std::experimental:: boyer_moore_horspool_searcher, std::experimental:: make_boyer_moore_horspool_searcher

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C++
Experimental
Library fundamentals
Defined in header <experimental/functional>
template < class RandomIt1,

class Hash = std:: hash < typename std:: iterator_traits < RandomIt1 > :: value_type > ,
class BinaryPredicate = std:: equal_to <> >

class boyer_moore_horspool_searcher ;
(library fundamentals TS)

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

boyer_moore_horspool_searcher is CopyConstructible and CopyAssignable .

RandomIt1 must meet the requirements of LegacyRandomAccessIterator .

Member functions

std::experimental::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 boyer_moore_horspool_searcher by storing copies of pat_first , pat_last , hf , and pred , setting up any necessary internal data structures.

The value type of RandomIt1 must be DefaultConstructible , CopyConstructible and CopyAssignable .

For any two values A and B of the type std:: iterator_traits < RandomIt1 > :: 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 operator 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::experimental::boyer_moore_horspool_searcher:: operator()

template < class RandomIt2 >
RandomIt2 operator ( ) ( RandomIt2 first, RandomIt2 last ) const ;
(until C++17)
template < class RandomIt2 >
std:: pair < RandomIt2,RandomIt2 > operator ( ) ( RandomIt2 first, RandomIt2 last ) const ;
(since C++17)

The member function called by std::experimental::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 first .

Otherwise, an iterator to the first position in [ first , last ) where a subsequence that compares equal to [ pat_first , pat_last ) as defined by pred is located, or a copy of last otherwise.

(until C++17)

If the pattern [ pat_first , pat_last ) is empty, returns 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 make_pair ( last, last ) otherwise.

(since C++17)

Helper Functions

template < class RandomIt,

class Hash = std:: hash < typename std:: iterator_traits < RandomIt > :: value_type > ,
class BinaryPredicate = std:: equal_to <> >
boyer_moore_horspool_searcher < RandomIt, Hash, BinaryPredicate >
make_boyer_moore_horspool_searcher ( RandomIt pat_first,
RandomIt pat_last,
Hash hf = Hash ( ) ,

BinaryPredicate pred = BinaryPredicate ( ) ) ;
(library fundamentals TS)

Helper function that constructs a std::experimental::boyer_moore_horspool_searcher using template argument deduction. Equivalent to return boyer_moore_horspool_searcher < RandomIt, Hash, BinaryPredicate > ( pat_first, pat_last, hf, pred ) ;

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

Return value

A boyer_moore_horspool_searcher constructed with the arguments pat_first , pat_last , hf , and pred .

Example

Run this code 
#include <experimental/algorithm>
#include <experimental/functional>
#include <iostream>
#include <string>
 
int main()
{
    std::string in = "Lorem ipsum dolor sit amet, consectetur adipiscing elit,"
                     " sed do eiusmod tempor incididunt ut labore et dolore magna aliqua";
    std::string needle = "pisci";
    auto it = std::experimental::search(in.begin(), in.end(),
                  std::experimental::make_boyer_moore_horspool_searcher(
                      needle.begin(), needle.end()));
    if (it != in.end())
        std::cout << "The string " << needle << " found at offset "
                  << it - in.begin() << '\n';
    else
        std::cout << "The string " << needle << " not found\n";
}

Output: 

The string pisci found at offset 43

See also

searches for the first occurrence of a range of elements
(function template)
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