public Par2RecoverySet ReadRecoverySet()
{
//int readsize = (int)Math.Min((long)buffer_size, fileInfo.Length);
int readsize = (int)fileInfo.Length;
byte[] bytes = ReadBytes(readsize);
int index = 0;
int file_offset = 0;
//while (BaseStream.Position < BaseStream.Length)
{
do
{
index = ToolKit.IndexOf(bytes, packet_magic, index);
if (index < 0)
{
break;
}
PacketHeader header = PacketHeader.Create(bytes, index);
switch (GetPacketType(header.type))
{
case PacketType.CreatorPacket:
CreatorPacket createPacket = CreatorPacket.Create(header, bytes, index + header.GetSize());
par2RecoverySet.AddCreatorPacket(createPacket);
index += createPacket.GetSize() - header.GetSize();
break;
case PacketType.DescriptionPacket:
FileDescriptionPacket descPacket = FileDescriptionPacket.Create(header, bytes, index + header.GetSize());
par2RecoverySet.AddDescriptionPacket(descPacket);
index += descPacket.GetSize() - header.GetSize();
break;
case PacketType.MainPacket:
MainPacket mainPacket = MainPacket.Create(header, bytes, index + header.GetSize());
par2RecoverySet.AddMainPacket(mainPacket);
index += mainPacket.GetSize() - header.GetSize();
break;
case PacketType.RecoveryPacket:
RecoveryPacket recoveryPacket = RecoveryPacket.Create(header, bytes, index + header.GetSize(), fileInfo.FullName, file_offset);
par2RecoverySet.AddRecoveryPacket(recoveryPacket);
index += recoveryPacket.GetSize() - header.GetSize();
break;
case PacketType.VerificationPacket:
FileVerificationPacket verPacket = FileVerificationPacket.Create(header, bytes, index + header.GetSize());
par2RecoverySet.AddVerificationPacket(verPacket);
index += verPacket.GetSize() - header.GetSize();
break;
case PacketType.Unknown:
// Unknown packettype
break;
}
} while (index >= 0);
index = 0;
readsize = (int)Math.Min((long)buffer_size, BaseStream.Length - BaseStream.Position);
file_offset += bytes.Length;
bytes = ReadBytes(readsize);
}
return(par2RecoverySet);
}
// Open the source file, compute the MD5 Hash of the whole file and the first
// 16k of the file, and then compute the FileId and store the results
// in a file description packet and a file verification packet.
public bool Open(string filename, ulong blocksize, bool deferhashcomputation)
{
// Get the filename and filesize
targetfilename = filename;
filesize = (ulong)new FileInfo(filename).Length;
// Work out how many blocks the file will be sliced into
blockcount = (uint)((filesize + blocksize - 1) / blocksize);
// Determine what filename to record in the PAR2 files
parfilename = Path.GetFileName(filename);
// Create the Description and Verification packets
FileDescriptionPacket = Packets.FileDescriptionPacket.Create(parfilename, filesize);
FileVerificationPacket = Packets.FileVerificationPacket.Create(blockcount);
// Create the diskfile object
targetfile = new DiskFile();
// Open the source file
if (!targetfile.Open(targetfilename, filesize))
{
return(false);
}
// Do we want to defer the computation of the full file hash, and
// the block crc and hashes. This is only permitted if there
// is sufficient memory available to create all recovery blocks
// in one pass of the source files (i.e. chunksize == blocksize)
if (deferhashcomputation)
{
// Initialise a buffer to read the first 16k of the source file
uint buffersize = Math.Min((uint)filesize, 16 * 1024);
byte[] buffer = new byte[buffersize];
// Read the data from the file
if (!targetfile.Read(0, buffer, buffersize))
{
targetfile.Close();
return(false);
}
// Compute the hash of the data read from the file
// Store the hash in the descriptionpacket and compute the file id
MD5 md5Hasher = MD5.Create();
FileDescriptionPacket.hash16k = md5Hasher.ComputeHash(buffer);
// Compute the fileid and store it in the verification packet.
FileDescriptionPacket.ComputeFileId();
FileVerificationPacket.fileid = (byte[])FileDescriptionPacket.fileid.Clone();
//// Allocate an MD5 context for computing the file hash
//// during the recovery data generation phase
contextfull = MD5.Create();
//contextfull = new MD5Context;
}
else
{
// Compute 16k MD5 hash
using (BinaryReader br = new BinaryReader(new FileStream(filename, FileMode.Open, FileAccess.Read, FileShare.Read)))
{
MD5 md5Hasher = MD5.Create();
byte[] buffer16k = br.ReadBytes(16 * 1024);
FileDescriptionPacket.hash16k = md5Hasher.ComputeHash(buffer16k);
}
// Compute the fileid and store it in the verification packet.
FileDescriptionPacket.ComputeFileId();
FileVerificationPacket.fileid = (byte[])FileDescriptionPacket.fileid.Clone();
// Compute full file MD5 hash & block CRC32 and MD5 hashes
//long readSize = 5 * (long)blocksize;
long readSize = (long)blocksize;
long fileSize = new FileInfo(filename).Length;
long nbSteps = fileSize / readSize;
long remaining = fileSize % readSize;
uint blocknumber = 0;
// TODO : switch to async filestream
using (BinaryReader br = new BinaryReader(new FileStream(filename, FileMode.Open, FileAccess.Read, FileShare.Read)))
{
MD5 md5FullHasher = MD5.Create();
MD5 md5Hasher = MD5.Create();
//FastCRC32.FastCRC32 crc32 = new FastCRC32.FastCRC32(blocksize);
FastCRC32.FastCRC32 crc32 = FastCRC32.FastCRC32.GetCRC32Instance(blocksize);
byte[] blockHash = new byte[16];
uint blockCRC32 = 0;
for (int i = 0; i < nbSteps + 1; ++i)
{
byte[] buffer = br.ReadBytes((int)(i == nbSteps ? remaining : readSize));
// Global MD5 hash
if (i == nbSteps)
{
md5FullHasher.TransformFinalBlock(buffer, 0, buffer.Length);
}
else
{
md5FullHasher.TransformBlock(buffer, 0, buffer.Length, null, 0);
}
//for (uint j = 0; j < 5; ++j)
//{
// Block MD5 hash & CRC32
uint length = (uint)blocksize;
//if (i == nbSteps && j == 4)
//if (i == nbSteps && (buffer.Length - (uint)(j * blocksize)) < (int)blocksize)
if (i == nbSteps && remaining != 0)
{
// We need arry padding since calculation **MUST** always be done on blocksize-length buffers
byte[] smallBuffer = buffer;
buffer = new byte[blocksize];
Buffer.BlockCopy(smallBuffer, 0, buffer, 0, smallBuffer.Length);
}
blockCRC32 = crc32.CRCUpdateBlock(0xFFFFFFFF, (uint)blocksize, buffer, 0) ^ 0xFFFFFFFF;
blockHash = md5Hasher.ComputeHash(buffer, 0, (int)blocksize);
//Console.WriteLine("blocknumber:{0},hash:{1},crc32:{2}", blocknumber, blockHash, blockCRC32);
FileVerificationPacket.SetBlockHashAndCRC(blocknumber++, blockHash, blockCRC32);
//}
}
FileDescriptionPacket.hashfull = md5FullHasher.Hash;
}
}
return(true);
}
