Stockfish/src/eval/nnue/features/index_list.h

// Definition of index list of input features

#ifndef _NNUE_FEATURES_INDEX_LIST_H_
#define _NNUE_FEATURES_INDEX_LIST_H_

#if defined(EVAL_NNUE)

#include "../../../position.h"
#include "../nnue_architecture.h"

namespace Eval {

namespace NNUE {

namespace Features {

// Class template used for feature index list
template <typename T, std::size_t MaxSize>
class ValueList {
 public:
  std::size_t size() const { return size_; }
  void resize(std::size_t size) { size_ = size; }
  void push_back(const T& value) { values_[size_++] = value; }
  T& operator[](std::size_t index) { return values_[index]; }
  T* begin() { return values_; }
  T* end() { return values_ + size_; }
  const T& operator[](std::size_t index) const { return values_[index]; }
  const T* begin() const { return values_; }
  const T* end() const { return values_ + size_; }
  void swap(ValueList& other) {
    const std::size_t max_size = std::max(size_, other.size_);
    for (std::size_t i = 0; i < max_size; ++i) {
      std::swap(values_[i], other.values_[i]);
    }
    std::swap(size_, other.size_);
  }
 private:
  T values_[MaxSize];
  std::size_t size_ = 0;
};

//Type of feature index list
class IndexList
    : public ValueList<IndexType, RawFeatures::kMaxActiveDimensions> {
};

}  // namespace Features

}  // namespace NNUE

}  // namespace Eval

#endif  // defined(EVAL_NNUE)

#endif