namespace nall {

string::string() : _data(nullptr), _capacity(SSO - 1), _size(0) {
}

auto string::pointer() -> char* {
  if(_capacity < SSO) return _text;
  if(*_refs > 1) _copy();
  return _data;
}

auto string::data() const -> const char* {
  if(_capacity < SSO) return _text;
  return _data;
}

auto string::reset() -> type& {
  if(_capacity >= SSO && !--*_refs) memory::free(_data);
  _data = nullptr;
  _capacity = SSO - 1;
  _size = 0;
  return *this;
}

auto string::reserve(unsigned capacity) -> type& {
  if(capacity <= _capacity) return *this;
  capacity = bit::round(capacity + 1) - 1;
  if(_capacity < SSO) {
    _capacity = capacity;
    _allocate();
  } else if(*_refs > 1) {
    _capacity = capacity;
    _copy();
  } else {
    _capacity = capacity;
    _resize();
  }
  return *this;
}

auto string::resize(unsigned size) -> type& {
  reserve(size);
  pointer()[_size = size] = 0;
  return *this;
}

auto string::operator=(const string& source) -> type& {
  if(&source == this) return *this;
  reset();
  if(source._capacity >= SSO) {
    _data = source._data;
    _refs = source._refs;
    _capacity = source._capacity;
    _size = source._size;
    ++*_refs;
  } else {
    memory::copy(_text, source._text, SSO);
    _capacity = source._capacity;
    _size = source._size;
  }
  return *this;
}

auto string::operator=(string&& source) -> type& {
  if(&source == this) return *this;
  reset();
  memory::copy(this, &source, sizeof(string));
  source._data = nullptr;
  source._capacity = SSO - 1;
  source._size = 0;
  return *this;
}

//SSO -> COW
auto string::_allocate() -> void {
  char _temp[SSO];
  memory::copy(_temp, _text, SSO);
  _data = (char*)memory::allocate(_capacity + 1 + sizeof(unsigned));
  memory::copy(_data, _temp, SSO);
  _refs = (unsigned*)(_data + _capacity + 1);  //always aligned by 32 via reserve()
  *_refs = 1;
}

//COW -> Unique
auto string::_copy() -> void {
  auto _temp = (char*)memory::allocate(_capacity + 1 + sizeof(unsigned));
  memory::copy(_temp, _data, _size = min(_capacity, _size));
  _temp[_size] = 0;
  --*_refs;
  _data = _temp;
  _refs = (unsigned*)(_data + _capacity + 1);
  *_refs = 1;
}

//COW -> Resize
auto string::_resize() -> void {
  _data = (char*)memory::resize(_data, _capacity + 1 + sizeof(unsigned));
  _refs = (unsigned*)(_data + _capacity + 1);
  *_refs = 1;
}

}