std::boyer_moore_searcher
| Defined in header <functional>
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| template< class RandomIt1, class Hash = std::hash<typename std::iterator_traits<RandomIt1>::value_type>, |
(since C++17) | |
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, |
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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
| 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
BinaryPredicateorHash.
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 last ) const; |
(since C++17) | |
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 | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_boyer_moore_searcher |
201603L |
(C++17) | searchers |
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"; }
Output:
The string "pisci" found at offset 43
See also
| searches for the first occurrence of a range of elements (function template) | |
| (C++17) |
standard C++ library search algorithm implementation (class template) |
| Boyer-Moore-Horspool search algorithm implementation (class template) |