+end;
+
+function TBinaryRxDatapacketReader.GetRecordRowState(out AUpdOrder: Integer
+  ): TRowState;
+var Buf : byte;
+begin
+  Buf := 0;
+  AUpdOrder := 0;
+
+  Stream.Read(Buf,1);
+  Result := ByteToRowState(Buf);
+  if Result<>[] then
+    Stream.ReadBuffer(AUpdOrder,sizeof(integer));
+
+end;
+
+procedure TBinaryRxDatapacketReader.FinalizeStoreRecords;
+begin
+//  Do nothing
+end;
+
+function TBinaryRxDatapacketReader.GetCurrentRecord: boolean;
+var
+  Buf : byte;
+begin
+  Buf := 0;
+  Result := (Stream.Read(Buf,1)=1) and (Buf=$fe);
+end;
+
+procedure TBinaryRxDatapacketReader.GotoNextRecord;
+begin
+//  Do Nothing
+end;
+
+procedure TBinaryRxDatapacketReader.InitLoadRecords;
+begin
+//  Do Nothing
+end;
+
+procedure TBinaryRxDatapacketReader.RestoreRecord(ADataset: TDataset);
+begin
+  Stream.ReadBuffer(ADataset.ActiveBuffer^,ADataset.RecordSize);
+end;
+
+procedure TBinaryRxDatapacketReader.StoreRecord(ADataset: TDataset;
+  ARowState: TRowState; AUpdOrder: integer);
+begin
+  Stream.WriteByte($fe);
+  Stream.WriteByte(RowStateToByte(ARowState));
+  if ARowState<>[] then
+    Stream.WriteBuffer(AUpdOrder,sizeof(integer));
+  Stream.WriteBuffer(ADataset.ActiveBuffer^,ADataset.RecordSize);
+end;
+
+class function TBinaryRxDatapacketReader.RecognizeStream(AStream: TStream
+  ): boolean;
+var s        : string;
+    len      : integer;
+begin
+  Len := length(RxBinaryIdent);
+  setlength(s,len);
+  if (AStream.Read (s[1],len) = len)
+  and (s=RxBinaryIdent) then
+    Result := True
+  else
+    Result := False;
+
+end;
+
+initialization
+  RegisterDatapacketReader(TBinaryRxDatapacketReader,dfBinary);
+end.
+