internal static SharedFile PrepareDownloadFile(SharedFileMetaData metaData, BitChat chat, BitChat.Peer seeder, BitChatProfile profile, SynchronizationContext syncCxt)
{
//check if file already exists
lock (_sharedFiles)
{
SharedFile sharedFile;
if (_sharedFiles.ContainsKey(metaData.FileID))
{
sharedFile = _sharedFiles[metaData.FileID];
}
else
{
sharedFile = new SharedFile(null, metaData, new FileBlockState[metaData.BlockHash.Length], 0, syncCxt);
sharedFile._profile = profile;
_sharedFiles.Add(metaData.FileID, sharedFile);
}
sharedFile.AddChat(chat);
sharedFile.AddSeeder(seeder);
return(sharedFile);
}
}
private SharedFile(FileStream fS, SharedFileMetaData metaData, FileBlockState[] blockAvailable, int availableBlocksCount, SynchronizationContext syncCxt)
{
_fileStream = fS;
_metaData = metaData;
_blockAvailable = blockAvailable;
_availableBlocksCount = availableBlocksCount;
_syncCxt = syncCxt;
_isComplete = (_blockAvailable.Length == _availableBlocksCount);
}
internal static SharedFile LoadFile(string filePath, SharedFileMetaData metaData, FileBlockState[] blockAvailable, bool isPaused, BitChat chat, SynchronizationContext syncCxt)
{
//check if file already shared
lock (_sharedFiles)
{
SharedFile sharedFile;
if (_sharedFiles.ContainsKey(metaData.FileID))
{
sharedFile = _sharedFiles[metaData.FileID];
}
else
{
int availableBlocksCount = 0;
for (int i = 0; i < blockAvailable.Length; i++)
{
if (blockAvailable[i] == FileBlockState.Available)
{
availableBlocksCount++;
}
}
FileStream fS;
if (blockAvailable.Length == availableBlocksCount)
{
fS = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read);
}
else
{
fS = new FileStream(filePath, FileMode.Open, FileAccess.ReadWrite);
}
sharedFile = new SharedFile(fS, metaData, blockAvailable, availableBlocksCount, syncCxt);
sharedFile._state = SharedFileState.Paused;
_sharedFiles.Add(metaData.FileID, sharedFile);
if (!isPaused)
{
sharedFile.Start();
}
}
sharedFile.AddChat(chat);
return(sharedFile);
}
}
internal static SharedFile ShareFile(string filePath, string hashAlgo, BitChat chat, SynchronizationContext syncCxt)
{
FileStream fS = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read);
HashAlgorithm hash = HashAlgorithm.Create(hashAlgo);
int hashSize = hash.HashSize / 8;
//calculate block size
int blockSize;
{
//header size = ChatMessage header + FileAdvertisement header
int packetHeaderSize = (20 + 1 + 2) + (1 + 1 + 255 + 1 + 255 + 8 + 8 + 4 + 1 + 10 + 1);
int packetDataSize = 65536 - packetHeaderSize;
int totalBlocksPossible = packetDataSize / hashSize;
blockSize = Convert.ToInt32(fS.Length / totalBlocksPossible);
if (blockSize <= short.MaxValue)
{
blockSize = short.MaxValue + 1;
}
else
{
//align to 16 bytes
int remainder = blockSize % 16;
if (remainder > 0)
{
blockSize = blockSize - remainder + 16;
}
}
}
//compute block hashes and file info hash
int totalBlocks = Convert.ToInt32(Math.Ceiling(Convert.ToDouble((double)fS.Length / blockSize)));
byte[][] blockHash = new byte[totalBlocks][];
FileBlockState[] blockAvailable = new FileBlockState[totalBlocks];
//init
for (int i = 0; i < totalBlocks; i++)
{
long offset = i * blockSize;
long length = blockSize;
if ((offset + length) > fS.Length)
{
length = fS.Length - offset;
}
blockHash[i] = hash.ComputeHash(new OffsetStream(fS, offset, length));
blockAvailable[i] = FileBlockState.Available;
}
//get file meta data
SharedFileMetaData metaData = new SharedFileMetaData(Path.GetFileName(fS.Name), WebUtilities.GetContentType(fS.Name), File.GetLastWriteTimeUtc(fS.Name), fS.Length, blockSize, hashAlgo, blockHash);
//check if file already shared
lock (_sharedFiles)
{
SharedFile sharedFile;
if (_sharedFiles.ContainsKey(metaData.FileID))
{
sharedFile = _sharedFiles[metaData.FileID];
if (sharedFile._isComplete)
{
fS.Dispose();
}
else
{
sharedFile.Remove(chat);
sharedFile = new SharedFile(fS, metaData, blockAvailable, blockAvailable.Length, syncCxt);
sharedFile.StartSharing();
_sharedFiles.Add(metaData.FileID, sharedFile);
}
}
else
{
sharedFile = new SharedFile(fS, metaData, blockAvailable, blockAvailable.Length, syncCxt);
sharedFile.StartSharing();
_sharedFiles.Add(metaData.FileID, sharedFile);
}
sharedFile.AddChat(chat);
return(sharedFile);
}
}
