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;

interface

uses
  Windows, SysUtils, Classes, Forms, IBHeader, IBErrorCodes, IBExternals,
  DB, IB, IBDatabase, IBUtils;

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, IBCustomDataSet;

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:	1
Committed:	Mon Jul 31 16:43:00 2000 UTC (24 years, 4 months ago) by tony
Content type:	text/x-pascal
File size:	12831 byte(s)
Log Message:	Borland IBX Open Source 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			interface
32
33			uses
34			Windows, SysUtils, Classes, Forms, IBHeader, IBErrorCodes, IBExternals,
35			DB, IB, IBDatabase, IBUtils;
36
37			const
38			DefaultBlobSegmentSize = 16 * 1024;
39
40			type
41			{ TIBBlobStream }
42			TIBBlobStream = class(TStream)
43			private
44			FBase: TIBBase;
45			FBlobID: TISC_QUAD;
46			FBlobMaxSegmentSize,
47			FBlobNumSegments,
48			FBlobSize: Long;
49			FBlobType: Short; { 0 = segmented, 1 = streamed }
50			FBuffer: PChar;
51			FBlobInitialized: Boolean;
52			FHandle: TISC_BLOB_HANDLE;
53			FMode: TBlobStreamMode;
54			FModified: Boolean;
55			FPosition: Long;
56			protected
57			procedure CloseBlob;
58			procedure CreateBlob;
59			procedure EnsureBlobInitialized;
60			procedure GetBlobInfo;
61			function GetDatabase: TIBDatabase;
62			function GetDBHandle: PISC_DB_HANDLE;
63			function GetTransaction: TIBTransaction;
64			function GetTRHandle: PISC_TR_HANDLE;
65			procedure OpenBlob;
66			procedure SetBlobID(Value: TISC_QUAD);
67			procedure SetDatabase(Value: TIBDatabase);
68			procedure SetMode(Value: TBlobStreamMode);
69			procedure SetTransaction(Value: TIBTransaction);
70			public
71			constructor Create;
72			destructor Destroy; override;
73			function Call(ErrCode: ISC_STATUS; RaiseError: Boolean): ISC_STATUS;
74			procedure CheckReadable;
75			procedure CheckWritable;
76			procedure Finalize;
77			procedure LoadFromFile(Filename: string);
78			procedure LoadFromStream(Stream: TStream);
79			function Read(var Buffer; Count: Longint): Longint; override;
80			procedure SaveToFile(Filename: string);
81			procedure SaveToStream(Stream: TStream);
82			function Seek(Offset: Longint; Origin: Word): Longint; override;
83			procedure SetSize(NewSize: Long); override;
84			procedure Truncate;
85			function Write(const Buffer; Count: Longint): Longint; override;
86			property Handle: TISC_BLOB_HANDLE read FHandle;
87			property BlobID: TISC_QUAD read FBlobID write SetBlobID;
88			property BlobMaxSegmentSize: Long read FBlobMaxSegmentSize;
89			property BlobNumSegments: Long read FBlobNumSegments;
90			property BlobSize: Long read FBlobSize;
91			property BlobType: Short read FBlobType;
92			property Database: TIBDatabase read GetDatabase write SetDatabase;
93			property DBHandle: PISC_DB_HANDLE read GetDBHandle;
94			property Mode: TBlobStreamMode read FMode write SetMode;
95			property Modified: Boolean read FModified;
96			property Transaction: TIBTransaction read GetTransaction write SetTransaction;
97			property TRHandle: PISC_TR_HANDLE read GetTRHandle;
98			end;
99
100			procedure GetBlobInfo(hBlobHandle: PISC_BLOB_HANDLE; var NumSegments, MaxSegmentSize,
101			TotalSize: Long; var BlobType: Short);
102			procedure ReadBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Long);
103			procedure WriteBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Long);
104
105			implementation
106
107			uses IBIntf, IBCustomDataSet;
108
109			procedure GetBlobInfo(hBlobHandle: PISC_BLOB_HANDLE; var NumSegments, MaxSegmentSize,
110			TotalSize: Long; var BlobType: Short);
111			var
112			items: array[0..3] of Char;
113			results: array[0..99] of Char;
114			i, item_length: Integer;
115			item: Integer;
116			begin
117			items[0] := Char(isc_info_blob_num_segments);
118			items[1] := Char(isc_info_blob_max_segment);
119			items[2] := Char(isc_info_blob_total_length);
120			items[3] := Char(isc_info_blob_type);
121
122			if isc_blob_info(StatusVector, hBlobHandle, 4, @items[0], SizeOf(results),
123			@results[0]) > 0 then
124			IBDatabaseError;
125
126			i := 0;
127			while (i < SizeOf(results)) and (results[i] <> Char(isc_info_end)) do
128			begin
129			item := Integer(results[i]); Inc(i);
130			item_length := isc_vax_integer(@results[i], 2); Inc(i, 2);
131			case item of
132			isc_info_blob_num_segments:
133			NumSegments := isc_vax_integer(@results[i], item_length);
134			isc_info_blob_max_segment:
135			MaxSegmentSize := isc_vax_integer(@results[i], item_length);
136			isc_info_blob_total_length:
137			TotalSize := isc_vax_integer(@results[i], item_length);
138			isc_info_blob_type:
139			BlobType := isc_vax_integer(@results[i], item_length);
140			end;
141			Inc(i, item_length);
142			end;
143			end;
144
145			procedure ReadBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Long);
146			var
147			CurPos: Long;
148			BytesRead, SegLen: UShort;
149			LocalBuffer: PChar;
150			begin
151			CurPos := 0;
152			LocalBuffer := Buffer;
153			SegLen := UShort(DefaultBlobSegmentSize);
154			while (CurPos < BlobSize) do
155			begin
156			if (CurPos + SegLen > BlobSize) then
157			SegLen := BlobSize - CurPos;
158			if not ((isc_get_segment(StatusVector, hBlobHandle, @BytesRead, SegLen,
159			LocalBuffer) = 0) or
160			(StatusVectorArray[1] = isc_segment)) then
161			IBDatabaseError;
162			Inc(LocalBuffer, BytesRead);
163			Inc(CurPos, BytesRead);
164			BytesRead := 0;
165			end;
166			end;
167
168			procedure WriteBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar;
169			BlobSize: Long);
170			var
171			CurPos, SegLen: Long;
172			begin
173			CurPos := 0;
174			SegLen := DefaultBlobSegmentSize;
175			while (CurPos < BlobSize) do
176			begin
177			if (CurPos + SegLen > BlobSize) then
178			SegLen := BlobSize - CurPos;
179			if isc_put_segment(StatusVector, hBlobHandle, SegLen,
180			PChar(@Buffer[CurPos])) > 0 then
181			IBDatabaseError;
182			Inc(CurPos, SegLen);
183			end;
184			end;
185
186
187			{ TIBBlobStream }
188			constructor TIBBlobStream.Create;
189			begin
190			inherited Create;
191			FBase := TIBBase.Create(Self);
192			FBuffer := nil;
193			FBlobSize := 0;
194			end;
195
196			destructor TIBBlobStream.Destroy;
197			begin
198			if (FHandle <> nil) and
199			(Call(isc_close_blob(StatusVector, @FHandle), False) > 0) then
200			IBDataBaseError;
201			FBase.Free;
202			SetSize(0);
203			inherited Destroy;
204			end;
205
206			function TIBBlobStream.Call(ErrCode: ISC_STATUS; RaiseError: Boolean): ISC_STATUS;
207			begin
208			result := 0;
209			if Transaction <> nil then
210			result := Transaction.Call(ErrCode, RaiseError)
211			else if RaiseError and (ErrCode > 0) then
212			IBDataBaseError;
213			end;
214
215			procedure TIBBlobStream.CheckReadable;
216			begin
217			if FMode = bmWrite then IBError(ibxeBlobCannotBeRead, [nil]);
218			end;
219
220			procedure TIBBlobStream.CheckWritable;
221			begin
222			if FMode = bmRead then IBError(ibxeBlobCannotBeWritten, [nil]);
223			end;
224
225			procedure TIBBlobStream.CloseBlob;
226			begin
227			Finalize;
228			if (FHandle <> nil) and
229			(Call(isc_close_blob(StatusVector, @FHandle), False) > 0) then
230			IBDataBaseError;
231			end;
232
233			procedure TIBBlobStream.CreateBlob;
234			begin
235			CheckWritable;
236			FBlobID.gds_quad_high := 0;
237			FBlobID.gds_quad_low := 0;
238			Truncate;
239			end;
240
241			procedure TIBBlobStream.EnsureBlobInitialized;
242			begin
243			if not FBlobInitialized then
244			case FMode of
245			bmWrite:
246			CreateBlob;
247			bmReadWrite: begin
248			if (FBlobID.gds_quad_high = 0) and
249			(FBlobID.gds_quad_low = 0) then
250			CreateBlob
251			else
252			OpenBlob;
253			end;
254			else
255			OpenBlob;
256			end;
257			FBlobInitialized := True;
258			end;
259
260			procedure TIBBlobStream.Finalize;
261			begin
262			if (not FBlobInitialized) or (FMode = bmRead) or (not FModified) then
263			exit;
264			{ need to start writing to a blob, create one }
265			Call(isc_create_blob2(StatusVector, DBHandle, TRHandle, @FHandle, @FBlobID,
266			0, nil), True);
267			IBBlob.WriteBlob(@FHandle, FBuffer, FBlobSize);
268			Call(isc_close_blob(StatusVector, @FHandle), True);
269			FModified := False;
270			end;
271
272			procedure TIBBlobStream.GetBlobInfo;
273			var
274			iBlobSize: Long;
275			begin
276			IBBlob.GetBlobInfo(@FHandle, FBlobNumSegments, FBlobMaxSegmentSize,
277			iBlobSize, FBlobType);
278			SetSize(iBlobSize);
279			end;
280
281			function TIBBlobStream.GetDatabase: TIBDatabase;
282			begin
283			result := FBase.Database;
284			end;
285
286			function TIBBlobStream.GetDBHandle: PISC_DB_HANDLE;
287			begin
288			result := FBase.DBHandle;
289			end;
290
291			function TIBBlobStream.GetTransaction: TIBTransaction;
292			begin
293			result := FBase.Transaction;
294			end;
295
296			function TIBBlobStream.GetTRHandle: PISC_TR_HANDLE;
297			begin
298			result := FBase.TRHandle;
299			end;
300
301			procedure TIBBlobStream.LoadFromFile(Filename: string);
302			var
303			Stream: TStream;
304			begin
305			Stream := TFileStream.Create(FileName, fmOpenRead);
306			try
307			LoadFromStream(Stream);
308			finally
309			Stream.Free;
310			end;
311			end;
312
313			procedure TIBBlobStream.LoadFromStream(Stream: TStream);
314			begin
315			CheckWritable;
316			EnsureBlobInitialized;
317			Stream.Position := 0;
318			SetSize(Stream.Size);
319			if FBlobSize <> 0 then
320			Stream.ReadBuffer(FBuffer^, FBlobSize);
321			FModified := True;
322			end;
323
324			procedure TIBBlobStream.OpenBlob;
325			begin
326			CheckReadable;
327			Call(isc_open_blob2(StatusVector, DBHandle, TRHandle, @FHandle,
328			@FBlobID, 0, nil), True);
329			try
330			GetBlobInfo;
331			SetSize(FBlobSize);
332			IBBlob.ReadBlob(@FHandle, FBuffer, FBlobSize);
333			except
334			Call(isc_close_blob(StatusVector, @FHandle), False);
335			raise;
336			end;
337			Call(isc_close_blob(StatusVector, @FHandle), True);
338			end;
339
340			function TIBBlobStream.Read(var Buffer; Count: Longint): Longint;
341			begin
342			CheckReadable;
343			EnsureBlobInitialized;
344			if (Count <= 0) then
345			begin
346			result := 0;
347			exit;
348			end;
349			if (FPosition + Count > FBlobSize) then
350			result := FBlobSize - FPosition
351			else
352			result := Count;
353			Move(FBuffer[FPosition], Buffer, result);
354			Inc(FPosition, Result);
355			end;
356
357			procedure TIBBlobStream.SaveToFile(Filename: string);
358			var
359			Stream: TStream;
360			begin
361			Stream := TFileStream.Create(FileName, fmCreate);
362			try
363			SaveToStream(Stream);
364			finally
365			Stream.Free;
366			end;
367			end;
368
369			procedure TIBBlobStream.SaveToStream(Stream: TStream);
370			begin
371			CheckReadable;
372			EnsureBlobInitialized;
373			if FBlobSize <> 0 then
374			begin
375			Seek(0, soFromBeginning);
376			Stream.WriteBuffer(FBuffer^, FBlobSize);
377			end;
378			end;
379
380			function TIBBlobStream.Seek(Offset: Longint; Origin: Word): Longint;
381			begin
382			EnsureBlobInitialized;
383			case Origin of
384			soFromBeginning : FPosition := Offset;
385			soFromCurrent : Inc(FPosition, Offset);
386			soFromEnd : FPosition := FBlobSize + Offset;
387			end;
388			result := FPosition;
389			end;
390
391			procedure TIBBlobStream.SetBlobID(Value: TISC_QUAD);
392			begin
393			System.Move(Value, FBlobID, SizeOf(TISC_QUAD));
394			FBlobInitialized := False;
395			end;
396
397			procedure TIBBlobStream.SetDatabase(Value: TIBDatabase);
398			begin
399			FBase.Database := Value;
400			FBlobInitialized := False;
401			end;
402
403			procedure TIBBlobStream.SetMode(Value: TBlobStreamMode);
404			begin
405			FMode := Value;
406			FBlobInitialized := False;
407			end;
408
409			procedure TIBBlobStream.SetSize(NewSize: Long);
410			begin
411			if (NewSize <> FBlobSize) then
412			begin
413			ReallocMem(FBuffer, NewSize);
414			FBlobSize := NewSize;
415			if NewSize = 0 then
416			FBuffer := nil;
417			end;
418			end;
419
420			procedure TIBBlobStream.SetTransaction(Value: TIBTransaction);
421			begin
422			FBase.Transaction := Value;
423			FBlobInitialized := False;
424			end;
425
426			procedure TIBBlobStream.Truncate;
427			begin
428			SetSize(0);
429			end;
430
431			function TIBBlobStream.Write(const Buffer; Count: Longint): Longint;
432			begin
433			CheckWritable;
434			EnsureBlobInitialized;
435			result := Count;
436			if Count <= 0 then
437			exit;
438			if (FPosition + Count > FBlobSize) then
439			SetSize(FPosition + Count);
440			Move(Buffer, FBuffer[FPosition], Count);
441			Inc(FPosition, Count);
442			FModified := True;
443			end;
444
445			end.