这并不难实现。只需明确说明您的项目需要哪些功能即可。以下是一个简单的示例。
#include <iostream>
#include <array>
#include <vector>
#include <cassert>
template<typename T, int dim>
class DimVector : public std::vector<T> {
public:
DimVector() {
clear();
}
void clear() {
for (auto& i : _sizes)
i = 0;
std::vector<T>::clear();
}
template<class ... Types>
void resize(Types ... args) {
std::array<int, dim> new_sizes = { args ... };
resize(new_sizes);
}
void resize(std::array<int, dim> new_sizes) {
clear();
for (int i = 0; i < dim; ++i)
if (new_sizes[i] == 0)
return;
_sizes = new_sizes;
int realsize = _sizes[0];
for (int i = 1; i < dim; ++i)
realsize *= _sizes[i];
std::vector<T>::resize(static_cast<size_t>(realsize));
}
decltype(auto) operator()(std::array<int, dim> pos) {
size_t index;
for (int i = 0; i < dim; ++i) {
assert(0 <= pos[i] && pos[i] < _sizes[i]);
index = (i == 0) ? pos[i] : (index * _sizes[i] + pos[i]);
}
return std::vector<T>::at(index);
}
template<class ... Types>
decltype(auto) at(Types ... args) {
std::array<int, dim> pos = { args ... };
return (*this)(pos);
}
int size(int d) const {
return _sizes[d];
}
class Iterator {
public:
T& operator*() const;
T* operator->() const;
bool operator!=(const Iterator& other) const {
if (&_vec != &other._vec)
return true;
for (int i = 0; i < dim; ++i)
if (_pos[i] != other._pos[i])
return true;
return false;
}
int get_dim(int d) const {
assert(0 <= d && d < dim);
return _pos[d];
}
void add_dim(int d, int value = 1) {
assert(0 <= d && d < dim);
_pos[d] += value;
assert(0 <= _pos[i] && _pos[i] < _vec._sizes[i]);
}
private:
DimVector &_vec;
std::array<int, dim> _pos;
Iterator(DimVector& vec, std::array<int, dim> pos) : _vec(vec), _pos(pos) { }
};
Iterator getIterator(int pos[dim]) {
return Iterator(*this, pos);
}
private:
std::array<int, dim> _sizes;
};
template<typename T, int dim>
inline T& DimVector<T, dim>::Iterator::operator*() const {
return _vec(_pos);
}
template<typename T, int dim>
inline T* DimVector<T, dim>::Iterator::operator->() const {
return &_vec(_pos);
}
using namespace std;
int main() {
DimVector<int, 4> v;
v.resize(1, 2, 3, 4);
v.at(0, 0, 0, 1) = 1;
v.at(0, 1, 0, 0) = 1;
for (int w = 0; w < v.size(0); ++w) {
for (int z = 0; z < v.size(1); ++z) {
for (int y = 0; y < v.size(2); ++y) {
for (int x = 0; x < v.size(3); ++x) {
cout << v.at(w, z, y, x) << ' ';
}
cout << endl;
}
cout << "----------------------------------" << endl;
}
cout << "==================================" << endl;
}
return 0;
}
待办事项清单:
- 优化:尽可能使用
T const&
- 优化迭代器:预计算实际索引,然后仅更改该实际索引
- 实现
const
存取器
- 实现
ConstIterator
- 实现将 DimVector 序列化到/从文件的
operator>>
和 operator<<
{x,y,z}
)的方法来自扁平化索引(反之亦然)。我不认为你可以以“标准”的方式做到这一点,除非提供自己的自定义类来实现这个目的。 - coincoin