ssize_t MyVorbisExtractor::readPage(off64_t offset, Page *page) {
uint8_t header[27];
ssize_t n;
if ((n = mSource->readAt(offset, header, sizeof(header)))
< (ssize_t)sizeof(header)) {
if (n < 0) {
return n;
} else if (n == 0) {
return ERROR_END_OF_STREAM;
} else {
return ERROR_IO;
}
}
if (memcmp(header, "OggS", 4)) {
return ERROR_MALFORMED;
}
if (header[4] != 0) {
// Wrong version.
return ERROR_UNSUPPORTED;
}
page->mFlags = header[5];
if (page->mFlags & ~7) {
// Only bits 0-2 are defined in version 0.
return ERROR_MALFORMED;
}
page->mGranulePosition = U64LE_AT(&header[6]);
page->mSerialNo = U32LE_AT(&header[14]);
page->mPageNo = U32LE_AT(&header[18]);
page->mNumSegments = header[26];
if (mSource->readAt(
offset + sizeof(header), page->mLace, page->mNumSegments)
< (ssize_t)page->mNumSegments) {
return ERROR_IO;
}
size_t totalSize = 0;;
for (size_t i = 0; i < page->mNumSegments; ++i) {
totalSize += page->mLace[i];
}
return sizeof(header) + page->mNumSegments + totalSize;
}
ssize_t MyVorbisExtractor::readPage(off64_t offset, Page *page) {
uint8_t header[27];
ssize_t n;
if ((n = mSource->readAt(offset, header, sizeof(header)))
< (ssize_t)sizeof(header)) {
LOGV("failed to read %d bytes at offset 0x%016llx, got %ld bytes",
sizeof(header), offset, n);
if (n < 0) {
return n;
} else if (n == 0) {
return ERROR_END_OF_STREAM;
} else {
return ERROR_IO;
}
}
if (memcmp(header, "OggS", 4)) {
return ERROR_MALFORMED;
}
if (header[4] != 0) {
// Wrong version.
return ERROR_UNSUPPORTED;
}
page->mFlags = header[5];
if (page->mFlags & ~7) {
// Only bits 0-2 are defined in version 0.
return ERROR_MALFORMED;
}
page->mGranulePosition = U64LE_AT(&header[6]);
#if 0
printf("granulePosition = %llu (0x%llx)\n",
page->mGranulePosition, page->mGranulePosition);
#endif
page->mSerialNo = U32LE_AT(&header[14]);
page->mPageNo = U32LE_AT(&header[18]);
page->mNumSegments = header[26];
if (mSource->readAt(
offset + sizeof(header), page->mLace, page->mNumSegments)
< (ssize_t)page->mNumSegments) {
return ERROR_IO;
}
size_t totalSize = 0;;
for (size_t i = 0; i < page->mNumSegments; ++i) {
totalSize += page->mLace[i];
}
#if 0
String8 tmp;
for (size_t i = 0; i < page->mNumSegments; ++i) {
char x[32];
sprintf(x, "%s%u", i > 0 ? ", " : "", (unsigned)page->mLace[i]);
tmp.append(x);
}
LOGV("%c %s", page->mFlags & 1 ? '+' : ' ', tmp.string());
#endif
return sizeof(header) + page->mNumSegments + totalSize;
}
int main(int argc, char* argv[])
{
int retval = 1;
int fdout = -1;
uint8_t* pIn = NULL;
uint8_t* pOut = NULL;
if (argc < 3 || argc > 3)
{
fprintf(stderr, "Usage: mfrafix infile outfile\n");
return 1;
}
int fdin = open(argv[1], O_RDONLY);
if (fdin < 0)
{
fprintf(stderr, "Error: failed to open '%s' for reading\n", argv[1]);
goto cleanup;
}
off_t length = lseek(fdin, 0, SEEK_END);
lseek(fdin, 0, SEEK_SET);
debug("Length of in file: %d\n", (int)length);
pIn = mmap(NULL, length, PROT_READ, MAP_SHARED, fdin, 0);
if (pIn == NULL)
{
fprintf(stderr, "Error: mmap failed with error %d - '%s'\n", errno, strerror(errno));
goto cleanup;
}
// Look for the mfra by checking the last four bytes in the mfro
// For now we assume that the mfra is at the end of the file...
uint32_t mfro = U32_AT(pIn + length - sizeof(uint32_t));
uint8_t* pMFRA = pIn + length - mfro;
uint32_t mfraSize = U32_AT(pMFRA);
uint8_t* pMFRAEnd = pMFRA + mfraSize;
SKIP(pMFRA, 4); // Size processed
debug("mfro offset %x\n", mfro);
debug("MFRA size %x\n", mfraSize);
debug("MFRA box '%08x'\n", U32_AT(pMFRA));
if (FOURCC('m', 'f', 'r', 'a') != U32_AT(pMFRA))
{
fprintf(stderr, "Error: The mfra box was not found\n");
goto cleanup;
}
SKIP(pMFRA, 4); // Type processed
debug("Found mfra\n");
TFRAEntry* tfraEntries = NULL;
int numTFRAEntries = 0;
while (pMFRA < pMFRAEnd)
{
uint32_t boxSize = U32_AT(pMFRA);
SKIP(pMFRA, 4); // Size read
debug("Box size %x\n", boxSize);
debug("Box type '%08x'\n", U32_AT(pMFRA));
switch (U32_AT(pMFRA))
{
case FOURCC('t', 'f', 'r', 'a'):
debug("Found tfra\n");
SKIP(pMFRA, 4); // Type processed
SKIP(pMFRA, 4); // Ignore version and flags
uint32_t trackId = U32_AT(pMFRA);
SKIP(pMFRA, 4); // trackId processed
uint32_t tmp = U32LE_AT(pMFRA);
int trafNum = (tmp >> 4) & 0x3;
int trunNum = (tmp >> 2) & 0x3;
int sampleNum = (tmp >> 0) & 0x3;
SKIP(pMFRA, 4); // Traf, trun and samples processed
debug("trackId %d\ntraf %d trun %d sample %d\n", trackId, trafNum, trunNum, sampleNum);
uint32_t numEntry = U32_AT(pMFRA);
SKIP(pMFRA, 4); // numEntry processed
debug("numEntry: %d\n", numEntry);
tfraEntries = realloc(tfraEntries, sizeof(TFRAEntry) * (numEntry + numTFRAEntries));
if (tfraEntries == NULL)
{
fprintf(stderr, "Error: Failed to allocate memory for tfra entries\n");
goto cleanup;
}
for (int i = numTFRAEntries; i < (numEntry + numTFRAEntries); ++i)
{
tfraEntries[i].trackId = trackId;
debug("time: %lx\n", U64_AT(pMFRA));
tfraEntries[i].time = U64_AT(pMFRA);
SKIP(pMFRA, 8); // Skip uint64, time
debug("moof: %lx\n", U64_AT(pMFRA));
tfraEntries[i].moof = U64_AT(pMFRA);
tfraEntries[i].moofOffset = (pMFRA - pIn);
SKIP(pMFRA, 8); // Skip uint64, moof offset
int skip = trafNum + 1 + trunNum + 1 + sampleNum + 1;
pMFRA = pMFRA + skip;
}
// Update here as we use numTFRAEntries as offset when indexing the array
numTFRAEntries += numEntry;
break;
case FOURCC('m', 'f', 'r', 'o'):
debug("found mfro box\n");
pMFRA = pMFRA + boxSize - sizeof(uint32_t);
break;
default:
fprintf(stderr, "Error: Unknown box found '%08x'\n", U32_AT(pMFRA));
goto cleanup;
}
}
if (numTFRAEntries == 0)
{
fprintf(stderr, "Error: No TFRA entries found.\n");
goto cleanup;
}
// Start by checking if the first entry points to a moof
uint8_t* p1 = pIn + tfraEntries[0].moof;
if (FOURCC('m', 'o', 'o', 'f') != U32_AT(p1 + 4))
{
uint32_t offset = U32_AT(p1);
fprintf(stdout, "We found '%08x' instead of moof, try to correct with offset %x\n", U32_AT(p1 + 4), offset);
for (int i = 0; i < numTFRAEntries; ++i)
{
debug("p = %x\n", tfraEntries[i].moof);
uint8_t *p = pIn + tfraEntries[i].moof + offset;
if (U32_AT(p + 4) == FOURCC('m', 'o', 'o', 'f'))
debug("Found moof\n");
else
{
debug("Found '%08x'\n", U32_AT(p + 4));
goto cleanup;
}
}
debug("Open output file\n");
fdout = open(argv[2], O_RDWR | O_CREAT | O_TRUNC);
if (fdout < 0)
{
fprintf(stderr, "Error: failed to open '%s' for writing\n", argv[2]);
goto cleanup;
}
debug("Set size of out file\n");
lseek(fdout, length - 1, SEEK_SET);
write(fdout, "", 1);
debug("Call mmap for output file\n");
pOut = mmap(NULL, length, PROT_WRITE | PROT_READ, MAP_SHARED, fdout, 0);
if (pOut == NULL)
{
fprintf(stderr, "Error: mmap failed with error %d - '%s'\n", errno, strerror(errno));
goto cleanup;
}
debug("Do memcpy\n");
memcpy(pOut, pIn, length);
debug("Update moof references\n");
for (int i = 0; i < numTFRAEntries; ++i)
{
debug("p = %x\n", tfraEntries[i].moof);
debug("offset = %x\n", offset);
debug("out = %x\n", tfraEntries[i].moof + offset);
uint64_t *p = (uint64_t*)(pOut + tfraEntries[i].moofOffset);
(*p) = TO_U64(tfraEntries[i].moof + offset);
}
debug("Do msync\n");
msync(pOut, length, MS_SYNC);
fprintf(stdout, "Fixed all entries...\n");
}
else
{
fprintf(stdout, "The first moof reference is correct, assume the rest are as well and exit\n");
}
retval = 0;
cleanup:
if (tfraEntries != NULL)
free(tfraEntries);
if (fdout >= 0)
close(fdout);
if (pOut != NULL)
munmap(pOut, length);
if (pIn != NULL)
munmap(pIn, length);
if (fdin >= 0)
close(fdin);
return retval;
}
