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| #include <iostream>
#include <string>
#include <memory>
#include <algorithm>
class StrVec {
public:
StrVec() : elements(nullptr), first_free(nullptr), cap(nullptr) {}
StrVec(const StrVec&);
StrVec& operator=(const StrVec&);
~StrVec();
void push_back(const std::string&);
size_t size() const { return first_free - elements; }
size_t capacity() const { return cap - elements; }
std::string *begin() const { return elements; }
std::string *end() const { return first_free; }
private:
std::allocator<std::string> alloc;
void chk_n_alloc() { if(size() == capacity()) reallocate(); }
std::pair<std::string*, std::string*>
alloc_n_copy(const std::string*, const std::string*);
void free();
void reallocate();
std::string *elements;
std::string *first_free;
std::string *cap;
};
void StrVec::push_back(const std::string &s) {
chk_n_alloc();
alloc.construct(first_free++, s);
}
std::pair<std::string*, std::string*>
StrVec::alloc_n_copy(const std::string *b, const std::string *e) {
auto data = alloc.allocate(e - b);
return { data, uninitialized_copy(b, e, data) };
}
void StrVec::free() {
if(elements) {
// for(auto p = first_free; p != elements; /* пусто */)
// alloc.destroy(--p);
// alloc.deallocate(elements, cap - elements);
std::for_each(elements, first_free, [&](std::string *p){ alloc.destroy(p); });
//alloc.deallocate(elements, cap - elements);
}
}
StrVec::StrVec(const StrVec &s) {
auto newdata = alloc_n_copy(s.begin(), s.end());
elements = newdata.first;
first_free = cap = newdata.second;
}
StrVec::~StrVec() { free(); }
StrVec& StrVec::operator=(const StrVec &rhs) {
auto data = alloc_n_copy(rhs.begin(), rhs.end());
free();
elements = data.first;
first_free = cap = data.second;
return *this;
}
void StrVec::reallocate() {
auto newcapacity = size() ? 2 * size() : 1;
auto newdata = alloc.allocate(newcapacity);
auto dest = newdata;
auto elem = elements;
for(size_t i = 0; i != size(); ++i)
alloc.construct(dest++, std::move(*elem++));
free();
elements = newdata;
first_free = dest;
cap = elements + newcapacity;
}
/////////////////////////////////////////////////////////////////////////
int main()
{
return EXIT_SUCCESS;
} |
(
Сообщение от FliXis
