Repo created

libs/coding/move_to_front.hpp

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+#pragma once
+
+#include <array>
+#include <cstddef>
+#include <cstdint>
+#include <limits>
+
+namespace coding
+{
+class MoveToFront
+{
+public:
+  static size_t constexpr kNumBytes = static_cast<size_t>(std::numeric_limits<uint8_t>::max()) + 1;
+
+  MoveToFront();
+
+  // Returns index of the byte |b| in the current sequence of bytes,
+  // then moves |b| to the first position.
+  uint8_t Transform(uint8_t b);
+
+  uint8_t operator[](uint8_t i) const { return m_order[i]; }
+
+private:
+  std::array<uint8_t, kNumBytes> m_order;
+};
+}  // namespace coding