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.
|