114     uint32_t position_ = 0;  member
158   maybe_const<T>& operator*() { return current_->items()[position_]; }
159   maybe_const<T>* operator->() { return &current_->items()[position_]; }
161     return other.current_ == current_ && other.position_ == position_;
199     position_ += amount;  in Advance()
200     while (position_ > 0 && position_ >= current_->capacity_) {  in Advance()
201       auto overshoot = position_ - current_->capacity_;  in Advance()
203       position_ = overshoot;  in Advance()
205       DCHECK(position_ == 0 || current_);  in Advance()
222     if (list->back_->position_ == 0) {  in Begin()
230     return ZoneChunkListIterator(list->back_, list->back_->position_ - 1);  in Begin()
240     DCHECK_LE(list->back_->position_, list->back_->capacity_);  in End()
241     if (list->back_->position_ == list->back_->capacity_) {  in End()
245     return ZoneChunkListIterator(list->back_, list->back_->position_);  in End()
249       : current_(current), position_(position) {  in ZoneChunkListIterator()
257       if (position_ == 0) {  in Move()
259         position_ = current_ ? current_->capacity_ - 1 : 0;  in Move()
261         --position_;  in Move()
265       ++position_;  in Move()
266       if (position_ >= current_->capacity_) {  in Move()
268         position_ = 0;  in Move()
274   size_t position_;  variable
287   if (back_->position_ == 0) {  in back()
288     return back_->previous_->items()[back_->previous_->position_ - 1];  in back()
290     return back_->items()[back_->position_ - 1];  in back()
301   DCHECK_LE(back_->position_, back_->capacity_);  in push_back()
302   if (back_->position_ == back_->capacity_) {  in push_back()
310   back_->items()[back_->position_] = item;  in push_back()
311   ++back_->position_;  in push_back()
313   DCHECK_LE(back_->position_, back_->capacity_);  in push_back()
319   if (back_->position_ == 0) {  in pop_back()
322   --back_->position_;  in pop_back()
338   chunk->position_ = 1;  in push_front()
363   seek_result.chunk_->position_ = seek_result.chunk_index_;  in Rewind()
371     current->position_ = 0;  in Rewind()
396     void* end = current->items() + current->position_;  in CopyTo()
401     ptr += current->position_;  in CopyTo()