diff options
Diffstat (limited to 'src/corelib/tools/qarraydatapointer.h')
-rw-r--r-- | src/corelib/tools/qarraydatapointer.h | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/src/corelib/tools/qarraydatapointer.h b/src/corelib/tools/qarraydatapointer.h index 5e89fd0026..b458dc3626 100644 --- a/src/corelib/tools/qarraydatapointer.h +++ b/src/corelib/tools/qarraydatapointer.h @@ -305,6 +305,53 @@ public: this->ptr = res; } + template <typename InputIterator> + void assign(InputIterator first, InputIterator last) + { + // This function only provides the basic exception guarantee. + constexpr bool IsFwdIt = std::is_convertible_v< + typename std::iterator_traits<InputIterator>::iterator_category, + std::forward_iterator_tag>; + + if constexpr (IsFwdIt) { + const qsizetype n = std::distance(first, last); + // Use of freeSpaceAtBegin() isn't, yet, implemented. + const auto usableCapacity = constAllocatedCapacity() - freeSpaceAtBegin(); + if (needsDetach() || n > usableCapacity) { + QArrayDataPointer allocated(Data::allocate(detachCapacity(n))); + swap(allocated); + } + } else if (needsDetach()) { + QArrayDataPointer allocated(Data::allocate(allocatedCapacity())); + swap(allocated); + // We don't want to copy data that we know we'll overwrite + } + + auto dst = begin(); + const auto dend = end(); + while (true) { + if (first == last) { // ran out of elements to assign + std::destroy(dst, dend); + break; + } + if (dst == dend) { // ran out of existing elements to overwrite + if constexpr (IsFwdIt) { + dst = std::uninitialized_copy(first, last, dst); + break; + } else { + do { + (*this)->emplace(size, *first); + } while (++first != last); + return; // size() is already correct (and dst invalidated)! + } + } + *dst = *first; // overwrite existing element + ++dst; + ++first; + } + size = dst - begin(); + } + // forwards from QArrayData qsizetype allocatedCapacity() noexcept { return d ? d->allocatedCapacity() : 0; } qsizetype constAllocatedCapacity() const noexcept { return d ? d->constAllocatedCapacity() : 0; } |