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std::boyer_moore_searcher(3) | C++ Standard Libary | std::boyer_moore_searcher(3) |
NAME¶
std::boyer_moore_searcher - std::boyer_moore_searcher
Synopsis¶
Defined in header <functional>
template< class RandomIt1,
class Hash = std::hash<typename
std::iterator_traits<RandomIt1>::value_type>, (since C++17)
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.
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 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
(since C++17)
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
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.
Notes¶
Feature-test macro: __cpp_lib_boyer_moore_searcher
Example¶
// Run this code
#include <iomanip>
#include <iostream>
#include <algorithm>
#include <functional>
#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 " << 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
See also¶
search searches for a range of elements
(function template)
default_searcher standard C++ library search algorithm implementation
(C++17) (class template)
boyer_moore_horspool_searcher Boyer-Moore-Horspool search algorithm
implementation
(C++17) (class template)
2022.07.31 | http://cppreference.com |