trunk/runtime/IBBlob.pas

{************************************************************************}
{                                                                        }
{       Borland Delphi Visual Component Library                          }
{       InterBase Express core components                                }
{                                                                        }
{       Copyright (c) 1998-2000 Inprise Corporation                      }
{                                                                        }
{    InterBase Express is based in part on the product                   }
{    Free IB Components, written by Gregory H. Deatz for                 }
{    Hoagland, Longo, Moran, Dunst & Doukas Company.                     }
{    Free IB Components is used under license.                           }
{                                                                        }
{    The contents of this file are subject to the InterBase              }
{    Public License Version 1.0 (the "License"); you may not             }
{    use this file except in compliance with the License. You            }
{    may obtain a copy of the License at http://www.Inprise.com/IPL.html }
{    Software distributed under the License is distributed on            }
{    an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either              }
{    express or implied. See the License for the specific language       }
{    governing rights and limitations under the License.                 }
{    The Original Code was created by InterBase Software Corporation     }
{       and its successors.                                              }
{    Portions created by Inprise Corporation are Copyright (C) Inprise   }
{       Corporation. All Rights Reserved.                                }
{    Contributor(s): Jeff Overcash                                       }
{                                                                        }
{************************************************************************}

unit IBBlob;

{$Mode Delphi}

interface

uses
  SysUtils, Classes, IBHeader, IBErrorCodes, IBExternals, DB, IB, IBDatabase;


const
  DefaultBlobSegmentSize = 16 * 1024; 

type
  { TIBBlobStream }
  TIBBlobStream = class(TStream)
  private
    FBase: TIBBase;
    FBlobID: TISC_QUAD;
    FBlobMaxSegmentSize,
    FBlobNumSegments,
    FBlobSize: Long;
    FBlobType: Short;  { 0 = segmented, 1 = streamed }
    FBuffer: PChar;
    FBlobInitialized: Boolean;
    FHandle: TISC_BLOB_HANDLE;
    FMode: TBlobStreamMode;
    FModified: Boolean;
    FPosition: Long;
  protected
    procedure CloseBlob;
    procedure CreateBlob;
    procedure EnsureBlobInitialized;
    procedure GetBlobInfo;
    function GetDatabase: TIBDatabase;
    function GetDBHandle: PISC_DB_HANDLE;
    function GetTransaction: TIBTransaction;
    function GetTRHandle: PISC_TR_HANDLE;
    procedure OpenBlob;
    procedure SetBlobID(Value: TISC_QUAD);
    procedure SetDatabase(Value: TIBDatabase);
    procedure SetMode(Value: TBlobStreamMode);
    procedure SetTransaction(Value: TIBTransaction);
  public
    constructor Create;
    destructor Destroy; override;
    function Call(ErrCode: ISC_STATUS; RaiseError: Boolean): ISC_STATUS;
    procedure CheckReadable;
    procedure CheckWritable;
    procedure Finalize;
    procedure LoadFromFile(Filename: string);
    procedure LoadFromStream(Stream: TStream);
    function Read(var Buffer; Count: Longint): Longint; override;
    procedure SaveToFile(Filename: string);
    procedure SaveToStream(Stream: TStream);
    function Seek(Offset: Longint; Origin: Word): Longint; override;
    procedure SetSize(NewSize: Long); override;
    procedure Truncate;
    function Write(const Buffer; Count: Longint): Longint; override;
    property Handle: TISC_BLOB_HANDLE read FHandle;
    property BlobID: TISC_QUAD read FBlobID write SetBlobID;
    property BlobMaxSegmentSize: Long read FBlobMaxSegmentSize;
    property BlobNumSegments: Long read FBlobNumSegments;
    property BlobSize: Long read FBlobSize;
    property BlobType: Short read FBlobType;
    property Database: TIBDatabase read GetDatabase write SetDatabase;
    property DBHandle: PISC_DB_HANDLE read GetDBHandle;
    property Mode: TBlobStreamMode read FMode write SetMode;
    property Modified: Boolean read FModified;
    property Transaction: TIBTransaction read GetTransaction write SetTransaction;
    property TRHandle: PISC_TR_HANDLE read GetTRHandle;
  end;

  procedure GetBlobInfo(hBlobHandle: PISC_BLOB_HANDLE; var NumSegments, MaxSegmentSize,
                       TotalSize: Long; var BlobType: Short);
  procedure ReadBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Long);
  procedure WriteBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Long);

implementation

uses IBIntf;

procedure GetBlobInfo(hBlobHandle: PISC_BLOB_HANDLE; var NumSegments, MaxSegmentSize,
                      TotalSize: Long; var BlobType: Short);
var
  items: array[0..3] of Char;
  results: array[0..99] of Char;
  i, item_length: Integer;
  item: Integer;
begin
  items[0] := Char(isc_info_blob_num_segments);
  items[1] := Char(isc_info_blob_max_segment);
  items[2] := Char(isc_info_blob_total_length);
  items[3] := Char(isc_info_blob_type);

  if isc_blob_info(StatusVector, hBlobHandle, 4, @items[0], SizeOf(results),
                    @results[0]) > 0 then
    IBDatabaseError;

  i := 0;
  while (i < SizeOf(results)) and (results[i] <> Char(isc_info_end)) do
  begin
    item := Integer(results[i]); Inc(i);
    item_length := isc_vax_integer(@results[i], 2); Inc(i, 2);
    case item of
      isc_info_blob_num_segments:
        NumSegments := isc_vax_integer(@results[i], item_length);
      isc_info_blob_max_segment:
        MaxSegmentSize := isc_vax_integer(@results[i], item_length);
      isc_info_blob_total_length:
        TotalSize := isc_vax_integer(@results[i], item_length);
      isc_info_blob_type:
        BlobType := isc_vax_integer(@results[i], item_length);
    end;
    Inc(i, item_length);
  end;
end;

procedure ReadBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Long);
var
  CurPos: Long;
  BytesRead, SegLen: UShort;
  LocalBuffer: PChar;
begin
  CurPos := 0;
  LocalBuffer := Buffer;
  SegLen := UShort(DefaultBlobSegmentSize);
  while (CurPos < BlobSize) do
  begin
    if (CurPos + SegLen > BlobSize) then
      SegLen := BlobSize - CurPos;
    if not ((isc_get_segment(StatusVector, hBlobHandle, @BytesRead, SegLen,
                             LocalBuffer) = 0) or
            (StatusVectorArray[1] = isc_segment)) then
      IBDatabaseError;
    Inc(LocalBuffer, BytesRead);
    Inc(CurPos, BytesRead);
    BytesRead := 0;
  end;
end;

procedure WriteBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar;
  BlobSize: Long);
var
  CurPos, SegLen: Long;
begin
  CurPos := 0;
  SegLen := DefaultBlobSegmentSize;
  while (CurPos < BlobSize) do
  begin
    if (CurPos + SegLen > BlobSize) then
      SegLen := BlobSize - CurPos;
    if isc_put_segment(StatusVector, hBlobHandle, SegLen,
         PChar(@Buffer[CurPos])) > 0 then
      IBDatabaseError;
    Inc(CurPos, SegLen);
  end;
end;


{ TIBBlobStream }
constructor TIBBlobStream.Create;
begin
  inherited Create;
  FBase := TIBBase.Create(Self);
  FBuffer := nil;
  FBlobSize := 0;
end;

destructor TIBBlobStream.Destroy;
begin
  if (FHandle <> nil) and
     (Call(isc_close_blob(StatusVector, @FHandle), False) > 0) then
    IBDataBaseError;
  FBase.Free;
  SetSize(0);
  inherited Destroy;
end;

function TIBBlobStream.Call(ErrCode: ISC_STATUS; RaiseError: Boolean): ISC_STATUS;
begin
  result := 0;
  if Transaction <> nil then
    result := Transaction.Call(ErrCode, RaiseError)
  else if RaiseError and (ErrCode > 0) then
    IBDataBaseError;
end;

procedure TIBBlobStream.CheckReadable;
begin
  if FMode = bmWrite then IBError(ibxeBlobCannotBeRead, [nil]);
end;

procedure TIBBlobStream.CheckWritable;
begin
  if FMode = bmRead then IBError(ibxeBlobCannotBeWritten, [nil]);
end;

procedure TIBBlobStream.CloseBlob;
begin
  Finalize;
  if (FHandle <> nil) and
     (Call(isc_close_blob(StatusVector, @FHandle), False) > 0) then
    IBDataBaseError;
end;

procedure TIBBlobStream.CreateBlob;
begin
  CheckWritable;
  FBlobID.gds_quad_high := 0;
  FBlobID.gds_quad_low := 0;
  Truncate;
end;

procedure TIBBlobStream.EnsureBlobInitialized;
begin
  if not FBlobInitialized then
    case FMode of
      bmWrite:
        CreateBlob;
      bmReadWrite: begin
        if (FBlobID.gds_quad_high = 0) and
           (FBlobID.gds_quad_low = 0) then
          CreateBlob
        else
          OpenBlob;
      end;
      else
        OpenBlob;
    end;
  FBlobInitialized := True;
end;

procedure TIBBlobStream.Finalize;
begin
  if (not FBlobInitialized) or (FMode = bmRead) or (not FModified) then
    exit;
  { need to start writing to a blob, create one }
  Call(isc_create_blob2(StatusVector, DBHandle, TRHandle, @FHandle, @FBlobID,
                       0, nil), True);
  IBBlob.WriteBlob(@FHandle, FBuffer, FBlobSize);
  Call(isc_close_blob(StatusVector, @FHandle), True);
  FModified := False;
end;

procedure TIBBlobStream.GetBlobInfo;
var
  iBlobSize: Long;
begin
  IBBlob.GetBlobInfo(@FHandle, FBlobNumSegments, FBlobMaxSegmentSize,
    iBlobSize, FBlobType);
  SetSize(iBlobSize);
end;

function TIBBlobStream.GetDatabase: TIBDatabase;
begin
  result := FBase.Database;
end;

function TIBBlobStream.GetDBHandle: PISC_DB_HANDLE;
begin
  result := FBase.DBHandle;
end;

function TIBBlobStream.GetTransaction: TIBTransaction;
begin
  result := FBase.Transaction;
end;

function TIBBlobStream.GetTRHandle: PISC_TR_HANDLE;
begin
  result := FBase.TRHandle;
end;

procedure TIBBlobStream.LoadFromFile(Filename: string);
var
  Stream: TStream;
begin
  Stream := TFileStream.Create(FileName, fmOpenRead);
  try
    LoadFromStream(Stream);
  finally
    Stream.Free;
  end;
end;

procedure TIBBlobStream.LoadFromStream(Stream: TStream);
begin
  CheckWritable;
  EnsureBlobInitialized;
  Stream.Position := 0;
  SetSize(Stream.Size);
  if FBlobSize <> 0 then
    Stream.ReadBuffer(FBuffer^, FBlobSize);
  FModified := True;
end;

procedure TIBBlobStream.OpenBlob;
begin
  CheckReadable;
  Call(isc_open_blob2(StatusVector, DBHandle, TRHandle, @FHandle,
                     @FBlobID, 0, nil), True);
  try
    GetBlobInfo;
    SetSize(FBlobSize);
    IBBlob.ReadBlob(@FHandle, FBuffer, FBlobSize);
  except
    Call(isc_close_blob(StatusVector, @FHandle), False);
    raise;
  end;
  Call(isc_close_blob(StatusVector, @FHandle), True);
end;

function TIBBlobStream.Read(var Buffer; Count: Longint): Longint;
begin
  CheckReadable;
  EnsureBlobInitialized;
  if (Count <= 0) then
  begin
    result := 0;
    exit;
  end;
  if (FPosition + Count > FBlobSize) then
    result := FBlobSize - FPosition
  else
    result := Count;
  Move(FBuffer[FPosition], Buffer, result);
  Inc(FPosition, Result);
end;

procedure TIBBlobStream.SaveToFile(Filename: string);
var
  Stream: TStream;
begin
  Stream := TFileStream.Create(FileName, fmCreate);
  try
    SaveToStream(Stream);
  finally
    Stream.Free;
  end;
end;

procedure TIBBlobStream.SaveToStream(Stream: TStream);
begin
  CheckReadable;
  EnsureBlobInitialized;
  if FBlobSize <> 0 then
  begin
    Seek(0, soFromBeginning);
    Stream.WriteBuffer(FBuffer^, FBlobSize);
  end;
end;

function TIBBlobStream.Seek(Offset: Longint; Origin: Word): Longint;
begin
  EnsureBlobInitialized;
  case Origin of
    soFromBeginning     : FPosition := Offset;
    soFromCurrent       : Inc(FPosition, Offset);
    soFromEnd           : FPosition := FBlobSize + Offset;
  end;
  result := FPosition;
end;

procedure TIBBlobStream.SetBlobID(Value: TISC_QUAD);
begin
  System.Move(Value, FBlobID, SizeOf(TISC_QUAD));
  FBlobInitialized := False;
end;

procedure TIBBlobStream.SetDatabase(Value: TIBDatabase);
begin
  FBase.Database := Value;
  FBlobInitialized := False;
end;

procedure TIBBlobStream.SetMode(Value: TBlobStreamMode);
begin
  FMode := Value;
  FBlobInitialized := False;
end;

procedure TIBBlobStream.SetSize(NewSize: Long);
begin
  if (NewSize <> FBlobSize) then
  begin
    ReallocMem(FBuffer, NewSize);
    FBlobSize := NewSize;
    if NewSize = 0 then
      FBuffer := nil;
  end;
end;

procedure TIBBlobStream.SetTransaction(Value: TIBTransaction);
begin
  FBase.Transaction := Value;
  FBlobInitialized := False;
end;

procedure TIBBlobStream.Truncate;
begin
  SetSize(0);
end;

function TIBBlobStream.Write(const Buffer; Count: Longint): Longint;
begin
  CheckWritable;
  EnsureBlobInitialized;
  result := Count;
  if Count <= 0 then
    exit;
  if (FPosition + Count > FBlobSize) then
    SetSize(FPosition + Count);
  Move(Buffer, FBuffer[FPosition], Count);
  Inc(FPosition, Count);
  FModified := True;
end;

end.
Revision:	5
Committed:	Fri Feb 18 16:26:16 2011 UTC (13 years, 2 months ago) by tony
Content type:	text/x-pascal
File size:	12804 byte(s)
Log Message:	Committing updates for Release pre-release
#	User	Rev	Content
1	tony	1	{************************************************************************}
2			{ }
3			{ Borland Delphi Visual Component Library }
4			{ InterBase Express core components }
5			{ }
6			{ Copyright (c) 1998-2000 Inprise Corporation }
7			{ }
8			{ InterBase Express is based in part on the product }
9			{ Free IB Components, written by Gregory H. Deatz for }
10			{ Hoagland, Longo, Moran, Dunst & Doukas Company. }
11			{ Free IB Components is used under license. }
12			{ }
13			{ The contents of this file are subject to the InterBase }
14			{ Public License Version 1.0 (the "License"); you may not }
15			{ use this file except in compliance with the License. You }
16			{ may obtain a copy of the License at http://www.Inprise.com/IPL.html }
17			{ Software distributed under the License is distributed on }
18			{ an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either }
19			{ express or implied. See the License for the specific language }
20			{ governing rights and limitations under the License. }
21			{ The Original Code was created by InterBase Software Corporation }
22			{ and its successors. }
23			{ Portions created by Inprise Corporation are Copyright (C) Inprise }
24			{ Corporation. All Rights Reserved. }
25			{ Contributor(s): Jeff Overcash }
26			{ }
27			{************************************************************************}
28
29			unit IBBlob;
30
31	tony	5	{$Mode Delphi}
32
33	tony	1	interface
34
35			uses
36	tony	5	SysUtils, Classes, IBHeader, IBErrorCodes, IBExternals, DB, IB, IBDatabase;
37	tony	1
38	tony	5
39	tony	1	const
40			DefaultBlobSegmentSize = 16 * 1024;
41
42			type
43			{ TIBBlobStream }
44			TIBBlobStream = class(TStream)
45			private
46			FBase: TIBBase;
47			FBlobID: TISC_QUAD;
48			FBlobMaxSegmentSize,
49			FBlobNumSegments,
50			FBlobSize: Long;
51			FBlobType: Short; { 0 = segmented, 1 = streamed }
52			FBuffer: PChar;
53			FBlobInitialized: Boolean;
54			FHandle: TISC_BLOB_HANDLE;
55			FMode: TBlobStreamMode;
56			FModified: Boolean;
57			FPosition: Long;
58			protected
59			procedure CloseBlob;
60			procedure CreateBlob;
61			procedure EnsureBlobInitialized;
62			procedure GetBlobInfo;
63			function GetDatabase: TIBDatabase;
64			function GetDBHandle: PISC_DB_HANDLE;
65			function GetTransaction: TIBTransaction;
66			function GetTRHandle: PISC_TR_HANDLE;
67			procedure OpenBlob;
68			procedure SetBlobID(Value: TISC_QUAD);
69			procedure SetDatabase(Value: TIBDatabase);
70			procedure SetMode(Value: TBlobStreamMode);
71			procedure SetTransaction(Value: TIBTransaction);
72			public
73			constructor Create;
74			destructor Destroy; override;
75			function Call(ErrCode: ISC_STATUS; RaiseError: Boolean): ISC_STATUS;
76			procedure CheckReadable;
77			procedure CheckWritable;
78			procedure Finalize;
79			procedure LoadFromFile(Filename: string);
80			procedure LoadFromStream(Stream: TStream);
81			function Read(var Buffer; Count: Longint): Longint; override;
82			procedure SaveToFile(Filename: string);
83			procedure SaveToStream(Stream: TStream);
84			function Seek(Offset: Longint; Origin: Word): Longint; override;
85			procedure SetSize(NewSize: Long); override;
86			procedure Truncate;
87			function Write(const Buffer; Count: Longint): Longint; override;
88			property Handle: TISC_BLOB_HANDLE read FHandle;
89			property BlobID: TISC_QUAD read FBlobID write SetBlobID;
90			property BlobMaxSegmentSize: Long read FBlobMaxSegmentSize;
91			property BlobNumSegments: Long read FBlobNumSegments;
92			property BlobSize: Long read FBlobSize;
93			property BlobType: Short read FBlobType;
94			property Database: TIBDatabase read GetDatabase write SetDatabase;
95			property DBHandle: PISC_DB_HANDLE read GetDBHandle;
96			property Mode: TBlobStreamMode read FMode write SetMode;
97			property Modified: Boolean read FModified;
98			property Transaction: TIBTransaction read GetTransaction write SetTransaction;
99			property TRHandle: PISC_TR_HANDLE read GetTRHandle;
100			end;
101
102			procedure GetBlobInfo(hBlobHandle: PISC_BLOB_HANDLE; var NumSegments, MaxSegmentSize,
103			TotalSize: Long; var BlobType: Short);
104			procedure ReadBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Long);
105			procedure WriteBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Long);
106
107			implementation
108
109	tony	5	uses IBIntf;
110	tony	1
111			procedure GetBlobInfo(hBlobHandle: PISC_BLOB_HANDLE; var NumSegments, MaxSegmentSize,
112			TotalSize: Long; var BlobType: Short);
113			var
114			items: array[0..3] of Char;
115			results: array[0..99] of Char;
116			i, item_length: Integer;
117			item: Integer;
118			begin
119			items[0] := Char(isc_info_blob_num_segments);
120			items[1] := Char(isc_info_blob_max_segment);
121			items[2] := Char(isc_info_blob_total_length);
122			items[3] := Char(isc_info_blob_type);
123
124			if isc_blob_info(StatusVector, hBlobHandle, 4, @items[0], SizeOf(results),
125			@results[0]) > 0 then
126			IBDatabaseError;
127
128			i := 0;
129			while (i < SizeOf(results)) and (results[i] <> Char(isc_info_end)) do
130			begin
131			item := Integer(results[i]); Inc(i);
132			item_length := isc_vax_integer(@results[i], 2); Inc(i, 2);
133			case item of
134			isc_info_blob_num_segments:
135			NumSegments := isc_vax_integer(@results[i], item_length);
136			isc_info_blob_max_segment:
137			MaxSegmentSize := isc_vax_integer(@results[i], item_length);
138			isc_info_blob_total_length:
139			TotalSize := isc_vax_integer(@results[i], item_length);
140			isc_info_blob_type:
141			BlobType := isc_vax_integer(@results[i], item_length);
142			end;
143			Inc(i, item_length);
144			end;
145			end;
146
147			procedure ReadBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Long);
148			var
149			CurPos: Long;
150			BytesRead, SegLen: UShort;
151			LocalBuffer: PChar;
152			begin
153			CurPos := 0;
154			LocalBuffer := Buffer;
155			SegLen := UShort(DefaultBlobSegmentSize);
156			while (CurPos < BlobSize) do
157			begin
158			if (CurPos + SegLen > BlobSize) then
159			SegLen := BlobSize - CurPos;
160			if not ((isc_get_segment(StatusVector, hBlobHandle, @BytesRead, SegLen,
161			LocalBuffer) = 0) or
162			(StatusVectorArray[1] = isc_segment)) then
163			IBDatabaseError;
164			Inc(LocalBuffer, BytesRead);
165			Inc(CurPos, BytesRead);
166			BytesRead := 0;
167			end;
168			end;
169
170			procedure WriteBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar;
171			BlobSize: Long);
172			var
173			CurPos, SegLen: Long;
174			begin
175			CurPos := 0;
176			SegLen := DefaultBlobSegmentSize;
177			while (CurPos < BlobSize) do
178			begin
179			if (CurPos + SegLen > BlobSize) then
180			SegLen := BlobSize - CurPos;
181			if isc_put_segment(StatusVector, hBlobHandle, SegLen,
182			PChar(@Buffer[CurPos])) > 0 then
183			IBDatabaseError;
184			Inc(CurPos, SegLen);
185			end;
186			end;
187
188
189			{ TIBBlobStream }
190			constructor TIBBlobStream.Create;
191			begin
192			inherited Create;
193			FBase := TIBBase.Create(Self);
194			FBuffer := nil;
195			FBlobSize := 0;
196			end;
197
198			destructor TIBBlobStream.Destroy;
199			begin
200			if (FHandle <> nil) and
201			(Call(isc_close_blob(StatusVector, @FHandle), False) > 0) then
202			IBDataBaseError;
203			FBase.Free;
204			SetSize(0);
205			inherited Destroy;
206			end;
207
208			function TIBBlobStream.Call(ErrCode: ISC_STATUS; RaiseError: Boolean): ISC_STATUS;
209			begin
210			result := 0;
211			if Transaction <> nil then
212			result := Transaction.Call(ErrCode, RaiseError)
213			else if RaiseError and (ErrCode > 0) then
214			IBDataBaseError;
215			end;
216
217			procedure TIBBlobStream.CheckReadable;
218			begin
219			if FMode = bmWrite then IBError(ibxeBlobCannotBeRead, [nil]);
220			end;
221
222			procedure TIBBlobStream.CheckWritable;
223			begin
224			if FMode = bmRead then IBError(ibxeBlobCannotBeWritten, [nil]);
225			end;
226
227			procedure TIBBlobStream.CloseBlob;
228			begin
229			Finalize;
230			if (FHandle <> nil) and
231			(Call(isc_close_blob(StatusVector, @FHandle), False) > 0) then
232			IBDataBaseError;
233			end;
234
235			procedure TIBBlobStream.CreateBlob;
236			begin
237			CheckWritable;
238			FBlobID.gds_quad_high := 0;
239			FBlobID.gds_quad_low := 0;
240			Truncate;
241			end;
242
243			procedure TIBBlobStream.EnsureBlobInitialized;
244			begin
245			if not FBlobInitialized then
246			case FMode of
247			bmWrite:
248			CreateBlob;
249			bmReadWrite: begin
250			if (FBlobID.gds_quad_high = 0) and
251			(FBlobID.gds_quad_low = 0) then
252			CreateBlob
253			else
254			OpenBlob;
255			end;
256			else
257			OpenBlob;
258			end;
259			FBlobInitialized := True;
260			end;
261
262			procedure TIBBlobStream.Finalize;
263			begin
264			if (not FBlobInitialized) or (FMode = bmRead) or (not FModified) then
265			exit;
266			{ need to start writing to a blob, create one }
267			Call(isc_create_blob2(StatusVector, DBHandle, TRHandle, @FHandle, @FBlobID,
268			0, nil), True);
269			IBBlob.WriteBlob(@FHandle, FBuffer, FBlobSize);
270			Call(isc_close_blob(StatusVector, @FHandle), True);
271			FModified := False;
272			end;
273
274			procedure TIBBlobStream.GetBlobInfo;
275			var
276			iBlobSize: Long;
277			begin
278			IBBlob.GetBlobInfo(@FHandle, FBlobNumSegments, FBlobMaxSegmentSize,
279			iBlobSize, FBlobType);
280			SetSize(iBlobSize);
281			end;
282
283			function TIBBlobStream.GetDatabase: TIBDatabase;
284			begin
285			result := FBase.Database;
286			end;
287
288			function TIBBlobStream.GetDBHandle: PISC_DB_HANDLE;
289			begin
290			result := FBase.DBHandle;
291			end;
292
293			function TIBBlobStream.GetTransaction: TIBTransaction;
294			begin
295			result := FBase.Transaction;
296			end;
297
298			function TIBBlobStream.GetTRHandle: PISC_TR_HANDLE;
299			begin
300			result := FBase.TRHandle;
301			end;
302
303			procedure TIBBlobStream.LoadFromFile(Filename: string);
304			var
305			Stream: TStream;
306			begin
307			Stream := TFileStream.Create(FileName, fmOpenRead);
308			try
309			LoadFromStream(Stream);
310			finally
311			Stream.Free;
312			end;
313			end;
314
315			procedure TIBBlobStream.LoadFromStream(Stream: TStream);
316			begin
317			CheckWritable;
318			EnsureBlobInitialized;
319			Stream.Position := 0;
320			SetSize(Stream.Size);
321			if FBlobSize <> 0 then
322			Stream.ReadBuffer(FBuffer^, FBlobSize);
323			FModified := True;
324			end;
325
326			procedure TIBBlobStream.OpenBlob;
327			begin
328			CheckReadable;
329			Call(isc_open_blob2(StatusVector, DBHandle, TRHandle, @FHandle,
330			@FBlobID, 0, nil), True);
331			try
332			GetBlobInfo;
333			SetSize(FBlobSize);
334			IBBlob.ReadBlob(@FHandle, FBuffer, FBlobSize);
335			except
336			Call(isc_close_blob(StatusVector, @FHandle), False);
337			raise;
338			end;
339			Call(isc_close_blob(StatusVector, @FHandle), True);
340			end;
341
342			function TIBBlobStream.Read(var Buffer; Count: Longint): Longint;
343			begin
344			CheckReadable;
345			EnsureBlobInitialized;
346			if (Count <= 0) then
347			begin
348			result := 0;
349			exit;
350			end;
351			if (FPosition + Count > FBlobSize) then
352			result := FBlobSize - FPosition
353			else
354			result := Count;
355			Move(FBuffer[FPosition], Buffer, result);
356			Inc(FPosition, Result);
357			end;
358
359			procedure TIBBlobStream.SaveToFile(Filename: string);
360			var
361			Stream: TStream;
362			begin
363			Stream := TFileStream.Create(FileName, fmCreate);
364			try
365			SaveToStream(Stream);
366			finally
367			Stream.Free;
368			end;
369			end;
370
371			procedure TIBBlobStream.SaveToStream(Stream: TStream);
372			begin
373			CheckReadable;
374			EnsureBlobInitialized;
375			if FBlobSize <> 0 then
376			begin
377			Seek(0, soFromBeginning);
378			Stream.WriteBuffer(FBuffer^, FBlobSize);
379			end;
380			end;
381
382			function TIBBlobStream.Seek(Offset: Longint; Origin: Word): Longint;
383			begin
384			EnsureBlobInitialized;
385			case Origin of
386			soFromBeginning : FPosition := Offset;
387			soFromCurrent : Inc(FPosition, Offset);
388			soFromEnd : FPosition := FBlobSize + Offset;
389			end;
390			result := FPosition;
391			end;
392
393			procedure TIBBlobStream.SetBlobID(Value: TISC_QUAD);
394			begin
395			System.Move(Value, FBlobID, SizeOf(TISC_QUAD));
396			FBlobInitialized := False;
397			end;
398
399			procedure TIBBlobStream.SetDatabase(Value: TIBDatabase);
400			begin
401			FBase.Database := Value;
402			FBlobInitialized := False;
403			end;
404
405			procedure TIBBlobStream.SetMode(Value: TBlobStreamMode);
406			begin
407			FMode := Value;
408			FBlobInitialized := False;
409			end;
410
411			procedure TIBBlobStream.SetSize(NewSize: Long);
412			begin
413			if (NewSize <> FBlobSize) then
414			begin
415			ReallocMem(FBuffer, NewSize);
416			FBlobSize := NewSize;
417			if NewSize = 0 then
418			FBuffer := nil;
419			end;
420			end;
421
422			procedure TIBBlobStream.SetTransaction(Value: TIBTransaction);
423			begin
424			FBase.Transaction := Value;
425			FBlobInitialized := False;
426			end;
427
428			procedure TIBBlobStream.Truncate;
429			begin
430			SetSize(0);
431			end;
432
433			function TIBBlobStream.Write(const Buffer; Count: Longint): Longint;
434			begin
435			CheckWritable;
436			EnsureBlobInitialized;
437			result := Count;
438			if Count <= 0 then
439			exit;
440			if (FPosition + Count > FBlobSize) then
441			SetSize(FPosition + Count);
442			Move(Buffer, FBuffer[FPosition], Count);
443			Inc(FPosition, Count);
444			FModified := True;
445			end;
446
447			end.