+
+ iterator insert(iterator I, size_type NumToInsert, const T &Elt) {
+ if (I == End) { // Important special case for empty vector.
+ append(NumToInsert, Elt);
+ return end()-1;
+ }
+
+ // Convert iterator to elt# to avoid invalidating iterator when we reserve()
+ size_t InsertElt = I-begin();
+
+ // Ensure there is enough space.
+ reserve(static_cast<unsigned>(size() + NumToInsert));
+
+ // Uninvalidate the iterator.
+ I = begin()+InsertElt;
+
+ // If there are more elements between the insertion point and the end of the
+ // range than there are being inserted, we can use a simple approach to
+ // insertion. Since we already reserved space, we know that this won't
+ // reallocate the vector.
+ if (size_t(end()-I) >= NumToInsert) {
+ T *OldEnd = End;
+ append(End-NumToInsert, End);
+
+ // Copy the existing elements that get replaced.
+ std::copy(I, OldEnd-NumToInsert, I+NumToInsert);
+
+ std::fill_n(I, NumToInsert, Elt);
+ 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;
+ size_t NumOverwritten = OldEnd-I;
+ std::uninitialized_copy(I, OldEnd, End-NumOverwritten);
+
+ // Replace the overwritten part.
+ std::fill_n(I, NumOverwritten, Elt);
+
+ // Insert the non-overwritten middle part.
+ std::uninitialized_fill_n(OldEnd, NumToInsert-NumOverwritten, Elt);
+ return I;
+ }
+
+ 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;
+ }
+
+ size_t NumToInsert = std::distance(From, To);
+ // Convert iterator to elt# to avoid invalidating iterator when we reserve()
+ size_t InsertElt = I-begin();
+
+ // Ensure there is enough space.
+ reserve(static_cast<unsigned>(size() + NumToInsert));
+
+ // Uninvalidate the iterator.
+ I = begin()+InsertElt;
+
+ // If there are more elements between the insertion point and the end of the
+ // range than there are being inserted, we can use a simple approach to
+ // insertion. Since we already reserved space, we know that this won't
+ // reallocate the vector.
+ if (size_t(end()-I) >= 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;
+ size_t 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;
+ }
+