Added more logging, fixed error with storage size for block length

1 files changed, 18 insertions, 3 deletions

diff --git a/FuseArchive/Chunk.py b/FuseArchive/Chunk.py
index 2ceb7ed..9f12f83 100644
--- a/FuseArchive/Chunk.py
+++ b/FuseArchive/Chunk.py
@@ -1,13 +1,17 @@
-import struct, zlib
+import struct, zlib, logging
 
 # Format version
 # Payload block size (so you don't have to uncompress it to see)
 # Data compression type (0 = none, 1 = zlib)
 # Ref count (number of files that use this)
 # filler to pad out ot 64 bytes for future expansion
-hformat = 'HHBL52x'
+hformat = 'HLBL48x'
 compress_level = 6
 
+assert struct.calcsize( hformat ) == 64, \
+    "Header struct must be 64 bytes not %d bytes" % \
+    struct.calcsize( hformat )
+
 # This handles serialization and deserialization of compressed chunks with
 # some header data
 class Chunk:
@@ -24,25 +28,35 @@ class Chunk:
     # Returns a string representing the serialized class to be sent to a
     # file
     def serialize(self, compression = 1):
+        l = len( self.chunk )
+
+        logging.debug( "Packing header: len: %d compression: %d count: %d" %
+            ( l, compression, self.count ) )
+
         data = struct.pack( hformat,
             0,
-            len( self.chunk ),
+            l,
             compression,
             self.count
         )
 
         if compression == 0:
+            logging.debug( "Saving chunk data raw" )
             data += self.chunk
         elif compression == 1:
+            logging.debug( "Saving chunk data using zlib" )
             data += zlib.compress( self.chunk, compress_level )
         else:
             raise ValueError( "Invalid compression type: %d" % compression )
 
+        logging.debug( "Returning serialized block, size is %d" % len( data) )
+
         return data
 
     # Converts the output of serialize back to a chunk object
     @staticmethod
     def deserialize(data):
+        logging.debug( "Deserializing data of length %d" % len( data ) )
         hd = Chunk.parse_header( data[ :64 ] )
         obj = Chunk()
         obj.count = hd[ 'count' ]
@@ -62,6 +76,7 @@ class Chunk:
     # involve potentially uncompressing some data
     @staticmethod
     def parse_header(data):
+        logging.debug( "Parsing header of length %d" % len( data ) )
         fields = struct.unpack( hformat, data )
         return {
             'version': fields[ 0 ],