oculus1: e2f9e4603129 libovr/Src/Kernel/OVR

oculus1

view libovr/Src/Kernel/OVR_File.cpp @ 1:e2f9e4603129

added LibOVR and started a simple vr wrapper.

author	John Tsiombikas <nuclear@member.fsf.org>
date	Sat, 14 Sep 2013 16:14:59 +0300
parents
children	b069a5c27388

line source

1 /**************************************************************************

3 Filename : OVR_File.cpp

4 Content : File wrapper class implementation (Win32)

6 Created : April 5, 1999

7 Authors : Michael Antonov

11 Use of this software is subject to the terms of the Oculus license

12 agreement provided at the time of installation or download, or which

13 otherwise accompanies this software in either electronic or hard copy form.

15 **************************************************************************/

17 #define GFILE_CXX

19 // Standard C library (Captain Obvious guarantees!)

20 #include <stdio.h>

22 #include "OVR_File.h"

24 namespace OVR {

26 // Buffered file adds buffering to an existing file

27 // FILEBUFFER_SIZE defines the size of internal buffer, while

28 // FILEBUFFER_TOLERANCE controls the amount of data we'll effectively try to buffer

29 #define FILEBUFFER_SIZE (8192-8)

30 #define FILEBUFFER_TOLERANCE 4096

32 // ** Constructor/Destructor

34 // Hidden constructor

35 // Not supposed to be used

36 BufferedFile::BufferedFile() : DelegatedFile(0)

37 {

38 pBuffer = (UByte*)OVR_ALLOC(FILEBUFFER_SIZE);

39 BufferMode = NoBuffer;

40 FilePos = 0;

41 Pos = 0;

42 DataSize = 0;

43 }

45 // Takes another file as source

46 BufferedFile::BufferedFile(File *pfile) : DelegatedFile(pfile)

47 {

48 pBuffer = (UByte*)OVR_ALLOC(FILEBUFFER_SIZE);

49 BufferMode = NoBuffer;

50 FilePos = pfile->LTell();

51 Pos = 0;

52 DataSize = 0;

53 }

56 // Destructor

57 BufferedFile::~BufferedFile()

58 {

59 // Flush in case there's data

60 if (pFile)

61 FlushBuffer();

62 // Get rid of buffer

63 if (pBuffer)

64 OVR_FREE(pBuffer);

65 }

67 /*

68 bool BufferedFile::VCopy(const Object &source)

69 {

70 if (!DelegatedFile::VCopy(source))

71 return 0;

73 // Data members

74 BufferedFile *psource = (BufferedFile*)&source;

76 // Buffer & the mode it's in

77 pBuffer = psource->pBuffer;

78 BufferMode = psource->BufferMode;

79 Pos = psource->Pos;

80 DataSize = psource->DataSize;

81 return 1;

82 }

83 */

85 // Initializes buffering to a certain mode

86 bool BufferedFile::SetBufferMode(BufferModeType mode)

87 {

88 if (!pBuffer)

89 return false;

90 if (mode == BufferMode)

91 return true;

93 FlushBuffer();

95 // Can't set write mode if we can't write

96 if ((mode==WriteBuffer) && (!pFile || !pFile->IsWritable()) )

97 return 0;

99 // And SetMode

100 BufferMode = mode;

101 Pos = 0;

102 DataSize = 0;

103 return 1;

104 }

105

106 // Flushes buffer

107 void BufferedFile::FlushBuffer()

108 {

109 switch(BufferMode)

110 {

111 case WriteBuffer:

112 // Write data in buffer

113 FilePos += pFile->Write(pBuffer,Pos);

114 Pos = 0;

115 break;

116

117 case ReadBuffer:

118 // Seek back & reset buffer data

119 if ((DataSize-Pos)>0)

120 FilePos = pFile->LSeek(-(int)(DataSize-Pos), Seek_Cur);

121 DataSize = 0;

122 Pos = 0;

123 break;

124 default:

125 // not handled!

126 break;

127 }

128 }

129

130 // Reloads data for ReadBuffer

131 void BufferedFile::LoadBuffer()

132 {

133 if (BufferMode == ReadBuffer)

134 {

135 // We should only reload once all of pre-loaded buffer is consumed.

136 OVR_ASSERT(Pos == DataSize);

137

138 // WARNING: Right now LoadBuffer() assumes the buffer's empty

139 int sz = pFile->Read(pBuffer,FILEBUFFER_SIZE);

140 DataSize = sz<0 ? 0 : (unsigned)sz;

141 Pos = 0;

142 FilePos += DataSize;

143 }

144 }

145

146

147 // ** Overridden functions

148

149 // We override all the functions that can possibly

150 // require buffer mode switch, flush, or extra calculations

151

152 // Tell() requires buffer adjustment

153 int BufferedFile::Tell()

154 {

155 if (BufferMode == ReadBuffer)

156 return int (FilePos - DataSize + Pos);

157

158 int pos = pFile->Tell();

159 // Adjust position based on buffer mode & data

160 if (pos!=-1)

161 {

162 OVR_ASSERT(BufferMode != ReadBuffer);

163 if (BufferMode == WriteBuffer)

164 pos += Pos;

165 }

166 return pos;

167 }

168

169 SInt64 BufferedFile::LTell()

170 {

171 if (BufferMode == ReadBuffer)

172 return FilePos - DataSize + Pos;

173

174 SInt64 pos = pFile->LTell();

175 if (pos!=-1)

176 {

177 OVR_ASSERT(BufferMode != ReadBuffer);

178 if (BufferMode == WriteBuffer)

179 pos += Pos;

180 }

181 return pos;

182 }

183

184 int BufferedFile::GetLength()

185 {

186 int len = pFile->GetLength();

187 // If writing through buffer, file length may actually be bigger

188 if ((len!=-1) && (BufferMode==WriteBuffer))

189 {

190 int currPos = pFile->Tell() + Pos;

191 if (currPos>len)

192 len = currPos;

193 }

194 return len;

195 }

196 SInt64 BufferedFile::LGetLength()

197 {

198 SInt64 len = pFile->LGetLength();

199 // If writing through buffer, file length may actually be bigger

200 if ((len!=-1) && (BufferMode==WriteBuffer))

201 {

202 SInt64 currPos = pFile->LTell() + Pos;

203 if (currPos>len)

204 len = currPos;

205 }

206 return len;

207 }

208

209 /*

210 bool BufferedFile::Stat(FileStats *pfs)

211 {

212 // Have to fix up length is stat

213 if (pFile->Stat(pfs))

214 {

215 if (BufferMode==WriteBuffer)

216 {

217 SInt64 currPos = pFile->LTell() + Pos;

218 if (currPos > pfs->Size)

219 {

220 pfs->Size = currPos;

221 // ??

222 pfs->Blocks = (pfs->Size+511) >> 9;

223 }

224 }

225 return 1;

226 }

227 return 0;

228 }

229 */

230

231 int BufferedFile::Write(const UByte *psourceBuffer, int numBytes)

232 {

233 if ( (BufferMode==WriteBuffer) || SetBufferMode(WriteBuffer))

234 {

235 // If not data space in buffer, flush

236 if ((FILEBUFFER_SIZE-(int)Pos)<numBytes)

237 {

238 FlushBuffer();

239 // If bigger then tolerance, just write directly

240 if (numBytes>FILEBUFFER_TOLERANCE)

241 {

242 int sz = pFile->Write(psourceBuffer,numBytes);

243 if (sz > 0)

244 FilePos += sz;

245 return sz;

246 }

247 }

248

249 // Enough space in buffer.. so copy to it

250 memcpy(pBuffer+Pos, psourceBuffer, numBytes);

251 Pos += numBytes;

252 return numBytes;

253 }

254 int sz = pFile->Write(psourceBuffer,numBytes);

255 if (sz > 0)

256 FilePos += sz;

257 return sz;

258 }

259

260 int BufferedFile::Read(UByte *pdestBuffer, int numBytes)

261 {

262 if ( (BufferMode==ReadBuffer) || SetBufferMode(ReadBuffer))

263 {

264 // Data in buffer... copy it

265 if ((int)(DataSize-Pos) >= numBytes)

266 {

267 memcpy(pdestBuffer, pBuffer+Pos, numBytes);

268 Pos += numBytes;

269 return numBytes;

270 }

271

272 // Not enough data in buffer, copy buffer

273 int readBytes = DataSize-Pos;

274 memcpy(pdestBuffer, pBuffer+Pos, readBytes);

275 numBytes -= readBytes;

276 pdestBuffer += readBytes;

277 Pos = DataSize;

278

279 // Don't reload buffer if more then tolerance

280 // (No major advantage, and we don't want to write a loop)

281 if (numBytes>FILEBUFFER_TOLERANCE)

282 {

283 numBytes = pFile->Read(pdestBuffer,numBytes);

284 if (numBytes > 0)

285 {

286 FilePos += numBytes;

287 Pos = DataSize = 0;

288 }

289 return readBytes + ((numBytes==-1) ? 0 : numBytes);

290 }

291

292 // Reload the buffer

293 // WARNING: Right now LoadBuffer() assumes the buffer's empty

294 LoadBuffer();

295 if ((int)(DataSize-Pos) < numBytes)

296 numBytes = (int)DataSize-Pos;

297

298 memcpy(pdestBuffer, pBuffer+Pos, numBytes);

299 Pos += numBytes;

300 return numBytes + readBytes;

301

302 /*

303 // Alternative Read implementation. The one above is probably better

304 // due to FILEBUFFER_TOLERANCE.

305 int total = 0;

306

307 do {

308 int bufferBytes = (int)(DataSize-Pos);

309 int copyBytes = (bufferBytes > numBytes) ? numBytes : bufferBytes;

310

311 memcpy(pdestBuffer, pBuffer+Pos, copyBytes);

312 numBytes -= copyBytes;

313 pdestBuffer += copyBytes;

314 Pos += copyBytes;

315 total += copyBytes;

316

317 if (numBytes == 0)

318 break;

319 LoadBuffer();

320

321 } while (DataSize > 0);

322

323 return total;

324 */

325 }

326 int sz = pFile->Read(pdestBuffer,numBytes);

327 if (sz > 0)

328 FilePos += sz;

329 return sz;

330 }

331

332

333 int BufferedFile::SkipBytes(int numBytes)

334 {

335 int skippedBytes = 0;

336

337 // Special case for skipping a little data in read buffer

338 if (BufferMode==ReadBuffer)

339 {

340 skippedBytes = (((int)DataSize-(int)Pos) >= numBytes) ? numBytes : (DataSize-Pos);

341 Pos += skippedBytes;

342 numBytes -= skippedBytes;

343 }

344

345 if (numBytes)

346 {

347 numBytes = pFile->SkipBytes(numBytes);

348 // Make sure we return the actual number skipped, or error

349 if (numBytes!=-1)

350 {

351 skippedBytes += numBytes;

352 FilePos += numBytes;

353 Pos = DataSize = 0;

354 }

355 else if (skippedBytes <= 0)

356 skippedBytes = -1;

357 }

358 return skippedBytes;

359 }

360

361 int BufferedFile::BytesAvailable()

362 {

363 int available = pFile->BytesAvailable();

364 // Adjust available size based on buffers

365 switch(BufferMode)

366 {

367 case ReadBuffer:

368 available += DataSize-Pos;

369 break;

370 case WriteBuffer:

371 available -= Pos;

372 if (available<0)

373 available= 0;

374 break;

375 default:

376 break;

377 }

378 return available;

379 }

380

381 bool BufferedFile::Flush()

382 {

383 FlushBuffer();

384 return pFile->Flush();

385 }

386

387 // Seeking could be optimized better..

388 int BufferedFile::Seek(int offset, int origin)

389 {

390 if (BufferMode == ReadBuffer)

391 {

392 if (origin == Seek_Cur)

393 {

394 // Seek can fall either before or after Pos in the buffer,

395 // but it must be within bounds.

396 if (((unsigned(offset) + Pos)) <= DataSize)

397 {

398 Pos += offset;

399 return int (FilePos - DataSize + Pos);

400 }

401

402 // Lightweight buffer "Flush". We do this to avoid an extra seek

403 // back operation which would take place if we called FlushBuffer directly.

404 origin = Seek_Set;

405 OVR_ASSERT(((FilePos - DataSize + Pos) + (UInt64)offset) < ~(UInt64)0);

406 offset = (int)(FilePos - DataSize + Pos) + offset;

407 Pos = DataSize = 0;

408 }

409 else if (origin == Seek_Set)

410 {

411 if (((unsigned)offset - (FilePos-DataSize)) <= DataSize)

412 {

413 OVR_ASSERT((FilePos-DataSize) < ~(UInt64)0);

414 Pos = (unsigned)offset - (unsigned)(FilePos-DataSize);

415 return offset;

416 }

417 Pos = DataSize = 0;

418 }

419 else

420 {

421 FlushBuffer();

422 }

423 }

424 else

425 {

426 FlushBuffer();

427 }

428

429 /*

430 // Old Seek Logic

431 if (origin == Seek_Cur && offset + Pos < DataSize)

432 {

433 //OVR_ASSERT((FilePos - DataSize) >= (FilePos - DataSize + Pos + offset));

434 Pos += offset;

435 OVR_ASSERT(int (Pos) >= 0);

436 return int (FilePos - DataSize + Pos);

437 }

438 else if (origin == Seek_Set && unsigned(offset) >= FilePos - DataSize && unsigned(offset) < FilePos)

439 {

440 Pos = unsigned(offset - FilePos + DataSize);

441 OVR_ASSERT(int (Pos) >= 0);

442 return int (FilePos - DataSize + Pos);

443 }

444

445 FlushBuffer();

446 */

447

448

449 FilePos = pFile->Seek(offset,origin);

450 return int (FilePos);

451 }

452

453 SInt64 BufferedFile::LSeek(SInt64 offset, int origin)

454 {

455 if (BufferMode == ReadBuffer)

456 {

457 if (origin == Seek_Cur)

458 {

459 // Seek can fall either before or after Pos in the buffer,

460 // but it must be within bounds.

461 if (((unsigned(offset) + Pos)) <= DataSize)

462 {

463 Pos += (unsigned)offset;

464 return SInt64(FilePos - DataSize + Pos);

465 }

466

467 // Lightweight buffer "Flush". We do this to avoid an extra seek

468 // back operation which would take place if we called FlushBuffer directly.

469 origin = Seek_Set;

470 offset = (SInt64)(FilePos - DataSize + Pos) + offset;

471 Pos = DataSize = 0;

472 }

473 else if (origin == Seek_Set)

474 {

475 if (((UInt64)offset - (FilePos-DataSize)) <= DataSize)

476 {

477 Pos = (unsigned)((UInt64)offset - (FilePos-DataSize));

478 return offset;

479 }

480 Pos = DataSize = 0;

481 }

482 else

483 {

484 FlushBuffer();

485 }

486 }

487 else

488 {

489 FlushBuffer();

490 }

491

492 /*

493 OVR_ASSERT(BufferMode != NoBuffer);

494

495 if (origin == Seek_Cur && offset + Pos < DataSize)

496 {

497 Pos += int (offset);

498 return FilePos - DataSize + Pos;

499 }

500 else if (origin == Seek_Set && offset >= SInt64(FilePos - DataSize) && offset < SInt64(FilePos))

501 {

502 Pos = unsigned(offset - FilePos + DataSize);

503 return FilePos - DataSize + Pos;

504 }

505

506 FlushBuffer();

507 */

508

509 FilePos = pFile->LSeek(offset,origin);

510 return FilePos;

511 }

512

513 int BufferedFile::CopyFromStream(File *pstream, int byteSize)

514 {

515 // We can't rely on overridden Write()

516 // because delegation doesn't override virtual pointers

517 // So, just re-implement

518 UByte buff[0x4000];

519 int count = 0;

520 int szRequest, szRead, szWritten;

521

522 while(byteSize)

523 {

524 szRequest = (byteSize > int(sizeof(buff))) ? int(sizeof(buff)) : byteSize;

525

526 szRead = pstream->Read(buff,szRequest);

527 szWritten = 0;

528 if (szRead > 0)

529 szWritten = Write(buff,szRead);

530

531 count +=szWritten;

532 byteSize-=szWritten;

533 if (szWritten < szRequest)

534 break;

535 }

536 return count;

537 }

538

539 // Closing files

540 bool BufferedFile::Close()

541 {

542 switch(BufferMode)

543 {

544 case WriteBuffer:

545 FlushBuffer();

546 break;

547 case ReadBuffer:

548 // No need to seek back on close

549 BufferMode = NoBuffer;

550 break;

551 default:

552 break;

553 }

554 return pFile->Close();

555 }

556

557

558 // ***** Global path helpers

559

560 // Find trailing short filename in a path.

561 const char* OVR_CDECL GetShortFilename(const char* purl)

562 {

563 UPInt len = OVR_strlen(purl);

564 for (UPInt i=len; i>0; i--)

565 if (purl[i]=='\\' || purl[i]=='/')

566 return purl+i+1;

567 return purl;

568 }

569

570 } // OVR

571