vector.h
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#ifndef __VECTOR_H__
#define __VECTOR_H__
#include <cstring>
#include <limits>
#include <type_traits>
template <class C> class vector {
C *data;
unsigned int size;
unsigned int cap;
private:
static unsigned int round_up_to_power_of_2(unsigned w) {
const auto bits = std::numeric_limits<unsigned>::digits;
--w;
for (unsigned s = 1; s < bits; s *= 2)
w |= w >> s;
return ++w;
};
void destroy_array(C *ptr, unsigned int s) {
for (unsigned j = 0; j < s; ++j)
(ptr + j)->~C();
free(ptr);
}
void resize_before_push() {
if (size >= cap) {
if (cap > std::numeric_limits<decltype(size)>::max() / (2 * sizeof(C)))
throw length_error("Vector too long");
unsigned int newcap = (cap == 0) ? 1 : 2 * cap;
C *newdata;
if constexpr (!std::is_trivially_copyable<C>()) {
newdata = static_cast<C *>(
std::aligned_alloc(alignof(C), newcap * sizeof(C)));
if (!newdata)
throw bad_alloc();
unsigned i;
try {
for (i = 0; i < size; i++)
new (newdata + i) C(std::move(data[i]));
} catch (...) {
destroy_array(newdata, i);
throw;
}
destroy_array(data, size);
} else {
newdata = static_cast<C *>(std::realloc(data, newcap * sizeof(C)));
if (!newdata)
throw bad_alloc();
}
data = newdata;
cap = newcap;
}
}
public:
class index_out_of_range {};
explicit vector(unsigned s) {
cap = round_up_to_power_of_2(s);
data = static_cast<C *>(std::aligned_alloc(alignof(C), cap * sizeof(C)));
if (!data)
throw bad_alloc();
size = s;
unsigned i;
try {
for (i = 0; i < size; i++)
new (data + i) C();
} catch (...) {
destroy_array(data, i);
throw;
}
}
~vector() { destroy_array(data, size); }
C &operator[](unsigned int pos) {
if (pos >= size)
throw index_out_of_range();
return data[pos];
}
C operator[](unsigned int pos) const {
if (pos >= size)
throw index_out_of_range();
return data[pos];
}
vector(const vector<C> &s) {
cap = s.cap;
data = static_cast<C *>(std::aligned_alloc(alignof(C), cap * sizeof(C)));
if (!data)
throw bad_alloc();
size = s.size;
unsigned i;
try {
for (i = 0; i < size; i++)
new (data + i) C(s.data[i]);
} catch (...) {
destroy_array(data, i);
throw;
}
}
void swap(vector<C> &s) {
C *t1 = s.data;
unsigned int t2 = s.size;
unsigned int t3 = s.cap;
s.data = data;
s.size = size;
data = t1;
size = t2;
cap = t3;
}
vector<C> &operator=(const vector<C> &s) {
if (this == &s)
return *this;
vector<C> n(s);
swap(n);
return *this;
}
friend ostream &operator<<(ostream &o, const vector<C> &v) {
o << '[';
for (unsigned i = 0; i < v.size; i++) {
o << v[i];
if (i != v.size - 1)
o << ',';
};
o << ']';
return o;
}
template <class... Args> C &emplace_back(Args &&... args) {
// cout << "emplace_back" << endl;
resize_before_push();
new (data + size) C(std::forward<Args>(args)...);
return *(data + size++);
}
#if 1
C &push_back(C &&s) {
// cout << "push_back with rvalue argument" << endl;
resize_before_push();
new (data + size) C(std::move(s));
// new (data + size) C(s);
return *(data + size++);
}
C &push_back(const C &s) {
// cout << "push_back with reference argument" << endl;
resize_before_push();
new (data + size) C(s);
return *(data + size++);
}
#else
template <class T> C &push_back(T &&s) {
resize_before_push();
new (data + size) C(std::forward<T>(s));
return *(data + size++);
}
#endif
};
#endif /* __VECTOR_H__ */