text: /*
      Copyright (c) 2005-2018 Intel Corporation
  
      Licensed under the Apache License, Version 2.0 (the "License");
      you may not use this file except in compliance with the License.
      You may obtain a copy of the License at
  
          http://www.apache.org/licenses/LICENSE-2.0
  
      Unless required by applicable law or agreed to in writing, software
      distributed under the License is distributed on an "AS IS" BASIS,
      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      See the License for the specific language governing permissions and
      limitations under the License.
  
  
  
  
  */
  
  #ifndef __TBB_enumerable_thread_specific_H
  #define __TBB_enumerable_thread_specific_H
  
  #include "atomic.h"
  #include "concurrent_vector.h"
  #include "tbb_thread.h"
  #include "tbb_allocator.h"
  #include "cache_aligned_allocator.h"
  #include "aligned_space.h"
  #include "internal/_template_helpers.h"
  #include "internal/_tbb_hash_compare_impl.h"
  #include "tbb_profiling.h"
  #include <string.h>  // for memcpy
  
  #if _WIN32||_WIN64
  #include "machine/windows_api.h"
  #else
  #include <pthread.h>
  #endif
  
  #define __TBB_ETS_USE_CPP11 \
      (__TBB_CPP11_RVALUE_REF_PRESENT && __TBB_CPP11_VARIADIC_TEMPLATES_PRESENT \
       && __TBB_CPP11_DECLTYPE_PRESENT && __TBB_CPP11_LAMBDAS_PRESENT)
  
  namespace tbb {
  
  //! enum for selecting between single key and key-per-instance versions
  enum ets_key_usage_type { ets_key_per_instance, ets_no_key };
  
  namespace interface6 {
  
      // Forward declaration to use in internal classes
      template <typename T, typename Allocator, ets_key_usage_type ETS_key_type>
      class enumerable_thread_specific;
  
      //! @cond
      namespace internal {
  
          using namespace tbb::internal;
  
          template<ets_key_usage_type ETS_key_type>
          class ets_base: tbb::internal::no_copy {
          protected:
              typedef tbb_thread::id key_type;
  #if __TBB_PROTECTED_NESTED_CLASS_BROKEN
          public:
  #endif
              struct slot;
  
              struct array {
                  array* next;
                  size_t lg_size;
                  slot& at( size_t k ) {
                      return ((slot*)(void*)(this+1))[k];
                  }
                  size_t size() const {return size_t(1)<<lg_size;}
                  size_t mask() const {return size()-1;}
                  size_t start( size_t h ) const {
                      return h>>(8*sizeof(size_t)-lg_size);
                  }
              };
              struct slot {
                  key_type key;
                  void* ptr;
                  bool empty() const {return key == key_type();}
                  bool match( key_type k ) const {return key == k;}
                  bool claim( key_type k ) {
                      // TODO: maybe claim ptr, because key_type is not guaranteed to fit into word size
                      return atomic_compare_and_swap(key, k, key_type()) == key_type();
                  }
              };
  #if __TBB_PROTECTED_NESTED_CLASS_BROKEN
          protected:
  #endif
  
              //! Root of linked list of arrays of decreasing size.
              /** NULL if and only if my_count==0.
                  Each array in the list is half the size of its predecessor. */
              atomic<array*> my_root;
              atomic<size_t> my_count;
              virtual void* create_local() = 0;
              virtual void* create_array(size_t _size) = 0;  // _size in bytes
              virtual void free_array(void* ptr, size_t _size) = 0; // _size in bytes
              array* allocate( size_t lg_size ) {
                  size_t n = size_t(1)<<lg_size;
                  array* a = static_cast<array*>(create_array( sizeof(array)+n*sizeof(slot) ));
                  a->lg_size = lg_size;
                  std::memset( a+1, 0, n*sizeof(slot) );
                  return a;
              }
              void free(array* a) {
                  size_t n = size_t(1)<<(a->lg_size);
                  free_array( (void *)a, size_t(sizeof(array)+n*sizeof(slot)) );
              }
  
              ets_base() {my_root=NULL; my_count=0;}
              virtual ~ets_base();  // g++ complains if this is not virtual
              void* table_lookup( bool& exists );
              void table_clear();
              // The following functions are not used in concurrent context,
              // so we don't need synchronization and ITT annotations there.
              void table_elementwise_copy( const ets_base& other,
                                           void*(*add_element)(ets_base&, void*) ) {
                  __TBB_ASSERT(!my_root,NULL);
                  __TBB_ASSERT(!my_count,NULL);
                  if( !other.my_root ) return;
                  array* root = my_root = allocate(other.my_root->lg_size);
                  root->next = NULL;
                  my_count = other.my_count;
                  size_t mask = root->mask();
                  for( array* r=other.my_root; r; r=r->next ) {
                      for( size_t i=0; i<r->size(); ++i ) {
                          slot& s1 = r->at(i);
                          if( !s1.empty() ) {
                              for( size_t j = root->start(tbb::tbb_hash<key_type>()(s1.key)); ; j=(j+1)&mask ) {
                                  slot& s2 = root->at(j);
                                  if( s2.empty() ) {
                                      s2.ptr = add_element(*this, s1.ptr);
                                      s2.key = s1.key;
                                      break;
                                  }
                                  else if( s2.match(s1.key) )
                                      break;
                              }
                          }
                      }
                  }
              }
              void table_swap( ets_base& other ) {
                 __TBB_ASSERT(this!=&other, "Don't swap an instance with itself");
                 tbb::internal::swap<relaxed>(my_root, other.my_root);
                 tbb::internal::swap<relaxed>(my_count, other.my_count);
              }
          };
  
          template<ets_key_usage_type ETS_key_type>
          ets_base<ETS_key_type>::~ets_base() {
              __TBB_ASSERT(!my_root, NULL);
          }
  
          template<ets_key_usage_type ETS_key_type>
          void ets_base<ETS_key_type>::table_clear() {
              while( array* r = my_root ) {
                  my_root = r->next;
                  free(r);
              }
              my_count = 0;
          }
  
          template<ets_key_usage_type ETS_key_type>
          void* ets_base<ETS_key_type>::table_lookup( bool& exists ) {
              const key_type k = tbb::this_tbb_thread::get_id();
  
              __TBB_ASSERT(k != key_type(),NULL);
              void* found;
              size_t h = tbb::tbb_hash<key_type>()(k);
              for( array* r=my_root; r; r=r->next ) {
                  call_itt_notify(acquired,r);
                  size_t mask=r->mask();
                  for(size_t i = r->start(h); ;i=(i+1)&mask) {
                      slot& s = r->at(i);
                      if( s.empty() ) break;
                      if( s.match(k) ) {
                          if( r==my_root ) {
                              // Success at top level
                              exists = true;
                              return s.ptr;
                          } else {
                              // Success at some other level.  Need to insert at top level.
                              exists = true;
                              found = s.ptr;
                              goto insert;
                          }
                      }
                  }
              }
              // Key does not yet exist.  The density of slots in the table does not exceed 0.5,
              // for if this will occur a new table is allocated with double the current table
              // size, which is swapped in as the new root table.  So an empty slot is guaranteed.
              exists = false;
              found = create_local();
              {
                  size_t c = ++my_count;
                  array* r = my_root;
                  call_itt_notify(acquired,r);
                  if( !r || c>r->size()/2 ) {
                      size_t s = r ? r->lg_size : 2;
                      while( c>size_t(1)<<(s-1) ) ++s;
                      array* a = allocate(s);
                      for(;;) {
                          a->next = r;
                          call_itt_notify(releasing,a);
                          array* new_r = my_root.compare_and_swap(a,r);
                          if( new_r==r ) break;
                          call_itt_notify(acquired, new_r);
                          if( new_r->lg_size>=s ) {
                              // Another thread inserted an equal or  bigger array, so our array is superfluous.
                              free(a);
                              break;
                          }
                          r = new_r;
                      }
                  }
              }
          insert:
          // Whether a slot has been found in an older table, or if it has been inserted at this level,
          // it has already been accounted for in the total.  Guaranteed to be room for it, and it is
          // not present, so search for empty slot and use it.
              array* ir = my_root;
              call_itt_notify(acquired, ir);
              size_t mask = ir->mask();
              for(size_t i = ir->start(h);;i=(i+1)&mask) {
                  slot& s = ir->at(i);
                  if( s.empty() ) {
                      if( s.claim(k) ) {
                          s.ptr = found;
                          return found;
                      }
                  }
              }
          }
  
          //! Specialization that exploits native TLS
          template <>
          class ets_base<ets_key_per_instance>: protected ets_base<ets_no_key> {
              typedef ets_base<ets_no_key> super;
  #if _WIN32||_WIN64
  #if __TBB_WIN8UI_SUPPORT
              typedef DWORD tls_key_t;
              void create_key() { my_key = FlsAlloc(NULL); }
              void destroy_key() { FlsFree(my_key); }
              void set_tls(void * value) { FlsSetValue(my_key, (LPVOID)value); }
              void* get_tls() { return (void *)FlsGetValue(my_key); }
  #else
              typedef DWORD tls_key_t;
              void create_key() { my_key = TlsAlloc(); }
              void destroy_key() { TlsFree(my_key); }
              void set_tls(void * value) { TlsSetValue(my_key, (LPVOID)value); }
              void* get_tls() { return (void *)TlsGetValue(my_key); }
  #endif
  #else
              typedef pthread_key_t tls_key_t;
              void create_key() { pthread_key_create(&my_key, NULL); }
              void destroy_key() { pthread_key_delete(my_key); }
              void set_tls( void * value ) const { pthread_setspecific(my_key, value); }
              void* get_tls() const { return pthread_getspecific(my_key); }
  #endif
              tls_key_t my_key;
              virtual void* create_local() __TBB_override = 0;
              virtual void* create_array(size_t _size) __TBB_override = 0;  // _size in bytes
              virtual void free_array(void* ptr, size_t _size) __TBB_override = 0; // size in bytes
          protected:
              ets_base() {create_key();}
              ~ets_base() {destroy_key();}
              void* table_lookup( bool& exists ) {
                  void* found = get_tls();
                  if( found ) {
                      exists=true;
                  } else {
                      found = super::table_lookup(exists);
                      set_tls(found);
                  }
                  return found;
              }
              void table_clear() {
                  destroy_key();
                  create_key();
                  super::table_clear();
              }
              void table_swap( ets_base& other ) {
                 using std::swap;
                 __TBB_ASSERT(this!=&other, "Don't swap an instance with itself");
                 swap(my_key, other.my_key);
                 super::table_swap(other);
              }
          };
  
          //! Random access iterator for traversing the thread local copies.
          template< typename Container, typename Value >
          class enumerable_thread_specific_iterator
  #if defined(_WIN64) && defined(_MSC_VER)
              // Ensure that Microsoft's internal template function _Val_type works correctly.
              : public std::iterator<std::random_access_iterator_tag,Value>
  #endif /* defined(_WIN64) && defined(_MSC_VER) */
          {
              //! current position in the concurrent_vector
  
              Container *my_container;
              typename Container::size_type my_index;
              mutable Value *my_value;
  
              template<typename C, typename T>
              friend enumerable_thread_specific_iterator<C,T>
              operator+( ptrdiff_t offset, const enumerable_thread_specific_iterator<C,T>& v );
  
              template<typename C, typename T, typename U>
              friend bool operator==( const enumerable_thread_specific_iterator<C,T>& i,
                                      const enumerable_thread_specific_iterator<C,U>& j );
  
              template<typename C, typename T, typename U>
              friend bool operator<( const enumerable_thread_specific_iterator<C,T>& i,
                                     const enumerable_thread_specific_iterator<C,U>& j );
  
              template<typename C, typename T, typename U>
              friend ptrdiff_t operator-( const enumerable_thread_specific_iterator<C,T>& i,
                                          const enumerable_thread_specific_iterator<C,U>& j );
  
              template<typename C, typename U>
              friend class enumerable_thread_specific_iterator;
  
              public:
  
              enumerable_thread_specific_iterator( const Container &container, typename Container::size_type index ) :
                  my_container(&const_cast<Container &>(container)), my_index(index), my_value(NULL) {}
  
              //! Default constructor
              enumerable_thread_specific_iterator() : my_container(NULL), my_index(0), my_value(NULL) {}
  
              template<typename U>
              enumerable_thread_specific_iterator( const enumerable_thread_specific_iterator<Container, U>& other ) :
                      my_container( other.my_container ), my_index( other.my_index), my_value( const_cast<Value *>(other.my_value) ) {}
  
              enumerable_thread_specific_iterator operator+( ptrdiff_t offset ) const {
                  return enumerable_thread_specific_iterator(*my_container, my_index + offset);
              }
  
              enumerable_thread_specific_iterator &operator+=( ptrdiff_t offset ) {
                  my_index += offset;
                  my_value = NULL;
                  return *this;
              }
  
              enumerable_thread_specific_iterator operator-( ptrdiff_t offset ) const {
                  return enumerable_thread_specific_iterator( *my_container, my_index-offset );
              }
  
              enumerable_thread_specific_iterator &operator-=( ptrdiff_t offset ) {
                  my_index -= offset;
                  my_value = NULL;
                  return *this;
              }
  
              Value& operator*() const {
                  Value* value = my_value;
                  if( !value ) {
                      value = my_value = (*my_container)[my_index].value();
                  }
                  __TBB_ASSERT( value==(*my_container)[my_index].value(), "corrupt cache" );
                  return *value;
              }
  
              Value& operator[]( ptrdiff_t k ) const {
                 return (*my_container)[my_index + k].value;
              }
  
              Value* operator->() const {return &operator*();}
  
              enumerable_thread_specific_iterator& operator++() {
                  ++my_index;
                  my_value = NULL;
                  return *this;
              }
  
              enumerable_thread_specific_iterator& operator--() {
                  --my_index;
                  my_value = NULL;
                  return *this;
              }
  
              //! Post increment
              enumerable_thread_specific_iterator operator++(int) {
                  enumerable_thread_specific_iterator result = *this;
                  ++my_index;
                  my_value = NULL;
                  return result;
              }
  
              //! Post decrement
              enumerable_thread_specific_iterator operator--(int) {
                  enumerable_thread_specific_iterator result = *this;
                  --my_index;
                  my_value = NULL;
                  return result;
              }
  
              // STL support
              typedef ptrdiff_t difference_type;
              typedef Value value_type;
              typedef Value* pointer;
              typedef Value& reference;
              typedef std::random_access_iterator_tag iterator_category;
          };
  
          template<typename Container, typename T>
          enumerable_thread_specific_iterator<Container,T>
          operator+( ptrdiff_t offset, const enumerable_thread_specific_iterator<Container,T>& v ) {
              return enumerable_thread_specific_iterator<Container,T>( v.my_container, v.my_index + offset );
          }
  
          template<typename Container, typename T, typename U>
          bool operator==( const enumerable_thread_specific_iterator<Container,T>& i,
                           const enumerable_thread_specific_iterator<Container,U>& j ) {
              return i.my_index==j.my_index && i.my_container == j.my_container;
          }
  
          template<typename Container, typename T, typename U>
          bool operator!=( const enumerable_thread_specific_iterator<Container,T>& i,
                           const enumerable_thread_specific_iterator<Container,U>& j ) {
              return !(i==j);
          }
  
          template<typename Container, typename T, typename U>
          bool operator<( const enumerable_thread_specific_iterator<Container,T>& i,
                          const enumerable_thread_specific_iterator<Container,U>& j ) {
              return i.my_index<j.my_index;
          }
  
          template<typename Container, typename T, typename U>
          bool operator>( const enumerable_thread_specific_iterator<Container,T>& i,
                          const enumerable_thread_specific_iterator<Container,U>& j ) {
              return j<i;
          }
  
          template<typename Container, typename T, typename U>
          bool operator>=( const enumerable_thread_specific_iterator<Container,T>& i,
                           const enumerable_thread_specific_iterator<Container,U>& j ) {
              return !(i<j);
          }
  
          template<typename Container, typename T, typename U>
          bool operator<=( const enumerable_thread_specific_iterator<Container,T>& i,
                           const enumerable_thread_specific_iterator<Container,U>& j ) {
              return !(j<i);
          }
  
          template<typename Container, typename T, typename U>
          ptrdiff_t operator-( const enumerable_thread_specific_iterator<Container,T>& i,
                               const enumerable_thread_specific_iterator<Container,U>& j ) {
              return i.my_index-j.my_index;
          }
  
      template<typename SegmentedContainer, typename Value >
          class segmented_iterator
  #if defined(_WIN64) && defined(_MSC_VER)
          : public std::iterator<std::input_iterator_tag, Value>
  #endif
          {
              template<typename C, typename T, typename U>
              friend bool operator==(const segmented_iterator<C,T>& i, const segmented_iterator<C,U>& j);
  
              template<typename C, typename T, typename U>
              friend bool operator!=(const segmented_iterator<C,T>& i, const segmented_iterator<C,U>& j);
  
              template<typename C, typename U>
              friend class segmented_iterator;
  
              public:
  
                  segmented_iterator() {my_segcont = NULL;}
  
                  segmented_iterator( const SegmentedContainer& _segmented_container ) :
                      my_segcont(const_cast<SegmentedContainer*>(&_segmented_container)),
                      outer_iter(my_segcont->end()) { }
  
                  ~segmented_iterator() {}
  
                  typedef typename SegmentedContainer::iterator outer_iterator;
                  typedef typename SegmentedContainer::value_type InnerContainer;
                  typedef typename InnerContainer::iterator inner_iterator;
  
                  // STL support
                  typedef ptrdiff_t difference_type;
                  typedef Value value_type;
                  typedef typename SegmentedContainer::size_type size_type;
                  typedef Value* pointer;
                  typedef Value& reference;
                  typedef std::input_iterator_tag iterator_category;
  
                  // Copy Constructor
                  template<typename U>
                  segmented_iterator(const segmented_iterator<SegmentedContainer, U>& other) :
                      my_segcont(other.my_segcont),
                      outer_iter(other.outer_iter),
                      // can we assign a default-constructed iterator to inner if we're at the end?
                      inner_iter(other.inner_iter)
                  {}
  
                  // assignment
                  template<typename U>
                  segmented_iterator& operator=( const segmented_iterator<SegmentedContainer, U>& other) {
                      if(this != &other) {
                          my_segcont = other.my_segcont;
                          outer_iter = other.outer_iter;
                          if(outer_iter != my_segcont->end()) inner_iter = other.inner_iter;
                      }
                      return *this;
                  }
  
                  // allow assignment of outer iterator to segmented iterator.  Once it is
                  // assigned, move forward until a non-empty inner container is found or
                  // the end of the outer container is reached.
                  segmented_iterator& operator=(const outer_iterator& new_outer_iter) {
                      __TBB_ASSERT(my_segcont != NULL, NULL);
                      // check that this iterator points to something inside the segmented container
                      for(outer_iter = new_outer_iter ;outer_iter!=my_segcont->end(); ++outer_iter) {
                          if( !outer_iter->empty() ) {
                              inner_iter = outer_iter->begin();
                              break;
                          }
                      }
                      return *this;
                  }
  
                  // pre-increment
                  segmented_iterator& operator++() {
                      advance_me();
                      return *this;
                  }
  
                  // post-increment
                  segmented_iterator operator++(int) {
                      segmented_iterator tmp = *this;
                      operator++();
                      return tmp;
                  }
  
                  bool operator==(const outer_iterator& other_outer) const {
                      __TBB_ASSERT(my_segcont != NULL, NULL);
                      return (outer_iter == other_outer &&
                              (outer_iter == my_segcont->end() || inner_iter == outer_iter->begin()));
                  }
  
                  bool operator!=(const outer_iterator& other_outer) const {
                      return !operator==(other_outer);
  
                  }
  
                  // (i)* RHS
                  reference operator*() const {
                      __TBB_ASSERT(my_segcont != NULL, NULL);
                      __TBB_ASSERT(outer_iter != my_segcont->end(), "Dereferencing a pointer at end of container");
                      __TBB_ASSERT(inner_iter != outer_iter->end(), NULL); // should never happen
                      return *inner_iter;
                  }
  
                  // i->
                  pointer operator->() const { return &operator*();}
  
              private:
                  SegmentedContainer*             my_segcont;
                  outer_iterator outer_iter;
                  inner_iterator inner_iter;
  
                  void advance_me() {
                      __TBB_ASSERT(my_segcont != NULL, NULL);
                      __TBB_ASSERT(outer_iter != my_segcont->end(), NULL); // not true if there are no inner containers
                      __TBB_ASSERT(inner_iter != outer_iter->end(), NULL); // not true if the inner containers are all empty.
                      ++inner_iter;
                      while(inner_iter == outer_iter->end() && ++outer_iter != my_segcont->end()) {
                          inner_iter = outer_iter->begin();
                      }
                  }
          };    // segmented_iterator
  
          template<typename SegmentedContainer, typename T, typename U>
          bool operator==( const segmented_iterator<SegmentedContainer,T>& i,
                           const segmented_iterator<SegmentedContainer,U>& j ) {
              if(i.my_segcont != j.my_segcont) return false;
              if(i.my_segcont == NULL) return true;
              if(i.outer_iter != j.outer_iter) return false;
              if(i.outer_iter == i.my_segcont->end()) return true;
              return i.inner_iter == j.inner_iter;
          }
  
          // !=
          template<typename SegmentedContainer, typename T, typename U>
          bool operator!=( const segmented_iterator<SegmentedContainer,T>& i,
                           const segmented_iterator<SegmentedContainer,U>& j ) {
              return !(i==j);
          }
  
          template<typename T>
          struct construct_by_default: tbb::internal::no_assign {
              void construct(void*where) {new(where) T();} // C++ note: the () in T() ensure zero initialization.
              construct_by_default( int ) {}
          };
  
          template<typename T>
          struct construct_by_exemplar: tbb::internal::no_assign {
              const T exemplar;
              void construct(void*where) {new(where) T(exemplar);}
              construct_by_exemplar( const T& t ) : exemplar(t) {}
  #if __TBB_ETS_USE_CPP11
              construct_by_exemplar( T&& t ) : exemplar(std::move(t)) {}
  #endif
          };
  
          template<typename T, typename Finit>
          struct construct_by_finit: tbb::internal::no_assign {
              Finit f;
              void construct(void* where) {new(where) T(f());}
              construct_by_finit( const Finit& f_ ) : f(f_) {}
  #if __TBB_ETS_USE_CPP11
              construct_by_finit( Finit&& f_ ) : f(std::move(f_)) {}
  #endif
          };
  
  #if __TBB_ETS_USE_CPP11
          template<typename T, typename... P>
          struct construct_by_args: tbb::internal::no_assign {
              internal::stored_pack<P...> pack;
              void construct(void* where) {
                  internal::call( [where](const typename strip<P>::type&... args ){
                     new(where) T(args...);
                  }, pack );
              }
              construct_by_args( P&& ... args ) : pack(std::forward<P>(args)...) {}
          };
  #endif
  
          // storage for initialization function pointer
          // TODO: consider removing the template parameter T here and in callback_leaf
          template<typename T>
          class callback_base {
          public:
              // Clone *this
              virtual callback_base* clone() const = 0;
              // Destruct and free *this
              virtual void destroy() = 0;
              // Need virtual destructor to satisfy GCC compiler warning
              virtual ~callback_base() { }
              // Construct T at where
              virtual void construct(void* where) = 0;
          };
  
          template <typename T, typename Constructor>
          class callback_leaf: public callback_base<T>, Constructor {
  #if __TBB_ETS_USE_CPP11
              template<typename... P> callback_leaf( P&& ... params ) : Constructor(std::forward<P>(params)...) {}
  #else
              template<typename X> callback_leaf( const X& x ) : Constructor(x) {}
  #endif
              // TODO: make the construction/destruction consistent (use allocator.construct/destroy)
              typedef typename tbb::tbb_allocator<callback_leaf> my_allocator_type;
  
              callback_base<T>* clone() const __TBB_override {
                  return make(*this);
              }
  
              void destroy() __TBB_override {
                  my_allocator_type().destroy(this);
                  my_allocator_type().deallocate(this,1);
              }
  
              void construct(void* where) __TBB_override {
                  Constructor::construct(where);
              }
          public:
  #if __TBB_ETS_USE_CPP11
              template<typename... P>
              static callback_base<T>* make( P&& ... params ) {
                  void* where = my_allocator_type().allocate(1);
                  return new(where) callback_leaf( std::forward<P>(params)... );
              }
  #else
              template<typename X>
              static callback_base<T>* make( const X& x ) {
                  void* where = my_allocator_type().allocate(1);
                  return new(where) callback_leaf(x);
              }
  #endif
          };
  
          //! Template for recording construction of objects in table
          /** All maintenance of the space will be done explicitly on push_back,
              and all thread local copies must be destroyed before the concurrent
              vector is deleted.
  
              The flag is_built is initialized to false.  When the local is
              successfully-constructed, set the flag to true or call value_committed().
              If the constructor throws, the flag will be false.
          */
          template<typename U>
          struct ets_element {
              tbb::aligned_space<U> my_space;
              bool is_built;
              ets_element() { is_built = false; }  // not currently-built
              U* value() { return my_space.begin(); }
              U* value_committed() { is_built = true; return my_space.begin(); }
              ~ets_element() {
                  if(is_built) {
                      my_space.begin()->~U();
                      is_built = false;
                  }
              }
          };
  
          // A predicate that can be used for a compile-time compatibility check of ETS instances
          // Ideally, it should have been declared inside the ETS class, but unfortunately
          // in that case VS2013 does not enable the variadic constructor.
          template<typename T, typename ETS> struct is_compatible_ets { static const bool value = false; };
          template<typename T, typename U, typename A, ets_key_usage_type C>
          struct is_compatible_ets< T, enumerable_thread_specific<U,A,C> > { static const bool value = internal::is_same_type<T,U>::value; };
  
  #if __TBB_ETS_USE_CPP11
          // A predicate that checks whether, for a variable 'foo' of type T, foo() is a valid expression
          template <typename T>
          class is_callable_no_args {
          private:
              typedef char yes[1];
              typedef char no [2];
  
              template<typename U> static yes& decide( decltype(declval<U>()())* );
              template<typename U> static no&  decide(...);
          public:
              static const bool value = (sizeof(decide<T>(NULL)) == sizeof(yes));
          };
  #endif
  
      } // namespace internal
      //! @endcond
  
      //! The enumerable_thread_specific container
      /** enumerable_thread_specific has the following properties:
          - thread-local copies are lazily created, with default, exemplar or function initialization.
          - thread-local copies do not move (during lifetime, and excepting clear()) so the address of a copy is invariant.
          - the contained objects need not have operator=() defined if combine is not used.
          - enumerable_thread_specific containers may be copy-constructed or assigned.
          - thread-local copies can be managed by hash-table, or can be accessed via TLS storage for speed.
          - outside of parallel contexts, the contents of all thread-local copies are accessible by iterator or using combine or combine_each methods
  
      @par Segmented iterator
          When the thread-local objects are containers with input_iterators defined, a segmented iterator may
          be used to iterate over all the elements of all thread-local copies.
  
      @par combine and combine_each
          - Both methods are defined for enumerable_thread_specific.
          - combine() requires the type T have operator=() defined.
          - neither method modifies the contents of the object (though there is no guarantee that the applied methods do not modify the object.)
          - Both are evaluated in serial context (the methods are assumed to be non-benign.)
  
      @ingroup containers */
      template <typename T,
                typename Allocator=cache_aligned_allocator<T>,
                ets_key_usage_type ETS_key_type=ets_no_key >
      class enumerable_thread_specific: internal::ets_base<ETS_key_type> {
  
          template<typename U, typename A, ets_key_usage_type C> friend class enumerable_thread_specific;
  
          typedef internal::padded< internal::ets_element<T> > padded_element;
  
          //! A generic range, used to create range objects from the iterators
          template<typename I>
          class generic_range_type: public blocked_range<I> {
          public:
              typedef T value_type;
              typedef T& reference;
              typedef const T& const_reference;
              typedef I iterator;
              typedef ptrdiff_t difference_type;
              generic_range_type( I begin_, I end_, size_t grainsize_ = 1) : blocked_range<I>(begin_,end_,grainsize_) {}
              template<typename U>
              generic_range_type( const generic_range_type<U>& r) : blocked_range<I>(r.begin(),r.end(),r.grainsize()) {}
              generic_range_type( generic_range_type& r, split ) : blocked_range<I>(r,split()) {}
          };
  
          typedef typename Allocator::template rebind< padded_element >::other padded_allocator_type;
          typedef tbb::concurrent_vector< padded_element, padded_allocator_type > internal_collection_type;
  
          internal::callback_base<T> *my_construct_callback;
  
          internal_collection_type my_locals;
  
          // TODO: consider unifying the callback mechanism for all create_local* methods below
          //   (likely non-compatible and requires interface version increase)
          void* create_local() __TBB_override {
              padded_element& lref = *my_locals.grow_by(1);
              my_construct_callback->construct(lref.value());
              return lref.value_committed();
          }
  
          static void* create_local_by_copy( internal::ets_base<ets_no_key>& base, void* p ) {
              enumerable_thread_specific& ets = static_cast<enumerable_thread_specific&>(base);
              padded_element& lref = *ets.my_locals.grow_by(1);
              new(lref.value()) T(*static_cast<T*>(p));
              return lref.value_committed();
          }
  
  #if __TBB_ETS_USE_CPP11
          static void* create_local_by_move( internal::ets_base<ets_no_key>& base, void* p ) {
              enumerable_thread_specific& ets = static_cast<enumerable_thread_specific&>(base);
              padded_element& lref = *ets.my_locals.grow_by(1);
              new(lref.value()) T(std::move(*static_cast<T*>(p)));
              return lref.value_committed();
          }
  #endif
  
          typedef typename Allocator::template rebind< uintptr_t >::other array_allocator_type;
  
          // _size is in bytes
          void* create_array(size_t _size) __TBB_override {
              size_t nelements = (_size + sizeof(uintptr_t) -1) / sizeof(uintptr_t);
              return array_allocator_type().allocate(nelements);
          }
  
          void free_array( void* _ptr, size_t _size) __TBB_override {
              size_t nelements = (_size + sizeof(uintptr_t) -1) / sizeof(uintptr_t);
              array_allocator_type().deallocate( reinterpret_cast<uintptr_t *>(_ptr),nelements);
          }
  
      public:
  
          //! Basic types
          typedef Allocator allocator_type;
          typedef T value_type;
          typedef T& reference;
          typedef const T& const_reference;
          typedef T* pointer;
          typedef const T* const_pointer;
          typedef typename internal_collection_type::size_type size_type;
          typedef typename internal_collection_type::difference_type difference_type;
  
          // Iterator types
          typedef typename internal::enumerable_thread_specific_iterator< internal_collection_type, value_type > iterator;
          typedef typename internal::enumerable_thread_specific_iterator< internal_collection_type, const value_type > const_iterator;
  
          // Parallel range types
          typedef generic_range_type< iterator > range_type;
          typedef generic_range_type< const_iterator > const_range_type;
  
          //! Default constructor.  Each local instance of T is default constructed.
          enumerable_thread_specific() : my_construct_callback(
              internal::callback_leaf<T,internal::construct_by_default<T> >::make(/*dummy argument*/0)
          ){}
  
          //! Constructor with initializer functor.  Each local instance of T is constructed by T(finit()).
          template <typename Finit
  #if __TBB_ETS_USE_CPP11
                    , typename = typename internal::enable_if<internal::is_callable_no_args<typename internal::strip<Finit>::type>::value>::type
  #endif
          >
          explicit enumerable_thread_specific( Finit finit ) : my_construct_callback(
              internal::callback_leaf<T,internal::construct_by_finit<T,Finit> >::make( tbb::internal::move(finit) )
          ){}
  
          //! Constructor with exemplar. Each local instance of T is copy-constructed from the exemplar.
          explicit enumerable_thread_specific( const T& exemplar ) : my_construct_callback(
              internal::callback_leaf<T,internal::construct_by_exemplar<T> >::make( exemplar )
          ){}
  
  #if __TBB_ETS_USE_CPP11
          explicit enumerable_thread_specific( T&& exemplar ) : my_construct_callback(
              internal::callback_leaf<T,internal::construct_by_exemplar<T> >::make( std::move(exemplar) )
          ){}
  
          //! Variadic constructor with initializer arguments.  Each local instance of T is constructed by T(args...)
          template <typename P1, typename... P,
                    typename = typename internal::enable_if<!internal::is_callable_no_args<typename internal::strip<P1>::type>::value
                                                            && !internal::is_compatible_ets<T, typename internal::strip<P1>::type>::value
                                                            && !internal::is_same_type<T, typename internal::strip<P1>::type>::value
                                                           >::type>
          enumerable_thread_specific( P1&& arg1, P&& ... args ) : my_construct_callback(
              internal::callback_leaf<T,internal::construct_by_args<T,P1,P...> >::make( std::forward<P1>(arg1), std::forward<P>(args)... )
          ){}
  #endif
  
          //! Destructor
          ~enumerable_thread_specific() {
              if(my_construct_callback) my_construct_callback->destroy();
              // Deallocate the hash table before overridden free_array() becomes inaccessible
              this->internal::ets_base<ets_no_key>::table_clear();
          }
  
          //! returns reference to local, discarding exists
          reference local() {
              bool exists;
              return local(exists);
          }
  
          //! Returns reference to calling thread's local copy, creating one if necessary
          reference local(bool& exists)  {
              void* ptr = this->table_lookup(exists);
              return *(T*)ptr;
          }
  
          //! Get the number of local copies
          size_type size() const { return my_locals.size(); }
  
          //! true if there have been no local copies created
          bool empty() const { return my_locals.empty(); }
  
          //! begin iterator
          iterator begin() { return iterator( my_locals, 0 ); }
          //! end iterator
          iterator end() { return iterator(my_locals, my_locals.size() ); }
  
          //! begin const iterator
          const_iterator begin() const { return const_iterator(my_locals, 0); }
  
          //! end const iterator
          const_iterator end() const { return const_iterator(my_locals, my_locals.size()); }
  
          //! Get range for parallel algorithms
          range_type range( size_t grainsize=1 ) { return range_type( begin(), end(), grainsize ); }
  
          //! Get const range for parallel algorithms
          const_range_type range( size_t grainsize=1 ) const { return const_range_type( begin(), end(), grainsize ); }
  
          //! Destroys local copies
          void clear() {
              my_locals.clear();
              this->table_clear();
              // callback is not destroyed
          }
  
      private:
  
          template<typename A2, ets_key_usage_type C2>
          void internal_copy(const enumerable_thread_specific<T, A2, C2>& other) {
  #if __TBB_ETS_USE_CPP11 && TBB_USE_ASSERT
              // this tests is_compatible_ets
              __TBB_STATIC_ASSERT( (internal::is_compatible_ets<T, typename internal::strip<decltype(other)>::type>::value), "is_compatible_ets fails" );
  #endif
              // Initialize my_construct_callback first, so that it is valid even if rest of this routine throws an exception.
              my_construct_callback = other.my_construct_callback->clone();
              __TBB_ASSERT(my_locals.size()==0,NULL);
              my_locals.reserve(other.size());
              this->table_elementwise_copy( other, create_local_by_copy );
          }
  
          void internal_swap(enumerable_thread_specific& other) {
              using std::swap;
              __TBB_ASSERT( this!=&other, NULL );
              swap(my_construct_callback, other.my_construct_callback);
              // concurrent_vector::swap() preserves storage space,
              // so addresses to the vector kept in ETS hash table remain valid.
              swap(my_locals, other.my_locals);
              this->internal::ets_base<ETS_key_type>::table_swap(other);
          }
  
  #if __TBB_ETS_USE_CPP11
          template<typename A2, ets_key_usage_type C2>
          void internal_move(enumerable_thread_specific<T, A2, C2>&& other) {
  #if TBB_USE_ASSERT
              // this tests is_compatible_ets
              __TBB_STATIC_ASSERT( (internal::is_compatible_ets<T, typename internal::strip<decltype(other)>::type>::value), "is_compatible_ets fails" );
  #endif
              my_construct_callback = other.my_construct_callback;
              other.my_construct_callback = NULL;
              __TBB_ASSERT(my_locals.size()==0,NULL);
              my_locals.reserve(other.size());
              this->table_elementwise_copy( other, create_local_by_move );
          }
  #endif
  
      public:
  
          enumerable_thread_specific( const enumerable_thread_specific& other )
          : internal::ets_base<ETS_key_type>() /* prevents GCC warnings with -Wextra */
          {
              internal_copy(other);
          }
  
          template<typename Alloc, ets_key_usage_type Cachetype>
          enumerable_thread_specific( const enumerable_thread_specific<T, Alloc, Cachetype>& other )
          {
              internal_copy(other);
          }
  
  #if __TBB_ETS_USE_CPP11
          enumerable_thread_specific( enumerable_thread_specific&& other ) : my_construct_callback()
          {
              internal_swap(other);
          }
  
          template<typename Alloc, ets_key_usage_type Cachetype>
          enumerable_thread_specific( enumerable_thread_specific<T, Alloc, Cachetype>&& other ) : my_construct_callback()
          {
              internal_move(std::move(other));
          }
  #endif
  
          enumerable_thread_specific& operator=( const enumerable_thread_specific& other )
          {
              if( this != &other ) {
                  this->clear();
                  my_construct_callback->destroy();
                  internal_copy( other );
              }
              return *this;
          }
  
          template<typename Alloc, ets_key_usage_type Cachetype>
          enumerable_thread_specific& operator=( const enumerable_thread_specific<T, Alloc, Cachetype>& other )
          {
              __TBB_ASSERT( static_cast<void*>(this)!=static_cast<const void*>(&other), NULL ); // Objects of different types
              this->clear();
              my_construct_callback->destroy();
              internal_copy(other);
              return *this;
          }
  
  #if __TBB_ETS_USE_CPP11
          enumerable_thread_specific& operator=( enumerable_thread_specific&& other )
          {
              if( this != &other )
                  internal_swap(other);
              return *this;
          }
  
          template<typename Alloc, ets_key_usage_type Cachetype>
          enumerable_thread_specific& operator=( enumerable_thread_specific<T, Alloc, Cachetype>&& other )
          {
              __TBB_ASSERT( static_cast<void*>(this)!=static_cast<const void*>(&other), NULL ); // Objects of different types
              this->clear();
              my_construct_callback->destroy();
              internal_move(std::move(other));
              return *this;
          }
  #endif
  
          // combine_func_t has signature T(T,T) or T(const T&, const T&)
          template <typename combine_func_t>
          T combine(combine_func_t f_combine) {
              if(begin() == end()) {
                  internal::ets_element<T> location;
                  my_construct_callback->construct(location.value());
                  return *location.value_committed();
              }
              const_iterator ci = begin();
              T my_result = *ci;
              while(++ci != end())
                  my_result = f_combine( my_result, *ci );
              return my_result;
          }
  
          // combine_func_t takes T by value or by [const] reference, and returns nothing
          template <typename combine_func_t>
          void combine_each(combine_func_t f_combine) {
              for(iterator ci = begin(); ci != end(); ++ci) {
                  f_combine( *ci );
              }
          }
  
      }; // enumerable_thread_specific
  
      template< typename Container >
      class flattened2d {
  
          // This intermediate typedef is to address issues with VC7.1 compilers
          typedef typename Container::value_type conval_type;
  
      public:
  
          //! Basic types
          typedef typename conval_type::size_type size_type;
          typedef typename conval_type::difference_type difference_type;
          typedef typename conval_type::allocator_type allocator_type;
          typedef typename conval_type::value_type value_type;
          typedef typename conval_type::reference reference;
          typedef typename conval_type::const_reference const_reference;
          typedef typename conval_type::pointer pointer;
          typedef typename conval_type::const_pointer const_pointer;
  
          typedef typename internal::segmented_iterator<Container, value_type> iterator;
          typedef typename internal::segmented_iterator<Container, const value_type> const_iterator;
  
          flattened2d( const Container &c, typename Container::const_iterator b, typename Container::const_iterator e ) :
              my_container(const_cast<Container*>(&c)), my_begin(b), my_end(e) { }
  
          explicit flattened2d( const Container &c ) :
              my_container(const_cast<Container*>(&c)), my_begin(c.begin()), my_end(c.end()) { }
  
          iterator begin() { return iterator(*my_container) = my_begin; }
          iterator end() { return iterator(*my_container) = my_end; }
          const_iterator begin() const { return const_iterator(*my_container) = my_begin; }
          const_iterator end() const { return const_iterator(*my_container) = my_end; }
  
          size_type size() const {
              size_type tot_size = 0;
              for(typename Container::const_iterator i = my_begin; i != my_end; ++i) {
                  tot_size += i->size();
              }
              return tot_size;
          }
  
      private:
  
          Container *my_container;
          typename Container::const_iterator my_begin;
          typename Container::const_iterator my_end;
  
      };
  
      template <typename Container>
      flattened2d<Container> flatten2d(const Container &c, const typename Container::const_iterator b, const typename Container::const_iterator e) {
          return flattened2d<Container>(c, b, e);
      }
  
      template <typename Container>
      flattened2d<Container> flatten2d(const Container &c) {
          return flattened2d<Container>(c);
      }
  
  } // interface6
  
  namespace internal {
  using interface6::internal::segmented_iterator;
  }
  
  using interface6::enumerable_thread_specific;
  using interface6::flattened2d;
  using interface6::flatten2d;
  
  } // namespace tbb
  
  #endif
  