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Showing content from https://en.cppreference.com/w/cpp/algorithm/../../cpp/utility/functional/boyer_moore_searcher.html below:

std::boyer_moore_searcher - cppreference.com

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

std::boyer_moore_searcher is CopyConstructible and CopyAssignable.

RandomIt1 must meet the requirements of LegacyRandomAccessIterator.

[edit] Member functions std::boyer_moore_searcher::boyer_moore_searcher boyer_moore_searcher( RandomIt1 pat_first, RandomIt1 pat_last, Hash hf = Hash(), BinaryPredicate pred = BinaryPredicate() );

Constructs a std::boyer_moore_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, and copy assignment operator of the value type of RandomIt1; or
the copy constructor and 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_searcher::operator() template< class RandomIt2 > std::pair<RandomIt2, RandomIt2> operator()( RandomIt2 first, RandomIt2 last ) const; (since C++17)

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.

[edit] Notes [edit] Example

#include <algorithm>
#include <functional>
#include <iomanip>
#include <iostream>
#include <string_view>
 
int main()
{
    constexpr std::string_view haystack =
        "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"};
 
    if (const auto it = std::search(haystack.begin(), haystack.end(),
            std::boyer_moore_searcher(needle.begin(), needle.end()));
        it != haystack.end()
    )
        std::cout << "The string " << std::quoted(needle) << " found at offset "
                  << it - haystack.begin() << '\n';
    else
        std::cout << "The string " << std::quoted(needle) << " not found\n";
}

Output:

The string "pisci" found at offset 43

[edit] See also

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