public static bool Cache(StreamBlock block)
{
if (!block.Header.HasFlag(StreamHeader.CACHEABLE))
{
throw new InvalidOperationException("Cannot cache block " + block + ", is not marked as CACHEABLE!");
}
CacheItem cacheItem = new CacheItem(block.ToString(), block);
CacheItemPolicy policy = new CacheItemPolicy();
policy.AbsoluteExpiration = DateTimeOffset.Now.Add(_expiration);
CacheItem existing = _cache.AddOrGetExisting(cacheItem, policy);
if (existing != null)
{
return(false);
}
return(true);
}
protected static StreamBlock BuildBlock(byte[] rawBlock)
{
StreamHeader header = (StreamHeader)rawBlock.Skip(HEADER_OFFSET).Take(HEADER_LENGTH).First();
short streamId = BitConverter.ToInt16(rawBlock.Skip(STREAM_ID_OFFSET).Take(STREAM_ID_LENGTH).ToArray(), 0);
byte[] checksum = rawBlock.Skip(CHECKSUM_OFFSET).Take(CHECKSUM_LENGTH).ToArray();
if (header.HasFlag(StreamHeader.CACHEABLE))
{
StreamBlock block = StreamCache.GetCache(checksum);
if (block != null)
{
return(block);
}
}
MD5 md5 = MD5.Create();
byte[] data = rawBlock.Skip(DATA_OFFSET).ToArray();
byte[] calculatedChecksum = md5.ComputeHash(data);
if (!calculatedChecksum.SequenceEqual(checksum))
{
throw new InvalidDataException("Checksums did not match when checking data in BuildBlock routine! Calculated: " + BitConverter.ToString(calculatedChecksum) + " | Stored: " + BitConverter.ToString(checksum));
}
if (header.HasFlag(StreamHeader.GZIPPED))
{
using (GZipStream stream = new GZipStream(new MemoryStream(data), CompressionMode.Decompress))
{
byte[] buffer = new byte[256];
using (MemoryStream memory = new MemoryStream())
{
int count = 0;
do
{
count = stream.Read(buffer, 0, buffer.Length);
if (count > 0)
{
memory.Write(buffer, 0, count);
}
}while (count > 0);
data = memory.ToArray();
}
}
}
return(new StreamBlock(streamId, header, checksum, data));
}
