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{************************************************************************}
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{ }
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{ Borland Delphi Visual Component Library }
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{ InterBase Express core components }
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{ }
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{ Copyright (c) 1998-2000 Inprise Corporation }
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{ }
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{ InterBase Express is based in part on the product }
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{ Free IB Components, written by Gregory H. Deatz for }
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{ Hoagland, Longo, Moran, Dunst & Doukas Company. }
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{ Free IB Components is used under license. }
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{ }
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{ The contents of this file are subject to the InterBase }
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{ Public License Version 1.0 (the "License"); you may not }
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{ use this file except in compliance with the License. You }
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{ may obtain a copy of the License at http://www.Inprise.com/IPL.html }
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{ Software distributed under the License is distributed on }
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{ an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either }
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{ express or implied. See the License for the specific language }
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{ governing rights and limitations under the License. }
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{ The Original Code was created by InterBase Software Corporation }
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{ and its successors. }
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{ Portions created by Inprise Corporation are Copyright (C) Inprise }
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{ Corporation. All Rights Reserved. }
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{ Contributor(s): Jeff Overcash }
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{ }
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{ IBX For Lazarus (Firebird Express) }
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{ Contributor: Tony Whyman, MWA Software http://www.mwasoftware.co.uk }
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{ Portions created by MWA Software are copyright McCallum Whyman }
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{ Associates Ltd 2011 - 2018 }
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{************************************************************************}
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unit IBBlob;
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{$mode Delphi}
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interface
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uses
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SysUtils, Classes, DB, IB, IBDatabase;
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const
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DefaultBlobSegmentSize = 16 * 1024;
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type
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TIBBlobStates = (bsUninitialised, bsDataPending, bsData, bsModified);
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{ TIBBlobStream }
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TIBBlobStream = class(TStream)
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private
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FBase: TIBBase;
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FBlob: IBlob;
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FBlobMaxSegmentSize: Int64;
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FBlobNumSegments: Int64;
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FBlobSize: Int64;
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FBlobType: TBlobType;
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FBuffer: PChar;
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FColumnName: string;
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FMode: TBlobStreamMode;
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FPosition: Int64;
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FBlobState: TIBBlobStates;
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FRelationName: string;
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function GetBlobID: TISC_QUAD;
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function GetModified: Boolean;
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procedure CheckActive;
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protected
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procedure CloseBlob;
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procedure EnsureBlobInitialized;
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procedure EnsureLoaded;
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procedure GetBlobInfo;
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function GetSize: Int64; override;
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function GetDatabase: TIBDatabase;
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function GetTransaction: TIBTransaction;
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procedure OpenBlob;
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procedure SetBlobID(Value: TISC_QUAD);
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procedure SetDatabase(Value: TIBDatabase);
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procedure SetMode(Value: TBlobStreamMode);
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procedure SetState(aValue: TIBBlobStates);
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procedure SetTransaction(Value: TIBTransaction);
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public
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constructor Create;
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destructor Destroy; override;
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procedure CheckReadable;
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procedure CheckWritable;
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procedure Finalize;
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procedure LoadFromFile(Filename: string);
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procedure LoadFromStream(Stream: TStream);
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function Read(var Buffer; Count: Longint): Longint; override;
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procedure SaveToFile(Filename: string);
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procedure SaveToStream(Stream: TStream);
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function Seek(const Offset: Int64; Origin: TSeekOrigin): Int64; override;
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procedure SetField(aField: TField);
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procedure SetSize(const NewSize: Int64); override;
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procedure SetSize(NewSize: Longint); override;
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procedure Truncate;
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function Write(const Buffer; Count: Longint): Longint; override;
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property BlobID: TISC_QUAD read GetBlobID write SetBlobID;
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property Blob: IBlob read FBlob;
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property BlobMaxSegmentSize: Int64 read FBlobMaxSegmentSize;
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property BlobNumSegments: Int64 read FBlobNumSegments;
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property BlobSize: Int64 read GetSize;
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property BlobType: TBlobType read FBlobType;
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property Database: TIBDatabase read GetDatabase write SetDatabase;
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property Mode: TBlobStreamMode read FMode write SetMode;
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property Modified: Boolean read GetModified;
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property Transaction: TIBTransaction read GetTransaction write SetTransaction;
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property RelationName: string read FRelationName;
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property ColumnName: string read FColumnName;
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end;
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implementation
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uses FBMessages, IBCustomDataSet;
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{ TIBBlobStream }
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constructor TIBBlobStream.Create;
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begin
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inherited Create;
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FBase := TIBBase.Create(Self);
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FBuffer := nil;
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FBlobSize := 0;
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FBlobState := bsUninitialised;
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FBlob := nil;
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end;
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destructor TIBBlobStream.Destroy;
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begin
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CloseBlob;
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FBase.Free;
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SetSize(0);
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inherited Destroy;
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end;
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procedure TIBBlobStream.CheckReadable;
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begin
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if FMode = bmWrite then IBError(ibxeBlobCannotBeRead, [nil]);
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end;
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procedure TIBBlobStream.CheckWritable;
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begin
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if FMode = bmRead then IBError(ibxeBlobCannotBeWritten, [nil]);
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end;
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function TIBBlobStream.GetModified: Boolean;
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begin
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Result := FBlobState = bsModified;
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end;
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procedure TIBBlobStream.CheckActive;
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begin
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if Database = nil then
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IBError(ibxeDatabaseNotAssigned,[nil]);
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if (Database.Attachment = nil) or
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not Database.Attachment.IsConnected then
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IBError(ibxeDatabaseClosed,[nil]);
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if Transaction = nil then
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IBError(ibxeTransactionNotAssigned,[nil]);
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if (Transaction.TransactionIntf = nil) or
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not Transaction.TransactionIntf.InTransaction then
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IBError(ibxeNotInTransaction,[nil]);
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end;
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function TIBBlobStream.GetBlobID: TISC_QUAD;
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begin
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if (FBlob = nil) or (FBlobSize = 0) then
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begin
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Result.gds_quad_high := 0;
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Result.gds_quad_low := 0;
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end
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else
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Result := FBlob.GetBlobID;
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end;
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procedure TIBBlobStream.CloseBlob;
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begin
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Finalize;
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FBlob := nil;
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SetState(bsUninitialised);
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end;
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procedure TIBBlobStream.EnsureBlobInitialized;
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begin
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if FBlobState <> bsUninitialised then Exit;
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if FMode = bmWrite then
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SetState(bsData)
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else
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begin
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CheckReadable;
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if FBlob = nil then Exit;
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try
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GetBlobInfo;
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{Defer reading in blob until read method called}
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except
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FBlob := nil;
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raise;
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end;
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SetState(bsDataPending);
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end;
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end;
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procedure TIBBlobStream.EnsureLoaded;
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begin
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EnsureBlobInitialized;
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if (FBlobState = bsDataPending) and (FBlob <> nil) then
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begin
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SetSize(FBlobSize);
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FBlob.Read(FBuffer^, FBlobSize);
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SetState(bsData);
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end;
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end;
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procedure TIBBlobStream.Finalize;
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begin
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if FBlobState <> bsModified then
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exit;
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CheckWritable;
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if FBlobSize > 0 then
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begin
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{ need to start writing to a blob, create one }
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FBlob := Database.Attachment.CreateBlob(Transaction.TransactionIntf,RelationName,ColumnName);
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FBlob.Write(FBuffer^, FBlobSize);
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FBlob.Close;
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end;
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SetState(bsData);
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end;
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procedure TIBBlobStream.GetBlobInfo;
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var
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iBlobSize: Int64;
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begin
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if FBlob = nil then Exit;
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FBlob.GetInfo(FBlobNumSegments, FBlobMaxSegmentSize, iBlobSize, FBlobType);
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SetSize(iBlobSize);
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end;
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function TIBBlobStream.GetSize: Int64;
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begin
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EnsureBlobInitialized;
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Result := FBlobSize;
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end;
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function TIBBlobStream.GetDatabase: TIBDatabase;
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begin
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result := FBase.Database;
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end;
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function TIBBlobStream.GetTransaction: TIBTransaction;
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begin
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result := FBase.Transaction;
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end;
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procedure TIBBlobStream.LoadFromFile(Filename: string);
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var
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Stream: TStream;
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begin
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Stream := TFileStream.Create(FileName, fmOpenRead);
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try
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LoadFromStream(Stream);
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finally
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Stream.Free;
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end;
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end;
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procedure TIBBlobStream.LoadFromStream(Stream: TStream);
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begin
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CheckWritable;
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EnsureBlobInitialized;
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Stream.Position := 0;
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SetSize(Stream.Size);
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if FBlobSize <> 0 then
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Stream.ReadBuffer(FBuffer^, FBlobSize);
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SetState(bsModified);
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end;
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procedure TIBBlobStream.OpenBlob;
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begin
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CheckReadable;
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try
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GetBlobInfo;
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{Defer reading in blob until read method called}
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except
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FBlob.Close;
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raise;
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end;
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SetState(bsDataPending);
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end;
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function TIBBlobStream.Read(var Buffer; Count: Longint): Longint;
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begin
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CheckReadable;
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EnsureLoaded;
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if Count <= 0 then
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begin
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result := 0;
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exit;
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end;
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if (FPosition + Count > FBlobSize) then
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result := FBlobSize - FPosition
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else
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result := Count;
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Move(FBuffer[FPosition], Buffer, result);
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Inc(FPosition, Result);
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end;
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procedure TIBBlobStream.SaveToFile(Filename: string);
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var
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Stream: TStream;
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begin
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Stream := TFileStream.Create(FileName, fmCreate);
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try
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SaveToStream(Stream);
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finally
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Stream.Free;
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end;
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end;
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procedure TIBBlobStream.SaveToStream(Stream: TStream);
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begin
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CheckReadable;
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EnsureLoaded;
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if FBlobSize <> 0 then
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begin
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Seek(0, soFromBeginning);
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Stream.WriteBuffer(FBuffer^, FBlobSize);
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end;
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end;
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function TIBBlobStream.Seek(const Offset: Int64; Origin: TSeekOrigin): Int64;
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begin
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EnsureBlobInitialized;
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case Origin of
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soBeginning : FPosition := Offset;
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soCurrent : Inc(FPosition, Offset);
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soEnd : FPosition := FBlobSize + Offset;
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end;
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result := FPosition;
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end;
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procedure TIBBlobStream.SetField(aField: TField);
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begin
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FRelationName := '';
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if aField.FieldDef <> nil then
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FRelationName := (aField.FieldDef as TIBFieldDef).RelationName;
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FColumnName := aField.FieldName;;
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end;
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procedure TIBBlobStream.SetBlobID(Value: TISC_QUAD);
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begin
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CheckActive;
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FBlob := nil;
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if (Value.gds_quad_high = 0) and (Value.gds_quad_low = 0) then
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Exit;
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FBlob := Database.Attachment.OpenBlob(Transaction.TransactionIntf,RelationName,ColumnName,Value);
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if FBlobState <> bsData then
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SetState(bsUninitialised);
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end;
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procedure TIBBlobStream.SetDatabase(Value: TIBDatabase);
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begin
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FBase.Database := Value;
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SetState(bsUninitialised);
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end;
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procedure TIBBlobStream.SetMode(Value: TBlobStreamMode);
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begin
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FMode := Value;
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SetState(bsUninitialised);
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end;
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procedure TIBBlobStream.SetState(aValue: TIBBlobStates);
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begin
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if FBlobState = aValue then Exit;
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if (FBlobState = bsDataPending) and (FBlob <> nil) then
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FBlob.Close;
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FBlobState := aValue;
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end;
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procedure TIBBlobStream.SetSize(const NewSize: Int64);
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begin
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if (NewSize <> FBlobSize) then
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begin
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ReallocMem(FBuffer, NewSize);
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FBlobSize := NewSize;
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if NewSize = 0 then
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FBuffer := nil;
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end;
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end;
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procedure TIBBlobStream.SetSize(NewSize: Longint);
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begin
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SetSize(Int64(NewSize));
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end;
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procedure TIBBlobStream.SetTransaction(Value: TIBTransaction);
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begin
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FBase.Transaction := Value;
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SetState(bsUninitialised);
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end;
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procedure TIBBlobStream.Truncate;
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begin
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SetSize(0);
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SetState(bsModified);
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end;
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function TIBBlobStream.Write(const Buffer; Count: Longint): Longint;
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begin
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CheckWritable;
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EnsureLoaded; {Could be an untruncated bmReadWrite Blob}
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result := Count;
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if Count <= 0 then
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exit;
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if (FPosition + Count > FBlobSize) then
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SetSize(FPosition + Count);
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Move(Buffer, FBuffer[FPosition], Count);
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Inc(FPosition, Count);
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SetState(bsModified);
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end;
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end.
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