62 lines
1.8 KiB
C++
62 lines
1.8 KiB
C++
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#include <cstdint>
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#include <iostream>
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#include "dpf.hpp"
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#include "dpf/app_flow.hpp"
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#include "dpf/app_plans.hpp"
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// A private range count. Each secret value is one comparison key. The
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// public interval is [lo, hi). The comparison opens to 1 at a query q
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// when q is strictly above the secret value, so the two endpoints
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// differ by 1 exactly on lo <= v < hi. The count is the sum of those
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// bits. The servers never see a value, and the interval is public.
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//
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// c++ -std=c++17 -march=native -I include -I thirdparty \
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// examples/applications/range_count.cpp
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namespace
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{
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std::uint64_t inside(std::uint8_t value, std::uint8_t lo, std::uint8_t hi)
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{
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auto [k0, k1] = dpf::make_dpf(value, dpf::gt(std::uint64_t{1}));
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const auto above_lo = dpf::reconstruct(
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dpf::eval_point(dpf::cmp, k0, lo),
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dpf::eval_point(dpf::cmp, k1, lo));
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const auto above_hi = dpf::reconstruct(
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dpf::eval_point(dpf::cmp, k0, hi),
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dpf::eval_point(dpf::cmp, k1, hi));
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// eval(q) = 1 iff q > value, so eval(hi) - eval(lo) = 1{lo <= value < hi}.
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return above_hi - above_lo;
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}
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} // namespace
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int main()
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{
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constexpr std::uint8_t lo = 10;
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constexpr std::uint8_t hi = 20;
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const std::uint8_t values[] = {3, 10, 12, 19, 20, 40};
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std::uint64_t count = 0;
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for (auto v : values)
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count += inside(v, lo, hi);
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// 10, 12, and 19. 3 and 40 are outside. 20 is the open end.
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if (count != 3 || inside(10, lo, hi) != 1 || inside(20, lo, hi) != 0
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|| inside(9, lo, hi) != 0)
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{
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std::cerr << "range count " << count << "\n";
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return 1;
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}
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{
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if (int rc = dpf::app::run_measured("range_count",
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dpf::protocol::range_count_plan(0), 8))
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return rc;
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}
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std::cout << count << "\n";
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return 0;
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}
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