Repo created

libs/coding/move_to_front.cpp

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+#include "coding/move_to_front.hpp"
+
+#include "base/assert.hpp"
+
+#include <algorithm>
+#include <cstring>
+#include <numeric>
+
+namespace coding
+{
+MoveToFront::MoveToFront()
+{
+  std::iota(m_order.begin(), m_order.end(), 0);
+}
+
+uint8_t MoveToFront::Transform(uint8_t b)
+{
+  auto const it = std::find(m_order.begin(), m_order.end(), b);
+  ASSERT(it != m_order.end(), ());
+
+  size_t const result = std::distance(m_order.begin(), it);
+  ASSERT_LESS(result, kNumBytes, ());
+
+  std::rotate(m_order.begin(), it, it + 1);
+  ASSERT_EQUAL(m_order[0], b, ());
+  return static_cast<uint8_t>(result);
+}
+}  // namespace coding