TMap.cxx

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// @(#)root/cont:$Id$
// Author: Fons Rademakers   12/11/95

/*************************************************************************
 * 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.             *
 *************************************************************************/

/** \class TMap
\ingroup Containers
TMap implements an associative array of (key,value) pairs using a
THashTable for efficient retrieval (therefore TMap does not conserve
the order of the entries). The hash value is calculated
using the value returned by the keys Hash() function and the
key comparison is done via the IsEqual() function.
Both key and value must inherit from TObject.
*/

#include "TMap.h"
#include "THashTable.h"
#include "TROOT.h"
#include "TBrowser.h"
#include "TRegexp.h"

ClassImp(TMap)

////////////////////////////////////////////////////////////////////////////////
/// TMap ctor. See THashTable for a description of the arguments.

TMap::TMap(Int_t capacity, Int_t rehashlevel)
{
   fSize  = 0;
   fTable = new THashTable(capacity, rehashlevel);
}

////////////////////////////////////////////////////////////////////////////////
/// TMap dtor. Objects are not deleted unless the TMap is the
/// owner (set via SetOwner()).

TMap::~TMap()
{
   Clear();
   delete fTable;
}

////////////////////////////////////////////////////////////////////////////////
/// This function may not be used (but we need to provide it since it is
/// a pure virtual in TCollection). Use Add(key,value) instead.

void TMap::Add(TObject *)
{
   MayNotUse("Add(TObject *obj)");
}

////////////////////////////////////////////////////////////////////////////////
/// Add a (key,value) pair to the map.

void TMap::Add(TObject *key, TObject *value)
{
   if (IsArgNull("Add", key)) return;

   fTable->Add(new TPair(key, value));
   fSize++;
}

////////////////////////////////////////////////////////////////////////////////
/// Return the ratio of entries vs occupied slots.

Float_t TMap::AverageCollisions() const
{
   return fTable->AverageCollisions();
}

////////////////////////////////////////////////////////////////////////////////
/// Return number of slots in the hashtable. Use GetSize() to get the
/// number of objects stored in the TMap.

Int_t TMap::Capacity() const
{
   return fTable->Capacity();
}

////////////////////////////////////////////////////////////////////////////////
/// Remove all (key,value) pairs from the map. The keys/values are
/// deleted depending on the state of key-ownership (SetOwner()) and
/// value-ownership (SetOwnerValue()).
///
/// To delete these objects regardless of the ownership state use:
///  - Delete()       to delete only keys;
///  - DeleteValues() to delete only values;
///  - DeleteAll()    to delete both keys and values.

void TMap::Clear(Option_t *option)
{
   if (IsOwner() && IsOwnerValue())
      DeleteAll();
   else if (IsOwner())
      Delete();
   else if (IsOwnerValue())
      DeleteValues();
   else {
      fTable->Delete(option);    // delete the TPair's
      fSize = 0;
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Returns the number of collisions for a key with a certain name
/// (i.e. number of objects in same slot in the hash table, i.e. length
/// of linked list).

Int_t TMap::Collisions(const char *keyname) const
{
   return fTable->Collisions(keyname);
}

////////////////////////////////////////////////////////////////////////////////
/// Returns the number of collisions for a key (i.e. number of objects
/// in same slot in the hash table, i.e. length of linked list).

Int_t TMap::Collisions(TObject *key) const
{
   return fTable->Collisions(key);
}

////////////////////////////////////////////////////////////////////////////////
/// Remove all (key,value) pairs from the map AND delete the keys
/// when they are allocated on the heap.

void TMap::Delete(Option_t *option)
{
   TIter next(fTable);
   TPair *a;

   while ((a = (TPair *)next()))
      if (a->Key() && a->Key()->IsOnHeap())
         TCollection::GarbageCollect(a->Key());

   fTable->Delete(option);   // delete the TPair's
   fSize = 0;
}

////////////////////////////////////////////////////////////////////////////////
/// Remove all (key,value) pairs from the map AND delete the values
/// when they are allocated on the heap.

void TMap::DeleteValues()
{
   TIter next(fTable);
   TPair *a;

   while ((a = (TPair *)next()))
      if (a->Value() && a->Value()->IsOnHeap())
         TCollection::GarbageCollect(a->Value());

   fTable->Delete();   // delete the TPair's
   fSize = 0;
}

////////////////////////////////////////////////////////////////////////////////
/// Remove all (key,value) pairs from the map AND delete the keys AND
/// values when they are allocated on the heap.

void TMap::DeleteAll()
{
   TIter next(fTable);
   TPair *a;

   while ((a = (TPair *)next())) {
      if (a->Key()   && a->Key()->IsOnHeap())
         TCollection::GarbageCollect(a->Key());
      if (a->Value() && a->Value()->IsOnHeap())
         TCollection::GarbageCollect(a->Value());
   }

   fTable->Delete();   // delete the TPair's
   fSize = 0;
}

////////////////////////////////////////////////////////////////////////////////
/// Remove (key,value) pair with key from the map. Returns true
/// if the key was found and removed, false otherwise.
/// The key and value objects are deleted if map is the owner
/// of keys and values respectively.

Bool_t TMap::DeleteEntry(TObject *key)
{
   if (!key) return kFALSE;

   TPair *a;
   if ((a = (TPair *)fTable->FindObject(key))) {
      if (fTable->Remove(key)) {
         if (IsOwner() && a->Key() && a->Key()->IsOnHeap())
            TCollection::GarbageCollect(a->Key());
         if (IsOwnerValue() && a->Value() && a->Value()->IsOnHeap())
            TCollection::GarbageCollect(a->Value());
         delete a;
         fSize--;
         return kTRUE;
      }
   }
   return kFALSE;
}

////////////////////////////////////////////////////////////////////////////////
/// Check if a (key,value) pair exists with keyname as name of the key.
/// Returns a TPair* (need to downcast from TObject). Use Key() and
/// Value() to get the pointers to the key and value, respectively.
/// Returns 0 if not found.

TObject *TMap::FindObject(const char *keyname) const
{
   return fTable->FindObject(keyname);
}

////////////////////////////////////////////////////////////////////////////////
/// Check if a (key,value) pair exists with key as key.
/// Returns a TPair* (need to downcast from TObject). Use Key() and
/// Value() to get the pointers to the key and value, respectively.
/// Returns 0 if not found.

TObject *TMap::FindObject(const TObject *key) const
{
   if (IsArgNull("FindObject", key)) return 0;

   return fTable->FindObject(key);
}

////////////////////////////////////////////////////////////////////////////////
/// Returns a pointer to the value associated with keyname as name of the key.

TObject *TMap::GetValue(const char *keyname) const
{
   TPair *a = (TPair *)fTable->FindObject(keyname);
   if (a) return a->Value();
   return 0;
}

////////////////////////////////////////////////////////////////////////////////
/// Returns a pointer to the value associated with key.

TObject *TMap::GetValue(const TObject *key) const
{
   if (IsArgNull("GetValue", key)) return 0;

   TPair *a = (TPair *)fTable->FindObject(key);
   if (a) return a->Value();
   return 0;
}

////////////////////////////////////////////////////////////////////////////////
/// Create an iterator for TMap.

TIterator *TMap::MakeIterator(Bool_t dir) const
{
   return new TMapIter(this, dir);
}

////////////////////////////////////////////////////////////////////////////////
/// Print the collection entry.

void TMap::PrintCollectionEntry(TObject* entry, Option_t* option, Int_t recurse) const
{
   TObject* val = GetValue(entry);

   TROOT::IndentLevel();
   printf("Key:   ");
   entry->Print();
   TROOT::IndentLevel();
   printf("Value: ");
   TCollection* coll = dynamic_cast<TCollection*>(val);
   if (coll) {
     coll->Print(option, recurse);
   } else {
     val->Print(option);
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Rehash the underlaying THashTable (see THashTable::Rehash()).

void TMap::Rehash(Int_t newCapacity, Bool_t checkObjValidity)
{
   fTable->Rehash(newCapacity, checkObjValidity);
}

////////////////////////////////////////////////////////////////////////////////
/// Remove the (key,value) pair with key from the map. Returns the
/// key object or 0 in case key was not found. If map is the owner
/// of values, the value is deleted.

TObject *TMap::Remove(TObject *key)
{
   if (!key) return 0;

   TPair *a;
   if ((a = (TPair *)fTable->FindObject(key))) {
      if (fTable->Remove(key)) {
         if (IsOwnerValue() && a->Value() && a->Value()->IsOnHeap())
            TCollection::GarbageCollect(a->Value());
         TObject *kobj = a->Key();
         delete a;
         fSize--;
         return kobj;
      }
   }
   return 0;
}

////////////////////////////////////////////////////////////////////////////////
/// Remove (key,value) pair with key from the map. Returns the
/// pair object or 0 in case the key was not found.
/// It is caller's responsibility to delete the pair and, eventually,
/// the key and value objects.

TPair *TMap::RemoveEntry(TObject *key)
{
   if (!key) return 0;

   TPair *a;
   if ((a = (TPair *)fTable->FindObject(key))) {
      if (fTable->Remove(key)) {
         fSize--;
         return a;
      }
   }
   return 0;
}

////////////////////////////////////////////////////////////////////////////////
/// Set whether this map is the owner (enable==true)
/// of its values.  If it is the owner of its contents,
/// these objects will be deleted whenever the collection itself
/// is deleted. The objects might also be deleted or destructed when Clear
/// is called (depending on the collection).

void TMap::SetOwnerValue(Bool_t enable)
{
   if (enable)
      SetBit(kIsOwnerValue);
   else
      ResetBit(kIsOwnerValue);
}

////////////////////////////////////////////////////////////////////////////////
/// Set ownership for keys and values.

void TMap::SetOwnerKeyValue(Bool_t ownkeys, Bool_t ownvals)
{
   SetOwner(ownkeys);
   SetOwnerValue(ownvals);
}

////////////////////////////////////////////////////////////////////////////////
/// Stream all key/value pairs in the map to or from the I/O buffer.

void TMap::Streamer(TBuffer &b)
{
   TObject *obj=0;
   UInt_t R__s, R__c;

   if (b.IsReading()) {
      Int_t    nobjects;
      TObject *value=0;

      Version_t v = b.ReadVersion(&R__s, &R__c);
      if (v > 2)
         TObject::Streamer(b);
      if (v > 1)
         fName.Streamer(b);
      b >> nobjects;
      for (Int_t i = 0; i < nobjects; i++) {
         b >> obj;
         b >> value;
         if (obj) Add(obj, value);
      }
      b.CheckByteCount(R__s, R__c,TMap::IsA());
   } else {
      R__c = b.WriteVersion(TMap::IsA(), kTRUE);
      TObject::Streamer(b);
      fName.Streamer(b);
      b << GetSize();
      TIter next(fTable);
      TPair *a;
      while ((a = (TPair*) next())) {
         b << a->Key();
         b << a->Value();
      }
      b.SetByteCount(R__c, kTRUE);
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Write all objects in this map. By default all objects in
/// the collection are written individually (each object gets its
/// own key). Note, this is recursive, i.e. objects in collections
/// in the collection are also written individually. To write all
/// objects using a single key specify a name and set option to
/// TObject::kSingleKey (i.e. 1).

Int_t TMap::Write(const char *name, Int_t option, Int_t bsize) const
{
   if ((option & kSingleKey)) {
      return TObject::Write(name, option, bsize);
   } else {
      option &= ~kSingleKey;
      Int_t nbytes = 0;
      TIter next(fTable);
      TPair *a;
      while ((a = (TPair*) next())) {
         if (a->Key())
            nbytes += a->Key()->Write(name, option, bsize);
         if (a->Value())
            nbytes += a->Value()->Write(name, option, bsize);
      }
      return nbytes;
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Write all objects in this map. By default all objects in
/// the collection are written individually (each object gets its
/// own key). Note, this is recursive, i.e. objects in collections
/// in the collection are also written individually. To write all
/// objects using a single key specify a name and set option to
/// TObject::kSingleKey (i.e. 1).

Int_t TMap::Write(const char *name, Int_t option, Int_t bsize)
{
   return ((const TMap*)this)->Write(name,option,bsize);
}

/** \class TPair
Class used by TMap to store (key,value) pairs.
*/

////////////////////////////////////////////////////////////////////////////////
/// Browse the pair.

void TPair::Browse(TBrowser *b)
{
   if (b) {
      if (fKey)   b->Add(fKey);
      if (fValue) b->Add(fValue);
   } else {
      if (fKey)   fKey->Browse(b);
      if (fValue) fValue->Browse(b);
   }
}

/** \class TMapIter
Iterator of map.
*/

ClassImp(TMapIter)

////////////////////////////////////////////////////////////////////////////////
/// Create a map iterator. Use dir to specify the desired iteration direction.

TMapIter::TMapIter(const TMap *m, Bool_t dir)
{
   fMap        = m;
   fDirection  = dir;
   fCursor     = 0;
}

////////////////////////////////////////////////////////////////////////////////
/// Copy ctor.

TMapIter::TMapIter(const TMapIter &iter) : TIterator(iter)
{
   fMap       = iter.fMap;
   fDirection = iter.fDirection;
   fCursor    = 0;
   if (iter.fCursor) {
      fCursor = (THashTableIter *)iter.fCursor->GetCollection()->MakeIterator();
      if (fCursor)
         fCursor->operator=(*iter.fCursor);
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Overridden assignment operator.

TIterator &TMapIter::operator=(const TIterator &rhs)
{
   if (this != &rhs && rhs.IsA() == TMapIter::Class()) {
      const TMapIter &rhs1 = (const TMapIter &)rhs;
      fMap       = rhs1.fMap;
      fDirection = rhs1.fDirection;
      if (rhs1.fCursor) {
         fCursor = (THashTableIter *)rhs1.fCursor->GetCollection()->MakeIterator();
         if (fCursor)
            fCursor->operator=(*rhs1.fCursor);
      }
   }
   return *this;
}

////////////////////////////////////////////////////////////////////////////////
/// Overloaded assignment operator.

TMapIter &TMapIter::operator=(const TMapIter &rhs)
{
   if (this != &rhs) {
      fMap       = rhs.fMap;
      fDirection = rhs.fDirection;
      if (rhs.fCursor) {
         fCursor = (THashTableIter *)rhs.fCursor->GetCollection()->MakeIterator();
         if (fCursor)
            fCursor->operator=(*rhs.fCursor);
      }
   }
   return *this;
}

////////////////////////////////////////////////////////////////////////////////
/// Map iterator dtor.

TMapIter::~TMapIter()
{
   Reset();
}

////////////////////////////////////////////////////////////////////////////////
/// Returns the next key from a map. Use TMap::GetValue() to get the value
/// associated with the key. Returns 0 when no more items in map.

TObject *TMapIter::Next()
{
   if (!fCursor)
      fCursor = new THashTableIter(fMap->fTable, fDirection);

   TPair *a = (TPair *)fCursor->Next();
   if (a) return a->Key();
   return 0;
}

////////////////////////////////////////////////////////////////////////////////
/// Reset the map iterator.

void TMapIter::Reset()
{
   SafeDelete(fCursor);
}

////////////////////////////////////////////////////////////////////////////////
/// This operator compares two TIterator objects.

Bool_t TMapIter::operator!=(const TIterator &aIter) const
{
   if (aIter.IsA() == TMapIter::Class()) {
      const TMapIter &iter(dynamic_cast<const TMapIter &>(aIter));
      return (fCursor->operator*() != iter.fCursor->operator*());
   }
   return false; // for base class we don't implement a comparison
}

////////////////////////////////////////////////////////////////////////////////
/// This operator compares two TMapIter objects.

Bool_t TMapIter::operator!=(const TMapIter &aIter) const
{
   return (fCursor->operator*() != aIter.fCursor->operator*());
}

////////////////////////////////////////////////////////////////////////////////
/// Return pointer to current object (a TPair) or nullptr.

TObject *TMapIter::operator*() const
{
   return (fCursor ? fCursor->operator*() : nullptr);
}