Accessor.hpp

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#ifndef CYTNX_ACCESSOR_H_
#define CYTNX_ACCESSOR_H_
 
#include "Type.hpp"
#include "cytnx_error.hpp"
#include <vector>
#include <cstring>
#include <string>
#include <iostream>
#include <initializer_list>
 
namespace cytnx {
 
  class Accessor {
   private:
    cytnx_int64 _type;
 
   public:
    cytnx_int64 _min{}, _max{}, _step{};
    cytnx_int64 loc{};
    std::vector<cytnx_int64> idx_list;
 
    std::vector<std::vector<cytnx_int64>> qns_list;
 
    // if type is singl, _min/_max/_step     are not used
    // if type is all  , _min/_max/_step/loc are not used
    // if type is range, loc              are not used.
    // if type is tilend, loc/_max are not used.
    // if type is Qns, only qns_list are used.
 
    enum : cytnx_int64 { none, Singl, All, Range, Tilend, Step, Tn, list, Qns };
 
    Accessor() : _type(Accessor::none){};
 
    // single constructor
    explicit Accessor(const cytnx_int64 &loc);
    // explicit Accessor(const Tensor &tn);// construct from Tensor, should be 1d with dtype
    // integer.
 
    template <class T>
    explicit Accessor(const std::initializer_list<T> &list) {
      std::vector<T> tmp = list;
      this->_type = this->list;
      this->idx_list = std::vector<cytnx_int64>(tmp.begin(), tmp.end());
    };  // construct from vector/list, should be 1d with dtype integer.
 
    template <class T>
    explicit Accessor(const std::vector<T> &list) {
      this->_type = this->list;
      this->idx_list = std::vector<cytnx_int64>(list.begin(), list.end());
    };  // construct from vector/list, should be 1d with dtype integer.
 
 
    // all constr. ( use string to dispatch )
    explicit Accessor(const std::string &str);
 
    // range constr.
    Accessor(const cytnx_int64 &min, const cytnx_int64 &max, const cytnx_int64 &step);
 
    // copy constructor:
    Accessor(const Accessor &rhs);
    // copy assignment:
    Accessor &operator=(const Accessor &rhs);
 
    // check equality
    bool operator==(const Accessor &rhs) const;
 
    int type() const { return this->_type; }
 
    // handy generator function :
    static Accessor all() { return Accessor(std::string(":")); };
 
    static Accessor range(const cytnx_int64 &min, const cytnx_int64 &max,
                          const cytnx_int64 &step = 1) {
      return Accessor(min, max, step);
    };
 
    static Accessor tilend(const cytnx_int64 &min, const cytnx_int64 &step = 1) {
      cytnx_error_msg(step == 0, "[ERROR] Cannot have _step=0 for tilend%s", "\n");
      Accessor out;
      out._type = Accessor::Tilend;
      out._min = min;
      out._step = step;
      return out;
    };
 
    static Accessor step(const cytnx_int64 &step) {
      cytnx_error_msg(step == 0, "[ERROR] Cannot have _step=0 for _step%s", "\n");
      Accessor out;
      out._type = Accessor::Step;
      // out._min = 0;
      out._step = step;
      return out;
    };
 
    static Accessor qns(const std::vector<std::vector<cytnx_int64>> &qns) {
      cytnx_error_msg(qns.size() == 0, "[ERROR] Cannot have empty qnums.%s", "\n");
      Accessor out;
 
      out._type = Accessor::Qns;
      out.qns_list = qns;
      return out;
    }
 
    // get the real len from dim
    // if type is all, pos will be null, and len == dim
    // if type is range, pos will be the locator, and len == len(pos)
    // if type is singl, pos will be pos, and len == 0
    void get_len_pos(const cytnx_uint64 &dim, cytnx_uint64 &len,
                     std::vector<cytnx_uint64> &pos) const;
  };  // class Accessor
 
  // layout:
  std::ostream &operator<<(std::ostream &os, const Accessor &in);
 
  // elements resolver
  template <class T>
  void _resolve_elems(std::vector<cytnx::Accessor> &cool, const T &a) {
    cool.push_back(cytnx::Accessor(a));
  }
 
  template <class T, class... Ts>
  void _resolve_elems(std::vector<cytnx::Accessor> &cool, const T &a, const Ts &...args) {
    cool.push_back(cytnx::Accessor(a));
    _resolve_elems(cool, args...);
  }
 
  template <class T, class... Ts>
  std::vector<cytnx::Accessor> Indices_resolver(const T &a, const Ts &...args) {
    std::vector<cytnx::Accessor> idxs;
    _resolve_elems(idxs, a, args...);
    return idxs;
  }
 
}  // namespace cytnx
 
#endif  // CYTNX_ACCESSOR_H_