Implement unified istream for ingestion layer

GCryptCLI/include/DataIngestionLayer.h

@@ -0,0 +1,28 @@
+#ifndef GCRYPTCLI_DATAINGESTIONLAYER_H
+#define GCRYPTCLI_DATAINGESTIONLAYER_H
+
+#include <istream>
+#include <fstream>
+#include <sstream>
+
+namespace IO {
+
+  // This class is used to read in data.
+  class DataIngestionLayer {
+    public:
+      //! Will initialize the ingestion
+      static void Init();
+
+    private:
+      static std::istream* in;
+
+      // We have to hold on to a reference to a filestream,
+      // even if we're always just reading from in.
+      // We still have to CLOSE the file handle afterwards!
+      static std::ifstream ifs;
+      static std::istringstream iss;
+  };
+}
+
+#endif
+