private static RC readMasterJournal(VirtualFile pJrnl, byte[] zMaster, uint nMaster)
{
int len = 0; // Length in bytes of master journal name
long szJ = 0; // Total size in bytes of journal file pJrnl
uint cksum = 0; // MJ checksum value read from journal
zMaster[0] = 0;
var aMagic = new byte[8]; // A buffer to hold the magic header
RC rc;
if (RC.OK != (rc = pJrnl.FileSize(ref szJ)) ||
szJ < 16 ||
RC.OK != (rc = pJrnl.ReadByte((int)(szJ - 16), ref len)) ||
len >= nMaster ||
RC.OK != (rc = pJrnl.ReadByte(szJ - 12, ref cksum)) ||
RC.OK != (rc = pJrnl.Read(aMagic, 8, szJ - 8)) ||
ArrayEx.Compare(aMagic, aJournalMagic, 8) != 0 ||
RC.OK != (rc = pJrnl.Read(zMaster, len, (long)(szJ - 16 - len))))
{
return(rc);
}
// See if the checksum matches the master journal name
for (var u = 0; u < len; u++)
{
cksum -= zMaster[u];
}
if (cksum != 0)
{
// If the checksum doesn't add up, then one or more of the disk sectors containing the master journal filename is corrupted. This means
// definitely roll back, so just return SQLITE.OK and report a (nul) master-journal filename.
len = 0;
}
if (len == 0)
{
zMaster[0] = 0;
}
return(RC.OK);
}