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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 }
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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, IBHeader, IBErrorCodes, IBExternals, DB, IB, IBDatabase;
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const
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DefaultBlobSegmentSize = 16 * 1024;
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type
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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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FBlobID: TISC_QUAD;
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FBlobMaxSegmentSize: Int64;
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FBlobNumSegments: Int64;
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FBlobSize: Int64;
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FBlobType: Short; { 0 = segmented, 1 = streamed }
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FBuffer: PChar;
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FBlobInitialized: Boolean;
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FHandle: TISC_BLOB_HANDLE;
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FMode: TBlobStreamMode;
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FModified: Boolean;
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FPosition: Int64;
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protected
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procedure CloseBlob;
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procedure CreateBlob;
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procedure EnsureBlobInitialized;
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procedure GetBlobInfo;
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function GetDatabase: TIBDatabase;
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function GetDBHandle: PISC_DB_HANDLE;
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function GetTransaction: TIBTransaction;
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function GetTRHandle: PISC_TR_HANDLE;
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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 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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function Call(ErrCode: ISC_STATUS; RaiseError: Boolean): ISC_STATUS;
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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 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 Handle: TISC_BLOB_HANDLE read FHandle;
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property BlobID: TISC_QUAD read FBlobID write SetBlobID;
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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 FBlobSize;
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property BlobType: Short read FBlobType;
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property Database: TIBDatabase read GetDatabase write SetDatabase;
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property DBHandle: PISC_DB_HANDLE read GetDBHandle;
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property Mode: TBlobStreamMode read FMode write SetMode;
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property Modified: Boolean read FModified;
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property Transaction: TIBTransaction read GetTransaction write SetTransaction;
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property TRHandle: PISC_TR_HANDLE read GetTRHandle;
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end;
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procedure GetBlobInfo(hBlobHandle: PISC_BLOB_HANDLE; var NumSegments: Int64; var MaxSegmentSize,
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TotalSize: Int64; var BlobType: Short);
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procedure ReadBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Int64);
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procedure WriteBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Int64);
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implementation
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uses IBIntf;
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procedure GetBlobInfo(hBlobHandle: PISC_BLOB_HANDLE; var NumSegments: Int64; var MaxSegmentSize,
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TotalSize: Int64; var BlobType: Short);
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var
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items: array[0..3] of Char;
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results: array[0..99] of Char;
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i, item_length: Integer;
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item: Integer;
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begin
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items[0] := Char(isc_info_blob_num_segments);
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items[1] := Char(isc_info_blob_max_segment);
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items[2] := Char(isc_info_blob_total_length);
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items[3] := Char(isc_info_blob_type);
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if isc_blob_info(StatusVector, hBlobHandle, 4, @items[0], SizeOf(results),
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@results[0]) > 0 then
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IBDatabaseError;
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i := 0;
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while (i < SizeOf(results)) and (results[i] <> Char(isc_info_end)) do
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begin
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item := Integer(results[i]); Inc(i);
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item_length := isc_vax_integer(@results[i], 2); Inc(i, 2);
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case item of
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isc_info_blob_num_segments:
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NumSegments := isc_portable_integer(@results[i], item_length);
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isc_info_blob_max_segment:
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MaxSegmentSize := isc_portable_integer(@results[i], item_length);
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isc_info_blob_total_length:
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TotalSize := isc_portable_integer(@results[i], item_length);
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isc_info_blob_type:
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BlobType := isc_portable_integer(@results[i], item_length);
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end;
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Inc(i, item_length);
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end;
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end;
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procedure ReadBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Int64);
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var
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CurPos: Int64;
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BytesRead, SegLen: UShort;
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LocalBuffer: PChar;
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begin
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CurPos := 0;
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LocalBuffer := Buffer;
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SegLen := UShort(DefaultBlobSegmentSize);
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while (CurPos < BlobSize) do
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begin
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if (CurPos + SegLen > BlobSize) then
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SegLen := BlobSize - CurPos;
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if not ((isc_get_segment(StatusVector, hBlobHandle, @BytesRead, SegLen,
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LocalBuffer) = 0) or
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(StatusVectorArray[1] = isc_segment)) then
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IBDatabaseError;
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Inc(LocalBuffer, BytesRead);
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Inc(CurPos, BytesRead);
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BytesRead := 0;
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end;
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end;
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procedure WriteBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar;
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BlobSize: Int64);
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var
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CurPos: Int64;
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SegLen: Long;
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begin
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CurPos := 0;
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SegLen := DefaultBlobSegmentSize;
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while (CurPos < BlobSize) do
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begin
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if (CurPos + SegLen > BlobSize) then
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SegLen := BlobSize - CurPos;
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if isc_put_segment(StatusVector, hBlobHandle, SegLen,
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PChar(@Buffer[CurPos])) > 0 then
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IBDatabaseError;
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Inc(CurPos, SegLen);
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end;
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end;
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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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end;
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destructor TIBBlobStream.Destroy;
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begin
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if (FHandle <> nil) and
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(Call(isc_close_blob(StatusVector, @FHandle), False) > 0) then
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IBDataBaseError;
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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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function TIBBlobStream.Call(ErrCode: ISC_STATUS; RaiseError: Boolean): ISC_STATUS;
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begin
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result := 0;
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if Transaction <> nil then
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result := Transaction.Call(ErrCode, RaiseError)
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else if RaiseError and (ErrCode > 0) then
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IBDataBaseError;
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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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procedure TIBBlobStream.CloseBlob;
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begin
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Finalize;
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if (FHandle <> nil) and
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(Call(isc_close_blob(StatusVector, @FHandle), False) > 0) then
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IBDataBaseError;
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end;
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procedure TIBBlobStream.CreateBlob;
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begin
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CheckWritable;
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FBlobID.gds_quad_high := 0;
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FBlobID.gds_quad_low := 0;
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Truncate;
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end;
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procedure TIBBlobStream.EnsureBlobInitialized;
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begin
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if not FBlobInitialized then
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case FMode of
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bmWrite:
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CreateBlob;
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bmReadWrite: begin
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if (FBlobID.gds_quad_high = 0) and
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(FBlobID.gds_quad_low = 0) then
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CreateBlob
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else
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OpenBlob;
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end;
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else
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OpenBlob;
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end;
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FBlobInitialized := True;
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end;
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procedure TIBBlobStream.Finalize;
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begin
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if (not FBlobInitialized) or (FMode = bmRead) or (not FModified) then
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exit;
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{ need to start writing to a blob, create one }
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Call(isc_create_blob2(StatusVector, DBHandle, TRHandle, @FHandle, @FBlobID,
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0, nil), True);
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IBBlob.WriteBlob(@FHandle, FBuffer, FBlobSize);
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Call(isc_close_blob(StatusVector, @FHandle), True);
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FModified := False;
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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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IBBlob.GetBlobInfo(@FHandle, FBlobNumSegments, FBlobMaxSegmentSize,
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iBlobSize, FBlobType);
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SetSize(iBlobSize);
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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.GetDBHandle: PISC_DB_HANDLE;
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begin
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result := FBase.DBHandle;
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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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function TIBBlobStream.GetTRHandle: PISC_TR_HANDLE;
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begin
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result := FBase.TRHandle;
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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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FModified := True;
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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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Call(isc_open_blob2(StatusVector, DBHandle, TRHandle, @FHandle,
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@FBlobID, 0, nil), True);
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try
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GetBlobInfo;
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SetSize(FBlobSize);
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IBBlob.ReadBlob(@FHandle, FBuffer, FBlobSize);
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except
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Call(isc_close_blob(StatusVector, @FHandle), False);
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raise;
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end;
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Call(isc_close_blob(StatusVector, @FHandle), True);
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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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EnsureBlobInitialized;
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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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EnsureBlobInitialized;
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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.SetBlobID(Value: TISC_QUAD);
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begin
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System.Move(Value, FBlobID, SizeOf(TISC_QUAD));
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FBlobInitialized := False;
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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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FBlobInitialized := False;
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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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FBlobInitialized := False;
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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;
|
427 |
|
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procedure TIBBlobStream.SetSize(NewSize: Longint);
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429 |
begin
|
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SetSize(Int64(NewSize));
|
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end;
|
432 |
|
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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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FBlobInitialized := False;
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end;
|
438 |
|
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procedure TIBBlobStream.Truncate;
|
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begin
|
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SetSize(0);
|
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end;
|
443 |
|
444 |
function TIBBlobStream.Write(const Buffer; Count: Longint): Longint;
|
445 |
begin
|
446 |
CheckWritable;
|
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EnsureBlobInitialized;
|
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result := Count;
|
449 |
if Count <= 0 then
|
450 |
exit;
|
451 |
if (FPosition + Count > FBlobSize) then
|
452 |
SetSize(FPosition + Count);
|
453 |
Move(Buffer, FBuffer[FPosition], Count);
|
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Inc(FPosition, Count);
|
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FModified := True;
|
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end;
|
457 |
|
458 |
end.
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