Add Database abstract class

include/aidge/aidge.hpp

@@ -16,6 +16,9 @@
 #include "aidge/backend/TensorImpl.hpp"
 #include "aidge/data/Data.hpp"
 #include "aidge/data/Tensor.hpp"
+#include "aidge/data/Database.hpp"
+#include "aidge/data/DatabaseTensor.hpp"
+#include "aidge/data/Dataloader.hpp"
 #include "aidge/graph/Connector.hpp"
 #include "aidge/graph/GraphView.hpp"
 #include "aidge/graph/Node.hpp"

include/aidge/data/Database.hpp

+#ifndef Database_H_
+#define Database_H_
+
+#include <cstring>
+
+#include "aidge/data/Tensor.hpp"
+
+namespace Aidge{
+
+/**
+ * @brief Database. An abstract class representing a database. All databases should inherit from this class. All subclasses should overwrite ```get_item()``` to fetch data from a given index.
+ * @todo Make the dataset generic. Currently supprting only tensor. Always ground truth.
+ */
+class Database {
+
+public:
+
+    virtual ~Database() = default; 
+
+    /**
+     * @brief Fetch a data sample and its corresponding ground_truth 
+     * @param index index of the pair (```data```, ```ground truth```) to fetch from the database
+     * @return A pair of pointers to the data (first) and its corresping ground truth (second)
+     */
+    virtual std::pair<std::shared_ptr<Tensor>,std::shared_ptr<Tensor>> get_item(unsigned int index) = 0;
+
+    /** 
+     * @return The number of data samples in the database.
+     */
+    virtual unsigned int get_len() = 0;
+
+    // void load(const std::string& /*dataPath*/, const std::string& labelPath = "");
+
+protected:
+    
+    std::vector<std::shared_ptr<Tensor>> mData;
+    std::vector<std::shared_ptr<Tensor>> mLabel;
+
+};
+
+}
+
+#endif /* Database_H_ */
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