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, 9 months ago) by tony
Content type:	text/x-pascal
File size:	12804 byte(s)
Log Message:	Committing updates for Release pre-release
#	Content
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	{$Mode Delphi}
32
33	interface
34
35	uses
36	SysUtils, Classes, IBHeader, IBErrorCodes, IBExternals, DB, IB, IBDatabase;
37
38
39	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	uses IBIntf;
110
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.