// @(#)root/cont:$Name:  $:$Id: TClassTable.cxx,v 1.1.1.1 2000/05/16 17:00:40 rdm Exp $
// Author: Fons Rademakers   11/08/95

/*************************************************************************
 * Copyright (C) 1995-2000, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

//////////////////////////////////////////////////////////////////////////
//                                                                      //
// This class registers for all classes their name, id and dictionary   //
// function in a hash table. Classes are automatically added by the     //
// ctor of a special init class when a global of this init class is     //
// initialized when the program starts (see the ClassImp macro).        //
//                                                                      //
//////////////////////////////////////////////////////////////////////////

#include <stdlib.h>

#include "TClassTable.h"
#include "TClass.h"
#include "TROOT.h"
#include "TMath.h"
#include "TString.h"
#include "TError.h"


TClassTable *gClassTable;

ClassRec_t **TClassTable::fgTable;
ClassRec_t **TClassTable::fgSortedTable;
int          TClassTable::fgSize;
int          TClassTable::fgTally;
Bool_t       TClassTable::fgSorted;
int          TClassTable::fgCursor;

ClassImp(TClassTable)

//______________________________________________________________________________
 TClassTable::TClassTable()
{
   // TClassTable is a singleton (i.e. only one can exist per application).

   if (gClassTable)
      Error("TClassTable", "only one instance of TClassTable allowed");
   fgSize  = (int)TMath::NextPrime(1000);
   fgTable = new ClassRec_t* [fgSize];
   memset(fgTable, 0, fgSize*sizeof(ClassRec_t*));
}

//______________________________________________________________________________
 TClassTable::~TClassTable()
{
   // TClassTable singleton is deleted in Terminate().
}

//______________________________________________________________________________
 void TClassTable::Print(Option_t *)
{
   // Print the class table.

   PrintTable();
}

//---- static members --------------------------------------------------------

//______________________________________________________________________________
 int   TClassTable::Classes() { return fgTally; }
//______________________________________________________________________________
 void  TClassTable::Init() { fgCursor = 0; SortTable(); }


//______________________________________________________________________________
 void TClassTable::Add(const char *cname, Version_t id, VoidFuncPtr_t dict)
{
   // Add a class to the class table (this is a static function).

   if (!gClassTable)
      gClassTable = new TClassTable;

   // check if already in table, if so return
   ClassRec_t *r = FindElement(cname, kTRUE);
   if (r->name) {
      ::Warning("Add", "class %s allready in TClassTable", cname);
      return;
   }

   r->name = StrDup(cname);
   r->id   = id;
   r->dict = dict;

   fgTally++;
   fgSorted = kFALSE;
}

//______________________________________________________________________________
 void TClassTable::Remove(const char *cname)
{
   // Remove a class from the class table. This happens when a shared library
   // is unloaded (i.e. the dtor's of the global init objects are called).

   if (!gClassTable || !fgTable) return;

   int slot = 0;
   const char *p = cname;

   while (*p) slot = slot<<1 ^ *p++;
   if (slot < 0) slot = -slot;
   slot %= fgSize;

   ClassRec_t *r;
   ClassRec_t *prev = 0;
   for (r = fgTable[slot]; r; r = r->next) {
      if (!strcmp(r->name, cname)) {
         if (prev)
            prev->next = r->next;
         else
            fgTable[slot] = r->next;
         delete [] r->name;
         delete r;
         fgTally--;
         fgSorted = kFALSE;
         break;
      }
      prev = r;
   }
}

//______________________________________________________________________________
 ClassRec_t *TClassTable::FindElement(const char *cname, Bool_t insert)
{
   // Find a class by name in the class table (using hash of name). Returns
   // 0 if the class is not in the table. Unless arguments insert is true in
   // which case a new entry is created and returned.

   if (!fgTable) return 0;

   int slot = 0;
   const char *p = cname;

   while (*p) slot = slot<<1 ^ *p++;
   if (slot < 0) slot = -slot;
   slot %= fgSize;

   ClassRec_t *r;

   for (r = fgTable[slot]; r; r = r->next)
      if (!strcmp(r->name, cname)) return r;

   if (!insert) return 0;

   r = new ClassRec_t;
   r->name = 0;
   r->id   = 0;
   r->dict = 0;
   r->next = fgTable[slot];
   fgTable[slot] = r;

   return r;
}

//______________________________________________________________________________
 Version_t TClassTable::GetID(const char *cname)
{
   // Returns the ID of a class.

   ClassRec_t *r = FindElement(cname);
   if (r) return r->id;
   return -1;
}

//______________________________________________________________________________
 VoidFuncPtr_t TClassTable::GetDict(const char *cname)
{
   // Given the class name returns the Dictionary() function of a class
   // (uses hash of name).

   ClassRec_t *r = FindElement(cname);
   if (r) return r->dict;
   return 0;
}

//______________________________________________________________________________
static int ClassComp(const void *a, const void *b)
{
   // Function used for sorting classes alphabetically.

   return strcmp((*(ClassRec_t **)a)->name, (*(ClassRec_t **)b)->name);
}

//______________________________________________________________________________
 char *TClassTable::Next()
{
    // Returns next class from sorted class table.

    if (fgCursor < fgTally) {
       ClassRec_t *r = fgSortedTable[fgCursor++];
       return r->name;
    } else
       return 0;
}

//______________________________________________________________________________
 void TClassTable::PrintTable()
{
   // Print the class table. Before printing the table is sorted
   // alphabetically.

   if (fgTally == 0 || !fgTable)
      return;

   SortTable();

   int n = 0, ninit = 0;

   Printf("");
   Printf("Defined classes");
   Printf("class                              version  initialized");
   Printf("=======================================================");
   for (int i = 0; i < fgTally; i++) {
      ClassRec_t *r = fgSortedTable[i];
      n++;
      if (gROOT->GetClass(r->name, kFALSE)) {
         ninit++;
         Printf("%-32s %7d        Yes", r->name, r->id);
      } else
         Printf("%-32s %7d        No", r->name, r->id);
   }
   Printf("-------------------------------------------------------");
   Printf("Total classes: %4d   initialized: %4d", n, ninit);
   Printf("=======================================================");

   Printf("");
}

//______________________________________________________________________________
 void TClassTable::SortTable()
{
   // Sort the class table by ascending class ID's.

   if (!fgSorted) {
      if (fgSortedTable) delete [] fgSortedTable;
      fgSortedTable = new ClassRec_t* [fgTally];

      int j = 0;
      for (int i = 0; i < fgSize; i++)
         for (ClassRec_t *r = fgTable[i]; r; r = r->next)
            fgSortedTable[j++] = r;

      ::qsort(fgSortedTable, fgTally, sizeof(ClassRec_t *), &::ClassComp);
      fgSorted = kTRUE;
   }
}

//______________________________________________________________________________
 void TClassTable::Terminate()
{
   // Deletes the class table (this static class function calls the dtor).

   if (gClassTable) {
      for (int i = 0; i < fgSize; i++)
         for (ClassRec_t *r = fgTable[i]; r; ) {
            ClassRec_t *t = r;
            r = r->next;
            delete [] t->name;
            delete t;
         }
      delete [] fgTable; fgTable = 0;
      SafeDelete(gClassTable);
   }
}

//______________________________________________________________________________
void AddClass(const char *cname, Version_t id, VoidFuncPtr_t dict)
{
   // Global function called by the ctor of a class's init class
   // (see the ClassImp macro).

   TClassTable::Add(cname, id, dict);
}

//______________________________________________________________________________
void RemoveClass(const char *cname)
{
   // Global function called by the dtor of a class's init class
   // (see the ClassImp macro).

   TClassTable::Remove(cname);
   if (gROOT && gROOT->GetListOfClasses()) {
      TClass *cl = gROOT->GetClass(cname, kFALSE);
      delete cl;  // interesting, for delete to call TClass::~TClass
   }              // Class.h needs to be included
}