switched from available to size_

include/boost/unordered/detail/foa/concurrent_table.hpp

@@ -255,9 +255,9 @@ public:
   std::size_t size()const noexcept
   {
     auto lck=shared_access();
-    std::size_t ml_=this->ml; /* load order matters */
+    std::size_t ml_=this->ml;
-    std::size_t available_=this->available;
+    std::size_t size_=this->size_;
-    return ml_-available_;
+    return size_<=ml_?size_:ml_;
   }
 
   using super::max_size; 
@@ -522,7 +522,7 @@ private:
       this->al(),std::forward<Args>(args)...);
     int res=unprotected_norehash_emplace_or_visit(
       std::forward<F>(f),type_policy::move(x.value()));
-    if(res>=0)return res!=0;
+    if(BOOST_LIKELY(res>=0))return res!=0;
 
     lck.unlock();
 
@@ -553,34 +553,30 @@ private:
         auto lck=shared_access();
         int res=unprotected_norehash_emplace_or_visit(
           std::forward<F>(f),std::forward<Args>(args)...);
-        if(res>=0)return res!=0;
+        if(BOOST_LIKELY(res>=0))return res!=0;
       }
       rehash_if_full();
     }
   }
 
-  struct reserve_available
+  struct reserve_size
   {
-    reserve_available(concurrent_table& x_):x{x_}
+    reserve_size(concurrent_table& x_):x{x_}
     {
-      do{
+      size_=++x.size_;
-        available=x.available.load(std::memory_order_relaxed);
-      }while(
-        available&&!x.available.compare_exchange_weak(available,available-1));
     }
 
-    ~reserve_available()
+    ~reserve_size()
     {
-      if(!commit_&&available){
+      if(!commit_)--x.size_;
-        x.available.fetch_add(1,std::memory_order_release);
-      }
     }
 
-    bool succeeded()const{return available!=0;}
+    bool succeeded()const{return size_<=x.ml;}
+
     void commit(){commit_=true;}
 
     concurrent_table &x;
-    std::size_t       available;
+    std::size_t       size_;
     bool              commit_=false;
   };
 
@@ -595,10 +591,10 @@ private:
     for(;;){
     startover:
       boost::uint32_t counter=insert_counter(pos0);
-      if(unprotected_visit(k,pos0,hash,f))return 0;
+      if(unprotected_visit(k,pos0,hash,std::forward<F>(f)))return 0;
 
-      reserve_available ra(*this);
+      reserve_size rs(*this);
-      if(BOOST_LIKELY(ra.succeeded())){
+      if(BOOST_LIKELY(rs.succeeded())){
         for(prober pb(pos0);;pb.next(this->arrays.groups_size_mask)){
           auto pos=pb.get();
           auto pg=this->arrays.groups+pos;
@@ -616,7 +612,7 @@ private:
                 }
                 auto p=this->arrays.elements+pos*N+n;
                 this->construct_element(p,std::forward<Args>(args)...);
-                ra.commit();
+                rs.commit();
                 f(type_policy::value_from(*p)); 
                 return 1;
               }
@@ -634,7 +630,7 @@ private:
   {
     auto lck=exclusive_access();
     // TODO: use same mechanism as unchecked_emplace_with_rehash
-    if(!this->available)this->super::rehash(super::capacity()+1);
+    if(this->size_==this->ml)this->super::rehash(super::capacity()+1);
   }
 
   shared_lock_guard shared_access()const

include/boost/unordered/detail/foa/core.hpp

@@ -1191,7 +1191,7 @@ public:
     const Pred& pred_=Pred(),const Allocator& al_=Allocator()):
     hash_base{empty_init,h_},pred_base{empty_init,pred_},
     allocator_base{empty_init,al_},arrays(new_arrays(n)),
-    ml{initial_max_load()},available{std::size_t(ml)}
+    ml{initial_max_load()},size_{0}
     {}
 
   table_core(const table_core& x):
@@ -1205,11 +1205,11 @@ public:
     hash_base{empty_init,std::move(x.h())},
     pred_base{empty_init,std::move(x.pred())},
     allocator_base{empty_init,std::move(x.al())},
-    arrays(x.arrays),ml{std::size_t(x.ml)},available{std::size_t(x.available)}
+    arrays(x.arrays),ml{std::size_t(x.ml)},size_{std::size_t(x.size_)}
   {
     x.arrays=x.new_arrays(0);
     x.ml=x.initial_max_load();
-    x.available=std::size_t(x.ml);
+    x.size_=std::size_t(x.size_);
   }
 
   table_core(const table_core& x,const Allocator& al_):
@@ -1224,7 +1224,7 @@ public:
     if(al()==x.al()){
       std::swap(arrays,x.arrays);
       std::swap(ml,x.ml);
-      std::swap(available,x.available);
+      std::swap(size_,x.size_);
     }
     else{
       reserve(x.size());
@@ -1323,7 +1323,7 @@ public:
         move_assign_if<pocma>(al(),x.al());
         swap(arrays,x.arrays);
         swap(ml,x.ml);
-        swap(available,x.available);
+        swap(size_,x.size_);
       }
       else{
         /* noshrink: favor memory reuse over tightness */
@@ -1349,7 +1349,7 @@ public:
   allocator_type get_allocator()const noexcept{return al();}
 
   bool        empty()const noexcept{return size()==0;}
-  std::size_t size()const noexcept{return ml-available;}
+  std::size_t size()const noexcept{return size_;}
   std::size_t max_size()const noexcept{return SIZE_MAX;}
 
   // TODO unify erase?
@@ -1391,7 +1391,7 @@ public:
     swap(pred(),x.pred());
     swap(arrays,x.arrays);
     swap(ml,x.ml);
-    swap(available,x.available);
+    swap(size_,x.size_);
   }
 
   void clear()noexcept
@@ -1410,7 +1410,7 @@ public:
       }
       arrays.groups[arrays.groups_size_mask].set_sentinel();
       ml=initial_max_load();
-      available=std::size_t(ml);
+      size_=0;
     }
   }
 
@@ -1545,7 +1545,7 @@ public:
   {
     auto res=nosize_unchecked_emplace_at(
       arrays,pos0,hash,std::forward<Args>(args)...);
-    --available;
+    ++size_;
     return res;
   }
 
@@ -1580,7 +1580,7 @@ public:
 
     /* new_arrays_ lifetime taken care of by unchecked_rehash */
     unchecked_rehash(new_arrays_);
-    --available;
+    ++size_;
     return it;
   }
 
@@ -1649,7 +1649,7 @@ public:
 
   arrays_type arrays;
   SizeImpl    ml;
-  SizeImpl    available;
+  SizeImpl    size_;
 
 private:
   template<typename,typename,typename,typename,typename,typename>
@@ -1712,7 +1712,7 @@ private:
       std::memcpy(
         arrays.groups,x.arrays.groups,
         (arrays.groups_size_mask+1)*sizeof(group_type));
-      available=std::size_t(x.available);
+      size_=std::size_t(x.size_);
     }
   }
 
@@ -1775,10 +1775,9 @@ private:
      * that average probe length won't increase unboundedly in repeated
      * insert/erase cycles (drift).
      */
-    bool ofw=group_type::maybe_caused_overflow(pc);
+    ml-=group_type::maybe_caused_overflow(pc);
     group_type::reset(pc);
-    ml-=ofw;
+    --size_;
-    available+=!ofw;
   }
 
   void recover_slot(group_type* pg,std::size_t pos)
@@ -1844,9 +1843,7 @@ private:
     }
     delete_arrays(arrays);
     arrays=new_arrays_;
-    auto s=size();
     ml=initial_max_load();
-    available=ml-s;
   }
 
   void noshrink_reserve(std::size_t n)
@@ -1862,9 +1859,7 @@ private:
         auto new_arrays_=new_arrays(n);
         delete_arrays(arrays);
         arrays=new_arrays_;
-        auto s=size();
         ml=initial_max_load();
-        available=ml-s;
       }
     }
   }

include/boost/unordered/detail/foa/table.hpp

@@ -492,7 +492,7 @@ private:
     if(it!=end()){
       return {it,false};
     }
-    if(BOOST_LIKELY(this->available!=0)){
+    if(BOOST_LIKELY(this->size_<this->ml)){
       return {
         make_iterator(
           this->unchecked_emplace_at(pos0,hash,std::forward<Args>(args)...)),