std::experimental::ranges::search (3) - Linux Manuals

std::experimental::ranges::search: std::experimental::ranges::search

NAME

std::experimental::ranges::search - std::experimental::ranges::search

Synopsis

Defined in header <experimental/ranges/algorithm>
template< ForwardIterator I1, Sentinel<I1> S1,
ForwardIterator I2, Sentinel<I2> S2, class Pred = ranges::equal_to<>,
class Proj1 = ranges::identity, class Proj2 = ranges::identity > (1) (ranges TS)
requires IndirectlyComparable<I1, I2, Pred, Proj1, Proj2>
I1 search(I1 first1, S1 last1, I2 first2, S2 last2,
Pred pred = Pred{}, Proj1 proj1 = Proj1{}, Proj2 proj2 = Proj2{});
template< ForwardRange R1, ForwardRange R2, class Pred = ranges::equal_to<>,
class Proj1 = ranges::identity, class Proj2 = ranges::identity >
requires IndirectlyComparable<ranges::iterator_t<R1>, ranges::iterator_t<R2>, (2) (ranges TS)
Pred, Proj1, Proj2>
ranges::safe_iterator_t<R1> search(R1&& r1, R2&& r2, Pred pred = Pred{},
Proj1 proj1 = Proj1{}, Proj2 proj2 = Proj2{});

1) Searches for the first occurrence of the sequence of elements [first2, last2) in the range [first1, last1). Elements are compared using pred after being projected with proj2 and proj1, respectively.
2) Same as (1), but uses r1 as the first source range and r2 as the second source range, as if using ranges::begin(r1) as first1, ranges::end(r1) as last1, ranges::begin(r2) as first2, and ranges::end(r2) as last2.
Notwithstanding the declarations depicted above, the actual number and order of template parameters for algorithm declarations is unspecified. Thus, if explicit template arguments are used when calling an algorithm, the program is probably non-portable.

Parameters

first1, last1 - the range of elements to examine
r1 - the range of elements to examine
first2, last2 - the range of elements to search for
r2 - the range of elements to search for
pred - predicate to apply to the projected elements
proj1 - projection to apply to the elements in the first range
proj2 - projection to apply to the elements in the second range

Return value

An iterator to the beginning of first occurrence of the sequence [first2, last2) in the range [first1, last1). If [first2, last2) is empty, first1 is returned. If If no such occurrence is found, an iterator that compares equal to last1 is returned.

Complexity

At most S*N applications of the predicate and each projection, where S = last2 - first2 and N = last1 - first1.

Possible implementation

  template< ForwardIterator I1, Sentinel<I1> S1,
            ForwardIterator I2, Sentinel<I2> S2, class Pred = ranges::equal_to<>,
            class Proj1 = ranges::identity, class Proj2 = ranges::identity >
    requires IndirectlyComparable<I1, I2, Pred, Proj1, Proj2>
  I1 search(I1 first1, S1 last1, I2 first2, S2 last2,
            Pred pred = Pred{}, Proj1 proj1 = Proj1{}, Proj2 proj2 = Proj2{})
  {
      for (; ; ++first1) {
          I1 it = first1;
          for (I2 it2 = first2; ; (void)++it, (void)++it2) {
              if (it2 == last2) {
                  return first1;
              }
              if (it == last1) {
                  return it;
              }
              if (!ranges::invoke(pred, ranges::invoke(proj1, *it),
                                        ranges::invoke(proj2, *it2))) {
                  break;
              }
          }
      }
  }

Example

 This section is incomplete
 Reason: no example