Ticket #2810: list.hpp.patch

list.hpp

@@ -1021 +1023 @@
    template<class Predicate>
    void merge(list_impl& x, Predicate p)
    {
-      const_iterator e(this->end());
-      const_iterator bx(x.begin());
-      const_iterator ex(x.end());
+      const_iterator b = this->cbegin(), e = this->cend();
+      const_iterator ex = x.cend();
 
-      for (const_iterator b = this->cbegin(); b != e; ++b) {
-         size_type n(0);
-         const_iterator ix(bx);
-         while(ix != ex && p(*ix, *b)){
-            ++ix; ++n;
+      while (!x.empty())
+      {
+         const_iterator bx = x.cbegin();
+         while (b != e && p(*bx, *b))
+         {
+            ++b;
          }
-         this->splice(b, x, bx, ix, n);
-         bx = ix;
+
+         if (b != e)
+         {
+            // determine the end of the range of x to inject at b
+            size_type n = 0;
+            do
+            {
+               ++bx;
+               ++n;
+            }
+            while (bx != ex && p(*bx, *b));
+            this->splice(b, x, x.cbegin(), bx, n);
+         }
+         else
+         {
+            // the rest of the list is to be appended to the end
+            this->splice(e, x);
+            break;
+         }
       }
-      //Now transfer the rest at the end of the container
-      this->splice(e, x);
    }
 
    //! <b>Effects</b>: Reverses the order of elements in the list.