std::experimental::boyer_moore_searcher, std::experimental::make_boyer_moore_searcher

 

C++

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Standard library headers

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Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

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Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Technical Specifications

 

Technical specifications

Filesystem library (filesystem TS)

Library fundamentals (library fundamentals TS)

Library fundamentals 2 (library fundamentals 2 TS)

Extensions for parallelism (parallelism TS)

Concepts (concepts TS)

Extensions for concurrency (concurrency TS)

 

Library fundamentals

experimental::optional

experimental::any

experimental::basic_string_view

experimental::sample

experimental::apply

experimental::search

experimental::default_searcher experimental::make_default_searcher

experimental::boyer_moore_searcher experimental::make_boyer_moore_searcher

experimental::boyer_moore_horspool_searcher experimental::make_boyer_moore_horspool_searcher

type-erased and polymorphic allocators

variable templates for type traits

 

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_searcher;		(library fundamentals TS)

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

boyer_moore_searcher is CopyConstructible and CopyAssignable.

RandomIt1 must meet the requirements of RandomAccessIterator.

Member functions

std::experimental::boyer_moore_searcher::boyer_moore_searcher

boyer_moore_searcher( RandomIt1 pat_first,                       RandomIt1 pat_last,                       Hash hf = Hash(),                       BinaryPredicate pred = BinaryPredicate());

Constructs a 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::experimental::boyer_moore_searcher::operator()

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

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

Helper Functions

template< class RandomIt,           class Hash = std::hash<typename std::iterator_traits<RandomIt>::value_type>,           class BinaryPredicate = std::equal_to<> > boyer_moore_searcher<RandomIt, Hash, BinaryPredicate> make_boyer_moore_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_searcher using template argument deduction. Equivalent to return boyer_moore_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_searcher constructed with the arguments pat_first, pat_last, hf, and pred.

Example

Run this code

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