std::boyer_moore_searcher

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

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.

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

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.

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

Notes

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";
}

The string "pisci" found at offset 43

See also