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