Repo created

libs/indexer/scale_index.hpp

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+#pragma once
+
+#include "indexer/interval_index.hpp"
+
+#include "coding/var_serial_vector.hpp"
+
+#include <memory>
+#include <vector>
+
+/// Index bucket <--> Draw scale range.
+/// Using default one-to-one mapping.
+class ScaleIndexBase
+{
+public:
+  static uint32_t GetBucketsCount() { return 18; }
+  static uint32_t BucketByScale(int scale) { return static_cast<uint32_t>(scale); }
+  /// @return Range like [x, y).
+  static std::pair<uint32_t, uint32_t> ScaleRangeForBucket(uint32_t bucket) { return {bucket, bucket + 1}; }
+};
+
+template <class Reader>
+class ScaleIndex : public ScaleIndexBase
+{
+public:
+  explicit ScaleIndex(Reader const & reader) { Attach(reader); }
+
+  ~ScaleIndex() { Clear(); }
+
+  void Clear() { m_IndexForScale.clear(); }
+
+  void Attach(Reader const & reader)
+  {
+    Clear();
+
+    ReaderSource<Reader> source(reader);
+    VarSerialVectorReader<Reader> treesReader(source);
+    for (uint32_t i = 0; i < treesReader.Size(); ++i)
+      m_IndexForScale.push_back(std::make_unique<IndexT>(treesReader.SubReader(i)));
+  }
+
+  template <class FnT>
+  void ForEachInIntervalAndScale(uint64_t beg, uint64_t end, int scale, FnT && fn) const
+  {
+    auto const scaleBucket = BucketByScale(scale);
+    if (scaleBucket < m_IndexForScale.size())
+      for (size_t i = 0; i <= scaleBucket; ++i)
+        m_IndexForScale[i]->ForEach(fn, beg, end);
+  }
+
+private:
+  using IndexT = IntervalIndex<Reader, uint32_t>;
+  std::vector<std::unique_ptr<IndexT>> m_IndexForScale;
+};