Repo created

libs/search/base/inverted_list.hpp

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+#pragma once
+
+#include "base/assert.hpp"
+
+#include <algorithm>
+#include <cstddef>
+#include <vector>
+
+namespace search_base
+{
+// This class is supposed to be used in inverted index to store list
+// of document ids.
+template <typename Id>
+class InvertedList
+{
+public:
+  using value_type = Id;
+  using Value = Id;
+
+  bool Add(Id const & id)
+  {
+    auto it = std::lower_bound(m_ids.begin(), m_ids.end(), id);
+    if (it != m_ids.end() && *it == id)
+      return false;
+    m_ids.insert(it, id);
+    return true;
+  }
+
+  bool Erase(Id const & id)
+  {
+    auto it = std::lower_bound(m_ids.begin(), m_ids.end(), id);
+    if (it == m_ids.end() || *it != id)
+      return false;
+    m_ids.erase(it);
+    return true;
+  }
+
+  template <typename ToDo>
+  void ForEach(ToDo && toDo) const
+  {
+    for (auto const & id : m_ids)
+      toDo(id);
+  }
+
+  size_t Size() const { return m_ids.size(); }
+
+  bool Empty() const { return Size() == 0; }
+
+  void Clear() { m_ids.clear(); }
+
+  void Swap(InvertedList & rhs) { m_ids.swap(rhs.m_ids); }
+
+private:
+  std::vector<Id> m_ids;
+};
+}  // namespace search_base