client/2.5/FB25Blob.pas

(*
 *  Firebird Interface (fbintf). The fbintf components provide a set of
 *  Pascal language bindings for the Firebird API. Although predominantly
 *  a new development they include source code taken from IBX and may be
 *  considered a derived product. This software thus also includes the copyright
 *  notice and license conditions from IBX.
 *
 *  Except for those parts dervied from IBX, contents of this file are subject
 *  to the Initial Developer's 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 here:
 *
 *    http://www.firebirdsql.org/index.php?op=doc&id=idpl
 *
 *  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 Initial Developer of the Original Code is Tony Whyman.
 *
 *  The Original Code is (C) 2016 Tony Whyman, MWA Software
 *  (http://www.mwasoftware.co.uk).
 *
 *  All Rights Reserved.
 *
 *  Contributor(s): ______________________________________.
 *
*)
{************************************************************************}
{                                                                        }
{       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                                       }
{                                                                        }
{    IBX For Lazarus (Firebird Express)                                  }
{    Contributor: Tony Whyman, MWA Software http://www.mwasoftware.co.uk }
{    Portions created by MWA Software are copyright McCallum Whyman      }
{    Associates Ltd 2011 - 2015                                                }
{                                                                        }
{************************************************************************}
unit FB25Blob;
{$IFDEF MSWINDOWS} 
{$DEFINE WINDOWS} 
{$ENDIF}

{$IFDEF FPC}
{$mode delphi}
{$interfaces COM}
{$ENDIF}

interface

uses
  Classes, SysUtils, IB,  IBHeader,IBExternals, FBClientAPI, FB25ClientAPI, FB25Attachment,
  FB25Transaction, FBActivityMonitor, FBBlob, FBOutputBlock;

type

   { TFB25BlobMetaData }

   TFB25BlobMetaData  = class(TFBBlobMetaData, IBlobMetaData)
   private
     FHasFullMetaData: boolean;
     FAttachment: TFB25Attachment;
     FTransaction: TFB25Transaction;
   protected
     procedure NeedFullMetadata; override;
   public
     constructor Create(Attachment: TFB25Attachment; Transaction: TFB25Transaction;
       RelationName, ColumnName: AnsiString); overload;
     constructor Create(Attachment: TFB25Attachment; Transaction: TFB25Transaction;
       RelationName, ColumnName: AnsiString; SubType: integer); overload;
  end;


  { TFB25Blob }

  TFB25Blob = class(TFBBlob,IBlob)
  private
    FHandle: TISC_BLOB_HANDLE;
    FEOB: boolean;
  protected
    procedure CheckReadable; override;
    procedure CheckWritable; override;
    function GetIntf: IBlob; override;
    procedure GetInfo(Request: array of byte; Response: IBlobInfo); override;
    procedure InternalClose(Force: boolean); override;
    procedure InternalCancel(Force: boolean); override;
  public
    constructor Create(Attachment: TFB25Attachment; Transaction: TFB25Transaction;
                       MetaData: IBlobMetaData; BPB: IBPB); overload;
    constructor Create(Attachment: TFB25Attachment; Transaction: TFB25Transaction;
                       SubType: integer; CharSetID: cardinal; BPB: IBPB); overload;
    constructor Create(Attachment: TFB25Attachment; Transaction: TFB25Transaction;
                       MetaData: IBlobMetaData; BlobID: TISC_QUAD; BPB: IBPB); overload;
    property Handle: TISC_BLOB_HANDLE read FHandle;

  public
    function Read(var Buffer; Count: Longint): Longint; override;
    function Write(const Buffer; Count: Longint): Longint; override;
  end;

implementation

uses IBErrorCodes, FBMessages, FBParamBlock;

{ TFB25BlobMetaData }

procedure TFB25BlobMetaData.NeedFullMetadata;
var
  BlobDesc: TISC_BLOB_DESC;
  Global: array [0..31] of char;
  RelName: AnsiString;
  ColName: AnsiString;
begin
  if FHasFullMetaData then Exit;

  FSegmentSize := 80;
  RelName := AnsiUpperCase(GetRelationName);
  ColName := AnsiUpperCase(GetColumnName);
  if (ColName <> '') and (RelName <> '') then
  begin
    with Firebird25ClientAPI do
      Call(isc_blob_lookup_desc(StatusVector,@(FAttachment.Handle),
                                            @(FTransaction.Handle),
                PAnsiChar(RelName),PAnsiChar(ColName),@BlobDesc,@Global));
    if FUnconfirmedCharacterSet then
      FCharSetID := BlobDesc.blob_desc_charset;
    FSubType := BlobDesc.blob_desc_subtype;
    FSegmentSize := BlobDesc.blob_desc_segment_size ;
  end;

  if FUnconfirmedCharacterSet and (FCharSetID > 1) and FAttachment.HasDefaultCharSet then
  begin
    FCharSetID := FAttachment.CharSetID;
    FUnconfirmedCharacterSet := false;
  end;


  FHasFullMetaData := true;
  FHasSubType := true;
end;

constructor TFB25BlobMetaData.Create(Attachment: TFB25Attachment;
  Transaction: TFB25Transaction; RelationName, ColumnName: AnsiString);
begin
  inherited Create(Transaction,RelationName,ColumnName);
  FAttachment := Attachment;
  FTransaction := Transaction;
end;

constructor TFB25BlobMetaData.Create(Attachment: TFB25Attachment;
  Transaction: TFB25Transaction; RelationName, ColumnName: AnsiString;
  SubType: integer);
begin
  Create(Attachment,Transaction,RelationName,ColumnName);
  FSubType := SubType;
  FHasSubType := true;
end;

{ TFB25Blob }

procedure TFB25Blob.CheckReadable;
begin
  if FCreating or (FHandle = nil) then
    IBError(ibxeBlobCannotBeRead, [nil]);
end;

procedure TFB25Blob.CheckWritable;
begin
  if not FCreating or (FHandle = nil) then
    IBError(ibxeBlobCannotBeWritten, [nil]);
end;

function TFB25Blob.GetIntf: IBlob;
begin
  Result := self;
end;

procedure TFB25Blob.GetInfo(Request: array of byte; Response: IBlobInfo);
begin
  if FHandle = nil then
    IBError(ibxeBlobNotOpen,[nil]);

  with Firebird25ClientAPI, Response as TBlobInfo do
    Call(isc_blob_info(StatusVector, @FHandle, Length(Request),@Request,
                                               GetBufSize, Buffer));
end;

procedure TFB25Blob.InternalClose(Force: boolean);
begin
  if FHandle = nil then
    Exit;
  with Firebird25ClientAPI do
    Call(isc_close_blob(StatusVector, @FHandle), not Force);
  FHandle := nil;
end;

procedure TFB25Blob.InternalCancel(Force: boolean);
begin
  if FHandle = nil then
    Exit;
  with Firebird25ClientAPI do
    Call(isc_cancel_blob(StatusVector,@FHandle),not Force);
  FHandle := nil;
end;

constructor TFB25Blob.Create(Attachment: TFB25Attachment; Transaction: TFB25Transaction;
  MetaData: IBlobMetaData; BPB: IBPB);
var DBHandle: TISC_DB_HANDLE;
    TRHandle: TISC_TR_HANDLE;
begin
  inherited Create(Attachment,Transaction,MetaData,BPB);
  DBHandle := Attachment.Handle;
  TRHandle := Transaction.Handle;
  with Firebird25ClientAPI do
  if BPB = nil then
    Call(isc_create_blob2(StatusVector, @DBHandle, @TRHandle, @FHandle, @FBlobID,
                           0, nil))
  else
  with BPB as TBPB do
    Call(isc_create_blob2(StatusVector, @DBHandle, @TRHandle, @FHandle, @FBlobID,
                         getDataLength, getBuffer));
end;

constructor TFB25Blob.Create(Attachment: TFB25Attachment;
  Transaction: TFB25Transaction; SubType: integer; CharSetID: cardinal;
  BPB: IBPB);
var DBHandle: TISC_DB_HANDLE;
    TRHandle: TISC_TR_HANDLE;
    MetaData: TFB25BlobMetaData;
begin
  MetaData := TFB25BlobMetaData.Create(Attachment,Transaction,'','',SubType);
  MetaData.FCharSetID := CharSetID;
  MetaData.FHasFullMetaData := true;
  inherited Create(Attachment,Transaction,MetaData,BPB);
  DBHandle := Attachment.Handle;
  TRHandle := Transaction.Handle;
  with Firebird25ClientAPI do
  if BPB = nil then
    Call(isc_create_blob2(StatusVector, @DBHandle, @TRHandle, @FHandle, @FBlobID,
                           0, nil))
  else
  with BPB as TBPB do
    Call(isc_create_blob2(StatusVector, @DBHandle, @TRHandle, @FHandle, @FBlobID,
                         getDataLength, getBuffer));
end;

constructor TFB25Blob.Create(Attachment: TFB25Attachment;
  Transaction: TFB25Transaction; MetaData: IBlobMetaData; BlobID: TISC_QUAD; BPB: IBPB);
var DBHandle: TISC_DB_HANDLE;
    TRHandle: TISC_TR_HANDLE;
begin
  inherited Create(Attachment,Transaction,MetaData,BlobID,BPB);
  DBHandle := Attachment.Handle;
  TRHandle := Transaction.Handle;
  if (BlobID.gds_quad_high = 0) and (BlobID.gds_quad_low = 0) then
    Exit;

  with Firebird25ClientAPI do
  if BPB = nil then
    Call(isc_open_blob2(StatusVector,  @DBHandle, @TRHandle, @FHandle,
                     @FBlobID, 0, nil))
  else
  with BPB as TBPB do
    Call(isc_open_blob2(StatusVector,  @DBHandle, @TRHandle, @FHandle,
                   @FBlobID, getDataLength, getBuffer));
end;

function TFB25Blob.Read(var Buffer; Count: Longint): Longint;
var
  BytesRead : UShort;
  LocalBuffer: PByte;
  returnCode: long;
  localCount: uShort;
begin
  CheckReadable;
  Result := 0;
  if FEOB then
    Exit;

  LocalBuffer := PByte(@Buffer);
  repeat
    if Count > MaxuShort then
      localCount := MaxuShort
    else
      localCount := Count;
    with Firebird25ClientAPI do
      returnCode := isc_get_segment(StatusVector, @FHandle, @BytesRead, localCount,
                           LocalBuffer);
    Inc(LocalBuffer,BytesRead);
    Inc(Result,BytesRead);
    Dec(Count,BytesRead);
  until ((returncode <> 0) and (returnCode <> isc_segment)) or (Count = 0);

  FEOB := returnCode = isc_segstr_eof;
  ClearStringCache;
  if (returnCode <> 0) and (returnCode <> isc_segment) and (returnCode <> isc_segstr_eof) then
    Firebird25ClientAPI.IBDataBaseError
end;

function TFB25Blob.Write(const Buffer; Count: Longint): Longint;
var
  LocalBuffer: PByte;
  localCount: uShort;
begin
  CheckWritable;
  LocalBuffer := PByte(@Buffer);
  Result := 0;
  if Count = 0 then Exit;

  repeat
    if Count > MaxuShort then
      localCount := MaxuShort
    else
      localCount := Count;
    with Firebird25ClientAPI do
      Call(isc_put_segment(StatusVector,@FHandle,localCount,LocalBuffer));
    Dec(Count,localCount);
    Inc(LocalBuffer,localCount);
    Inc(Result,localCount);
  until Count = 0;
  ClearStringCache;
end;


end.

Revision:	56
Committed:	Mon Mar 6 10:20:02 2017 UTC (7 years, 8 months ago) by tony
Content type:	text/x-pascal
Original Path:	*ibx/trunk/fbintf/client/2.5/FB25Blob.pas*
File size:	12058 byte(s)
Log Message:	Committing updates for Trunk
#	User	Rev	Content
1	tony	45	(*
2			* Firebird Interface (fbintf). The fbintf components provide a set of
3			* Pascal language bindings for the Firebird API. Although predominantly
4			* a new development they include source code taken from IBX and may be
5			* considered a derived product. This software thus also includes the copyright
6			* notice and license conditions from IBX.
7			*
8			* Except for those parts dervied from IBX, contents of this file are subject
9			* to the Initial Developer's Public License Version 1.0 (the "License"); you
10			* may not use this file except in compliance with the License. You may obtain a
11			* copy of the License here:
12			*
13			* http://www.firebirdsql.org/index.php?op=doc&id=idpl
14			*
15			* Software distributed under the License is distributed on an "AS
16			* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
17			* implied. See the License for the specific language governing rights
18			* and limitations under the License.
19			*
20			* The Initial Developer of the Original Code is Tony Whyman.
21			*
22			* The Original Code is (C) 2016 Tony Whyman, MWA Software
23			* (http://www.mwasoftware.co.uk).
24			*
25			* All Rights Reserved.
26			*
27			* Contributor(s): ______________________________________.
28			*
29			*)
30			{************************************************************************}
31			{ }
32			{ Borland Delphi Visual Component Library }
33			{ InterBase Express core components }
34			{ }
35			{ Copyright (c) 1998-2000 Inprise Corporation }
36			{ }
37			{ InterBase Express is based in part on the product }
38			{ Free IB Components, written by Gregory H. Deatz for }
39			{ Hoagland, Longo, Moran, Dunst & Doukas Company. }
40			{ Free IB Components is used under license. }
41			{ }
42			{ The contents of this file are subject to the InterBase }
43			{ Public License Version 1.0 (the "License"); you may not }
44			{ use this file except in compliance with the License. You }
45			{ may obtain a copy of the License at http://www.Inprise.com/IPL.html }
46			{ Software distributed under the License is distributed on }
47			{ an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either }
48			{ express or implied. See the License for the specific language }
49			{ governing rights and limitations under the License. }
50			{ The Original Code was created by InterBase Software Corporation }
51			{ and its successors. }
52			{ Portions created by Inprise Corporation are Copyright (C) Inprise }
53			{ Corporation. All Rights Reserved. }
54			{ Contributor(s): Jeff Overcash }
55			{ }
56			{ IBX For Lazarus (Firebird Express) }
57			{ Contributor: Tony Whyman, MWA Software http://www.mwasoftware.co.uk }
58			{ Portions created by MWA Software are copyright McCallum Whyman }
59			{ Associates Ltd 2011 - 2015 }
60			{ }
61			{************************************************************************}
62			unit FB25Blob;
63	tony	56	{$IFDEF MSWINDOWS}
64			{$DEFINE WINDOWS}
65			{$ENDIF}
66	tony	45
67			{$IFDEF FPC}
68	tony	56	{$mode delphi}
69	tony	45	{$interfaces COM}
70			{$ENDIF}
71
72			interface
73
74			uses
75			Classes, SysUtils, IB, IBHeader,IBExternals, FBClientAPI, FB25ClientAPI, FB25Attachment,
76	tony	56	FB25Transaction, FBActivityMonitor, FBBlob, FBOutputBlock;
77	tony	45
78			type
79
80			{ TFB25BlobMetaData }
81
82			TFB25BlobMetaData = class(TFBBlobMetaData, IBlobMetaData)
83			private
84			FHasFullMetaData: boolean;
85			FAttachment: TFB25Attachment;
86			FTransaction: TFB25Transaction;
87			protected
88			procedure NeedFullMetadata; override;
89			public
90			constructor Create(Attachment: TFB25Attachment; Transaction: TFB25Transaction;
91	tony	56	RelationName, ColumnName: AnsiString); overload;
92	tony	45	constructor Create(Attachment: TFB25Attachment; Transaction: TFB25Transaction;
93	tony	56	RelationName, ColumnName: AnsiString; SubType: integer); overload;
94	tony	45	end;
95
96
97			{ TFB25Blob }
98
99			TFB25Blob = class(TFBBlob,IBlob)
100			private
101			FHandle: TISC_BLOB_HANDLE;
102			FEOB: boolean;
103			protected
104			procedure CheckReadable; override;
105			procedure CheckWritable; override;
106			function GetIntf: IBlob; override;
107	tony	56	procedure GetInfo(Request: array of byte; Response: IBlobInfo); override;
108	tony	45	procedure InternalClose(Force: boolean); override;
109			procedure InternalCancel(Force: boolean); override;
110			public
111			constructor Create(Attachment: TFB25Attachment; Transaction: TFB25Transaction;
112			MetaData: IBlobMetaData; BPB: IBPB); overload;
113			constructor Create(Attachment: TFB25Attachment; Transaction: TFB25Transaction;
114			SubType: integer; CharSetID: cardinal; BPB: IBPB); overload;
115			constructor Create(Attachment: TFB25Attachment; Transaction: TFB25Transaction;
116			MetaData: IBlobMetaData; BlobID: TISC_QUAD; BPB: IBPB); overload;
117			property Handle: TISC_BLOB_HANDLE read FHandle;
118
119			public
120			function Read(var Buffer; Count: Longint): Longint; override;
121			function Write(const Buffer; Count: Longint): Longint; override;
122			end;
123
124			implementation
125
126			uses IBErrorCodes, FBMessages, FBParamBlock;
127
128			{ TFB25BlobMetaData }
129
130			procedure TFB25BlobMetaData.NeedFullMetadata;
131			var
132			BlobDesc: TISC_BLOB_DESC;
133			Global: array [0..31] of char;
134	tony	56	RelName: AnsiString;
135			ColName: AnsiString;
136	tony	45	begin
137			if FHasFullMetaData then Exit;
138
139			FSegmentSize := 80;
140	tony	56	RelName := AnsiUpperCase(GetRelationName);
141			ColName := AnsiUpperCase(GetColumnName);
142			if (ColName <> '') and (RelName <> '') then
143	tony	45	begin
144			with Firebird25ClientAPI do
145			Call(isc_blob_lookup_desc(StatusVector,@(FAttachment.Handle),
146			@(FTransaction.Handle),
147	tony	56	PAnsiChar(RelName),PAnsiChar(ColName),@BlobDesc,@Global));
148	tony	47	if FUnconfirmedCharacterSet then
149			FCharSetID := BlobDesc.blob_desc_charset;
150	tony	45	FSubType := BlobDesc.blob_desc_subtype;
151			FSegmentSize := BlobDesc.blob_desc_segment_size ;
152	tony	47	end;
153	tony	45
154	tony	47	if FUnconfirmedCharacterSet and (FCharSetID > 1) and FAttachment.HasDefaultCharSet then
155	tony	45	begin
156			FCharSetID := FAttachment.CharSetID;
157			FUnconfirmedCharacterSet := false;
158			end;
159
160
161			FHasFullMetaData := true;
162			FHasSubType := true;
163			end;
164
165			constructor TFB25BlobMetaData.Create(Attachment: TFB25Attachment;
166	tony	56	Transaction: TFB25Transaction; RelationName, ColumnName: AnsiString);
167	tony	45	begin
168			inherited Create(Transaction,RelationName,ColumnName);
169			FAttachment := Attachment;
170			FTransaction := Transaction;
171			end;
172
173			constructor TFB25BlobMetaData.Create(Attachment: TFB25Attachment;
174	tony	56	Transaction: TFB25Transaction; RelationName, ColumnName: AnsiString;
175	tony	45	SubType: integer);
176			begin
177			Create(Attachment,Transaction,RelationName,ColumnName);
178			FSubType := SubType;
179			FHasSubType := true;
180			end;
181
182			{ TFB25Blob }
183
184			procedure TFB25Blob.CheckReadable;
185			begin
186			if FCreating or (FHandle = nil) then
187			IBError(ibxeBlobCannotBeRead, [nil]);
188			end;
189
190			procedure TFB25Blob.CheckWritable;
191			begin
192			if not FCreating or (FHandle = nil) then
193			IBError(ibxeBlobCannotBeWritten, [nil]);
194			end;
195
196			function TFB25Blob.GetIntf: IBlob;
197			begin
198			Result := self;
199			end;
200
201	tony	56	procedure TFB25Blob.GetInfo(Request: array of byte; Response: IBlobInfo);
202			begin
203			if FHandle = nil then
204			IBError(ibxeBlobNotOpen,[nil]);
205
206			with Firebird25ClientAPI, Response as TBlobInfo do
207			Call(isc_blob_info(StatusVector, @FHandle, Length(Request),@Request,
208			GetBufSize, Buffer));
209			end;
210
211	tony	45	procedure TFB25Blob.InternalClose(Force: boolean);
212			begin
213			if FHandle = nil then
214			Exit;
215			with Firebird25ClientAPI do
216			Call(isc_close_blob(StatusVector, @FHandle), not Force);
217			FHandle := nil;
218			end;
219
220			procedure TFB25Blob.InternalCancel(Force: boolean);
221			begin
222			if FHandle = nil then
223			Exit;
224			with Firebird25ClientAPI do
225			Call(isc_cancel_blob(StatusVector,@FHandle),not Force);
226			FHandle := nil;
227			end;
228
229			constructor TFB25Blob.Create(Attachment: TFB25Attachment; Transaction: TFB25Transaction;
230			MetaData: IBlobMetaData; BPB: IBPB);
231			var DBHandle: TISC_DB_HANDLE;
232			TRHandle: TISC_TR_HANDLE;
233			begin
234			inherited Create(Attachment,Transaction,MetaData,BPB);
235			DBHandle := Attachment.Handle;
236			TRHandle := Transaction.Handle;
237			with Firebird25ClientAPI do
238			if BPB = nil then
239			Call(isc_create_blob2(StatusVector, @DBHandle, @TRHandle, @FHandle, @FBlobID,
240			0, nil))
241			else
242			with BPB as TBPB do
243			Call(isc_create_blob2(StatusVector, @DBHandle, @TRHandle, @FHandle, @FBlobID,
244			getDataLength, getBuffer));
245			end;
246
247			constructor TFB25Blob.Create(Attachment: TFB25Attachment;
248			Transaction: TFB25Transaction; SubType: integer; CharSetID: cardinal;
249			BPB: IBPB);
250			var DBHandle: TISC_DB_HANDLE;
251			TRHandle: TISC_TR_HANDLE;
252			MetaData: TFB25BlobMetaData;
253			begin
254			MetaData := TFB25BlobMetaData.Create(Attachment,Transaction,'','',SubType);
255			MetaData.FCharSetID := CharSetID;
256			MetaData.FHasFullMetaData := true;
257			inherited Create(Attachment,Transaction,MetaData,BPB);
258			DBHandle := Attachment.Handle;
259			TRHandle := Transaction.Handle;
260			with Firebird25ClientAPI do
261			if BPB = nil then
262			Call(isc_create_blob2(StatusVector, @DBHandle, @TRHandle, @FHandle, @FBlobID,
263			0, nil))
264			else
265			with BPB as TBPB do
266			Call(isc_create_blob2(StatusVector, @DBHandle, @TRHandle, @FHandle, @FBlobID,
267			getDataLength, getBuffer));
268			end;
269
270			constructor TFB25Blob.Create(Attachment: TFB25Attachment;
271			Transaction: TFB25Transaction; MetaData: IBlobMetaData; BlobID: TISC_QUAD; BPB: IBPB);
272			var DBHandle: TISC_DB_HANDLE;
273			TRHandle: TISC_TR_HANDLE;
274			begin
275			inherited Create(Attachment,Transaction,MetaData,BlobID,BPB);
276			DBHandle := Attachment.Handle;
277			TRHandle := Transaction.Handle;
278			if (BlobID.gds_quad_high = 0) and (BlobID.gds_quad_low = 0) then
279			Exit;
280
281			with Firebird25ClientAPI do
282			if BPB = nil then
283			Call(isc_open_blob2(StatusVector, @DBHandle, @TRHandle, @FHandle,
284			@FBlobID, 0, nil))
285			else
286			with BPB as TBPB do
287			Call(isc_open_blob2(StatusVector, @DBHandle, @TRHandle, @FHandle,
288			@FBlobID, getDataLength, getBuffer));
289			end;
290
291			function TFB25Blob.Read(var Buffer; Count: Longint): Longint;
292			var
293			BytesRead : UShort;
294	tony	56	LocalBuffer: PByte;
295	tony	45	returnCode: long;
296			localCount: uShort;
297			begin
298			CheckReadable;
299			Result := 0;
300			if FEOB then
301			Exit;
302
303	tony	56	LocalBuffer := PByte(@Buffer);
304	tony	45	repeat
305			if Count > MaxuShort then
306			localCount := MaxuShort
307			else
308			localCount := Count;
309			with Firebird25ClientAPI do
310			returnCode := isc_get_segment(StatusVector, @FHandle, @BytesRead, localCount,
311			LocalBuffer);
312			Inc(LocalBuffer,BytesRead);
313			Inc(Result,BytesRead);
314			Dec(Count,BytesRead);
315			until ((returncode <> 0) and (returnCode <> isc_segment)) or (Count = 0);
316
317			FEOB := returnCode = isc_segstr_eof;
318			ClearStringCache;
319			if (returnCode <> 0) and (returnCode <> isc_segment) and (returnCode <> isc_segstr_eof) then
320			Firebird25ClientAPI.IBDataBaseError
321			end;
322
323			function TFB25Blob.Write(const Buffer; Count: Longint): Longint;
324			var
325	tony	56	LocalBuffer: PByte;
326	tony	45	localCount: uShort;
327			begin
328			CheckWritable;
329	tony	56	LocalBuffer := PByte(@Buffer);
330	tony	45	Result := 0;
331			if Count = 0 then Exit;
332
333			repeat
334			if Count > MaxuShort then
335			localCount := MaxuShort
336			else
337			localCount := Count;
338			with Firebird25ClientAPI do
339			Call(isc_put_segment(StatusVector,@FHandle,localCount,LocalBuffer));
340			Dec(Count,localCount);
341			Inc(LocalBuffer,localCount);
342			Inc(Result,localCount);
343			until Count = 0;
344			ClearStringCache;
345			end;
346
347
348			end.
349