183 class CountIter : public std::iterator<std::forward_iterator_tag, size_t, size_t, size_t, size_t> {
185   CountIter() : count_(0) {}  in CountIter()  function
186   explicit CountIter(size_t count) : count_(count) {}  in CountIter()  function
187   CountIter& operator++() {
191   CountIter operator++(int) {
194     return CountIter(ret);
196   bool operator==(const CountIter& other) const {
199   bool operator!=(const CountIter& other) const {
212 static inline IterationRange<ZipLeftIter<Iter, CountIter>> ZipCount(IterationRange<Iter> iter) {  in ZipCount()
213   return IterationRange(ZipLeftIter(iter.begin(), CountIter(0)),  in ZipCount()
214                         ZipLeftIter(iter.end(), CountIter(-1)));  in ZipCount()