//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___FUNCTIONAL_BOYER_MOORE_SEARCHER_H
#define _LIBCPP___FUNCTIONAL_BOYER_MOORE_SEARCHER_H
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
#include <__algorithm/fill_n.h>
#include <__config>
#include <__functional/hash.h>
#include <__functional/operations.h>
#include <__iterator/distance.h>
#include <__iterator/iterator_traits.h>
#include <__memory/shared_ptr.h>
#include <__type_traits/make_unsigned.h>
#include <__utility/pair.h>
#include <array>
#include <unordered_map>
#include <vector>
#if _LIBCPP_STD_VER >= 17
_LIBCPP_PUSH_MACROS
# include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _Key, class _Value, class _Hash, class _BinaryPredicate, bool /*useArray*/>
class _BMSkipTable;
// General case for BM data searching; use a map
template <class _Key, class _Value, class _Hash, class _BinaryPredicate>
class _BMSkipTable<_Key, _Value, _Hash, _BinaryPredicate, false> {
private:
using value_type = _Value;
using key_type = _Key;
const value_type __default_value_;
unordered_map<_Key, _Value, _Hash, _BinaryPredicate> __table_;
public:
_LIBCPP_HIDE_FROM_ABI explicit _BMSkipTable(
size_t __sz, value_type __default_value, _Hash __hash, _BinaryPredicate __pred)
: __default_value_(__default_value), __table_(__sz, __hash, __pred) {}
_LIBCPP_HIDE_FROM_ABI void insert(const key_type& __key, value_type __val) { __table_[__key] = __val; }
_LIBCPP_HIDE_FROM_ABI value_type operator[](const key_type& __key) const {
auto __it = __table_.find(__key);
return __it == __table_.end() ? __default_value_ : __it->second;
}
};
// Special case small numeric values; use an array
template <class _Key, class _Value, class _Hash, class _BinaryPredicate>
class _BMSkipTable<_Key, _Value, _Hash, _BinaryPredicate, true> {
private:
using value_type = _Value;
using key_type = _Key;
using unsigned_key_type = make_unsigned_t<key_type>;
std::array<value_type, 256> __table_;
static_assert(numeric_limits<unsigned_key_type>::max() < 256);
public:
_LIBCPP_HIDE_FROM_ABI explicit _BMSkipTable(size_t, value_type __default_value, _Hash, _BinaryPredicate) {
std::fill_n(__table_.data(), __table_.size(), __default_value);
}
_LIBCPP_HIDE_FROM_ABI void insert(key_type __key, value_type __val) {
__table_[static_cast<unsigned_key_type>(__key)] = __val;
}
_LIBCPP_HIDE_FROM_ABI value_type operator[](key_type __key) const {
return __table_[static_cast<unsigned_key_type>(__key)];
}
};
template <class _RandomAccessIterator1,
class _Hash = hash<typename iterator_traits<_RandomAccessIterator1>::value_type>,
class _BinaryPredicate = equal_to<>>
class _LIBCPP_TEMPLATE_VIS boyer_moore_searcher {
private:
using difference_type = typename std::iterator_traits<_RandomAccessIterator1>::difference_type;
using value_type = typename std::iterator_traits<_RandomAccessIterator1>::value_type;
using __skip_table_type =
_BMSkipTable<value_type,
difference_type,
_Hash,
_BinaryPredicate,
is_integral_v<value_type> && sizeof(value_type) == 1 && is_same_v<_Hash, hash<value_type>> &&
is_same_v<_BinaryPredicate, equal_to<>>>;
public:
_LIBCPP_HIDE_FROM_ABI boyer_moore_searcher(
_RandomAccessIterator1 __first,
_RandomAccessIterator1 __last,
_Hash __hash = _Hash(),
_BinaryPredicate __pred = _BinaryPredicate())
: __first_(__first),
__last_(__last),
__pred_(__pred),
__pattern_length_(__last - __first),
__skip_table_(std::make_shared<__skip_table_type>(__pattern_length_, -1, __hash, __pred_)),
__suffix_(std::__allocate_shared_unbounded_array<difference_type[]>(
allocator<difference_type>(), __pattern_length_ + 1)) {
difference_type __i = 0;
while (__first != __last) {
__skip_table_->insert(*__first, __i);
++__first;
++__i;
}
__build_suffix_table(__first_, __last_, __pred_);
}
template <class _RandomAccessIterator2>
_LIBCPP_HIDE_FROM_ABI pair<_RandomAccessIterator2, _RandomAccessIterator2>
operator()(_RandomAccessIterator2 __first, _RandomAccessIterator2 __last) const {
static_assert(__is_same_uncvref<typename iterator_traits<_RandomAccessIterator1>::value_type,
typename iterator_traits<_RandomAccessIterator2>::value_type>::value,
"Corpus and Pattern iterators must point to the same type");
if (__first == __last)
return std::make_pair(__last, __last);
if (__first_ == __last_)
return std::make_pair(__first, __first);
if (__pattern_length_ > (__last - __first))
return std::make_pair(__last, __last);
return __search(__first, __last);
}
private:
_RandomAccessIterator1 __first_;
_RandomAccessIterator1 __last_;
_BinaryPredicate __pred_;
difference_type __pattern_length_;
shared_ptr<__skip_table_type> __skip_table_;
shared_ptr<difference_type[]> __suffix_;
template <class _RandomAccessIterator2>
_LIBCPP_HIDE_FROM_ABI pair<_RandomAccessIterator2, _RandomAccessIterator2>
__search(_RandomAccessIterator2 __f, _RandomAccessIterator2 __l) const {
_RandomAccessIterator2 __current = __f;
const _RandomAccessIterator2 __last = __l - __pattern_length_;
const __skip_table_type& __skip_table = *__skip_table_;
while (__current <= __last) {
difference_type __j = __pattern_length_;
while (__pred_(__first_[__j - 1], __current[__j - 1])) {
--__j;
if (__j == 0)
return std::make_pair(__current, __current + __pattern_length_);
}
difference_type __k = __skip_table[__current[__j - 1]];
difference_type __m = __j - __k - 1;
if (__k < __j && __m > __suffix_[__j])
__current += __m;
else
__current += __suffix_[__j];
}
return std::make_pair(__l, __l);
}
template <class _Iterator, class _Container>
_LIBCPP_HIDE_FROM_ABI void
__compute_bm_prefix(_Iterator __first, _Iterator __last, _BinaryPredicate __pred, _Container& __prefix) {
const size_t __count = __last - __first;
__prefix[0] = 0;
size_t __k = 0;
for (size_t __i = 1; __i != __count; ++__i) {
while (__k > 0 && !__pred(__first[__k], __first[__i]))
__k = __prefix[__k - 1];
if (__pred(__first[__k], __first[__i]))
++__k;
__prefix[__i] = __k;
}
}
_LIBCPP_HIDE_FROM_ABI void
__build_suffix_table(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _BinaryPredicate __pred) {
const size_t __count = __last - __first;
if (__count == 0)
return;
vector<difference_type> __scratch(__count);
__compute_bm_prefix(__first, __last, __pred, __scratch);
for (size_t __i = 0; __i <= __count; ++__i)
__suffix_[__i] = __count - __scratch[__count - 1];
using _ReverseIter = reverse_iterator<_RandomAccessIterator1>;
__compute_bm_prefix(_ReverseIter(__last), _ReverseIter(__first), __pred, __scratch);
for (size_t __i = 0; __i != __count; ++__i) {
const size_t __j = __count - __scratch[__i];
const difference_type __k = __i - __scratch[__i] + 1;
if (__suffix_[__j] > __k)
__suffix_[__j] = __k;
}
}
};
_LIBCPP_CTAD_SUPPORTED_FOR_TYPE(boyer_moore_searcher);
template <class _RandomAccessIterator1,
class _Hash = hash<typename iterator_traits<_RandomAccessIterator1>::value_type>,
class _BinaryPredicate = equal_to<>>
class _LIBCPP_TEMPLATE_VIS boyer_moore_horspool_searcher {
private:
using difference_type = typename iterator_traits<_RandomAccessIterator1>::difference_type;
using value_type = typename iterator_traits<_RandomAccessIterator1>::value_type;
using __skip_table_type =
_BMSkipTable<value_type,
difference_type,
_Hash,
_BinaryPredicate,
is_integral_v<value_type> && sizeof(value_type) == 1 && is_same_v<_Hash, hash<value_type>> &&
is_same_v<_BinaryPredicate, equal_to<>>>;
public:
_LIBCPP_HIDE_FROM_ABI boyer_moore_horspool_searcher(
_RandomAccessIterator1 __first,
_RandomAccessIterator1 __last,
_Hash __hash = _Hash(),
_BinaryPredicate __pred = _BinaryPredicate())
: __first_(__first),
__last_(__last),
__pred_(__pred),
__pattern_length_(__last - __first),
__skip_table_(std::make_shared<__skip_table_type>(__pattern_length_, __pattern_length_, __hash, __pred_)) {
if (__first == __last)
return;
--__last;
difference_type __i = 0;
while (__first != __last) {
__skip_table_->insert(*__first, __pattern_length_ - 1 - __i);
++__first;
++__i;
}
}
template <class _RandomAccessIterator2>
_LIBCPP_HIDE_FROM_ABI pair<_RandomAccessIterator2, _RandomAccessIterator2>
operator()(_RandomAccessIterator2 __first, _RandomAccessIterator2 __last) const {
static_assert(__is_same_uncvref<typename std::iterator_traits<_RandomAccessIterator1>::value_type,
typename std::iterator_traits<_RandomAccessIterator2>::value_type>::value,
"Corpus and Pattern iterators must point to the same type");
if (__first == __last)
return std::make_pair(__last, __last);
if (__first_ == __last_)
return std::make_pair(__first, __first);
if (__pattern_length_ > __last - __first)
return std::make_pair(__last, __last);
return __search(__first, __last);
}
private:
_RandomAccessIterator1 __first_;
_RandomAccessIterator1 __last_;
_BinaryPredicate __pred_;
difference_type __pattern_length_;
shared_ptr<__skip_table_type> __skip_table_;
template <class _RandomAccessIterator2>
_LIBCPP_HIDE_FROM_ABI pair<_RandomAccessIterator2, _RandomAccessIterator2>
__search(_RandomAccessIterator2 __f, _RandomAccessIterator2 __l) const {
_RandomAccessIterator2 __current = __f;
const _RandomAccessIterator2 __last = __l - __pattern_length_;
const __skip_table_type& __skip_table = *__skip_table_;
while (__current <= __last) {
difference_type __j = __pattern_length_;
while (__pred_(__first_[__j - 1], __current[__j - 1])) {
--__j;
if (__j == 0)
return std::make_pair(__current, __current + __pattern_length_);
}
__current += __skip_table[__current[__pattern_length_ - 1]];
}
return std::make_pair(__l, __l);
}
};
_LIBCPP_CTAD_SUPPORTED_FOR_TYPE(boyer_moore_horspool_searcher);
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP_STD_VER >= 17
#endif // _LIBCPP___FUNCTIONAL_BOYER_MOORE_SEARCHER_H
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