private List <uint> ReadFileSectorOffsetTable
(
[NotNull] BlockTableEntry fileBlockEntry,
uint fileKey = 0
)
{
var sectorOffsets = new List <uint>();
if (fileBlockEntry.IsEncrypted())
{
MPQCrypt.DecryptSectorOffsetTable(_archiveReader, ref sectorOffsets, fileBlockEntry.GetBlockSize(), fileKey - 1);
}
else
{
// As protection against corrupt or maliciously zeroed blocks or corrupt blocks,
// reading will be escaped early if the sector offset table is not consistent.
// Should the total size as predicted by the sector offset table go beyond the total
// block size, or if an offset is not unique, no file will be read and the function will
// escape early.
uint sectorOffset = 0;
while (sectorOffset != fileBlockEntry.GetBlockSize())
{
sectorOffset = _archiveReader.ReadUInt32();
// Should the resulting sector offset be less than the previous data, then the data is inconsistent
// and no table should be returned.
if (sectorOffsets.LastOrDefault() > sectorOffset)
{
throw new InvalidFileSectorTableException(
"The read offset in the sector table was less than the previous offset.");
}
// Should the resulting sector offset be greater than the total block size, then the data is
// inconsistent and no file should be returned.
if (sectorOffset > fileBlockEntry.GetBlockSize())
{
throw new InvalidFileSectorTableException(
"The read offset in the sector table was greater than the total size of the data block.");
}
// Should the resulting sector not be unique, something is wrong and no table should be returned.
if (sectorOffsets.Contains(sectorOffset))
{
throw new InvalidFileSectorTableException(
"The read offset in the sector table was not unique to the whole table.");
}
// The offset should be valid, so add it to the table.
sectorOffsets.Add(sectorOffset);
}
}
return(sectorOffsets);
}
/// <summary>
/// Extracts a file which is stored as a single unit in the archive.
/// </summary>
/// <param name="fileBlockEntry">The block entry of the file.</param>
/// <param name="fileKey">The encryption key of the file.</param>
/// <returns>The complete file data.</returns>
private byte[] ExtractSingleUnitFile(BlockTableEntry fileBlockEntry, uint fileKey)
{
// This file does not use sectoring, but may still be encrypted or compressed.
byte[] fileData = this.ArchiveReader.ReadBytes((int)fileBlockEntry.GetBlockSize());
if (fileBlockEntry.IsEncrypted())
{
// Decrypt the block
fileData = MPQCrypt.DecryptData(fileData, fileKey);
}
// Decompress the sector if neccesary
if (fileBlockEntry.IsCompressed())
{
fileData = Compression.DecompressSector(fileData, fileBlockEntry.Flags);
}
return(fileData);
}