home | help 
std::boyer_...ol_searcher(3)   C++ Standard Libary  std::boyer_...ol_searcher(3)

NAME
     std::boyer_moore_horspool_searcher - std::boyer_moore_horspool_searcher

Synopsis
	Defined in header <functional>
	template< class RandomIt1,

		  class Hash = std::hash<typename
	std::iterator_traits<RandomIt1>::value_type>,
     (since C++17)
		  class BinaryPredicate = std::equal_to<> >

	class boyer_moore_horspool_searcher;

	A  searcher  suitable  for use with the Searcher overload of std::search
     that
	implements the Boyer-Moore-Horspool string searching algorithm.

	std::boyer_moore_horspool_searcher is CopyConstructible and CopyAssigna-
     ble.

	RandomIt1 must meet the requirements of LegacyRandomAccessIterator.

Member functions
     std::boyer_moore_horspool_searcher::boyer_moore_horspool_searcher

	boyer_moore_horspool_searcher( RandomIt1 pat_first,

				       RandomIt1 pat_last,
				       Hash hf = Hash(),

				       BinaryPredicate pred =  BinaryPredicate()
     );

	Constructs  a  std::boyer_moore_horspool_searcher  by  storing copies of
     pat_first,
	pat_last, hf, and pred, setting up any necessary  internal  data  struc-
     tures.

	The  value  type  of  RandomIt1  must  be DefaultConstructible, CopyCon-
     structible and
	CopyAssignable.

	For any two  values  A	and  B	of  the  type  std::iterator_traits<Ran-
     domIt1>::value_type,
	if pred(A, B) == true, then hf(A) == hf(B) shall be true.

Parameters
	pat_first,  pat_last  - a pair of iterators designating the string to be
     searched for
	hf		    - a callable object used to hash the elements of the
     string
	pred		    - a callable object used to determine equality

Exceptions
	Any exceptions thrown by

	  * the copy constructor of RandomIt1;
	  * the default constructor, copy constructor, or copy assignment opera-
     tor of the
	    value type of RandomIt1; or
	  * the copy constructor or function call operator of BinaryPredicate or
     Hash.

	May also throw std::bad_alloc if additional memory required for internal
     data
	structures cannot be allocated.

     std::boyer_moore_horspool_searcher::operator()

	template< class RandomIt2 >
	std::pair<RandomIt2, RandomIt2> operator()( RandomIt2  first,  RandomIt2
     last )
	const;

	The  member  function  called by the Searcher overload of std::search to
     perform a
	search with this searcher. RandomIt2 must meet the requirements of
	LegacyRandomAccessIterator.

	RandomIt1 and RandomIt2 must have the same value type.

Parameters
	first, last - a pair of iterators designating the string to be examined

Return value
	If   the   pattern   [pat_first,    pat_last)	 is    empty,	 returns
     std::make_pair(first, first).

	Otherwise,  returns  a	pair of iterators to the first and one past last
     positions in
	[first, last) where a subsequence that	compares  equal  to  [pat_first,
     pat_last) as
	defined by pred is located, or std::make_pair(last, last) otherwise.

Notes
	      Feature-test macro	Value	 Std	Feature
	__cpp_lib_boyer_moore_searcher 201603L (C++17) searchers

Example
     // Run this code

      #include <algorithm>
      #include <functional>
      #include <iomanip>
      #include <iostream>
      #include <string_view>

      int main()
      {
	  constexpr std::string_view in =
	      "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed "
	      "do eiusmod tempor incididunt ut labore et dolore magna aliqua";

	  const std::string_view needle{"pisci"};

	  auto it = std::search(in.begin(), in.end(),
			std::boyer_moore_horspool_searcher(
			    needle.begin(), needle.end()));
	  if (it != in.end())
	      std::cout  <<  "The  string " << std::quoted(needle) << " found at
     offset "
			<< it - in.begin() << '\n';
	  else
	      std::cout <<  "The  string  "  <<  std::quoted(needle)  <<  "  not
     found\n";
      }

Output:
      The string "pisci" found at offset 43

See also
	search		     searches for a range of elements
			     (function template)
	default_searcher      standard	C++ library search algorithm implementa-
     tion
	(C++17) 	     (class template)
	boyer_moore_searcher Boyer-Moore search algorithm implementation
	(C++17) 	     (class template)

http://cppreference.com 	   2024.06.10	    std::boyer_...ol_searcher(3)
home | help