[root] Log of /trunk/core/meta/src/TRealData.cxx

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Modified Sat Jan 10 10:52:31 2004 UTC (11 years ago) by brun
Original Path: trunk/meta/src/TRealData.cxx
File length: 3195 byte(s)
Diff to previous 1024
From Philippe:

This mega patch introduces a new implementation of the STL I/O
which is backward and forward compatible.  In addition this is more
exactly a new implementation or an extension of the container I/O.

We are introducing a new abstract interface:
"TVirtualContainerProxy", which can be implemented to present a
proxy to any collection which the I/O (and TTreeFormula) can use
then transparently.

The TVirtualContainerProxy interface allows to the I/O system to
request some information and to execute some essential function of
the container:
   what kind of object/data does it contain
   does it contain pointers
   how to insert data into the container
   how to retrieve an array of pointer to the elements inside
   how to create a collection object
   how to clear the collection
   how to resize the collection
   how to streamer the collection (if needed)
   how to calculate the sizeof the collection
   how to calculate the number of elements of the collection.

Using those primitives, the I/O and TTreeFormula should be able to
access any collection.   The I/O should also be able to handle the
splitting of collections that can be split (i.e. contains a single
type of object/data).

The current compromise selected between code duplication,
performance of the I/O of TClonesArray and vector of pointers and
the performance of the I/O of other containers, was to have on
function handle all collection as if they were a C-style array of
pointers to data.  This implies for example that the I/O of vector
of object current passes via the construction of temporary array
of pointer.  The cost of this construction is usually ~Qjust~R the
cost of calculating the addresses of the elements and assigning it
to an array element.

Registering a collection proxy will be similar to
     static int dummy = GenerateInitInstance((CollectType*)0x0)-
>AdoptCollectionProxy(new CollectTypeProxy));

Follows a few details on the modifications made to some of the
files and classes.

Bytes.h:
   Work around a problem in the MSVC++ 6.0 optimizer.  This should
not affect other compilers.

String:
   Included the std::string dictionary into G__Base2.cxx, this
insures its presence at all time.
   Added a new file string.cxx holding the streamer for
std::string.

RConfig.h
   Added proper ansi stream configuration for AIX, KCC
   Added template specialization defect for MSVC

TBrowser
   Start adding the ability to browser non TObject classes

TBuffer
   To handle the reading and writing array of objects, added:
     Int_t    CheckByteCount(UInt_t startpos, UInt_t bcnt, const
TClass *clss, const char* classname);
     Int_t    CheckByteCount(UInt_t startpos, UInt_t bcnt, const
char *classname);
     void     ReadFastArray(void  *start , TClass *cl, Int_t n=1,
TMemberStreamer *s=0);
     void     ReadFastArray(void **startp, TClass *cl, Int_t n=1,
Bool_t isPreAlloc=kFALSE, TMemberStreamer *s=0);
     void     WriteFastArray(void  *start,  TClass *cl, Int_t n=1,
TMemberStreamer *s=0);
     Int_t    WriteFastArray(void **startp, TClass *cl, Int_t n=1,
Bool_t isPreAlloc=kFALSE, TMemberStreamer *s=0);

TROOT
   Enhancement to make the access to gROOT not dependent for the
library loading order.  In particular we added:
      ROOT::GetROOT()
   which should be used instead of gROOT.

   Improve support for STL.  In particular, now STL containers do
have a corresponding TClass object


TRealData
   Replace SetStreamer by AdoptStreamer that allow to use not only
a streamer function but also streamer object (allowing streamer
with a state for Foreign classes)

TString:
   Improve streamer performance

TSystem:
   More consistency of the return value of TSystem::CompileMacro

build/unix/makecintdlls.sh
   Stop making the string.dll

config:
   enhance sgicc makefiles

cont:
   fix TBits::operator=
   TClassTable now warns for duplicate only for non stl classes
   TClonesArray fix a typo

gpad:
   Add a new class TInspectObject to enable inspect non TObject
classes
   TRootBrowser : enable inspect non TObject classes

TFormula/TTreeFormula
   To enhance performance switch from using one array fOper which
contained the operation code and its arguments to using 2 arrays
fActions and fActionParams to store respectively the operation and
its parameters.
   A new function Convert is used to convert old version from the
fOper to fActions.  This allows cleaner coding and offer
optimization opportunities.

TTreePlayer
   Start adding support in MakeClass for STL containers.

TRint/TProofServ
   Insure the loading of the string support

Event.cxx
   make sure to avoid memory over-write

stress.cxx
   Add new parameters
      stress <nevent> <style> <subbench> <portion>
   if <subbench> is 1 or higher, print the benchmark results after
each test.  This allows understand
   which test is affect by a performance change.
   portion is a binary field to indicate which test to run.  This
allows to focus on a particular test.

TVirtualCollectionProxy
   Abstract interface used to access any type of containers from
the I/O system and TTreeFormula. See TVectorProxy and
TEmulatedVectorProxy for examples.

TEmulatedVectorProxy
   Implementation of a std::vector proxy to be able to read a
std::vector without any libraries.

TVectorProxy
   Implementation of TVirtualCollectionProxy for a std::vector for
which we have the library.

TStreamerInfo.cxx
   Split in 3 files:  TStreamerInfo.cxx
TStreamerInfoReadBuffer.cxx TStreamerInfoWriteBuffer.cxx

   All the ReadBuffer, ReadBufferClones and the new ReadBufferSTL
(similarly for  WriteBuffer) have been factorized into one
function and 2 short wrappers.  The new main function expect an
array of pointer to the objects (this array is most often of size
one).

   TClonesArray objects pass GetObjectRef(0) to the common
ReadBuffer
   vector<bla*> v pass &(v[0])
   vector<bla> needs to create an intermediary array to hold the
address

   This mechanism is sometimes not optimal (vector<blah>) but
allows extremely flexibly and extension.  Basically, to add
support for a new container type using the StreamerInfo mechanism
(in particular allows splitting), one 'just' need to implement a
TVirtualCollectionProxy, which, in particular, will return an
array of address to the object it contains.  Even std::map can be
handled with this mechanism, since, for I/O purposes, it can be
consider as a container of pairs.

   Add a few optimization, including more caching via a new array
of a new struct (fComp).

   Fixed a problem (re)introduced while implementing the Foreign
class CheckSum.  Doing:
      class Event;
      f = new TFile("Event.root");
   resulted in errors.

TCint
   Add proper support for TClass of STL containers. Fix a memory
leak.
   Add support for load TClass via a typedef.
   Fix a problem with multiple inheritance

TClass
   Fixed a problem (re)introduced while implementing the Foreign
class CheckSum.  Doing:
      class Event;
      f = new TFile("Event.root");
   resulted in errors.
   Add a

TClass/TGenericClassInfo/TDataMember
   Add support for a new interface (TVirtualCollectionProxy)
useable for STL containers or any user defined containers.
   Add support for streamer with are objects (as opposed to free
standing function or methods).  This allows the user a greater
flexibility in writing a streamer.
   Add a few optimizations
   Add CanSplit to answer the question for a whole Class (for
example some collection can not be splitted).

TClassStreamer
   New class to wrap a class wide streamer

ClassStreamerFunc_t
   typedef for a class wide streamer function

TMemberStreamer
   New class to wrap a specific class member streamer

MemberStreamerFunc_t
   typedef for  a specific class member streamer function

RootStreamer
   Macro to specify a free standing streamer object or function
for a class
   For example:
      RootStreamer(string,std_string_streamer);

TStreamerElement:
   A couple of optimization/simplification.
   Add support for the new STL I/O
   Extend the useful

TBranchElement:
   add a connection to the proper TVirtualCollectionProxy
   add support for STL containers (non-split and split mode)

TTree
   Make the function TTree::GetMakeClass NON-virtual for better
efficiency
   Add support for STL containers

TBasket
   Left (in comment) a yet unproved improvement proposed by
Victor.  The preliminary tests were inconclusive performance wise
and it had (seemingly) problem with backward and forward
compatibility.

TBranch
   Performance improvements

metautils
   This is a new package for C++ files shared between rootcint and
meta.
   It contains TClassEdit a class to help determine some property
of a class given its class name (stl, template, etc).

utils
   Introduced a new file RStl.cxx to start separating rootcint in
modules.
   Modified rootcint to support the new STL I/O methods.
   In particular a new class RStl is in charge of doing the
generating of code for STL containers.
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