[base] Factor out sequence_generator

base/sequence_generator.h

@@ -0,0 +1,27 @@
+#ifndef BASE_SEQUENCE_GENERATOR_H
+#define BASE_SEQUENCE_GENERATOR_H
+
+#include <memory>
+
+//----------------------------------------------------------------
+
+namespace base {
+	class sequence_generator {
+	public:
+		typedef std::shared_ptr<sequence_generator> ptr;
+
+		virtual uint64_t next() = 0;
+	};
+
+	sequence_generator::ptr
+	create_forward_sequence_generator(uint64_t begin, uint64_t size,
+			uint64_t step);
+
+	sequence_generator::ptr
+	create_random_sequence_generator(uint64_t begin, uint64_t size,
+			uint64_t step, unsigned seq_nr = 1);
+}
+
+//----------------------------------------------------------------
+
+#endif