+ construct_range(Begin, End, Elt);
+ }
+
+ void erase(iterator I) {
+ // Shift all elts down one.
+ std::copy(I+1, End, I);
+ // Drop the last elt.
+ pop_back();
+ }
+
+ void erase(iterator S, iterator E) {
+ // Shift all elts down.
+ iterator I = std::copy(E, End, S);
+ // Drop the last elts.
+ destroy_range(I, End);
+ End = I;
+ }
+
+ iterator insert(iterator I, const T &Elt) {
+ if (I == End) { // Important special case for empty vector.
+ push_back(Elt);
+ return end()-1;
+ }
+
+ if (End < Capacity) {
+ Retry:
+ new (End) T(back());
+ ++End;
+ // Push everything else over.
+ std::copy_backward(I, End-1, End);
+ *I = Elt;
+ return I;
+ }
+ unsigned EltNo = I-Begin;
+ grow();
+ I = Begin+EltNo;
+ goto Retry;
+ }
+
+ template<typename ItTy>
+ iterator insert(iterator I, ItTy From, ItTy To) {
+ if (I == End) { // Important special case for empty vector.
+ append(From, To);
+ return end()-1;
+ }
+
+ unsigned NumToInsert = std::distance(From, To);
+ // Convert iterator to elt# to avoid invalidating iterator when we reserve()
+ unsigned InsertElt = I-begin();
+
+ // Ensure there is enough space.
+ reserve(size() + NumToInsert);
+
+ // Uninvalidate the iterator.
+ I = begin()+InsertElt;
+
+ // If we already have this many elements in the collection, append the
+ // dest elements at the end, then copy over the appropriate elements. Since
+ // we already reserved space, we know that this won't reallocate the vector.
+ if (size() >= NumToInsert) {
+ T *OldEnd = End;
+ append(End-NumToInsert, End);
+
+ // Copy the existing elements that get replaced.
+ std::copy(I, OldEnd-NumToInsert, I+NumToInsert);
+
+ std::copy(From, To, I);
+ return I;
+ }
+
+ // Otherwise, we're inserting more elements than exist already, and we're
+ // not inserting at the end.
+
+ // Copy over the elements that we're about to overwrite.
+ T *OldEnd = End;
+ End += NumToInsert;
+ unsigned NumOverwritten = OldEnd-I;
+ std::uninitialized_copy(I, OldEnd, End-NumOverwritten);
+
+ // Replace the overwritten part.
+ std::copy(From, From+NumOverwritten, I);
+
+ // Insert the non-overwritten middle part.
+ std::uninitialized_copy(From+NumOverwritten, To, OldEnd);
+ return I;