std::experimental::boyer_moore_horspool_searcher, (3) - Linux Manuals

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

NAME

std::experimental::boyer_moore_horspool_searcher, - std::experimental::boyer_moore_horspool_searcher,

Synopsis

Defined in header <experimental/functional>
template< class RandomIt1,

class Hash = std::hash<typename                                    (library
std::iterator_traits<RandomIt1>::value_type>,                      fundamentals TS)
class BinaryPredicate = std::equal_to<> >

class boyer_moore_horspool_searcher;

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

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  (until C++17)
subsequence that compares equal to [pat_first, pat_last) as defined by
pred is located, or a copy of last otherwise.
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  (since C++17)
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.

  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,                  (library fundamentals
BinaryPredicate>                                               TS)
make_boyer_moore_horspool_searcher( RandomIt pat_first,
RandomIt pat_last,
Hash hf = Hash(),

BinaryPredicate pred = BinaryPredicate());

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 <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_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