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unit IBBlob; |
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< |
{$Mode Delphi} |
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> |
{$mode Delphi} |
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interface |
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const |
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< |
DefaultBlobSegmentSize = 16 * 1024; |
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> |
DefaultBlobSegmentSize = 16 * 1024; |
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|
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type |
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+ |
TIBBlobStates = (bsUninitialised, bsDataPending, bsData, bsModified); |
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|
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{ TIBBlobStream } |
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TIBBlobStream = class(TStream) |
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private |
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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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FBlobState: TIBBlobStates; |
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function GetModified: Boolean; |
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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 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 GetDBHandle: PISC_DB_HANDLE; |
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function GetTransaction: TIBTransaction; |
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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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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 BlobSize: Int64 read GetSize; |
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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 Modified: Boolean read GetModified; |
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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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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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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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SetState(bsUninitialised); |
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FBase.Free; |
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SetSize(0); |
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inherited Destroy; |
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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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|
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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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SetState(bsUninitialised); |
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end; |
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procedure TIBBlobStream.CreateBlob; |
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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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> |
SetState(bsData); |
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> |
SetSize(0); |
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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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if FBlobState = bsUninitialised then |
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case FMode of |
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bmWrite: |
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CreateBlob; |
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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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> |
|
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> |
procedure TIBBlobStream.EnsureLoaded; |
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begin |
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EnsureBlobInitialized; |
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if FBlobState = bsDataPending then |
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begin |
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SetSize(FBlobSize); |
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try |
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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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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 (not FBlobInitialized) or (FMode = bmRead) or (not FModified) then |
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if FBlobState <> bsModified 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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> |
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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> |
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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end |
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else |
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begin |
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> |
FBlobID.gds_quad_high := 0; |
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FBlobID.gds_quad_low := 0; |
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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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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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|
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function TIBBlobStream.GetDatabase: TIBDatabase; |
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begin |
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result := FBase.Database; |
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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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> |
SetState(bsModified); |
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end; |
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procedure TIBBlobStream.OpenBlob; |
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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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> |
{Defer reading in blob until read method called} |
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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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> |
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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< |
EnsureBlobInitialized; |
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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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procedure TIBBlobStream.SaveToStream(Stream: TStream); |
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begin |
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CheckReadable; |
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< |
EnsureBlobInitialized; |
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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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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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> |
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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< |
FBlobInitialized := False; |
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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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FBlobInitialized := False; |
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> |
SetState(bsUninitialised); |
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> |
end; |
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> |
|
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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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> |
|
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> |
if FBlobState = bsDataPending then |
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Call(isc_close_blob(StatusVector, @FHandle), True); |
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> |
|
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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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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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> |
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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< |
EnsureBlobInitialized; |
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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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SetSize(FPosition + Count); |
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Move(Buffer, FBuffer[FPosition], Count); |
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Inc(FPosition, Count); |
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< |
FModified := True; |
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> |
SetState(bsModified); |
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end; |
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end. |