class TTreeCache: public TFileCacheRead

 Default Constructor.

 Constructor.

 destructor. (in general called by the TFile destructor

add a branch to the list of branches to be stored in the cache
this function is called by TBranch::GetBasket

 Add a branch to the list of branches to be stored in the cache
 this is to be used by user (thats why we pass the name of the branch).
 It works in exactly the same way as TTree::SetBranchStatus so you
 probably want to look over ther for details about the use of bname
 with regular expresions.
 The branches are taken with respect to the Owner of this TTreeCache
 (i.e. the original Tree)

 Fill the cache buffer with the branches in the cache.

 Give the total efficiency of the cache... defined as the ratio
 of blocks found in the cache vs. the number of blocks prefetched
 ( it could be more than 1 if we read the same block from the cache more
   than once )
 Note: This should eb used at the end of the processing or we will
       get uncomplete stats

 This will indicate a sort of relative efficiency... a ratio of the
 reads found in the cache to the number of reads so far

static function returning the number of entries used to train the cache
see SetLearnEntries

return the owner of this cache.

return Tree in the cache

 Read buffer at position pos.
 If pos is in the list of prefetched blocks read from fBuffer.
 Otherwise try to fill the cache from the list of selected branches,
 and recheck if pos is now in the list.
 Returns
    -1 in case of read failure,
     0 in case not in cache,
     1 in case read from cache.
 This function overloads TFileCacheRead::ReadBuffer.

 This will simply clear the cache

 Set the minimum and maximum entry number to be processed
 this information helps to optimize the number of baskets to read
 when prefetching the branch buffers.

 Static function to set the number of entries to be used in learning mode
 The default value for n is 10. n must be >= 1

 The name should be enough to explain the method.
 The only additional comments is that the cache is cleaned before
 the new learning phase.

 This is the counterpart of StartLearningPhase() and can be used to stop
 the learning phase. It's useful when the user knows exactly what branches
 he is going to use.
 For the moment it's just a call to FillBuffer() since that method
 will create the buffer lists from the specified branches.

update pointer to current Tree and recompute pointers to the branches in the cache