1 /* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 //#define LOG_NDEBUG 0 18 #define LOG_TAG "ATSParser" 19 #include <utils/Log.h> 20 21 #include "ATSParser.h" 22 23 #include "AnotherPacketSource.h" 24 #include "ESQueue.h" 25 #include "include/avc_utils.h" 26 27 #include <media/stagefright/foundation/ABitReader.h> 28 #include <media/stagefright/foundation/ABuffer.h> 29 #include <media/stagefright/foundation/ADebug.h> 30 #include <media/stagefright/foundation/AMessage.h> 31 #include <media/stagefright/foundation/hexdump.h> 32 #include <media/stagefright/MediaDefs.h> 33 #include <media/stagefright/MediaErrors.h> 34 #include <media/stagefright/MetaData.h> 35 #include <utils/KeyedVector.h> 36 37 namespace android { 38 39 // I want the expression "y" evaluated even if verbose logging is off. 40 #define MY_LOGV(x, y) \ 41 do { unsigned tmp = y; LOGV(x, tmp); } while (0) 42 43 static const size_t kTSPacketSize = 188; 44 45 struct ATSParser::Program : public RefBase { 46 Program(unsigned programMapPID); 47 48 bool parsePID( 49 unsigned pid, unsigned payload_unit_start_indicator, 50 ABitReader *br); 51 52 void signalDiscontinuity(bool isASeek); 53 54 sp<MediaSource> getSource(SourceType type); 55 56 int64_t convertPTSToTimestamp(uint64_t PTS); 57 58 private: 59 unsigned mProgramMapPID; 60 KeyedVector<unsigned, sp<Stream> > mStreams; 61 bool mFirstPTSValid; 62 uint64_t mFirstPTS; 63 64 void parseProgramMap(ABitReader *br); 65 66 DISALLOW_EVIL_CONSTRUCTORS(Program); 67 }; 68 69 struct ATSParser::Stream : public RefBase { 70 Stream(Program *program, unsigned elementaryPID, unsigned streamType); 71 72 void parse( 73 unsigned payload_unit_start_indicator, 74 ABitReader *br); 75 76 void signalDiscontinuity(bool isASeek); 77 78 sp<MediaSource> getSource(SourceType type); 79 80 protected: 81 virtual ~Stream(); 82 83 private: 84 Program *mProgram; 85 unsigned mElementaryPID; 86 unsigned mStreamType; 87 88 sp<ABuffer> mBuffer; 89 sp<AnotherPacketSource> mSource; 90 bool mPayloadStarted; 91 92 ElementaryStreamQueue mQueue; 93 94 void flush(); 95 void parsePES(ABitReader *br); 96 97 void onPayloadData( 98 unsigned PTS_DTS_flags, uint64_t PTS, uint64_t DTS, 99 const uint8_t *data, size_t size); 100 101 void extractAACFrames(const sp<ABuffer> &buffer); 102 103 DISALLOW_EVIL_CONSTRUCTORS(Stream); 104 }; 105 106 //////////////////////////////////////////////////////////////////////////////// 107 108 ATSParser::Program::Program(unsigned programMapPID) 109 : mProgramMapPID(programMapPID), 110 mFirstPTSValid(false), 111 mFirstPTS(0) { 112 } 113 114 bool ATSParser::Program::parsePID( 115 unsigned pid, unsigned payload_unit_start_indicator, 116 ABitReader *br) { 117 if (pid == mProgramMapPID) { 118 if (payload_unit_start_indicator) { 119 unsigned skip = br->getBits(8); 120 br->skipBits(skip * 8); 121 } 122 123 parseProgramMap(br); 124 return true; 125 } 126 127 ssize_t index = mStreams.indexOfKey(pid); 128 if (index < 0) { 129 return false; 130 } 131 132 mStreams.editValueAt(index)->parse( 133 payload_unit_start_indicator, br); 134 135 return true; 136 } 137 138 void ATSParser::Program::signalDiscontinuity(bool isASeek) { 139 for (size_t i = 0; i < mStreams.size(); ++i) { 140 mStreams.editValueAt(i)->signalDiscontinuity(isASeek); 141 } 142 } 143 144 void ATSParser::Program::parseProgramMap(ABitReader *br) { 145 unsigned table_id = br->getBits(8); 146 LOGV(" table_id = %u", table_id); 147 CHECK_EQ(table_id, 0x02u); 148 149 unsigned section_syntax_indicator = br->getBits(1); 150 LOGV(" section_syntax_indicator = %u", section_syntax_indicator); 151 CHECK_EQ(section_syntax_indicator, 1u); 152 153 CHECK_EQ(br->getBits(1), 0u); 154 MY_LOGV(" reserved = %u", br->getBits(2)); 155 156 unsigned section_length = br->getBits(12); 157 LOGV(" section_length = %u", section_length); 158 CHECK((section_length & 0xc00) == 0); 159 CHECK_LE(section_length, 1021u); 160 161 MY_LOGV(" program_number = %u", br->getBits(16)); 162 MY_LOGV(" reserved = %u", br->getBits(2)); 163 MY_LOGV(" version_number = %u", br->getBits(5)); 164 MY_LOGV(" current_next_indicator = %u", br->getBits(1)); 165 MY_LOGV(" section_number = %u", br->getBits(8)); 166 MY_LOGV(" last_section_number = %u", br->getBits(8)); 167 MY_LOGV(" reserved = %u", br->getBits(3)); 168 MY_LOGV(" PCR_PID = 0x%04x", br->getBits(13)); 169 MY_LOGV(" reserved = %u", br->getBits(4)); 170 171 unsigned program_info_length = br->getBits(12); 172 LOGV(" program_info_length = %u", program_info_length); 173 CHECK((program_info_length & 0xc00) == 0); 174 175 br->skipBits(program_info_length * 8); // skip descriptors 176 177 // infoBytesRemaining is the number of bytes that make up the 178 // variable length section of ES_infos. It does not include the 179 // final CRC. 180 size_t infoBytesRemaining = section_length - 9 - program_info_length - 4; 181 182 while (infoBytesRemaining > 0) { 183 CHECK_GE(infoBytesRemaining, 5u); 184 185 unsigned streamType = br->getBits(8); 186 LOGV(" stream_type = 0x%02x", streamType); 187 188 MY_LOGV(" reserved = %u", br->getBits(3)); 189 190 unsigned elementaryPID = br->getBits(13); 191 LOGV(" elementary_PID = 0x%04x", elementaryPID); 192 193 MY_LOGV(" reserved = %u", br->getBits(4)); 194 195 unsigned ES_info_length = br->getBits(12); 196 LOGV(" ES_info_length = %u", ES_info_length); 197 CHECK((ES_info_length & 0xc00) == 0); 198 199 CHECK_GE(infoBytesRemaining - 5, ES_info_length); 200 201 #if 0 202 br->skipBits(ES_info_length * 8); // skip descriptors 203 #else 204 unsigned info_bytes_remaining = ES_info_length; 205 while (info_bytes_remaining >= 2) { 206 MY_LOGV(" tag = 0x%02x", br->getBits(8)); 207 208 unsigned descLength = br->getBits(8); 209 LOGV(" len = %u", descLength); 210 211 CHECK_GE(info_bytes_remaining, 2 + descLength); 212 213 br->skipBits(descLength * 8); 214 215 info_bytes_remaining -= descLength + 2; 216 } 217 CHECK_EQ(info_bytes_remaining, 0u); 218 #endif 219 220 ssize_t index = mStreams.indexOfKey(elementaryPID); 221 #if 0 // XXX revisit 222 CHECK_LT(index, 0); 223 mStreams.add(elementaryPID, 224 new Stream(this, elementaryPID, streamType)); 225 #else 226 if (index < 0) { 227 mStreams.add(elementaryPID, 228 new Stream(this, elementaryPID, streamType)); 229 } 230 #endif 231 232 infoBytesRemaining -= 5 + ES_info_length; 233 } 234 235 CHECK_EQ(infoBytesRemaining, 0u); 236 237 MY_LOGV(" CRC = 0x%08x", br->getBits(32)); 238 } 239 240 sp<MediaSource> ATSParser::Program::getSource(SourceType type) { 241 for (size_t i = 0; i < mStreams.size(); ++i) { 242 sp<MediaSource> source = mStreams.editValueAt(i)->getSource(type); 243 if (source != NULL) { 244 return source; 245 } 246 } 247 248 return NULL; 249 } 250 251 int64_t ATSParser::Program::convertPTSToTimestamp(uint64_t PTS) { 252 if (!mFirstPTSValid) { 253 mFirstPTSValid = true; 254 mFirstPTS = PTS; 255 PTS = 0; 256 } else if (PTS < mFirstPTS) { 257 PTS = 0; 258 } else { 259 PTS -= mFirstPTS; 260 } 261 262 return (PTS * 100) / 9; 263 } 264 265 //////////////////////////////////////////////////////////////////////////////// 266 267 ATSParser::Stream::Stream( 268 Program *program, unsigned elementaryPID, unsigned streamType) 269 : mProgram(program), 270 mElementaryPID(elementaryPID), 271 mStreamType(streamType), 272 mBuffer(new ABuffer(128 * 1024)), 273 mPayloadStarted(false), 274 mQueue(streamType == 0x1b 275 ? ElementaryStreamQueue::H264 : ElementaryStreamQueue::AAC) { 276 mBuffer->setRange(0, 0); 277 } 278 279 ATSParser::Stream::~Stream() { 280 } 281 282 void ATSParser::Stream::parse( 283 unsigned payload_unit_start_indicator, ABitReader *br) { 284 if (payload_unit_start_indicator) { 285 if (mPayloadStarted) { 286 // Otherwise we run the danger of receiving the trailing bytes 287 // of a PES packet that we never saw the start of and assuming 288 // we have a a complete PES packet. 289 290 flush(); 291 } 292 293 mPayloadStarted = true; 294 } 295 296 if (!mPayloadStarted) { 297 return; 298 } 299 300 size_t payloadSizeBits = br->numBitsLeft(); 301 CHECK((payloadSizeBits % 8) == 0); 302 303 CHECK_LE(mBuffer->size() + payloadSizeBits / 8, mBuffer->capacity()); 304 305 memcpy(mBuffer->data() + mBuffer->size(), br->data(), payloadSizeBits / 8); 306 mBuffer->setRange(0, mBuffer->size() + payloadSizeBits / 8); 307 } 308 309 void ATSParser::Stream::signalDiscontinuity(bool isASeek) { 310 LOGV("Stream discontinuity"); 311 mPayloadStarted = false; 312 mBuffer->setRange(0, 0); 313 314 mQueue.clear(); 315 316 if (isASeek) { 317 // This is only a "minor" discontinuity, we stay within the same 318 // bitstream. 319 320 mSource->clear(); 321 return; 322 } 323 324 if (mStreamType == 0x1b && mSource != NULL) { 325 // Don't signal discontinuities on audio streams. 326 mSource->queueDiscontinuity(); 327 } 328 } 329 330 void ATSParser::Stream::parsePES(ABitReader *br) { 331 unsigned packet_startcode_prefix = br->getBits(24); 332 333 LOGV("packet_startcode_prefix = 0x%08x", packet_startcode_prefix); 334 335 CHECK_EQ(packet_startcode_prefix, 0x000001u); 336 337 unsigned stream_id = br->getBits(8); 338 LOGV("stream_id = 0x%02x", stream_id); 339 340 unsigned PES_packet_length = br->getBits(16); 341 LOGV("PES_packet_length = %u", PES_packet_length); 342 343 if (stream_id != 0xbc // program_stream_map 344 && stream_id != 0xbe // padding_stream 345 && stream_id != 0xbf // private_stream_2 346 && stream_id != 0xf0 // ECM 347 && stream_id != 0xf1 // EMM 348 && stream_id != 0xff // program_stream_directory 349 && stream_id != 0xf2 // DSMCC 350 && stream_id != 0xf8) { // H.222.1 type E 351 CHECK_EQ(br->getBits(2), 2u); 352 353 MY_LOGV("PES_scrambling_control = %u", br->getBits(2)); 354 MY_LOGV("PES_priority = %u", br->getBits(1)); 355 MY_LOGV("data_alignment_indicator = %u", br->getBits(1)); 356 MY_LOGV("copyright = %u", br->getBits(1)); 357 MY_LOGV("original_or_copy = %u", br->getBits(1)); 358 359 unsigned PTS_DTS_flags = br->getBits(2); 360 LOGV("PTS_DTS_flags = %u", PTS_DTS_flags); 361 362 unsigned ESCR_flag = br->getBits(1); 363 LOGV("ESCR_flag = %u", ESCR_flag); 364 365 unsigned ES_rate_flag = br->getBits(1); 366 LOGV("ES_rate_flag = %u", ES_rate_flag); 367 368 unsigned DSM_trick_mode_flag = br->getBits(1); 369 LOGV("DSM_trick_mode_flag = %u", DSM_trick_mode_flag); 370 371 unsigned additional_copy_info_flag = br->getBits(1); 372 LOGV("additional_copy_info_flag = %u", additional_copy_info_flag); 373 374 MY_LOGV("PES_CRC_flag = %u", br->getBits(1)); 375 MY_LOGV("PES_extension_flag = %u", br->getBits(1)); 376 377 unsigned PES_header_data_length = br->getBits(8); 378 LOGV("PES_header_data_length = %u", PES_header_data_length); 379 380 unsigned optional_bytes_remaining = PES_header_data_length; 381 382 uint64_t PTS = 0, DTS = 0; 383 384 if (PTS_DTS_flags == 2 || PTS_DTS_flags == 3) { 385 CHECK_GE(optional_bytes_remaining, 5u); 386 387 CHECK_EQ(br->getBits(4), PTS_DTS_flags); 388 389 PTS = ((uint64_t)br->getBits(3)) << 30; 390 CHECK_EQ(br->getBits(1), 1u); 391 PTS |= ((uint64_t)br->getBits(15)) << 15; 392 CHECK_EQ(br->getBits(1), 1u); 393 PTS |= br->getBits(15); 394 CHECK_EQ(br->getBits(1), 1u); 395 396 LOGV("PTS = %llu", PTS); 397 // LOGI("PTS = %.2f secs", PTS / 90000.0f); 398 399 optional_bytes_remaining -= 5; 400 401 if (PTS_DTS_flags == 3) { 402 CHECK_GE(optional_bytes_remaining, 5u); 403 404 CHECK_EQ(br->getBits(4), 1u); 405 406 DTS = ((uint64_t)br->getBits(3)) << 30; 407 CHECK_EQ(br->getBits(1), 1u); 408 DTS |= ((uint64_t)br->getBits(15)) << 15; 409 CHECK_EQ(br->getBits(1), 1u); 410 DTS |= br->getBits(15); 411 CHECK_EQ(br->getBits(1), 1u); 412 413 LOGV("DTS = %llu", DTS); 414 415 optional_bytes_remaining -= 5; 416 } 417 } 418 419 if (ESCR_flag) { 420 CHECK_GE(optional_bytes_remaining, 6u); 421 422 br->getBits(2); 423 424 uint64_t ESCR = ((uint64_t)br->getBits(3)) << 30; 425 CHECK_EQ(br->getBits(1), 1u); 426 ESCR |= ((uint64_t)br->getBits(15)) << 15; 427 CHECK_EQ(br->getBits(1), 1u); 428 ESCR |= br->getBits(15); 429 CHECK_EQ(br->getBits(1), 1u); 430 431 LOGV("ESCR = %llu", ESCR); 432 MY_LOGV("ESCR_extension = %u", br->getBits(9)); 433 434 CHECK_EQ(br->getBits(1), 1u); 435 436 optional_bytes_remaining -= 6; 437 } 438 439 if (ES_rate_flag) { 440 CHECK_GE(optional_bytes_remaining, 3u); 441 442 CHECK_EQ(br->getBits(1), 1u); 443 MY_LOGV("ES_rate = %u", br->getBits(22)); 444 CHECK_EQ(br->getBits(1), 1u); 445 446 optional_bytes_remaining -= 3; 447 } 448 449 br->skipBits(optional_bytes_remaining * 8); 450 451 // ES data follows. 452 453 if (PES_packet_length != 0) { 454 CHECK_GE(PES_packet_length, PES_header_data_length + 3); 455 456 unsigned dataLength = 457 PES_packet_length - 3 - PES_header_data_length; 458 459 CHECK_GE(br->numBitsLeft(), dataLength * 8); 460 461 onPayloadData( 462 PTS_DTS_flags, PTS, DTS, br->data(), dataLength); 463 464 br->skipBits(dataLength * 8); 465 } else { 466 onPayloadData( 467 PTS_DTS_flags, PTS, DTS, 468 br->data(), br->numBitsLeft() / 8); 469 470 size_t payloadSizeBits = br->numBitsLeft(); 471 CHECK((payloadSizeBits % 8) == 0); 472 473 LOGV("There's %d bytes of payload.", payloadSizeBits / 8); 474 } 475 } else if (stream_id == 0xbe) { // padding_stream 476 CHECK_NE(PES_packet_length, 0u); 477 br->skipBits(PES_packet_length * 8); 478 } else { 479 CHECK_NE(PES_packet_length, 0u); 480 br->skipBits(PES_packet_length * 8); 481 } 482 } 483 484 void ATSParser::Stream::flush() { 485 if (mBuffer->size() == 0) { 486 return; 487 } 488 489 LOGV("flushing stream 0x%04x size = %d", mElementaryPID, mBuffer->size()); 490 491 ABitReader br(mBuffer->data(), mBuffer->size()); 492 parsePES(&br); 493 494 mBuffer->setRange(0, 0); 495 } 496 497 void ATSParser::Stream::onPayloadData( 498 unsigned PTS_DTS_flags, uint64_t PTS, uint64_t DTS, 499 const uint8_t *data, size_t size) { 500 LOGV("onPayloadData mStreamType=0x%02x", mStreamType); 501 502 CHECK(PTS_DTS_flags == 2 || PTS_DTS_flags == 3); 503 int64_t timeUs = mProgram->convertPTSToTimestamp(PTS); 504 505 status_t err = mQueue.appendData(data, size, timeUs); 506 CHECK_EQ(err, (status_t)OK); 507 508 sp<ABuffer> accessUnit; 509 while ((accessUnit = mQueue.dequeueAccessUnit()) != NULL) { 510 if (mSource == NULL) { 511 sp<MetaData> meta = mQueue.getFormat(); 512 513 if (meta != NULL) { 514 LOGV("created source!"); 515 mSource = new AnotherPacketSource(meta); 516 mSource->queueAccessUnit(accessUnit); 517 } 518 } else if (mQueue.getFormat() != NULL) { 519 // After a discontinuity we invalidate the queue's format 520 // and won't enqueue any access units to the source until 521 // the queue has reestablished the new format. 522 mSource->queueAccessUnit(accessUnit); 523 } 524 } 525 } 526 527 sp<MediaSource> ATSParser::Stream::getSource(SourceType type) { 528 if ((type == AVC_VIDEO && mStreamType == 0x1b) 529 || (type == MPEG2ADTS_AUDIO && mStreamType == 0x0f)) { 530 return mSource; 531 } 532 533 return NULL; 534 } 535 536 //////////////////////////////////////////////////////////////////////////////// 537 538 ATSParser::ATSParser() { 539 } 540 541 ATSParser::~ATSParser() { 542 } 543 544 void ATSParser::feedTSPacket(const void *data, size_t size) { 545 CHECK_EQ(size, kTSPacketSize); 546 547 ABitReader br((const uint8_t *)data, kTSPacketSize); 548 parseTS(&br); 549 } 550 551 void ATSParser::signalDiscontinuity(bool isASeek) { 552 for (size_t i = 0; i < mPrograms.size(); ++i) { 553 mPrograms.editItemAt(i)->signalDiscontinuity(isASeek); 554 } 555 } 556 557 void ATSParser::parseProgramAssociationTable(ABitReader *br) { 558 unsigned table_id = br->getBits(8); 559 LOGV(" table_id = %u", table_id); 560 CHECK_EQ(table_id, 0x00u); 561 562 unsigned section_syntax_indictor = br->getBits(1); 563 LOGV(" section_syntax_indictor = %u", section_syntax_indictor); 564 CHECK_EQ(section_syntax_indictor, 1u); 565 566 CHECK_EQ(br->getBits(1), 0u); 567 MY_LOGV(" reserved = %u", br->getBits(2)); 568 569 unsigned section_length = br->getBits(12); 570 LOGV(" section_length = %u", section_length); 571 CHECK((section_length & 0xc00) == 0); 572 573 MY_LOGV(" transport_stream_id = %u", br->getBits(16)); 574 MY_LOGV(" reserved = %u", br->getBits(2)); 575 MY_LOGV(" version_number = %u", br->getBits(5)); 576 MY_LOGV(" current_next_indicator = %u", br->getBits(1)); 577 MY_LOGV(" section_number = %u", br->getBits(8)); 578 MY_LOGV(" last_section_number = %u", br->getBits(8)); 579 580 size_t numProgramBytes = (section_length - 5 /* header */ - 4 /* crc */); 581 CHECK_EQ((numProgramBytes % 4), 0u); 582 583 for (size_t i = 0; i < numProgramBytes / 4; ++i) { 584 unsigned program_number = br->getBits(16); 585 LOGV(" program_number = %u", program_number); 586 587 MY_LOGV(" reserved = %u", br->getBits(3)); 588 589 if (program_number == 0) { 590 MY_LOGV(" network_PID = 0x%04x", br->getBits(13)); 591 } else { 592 unsigned programMapPID = br->getBits(13); 593 594 LOGV(" program_map_PID = 0x%04x", programMapPID); 595 596 mPrograms.push(new Program(programMapPID)); 597 } 598 } 599 600 MY_LOGV(" CRC = 0x%08x", br->getBits(32)); 601 } 602 603 void ATSParser::parsePID( 604 ABitReader *br, unsigned PID, 605 unsigned payload_unit_start_indicator) { 606 if (PID == 0) { 607 if (payload_unit_start_indicator) { 608 unsigned skip = br->getBits(8); 609 br->skipBits(skip * 8); 610 } 611 parseProgramAssociationTable(br); 612 return; 613 } 614 615 bool handled = false; 616 for (size_t i = 0; i < mPrograms.size(); ++i) { 617 if (mPrograms.editItemAt(i)->parsePID( 618 PID, payload_unit_start_indicator, br)) { 619 handled = true; 620 break; 621 } 622 } 623 624 if (!handled) { 625 LOGV("PID 0x%04x not handled.", PID); 626 } 627 } 628 629 void ATSParser::parseAdaptationField(ABitReader *br) { 630 unsigned adaptation_field_length = br->getBits(8); 631 if (adaptation_field_length > 0) { 632 br->skipBits(adaptation_field_length * 8); // XXX 633 } 634 } 635 636 void ATSParser::parseTS(ABitReader *br) { 637 LOGV("---"); 638 639 unsigned sync_byte = br->getBits(8); 640 CHECK_EQ(sync_byte, 0x47u); 641 642 MY_LOGV("transport_error_indicator = %u", br->getBits(1)); 643 644 unsigned payload_unit_start_indicator = br->getBits(1); 645 LOGV("payload_unit_start_indicator = %u", payload_unit_start_indicator); 646 647 MY_LOGV("transport_priority = %u", br->getBits(1)); 648 649 unsigned PID = br->getBits(13); 650 LOGV("PID = 0x%04x", PID); 651 652 MY_LOGV("transport_scrambling_control = %u", br->getBits(2)); 653 654 unsigned adaptation_field_control = br->getBits(2); 655 LOGV("adaptation_field_control = %u", adaptation_field_control); 656 657 unsigned continuity_counter = br->getBits(4); 658 LOGV("continuity_counter = %u", continuity_counter); 659 660 // LOGI("PID = 0x%04x, continuity_counter = %u", PID, continuity_counter); 661 662 if (adaptation_field_control == 2 || adaptation_field_control == 3) { 663 parseAdaptationField(br); 664 } 665 666 if (adaptation_field_control == 1 || adaptation_field_control == 3) { 667 parsePID(br, PID, payload_unit_start_indicator); 668 } 669 } 670 671 sp<MediaSource> ATSParser::getSource(SourceType type) { 672 for (size_t i = 0; i < mPrograms.size(); ++i) { 673 sp<MediaSource> source = mPrograms.editItemAt(i)->getSource(type); 674 675 if (source != NULL) { 676 return source; 677 } 678 } 679 680 return NULL; 681 } 682 683 } // namespace android 684
