status_t MyVorbisExtractor::seekToOffset(off64_t offset) {
if (mFirstDataOffset >= 0 && offset < mFirstDataOffset) {
// Once we know where the actual audio data starts (past the headers)
// don't ever seek to anywhere before that.
offset = mFirstDataOffset;
}
off64_t pageOffset;
status_t err = findNextPage(offset, &pageOffset);
if (err != OK) {
return err;
}
// We found the page we wanted to seek to, but we'll also need
// the page preceding it to determine how many valid samples are on
// this page.
findPrevGranulePosition(pageOffset, &mPrevGranulePosition);
mOffset = pageOffset;
mCurrentPageSize = 0;
mFirstPacketInPage = true;
mCurrentPageSamples = 0;
mCurrentPage.mNumSegments = 0;
mNextLaceIndex = 0;
// XXX what if new page continues packet from last???
return OK;
}
// Given the offset of the "current" page, find the page immediately preceding
// it (if any) and return its granule position.
// To do this we back up from the "current" page's offset until we find any
// page preceding it and then scan forward to just before the current page.
status_t MyVorbisExtractor::findPrevGranulePosition(
off64_t pageOffset, uint64_t *granulePos) {
*granulePos = 0;
off64_t prevPageOffset = 0;
off64_t prevGuess = pageOffset;
for (;;) {
if (prevGuess >= 5000) {
prevGuess -= 5000;
} else {
prevGuess = 0;
}
ALOGV("backing up %lld bytes", pageOffset - prevGuess);
status_t err = findNextPage(prevGuess, &prevPageOffset);
if (err != OK) {
#ifdef MTK_AOSP_ENHANCEMENT
if((prevGuess == 0) || ((prevGuess + 5000 * 20) < pageOffset))
return err;
else
continue;
#else
return err;
#endif
}
if (prevPageOffset < pageOffset || prevGuess == 0) {
break;
}
}
if (prevPageOffset == pageOffset) {
// We did not find a page preceding this one.
return UNKNOWN_ERROR;
}
ALOGV("prevPageOffset at %lld, pageOffset at %lld",
prevPageOffset, pageOffset);
for (;;) {
Page prevPage;
ssize_t n = readPage(prevPageOffset, &prevPage);
if (n <= 0) {
return (status_t)n;
}
prevPageOffset += n;
if (prevPageOffset == pageOffset) {
*granulePos = prevPage.mGranulePosition;
return OK;
}
}
}
// Given the offset of the "current" page, find the page immediately preceding
// it (if any) and return its granule position.
// To do this we back up from the "current" page's offset until we find any
// page preceding it and then scan forward to just before the current page.
status_t MyVorbisExtractor::findPrevGranulePosition(
off64_t pageOffset, uint64_t *granulePos) {
*granulePos = 0;
off64_t prevPageOffset = 0;
off64_t prevGuess = pageOffset;
for (;;) {
if (prevGuess >= 5000) {
prevGuess -= 5000;
} else {
prevGuess = 0;
}
status_t err = findNextPage(prevGuess, &prevPageOffset);
if (err != OK) {
return err;
}
if (prevPageOffset < pageOffset || prevGuess == 0) {
break;
}
}
if (prevPageOffset == pageOffset) {
// We did not find a page preceding this one.
return UNKNOWN_ERROR;
}
for (;;) {
Page prevPage;
ssize_t n = readPage(prevPageOffset, &prevPage);
if (n <= 0) {
return (status_t)n;
}
prevPageOffset += n;
if (prevPageOffset == pageOffset) {
*granulePos = prevPage.mGranulePosition;
return OK;
}
}
}
status_t MyVorbisExtractor::findGranulePositionofPage(off64_t offset,uint64_t *granulePositionofPage)
{
if (mFirstDataOffset >= 0 && offset < mFirstDataOffset) {
// Once we know where the actual audio data starts (past the headers)
// don't ever seek to anywhere before that.
offset = mFirstDataOffset;
}
if(((uint64_t)offset) == mFileSize)
{
findPrevGranulePosition(mFileSize, granulePositionofPage);
if((*granulePositionofPage) < 0xFFFFFFFFFFFF)
return OK;
else
return UNKNOWN_ERROR;
}
off64_t pageOffset;
status_t err = findNextPage_l(offset, &pageOffset);
if (err != OK) {
err = findNextPage(offset, &pageOffset);
if((err == OK) && (offset == pageOffset))
{
Page page;
readPage(offset, &page);
*granulePositionofPage = page.mGranulePosition;
}
else
findPrevGranulePosition(mFileSize, granulePositionofPage);
if((*granulePositionofPage) < 0xFFFFFFFFFFFF)
return OK;
else
return UNKNOWN_ERROR;
}
// We found the page we wanted to seek to, but we'll also need
// the page preceding it to determine how many valid samples are on
// this page.
findPrevGranulePosition(pageOffset, granulePositionofPage);
if((*granulePositionofPage) < 0xFFFFFFFFFFFF)
return OK;
else
return UNKNOWN_ERROR;
}
// Given the offset of the "current" page, find the page immediately preceding
// it (if any) and return its granule position.
// To do this we back up from the "current" page's offset until we find any
// page preceding it and then scan forward to just before the current page.
uint64_t MyVorbisExtractor::findPrevGranulePosition(off_t pageOffset) {
off_t prevPageOffset = 0;
off_t prevGuess = pageOffset;
for (;;) {
if (prevGuess >= 5000) {
prevGuess -= 5000;
} else {
prevGuess = 0;
}
LOGV("backing up %ld bytes", pageOffset - prevGuess);
CHECK_EQ(findNextPage(prevGuess, &prevPageOffset), (status_t)OK);
if (prevPageOffset < pageOffset || prevGuess == 0) {
break;
}
}
if (prevPageOffset == pageOffset) {
// We did not find a page preceding this one.
return 0;
}
LOGV("prevPageOffset at %ld, pageOffset at %ld", prevPageOffset, pageOffset);
for (;;) {
Page prevPage;
ssize_t n = readPage(prevPageOffset, &prevPage);
if (n <= 0) {
return 0;
}
prevPageOffset += n;
if (prevPageOffset == pageOffset) {
return prevPage.mGranulePosition;
}
}
}