text: 
  #include <algorithm>
  #include <boost/thread/locks.hpp>
  #include <boost/thread/mutex.hpp>
  
  #include "cryptonote_core/cryptonote_core.h"
  
  namespace cryptonote
  {
  namespace rpc
  {
    namespace
    {
      output_distribution_data
        process_distribution(bool cumulative, std::uint64_t start_height, std::vector<std::uint64_t> distribution, std::uint64_t base)
      {
        if (!cumulative && !distribution.empty())
        {
          for (std::size_t n = distribution.size() - 1; 0 < n; --n)
            distribution[n] -= distribution[n - 1];
          distribution[0] -= base;
        }
  
        return {std::move(distribution), start_height, base};
      }
    }
  
    boost::optional<output_distribution_data>
      RpcHandler::get_output_distribution(core& src, std::uint64_t amount, std::uint64_t from_height, std::uint64_t to_height, bool cumulative)
    {
        static struct D
        {
          boost::mutex mutex;
          std::vector<std::uint64_t> cached_distribution;
          std::uint64_t cached_from, cached_to, cached_start_height, cached_base;
          bool cached;
          D(): cached_from(0), cached_to(0), cached_start_height(0), cached_base(0), cached(false) {}
        } d;
        const boost::unique_lock<boost::mutex> lock(d.mutex);
  
        if (d.cached && amount == 0 && d.cached_from == from_height && d.cached_to == to_height)
          return process_distribution(cumulative, d.cached_start_height, d.cached_distribution, d.cached_base);
  
        std::vector<std::uint64_t> distribution;
        std::uint64_t start_height, base;
        if (!src.get_output_distribution(amount, from_height, to_height, start_height, distribution, base))
          return boost::none;
  
        if (to_height > 0 && to_height >= from_height)
        {
          const std::uint64_t offset = std::max(from_height, start_height);
          if (offset <= to_height && to_height - offset + 1 < distribution.size())
            distribution.resize(to_height - offset + 1);
        }
  
        if (amount == 0)
        {
          d.cached_from = from_height;
          d.cached_to = to_height;
          d.cached_distribution = distribution;
          d.cached_start_height = start_height;
          d.cached_base = base;
          d.cached = true;
        }
  
        return process_distribution(cumulative, start_height, std::move(distribution), base);
    }
  } // rpc
  } // cryptonote
  