New cpp folder structure

Signed-off-by: Alexander Borsuk <me@alex.bio>

libs/indexer/unique_index.hpp

@@ -0,0 +1,40 @@
+#pragma once
+
+#include "base/base.hpp"
+
+#include <unordered_set>
+#include <vector>
+
+class CheckUniqueIndexes
+{
+public:
+  bool operator()(uint32_t index) { return Add(index); }
+
+private:
+  /// Add index to the set.
+  /// @return true If index was absent.
+  bool Add(uint32_t index)
+  {
+    if (m_v.size() <= index)
+      m_v.resize(index + 1);
+    bool const ret = !m_v[index];
+    m_v[index] = true;
+    return ret;
+  }
+
+  /// Remove index from the set.
+  /// @return true If index was present.
+  bool Remove(uint32_t index)
+  {
+    if (m_v.size() > index)
+    {
+      bool const ret = m_v[index];
+      m_v[index] = false;
+      return ret;
+    }
+    else
+      return false;
+  }
+
+  std::vector<bool> m_v;
+};