std::boyer_moore_horspool_searcher

 

C++

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Negators
not_fn not1 (deprecated) not2 (deprecated)	unary_negate (deprecated) binary_negate (deprecated)
Searchers
default_searcher (C++17)
boyer_moore_searcher (C++17)
boyer_moore_horspool_searcher (C++17)
Old binders and adaptors
unary_function (until C++17) binary_function (until C++17) ptr_fun (until C++17) pointer_to_unary_function (until C++17) pointer_to_binary_function (until C++17) mem_fun (until C++17) mem_fun_tmem_fun1_tconst_mem_fun_tconst_mem_fun1_t (until C++17)(until C++17)(until C++17)(until C++17)	binder1stbinder2nd (until C++17)(until C++17) bind1stbind2nd (until C++17)(until C++17) mem_fun_ref (until C++17) mem_fun_ref_tmem_fun1_ref_tconst_mem_fun_ref_tconst_mem_fun1_ref_t (until C++17)(until C++17)(until C++17)(until C++17)

 

Defined in header <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;		(since C++17)

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

boyer_moore_horspool_searcher is CopyConstructible and CopyAssignable.

RandomIt1 must meet the requirements of RandomAccessIterator.

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 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::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 RandomAccessIterator.

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 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.

Example

Run this code

#include <iostream>
#include <string>
#include <algorithm>
#include <functional>
 
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::search(in.begin(), in.end(),
                   std::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

search

searches for a range of elements (function template)