std::experi...nges::search(3)

👑 std::experimental::ranges::search 👑

okay so bestie, welcome to the std::experi...nges::search(3) page from the C++ Standard Libary (yes, that spelling is literally what the header says, we don’t make the rules 💅). this one is all about hunting down one sequence inside another, and it’s giving “where is that subsequence at?” energy. no cap.

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🌸 NAME 🌸

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

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✨ Synopsis ✨

Defined in header <experimental/ranges/algorithm> — and here’s the whole declaration moment, literally:

          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. It 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 it 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. So if explicit template arguments are used when calling an algorithm, the program is probably non-portable. that’s the tea. ☕

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🎀 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

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🫶 Return value 🫶

An iterator to the beginning of the first occurrence of the sequence [first2, last2) in the range [first1, last1).

If [first2, last2) is empty, first1 is returned. If no such occurrence is found, an iterator that compares equal to last1 is returned. periodt. 💅

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🔥 Complexity 🔥

At most S * N applications of the predicate and each projection, where S = last2 - first2 and N = last1 - first1. that’s the budget, bestie — don’t blow it. ⭐

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🧚 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;
                  }
              }
          }

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💀 Example 💀

This section is incomplete.

Reason: no example.

😭 we’re manifesting an example for the next update, fr fr.

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🌈 See also 🌈

• search — searches for a range of elements (function template)
• find_end — finds the last sequence of elements in a certain range (function template)
• includes — returns true if one set is a subset of another (function template)
• equal — determines if two sets of elements are the same (function template)
• find — finds the first element satisfying specific criteria
• find_if — (function template)
• find_if_not — see-also entry in the same cluster; this page doesn’t give it a separate description
• lexicographical_compare — returns true if one range is lexicographically less than another (function template)
• mismatch — finds the first position where two ranges differ (function template)
• search_n — searches for a number consecutive copies of an element in a range (function template)

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🍓 Category 🍓

• * Todo no example

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💖 source/version: http://cppreference.com, dated 2024.06.10 — bye bestie, go find those subsequences! 💖