private static byte[] InternalCompress(byte[] bytes, bool useHeader, CompressionImplementation compressionImplementation)
{
switch (compressionImplementation)
{
case CompressionImplementation.ManagedZLib:
return(ManagedZLibWrapper.Compress(bytes, zLibCompressionAmount, useHeader));
default:
throw new ApplicationException(string.Format("Unknown compression implementation {0}", compressionImplementation));
}
}
private static byte[] InternalDecompress(byte[] bytes, bool useHeader, CompressionImplementation compressionImplementation)
{
switch (compressionImplementation)
{
case CompressionImplementation.ManagedZLib:
byte[] decompressed = null;
try
{
decompressed = ManagedZLibWrapper.Decompress(bytes, useHeader);
}
catch (Exception e)
{
if (useHeader)
{
if (e.Message.Contains("Invalid GZip header"))
{
//we're probably trying to decompress data that has no header with the header flag. if it throws again, just let it go
log.WarnFormat("Tried to decompress using header and got error {0}. Attempting decompress with no header.",
e.Message);
try
{
decompressed = ManagedZLibWrapper.Decompress(bytes, false);
}
catch (Exception e2)
{
if (e2.Message.Contains("Z_DATA_ERROR")) //then the data is actually invalid; it may not be compressed at all. we'll try just returning the data as it was
{
log.WarnFormat("Tried to decompress with no header after getting error with header and got error {0}. Returning bytes as they were.", e2.Message);
decompressed = bytes;
}
else
{
throw;
}
}
}
else
{
throw;
}
}
else
{
if (e.Message.Contains("Z_DATA_ERROR"))
{
//probably the inverse; tried to decompress data with a header without one.
log.WarnFormat("Tried to decompress with no header and got error {0}. Attempting decompress with header.",
e.Message);
try
{
decompressed = ManagedZLibWrapper.Decompress(bytes, true);
}
catch (Exception e2)
{
if (e2.Message.Contains("Invalid GZip header"))
{
log.WarnFormat("Tried to decompress with header after getting error with header and got error {0}. Returning byte as they were.", e2.Message);
decompressed = bytes;
}
else
{
throw;
}
}
}
else
{
throw;
}
}
}
return(decompressed);
default:
throw new ApplicationException(string.Format("Unknown compression implementation {0}", compressionImplementation));
}
}