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https://github.com/XRPLF/rippled.git
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Introduce rounding modes for Number:
You can set a thread-local flag to direct Number how to round
non-exact results with the syntax:
Number::rounding_mode prev_mode = Number::setround(Number::towards_zero);
This flag will stay in effect for this thread only until another call
to setround. The previously set rounding mode is returned.
You can also retrieve the current rounding mode with:
Number::rounding_mode current_mode = Number::getround();
The available rounding modes are:
* to_nearest : Rounds to nearest representable value. On tie, rounds
to even.
* towards_zero : Rounds towards zero.
* downward : Rounds towards negative infinity.
* upward : Rounds towards positive infinity.
The default rounding mode is to_nearest.
This commit is contained in:
Howard Hinnant
committed by
Elliot Lee
Elliot Lee
parent
a82ad5ba76
commit
3f33471220
@@ -26,6 +26,24 @@
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namespace ripple {
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class saveNumberRoundMode
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{
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Number::rounding_mode mode_;
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public:
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~saveNumberRoundMode()
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{
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Number::setround(mode_);
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}
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explicit saveNumberRoundMode(Number::rounding_mode mode) noexcept
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: mode_{mode}
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{
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}
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saveNumberRoundMode(saveNumberRoundMode const&) = delete;
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saveNumberRoundMode&
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operator=(saveNumberRoundMode const&) = delete;
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};
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class Number_test : public beast::unit_test::suite
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{
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public:
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@@ -338,39 +356,156 @@ public:
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{
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testcase("test_to_integer");
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using Case = std::tuple<Number, std::int64_t>;
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Case c[]{
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{Number{0}, 0},
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{Number{1}, 1},
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{Number{2}, 2},
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{Number{3}, 3},
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{Number{-1}, -1},
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{Number{-2}, -2},
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{Number{-3}, -3},
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{Number{10}, 10},
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{Number{99}, 99},
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{Number{1155}, 1155},
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{Number{9'999'999'999'999'999, 0}, 9'999'999'999'999'999},
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{Number{9'999'999'999'999'999, 1}, 99'999'999'999'999'990},
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{Number{9'999'999'999'999'999, 2}, 999'999'999'999'999'900},
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{Number{-9'999'999'999'999'999, 2}, -999'999'999'999'999'900},
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{Number{15, -1}, 2},
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{Number{14, -1}, 1},
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{Number{16, -1}, 2},
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{Number{25, -1}, 2},
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{Number{6, -1}, 1},
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{Number{5, -1}, 0},
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{Number{4, -1}, 0},
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{Number{-15, -1}, -2},
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{Number{-14, -1}, -1},
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{Number{-16, -1}, -2},
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{Number{-25, -1}, -2},
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{Number{-6, -1}, -1},
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{Number{-5, -1}, 0},
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{Number{-4, -1}, 0}};
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for (auto const& [x, y] : c)
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saveNumberRoundMode save{Number::setround(Number::to_nearest)};
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{
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auto j = static_cast<std::int64_t>(x);
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BEAST_EXPECT(j == y);
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Case c[]{
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{Number{0}, 0},
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{Number{1}, 1},
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{Number{2}, 2},
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{Number{3}, 3},
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{Number{-1}, -1},
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{Number{-2}, -2},
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{Number{-3}, -3},
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{Number{10}, 10},
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{Number{99}, 99},
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{Number{1155}, 1155},
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{Number{9'999'999'999'999'999, 0}, 9'999'999'999'999'999},
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{Number{9'999'999'999'999'999, 1}, 99'999'999'999'999'990},
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{Number{9'999'999'999'999'999, 2}, 999'999'999'999'999'900},
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{Number{-9'999'999'999'999'999, 2}, -999'999'999'999'999'900},
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{Number{15, -1}, 2},
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{Number{14, -1}, 1},
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{Number{16, -1}, 2},
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{Number{25, -1}, 2},
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{Number{6, -1}, 1},
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{Number{5, -1}, 0},
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{Number{4, -1}, 0},
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{Number{-15, -1}, -2},
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{Number{-14, -1}, -1},
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{Number{-16, -1}, -2},
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{Number{-25, -1}, -2},
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{Number{-6, -1}, -1},
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{Number{-5, -1}, 0},
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{Number{-4, -1}, 0}};
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for (auto const& [x, y] : c)
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{
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auto j = static_cast<std::int64_t>(x);
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BEAST_EXPECT(j == y);
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}
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}
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auto prev_mode = Number::setround(Number::towards_zero);
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BEAST_EXPECT(prev_mode == Number::to_nearest);
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{
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Case c[]{
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{Number{0}, 0},
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{Number{1}, 1},
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{Number{2}, 2},
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{Number{3}, 3},
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{Number{-1}, -1},
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{Number{-2}, -2},
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{Number{-3}, -3},
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{Number{10}, 10},
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{Number{99}, 99},
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{Number{1155}, 1155},
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{Number{9'999'999'999'999'999, 0}, 9'999'999'999'999'999},
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{Number{9'999'999'999'999'999, 1}, 99'999'999'999'999'990},
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{Number{9'999'999'999'999'999, 2}, 999'999'999'999'999'900},
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{Number{-9'999'999'999'999'999, 2}, -999'999'999'999'999'900},
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{Number{15, -1}, 1},
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{Number{14, -1}, 1},
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{Number{16, -1}, 1},
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{Number{25, -1}, 2},
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{Number{6, -1}, 0},
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{Number{5, -1}, 0},
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{Number{4, -1}, 0},
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{Number{-15, -1}, -1},
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{Number{-14, -1}, -1},
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{Number{-16, -1}, -1},
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{Number{-25, -1}, -2},
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{Number{-6, -1}, 0},
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{Number{-5, -1}, 0},
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{Number{-4, -1}, 0}};
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for (auto const& [x, y] : c)
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{
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auto j = static_cast<std::int64_t>(x);
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BEAST_EXPECT(j == y);
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}
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}
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prev_mode = Number::setround(Number::downward);
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BEAST_EXPECT(prev_mode == Number::towards_zero);
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{
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Case c[]{
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{Number{0}, 0},
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{Number{1}, 1},
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{Number{2}, 2},
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{Number{3}, 3},
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{Number{-1}, -1},
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{Number{-2}, -2},
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{Number{-3}, -3},
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{Number{10}, 10},
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{Number{99}, 99},
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{Number{1155}, 1155},
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{Number{9'999'999'999'999'999, 0}, 9'999'999'999'999'999},
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{Number{9'999'999'999'999'999, 1}, 99'999'999'999'999'990},
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{Number{9'999'999'999'999'999, 2}, 999'999'999'999'999'900},
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{Number{-9'999'999'999'999'999, 2}, -999'999'999'999'999'900},
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{Number{15, -1}, 1},
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{Number{14, -1}, 1},
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{Number{16, -1}, 1},
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{Number{25, -1}, 2},
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{Number{6, -1}, 0},
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{Number{5, -1}, 0},
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{Number{4, -1}, 0},
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{Number{-15, -1}, -2},
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{Number{-14, -1}, -2},
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{Number{-16, -1}, -2},
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{Number{-25, -1}, -3},
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{Number{-6, -1}, -1},
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{Number{-5, -1}, -1},
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{Number{-4, -1}, -1}};
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for (auto const& [x, y] : c)
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{
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auto j = static_cast<std::int64_t>(x);
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BEAST_EXPECT(j == y);
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}
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}
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prev_mode = Number::setround(Number::upward);
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BEAST_EXPECT(prev_mode == Number::downward);
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{
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Case c[]{
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{Number{0}, 0},
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{Number{1}, 1},
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{Number{2}, 2},
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{Number{3}, 3},
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{Number{-1}, -1},
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{Number{-2}, -2},
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{Number{-3}, -3},
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{Number{10}, 10},
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{Number{99}, 99},
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{Number{1155}, 1155},
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{Number{9'999'999'999'999'999, 0}, 9'999'999'999'999'999},
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{Number{9'999'999'999'999'999, 1}, 99'999'999'999'999'990},
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{Number{9'999'999'999'999'999, 2}, 999'999'999'999'999'900},
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{Number{-9'999'999'999'999'999, 2}, -999'999'999'999'999'900},
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{Number{15, -1}, 2},
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{Number{14, -1}, 2},
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{Number{16, -1}, 2},
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{Number{25, -1}, 3},
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{Number{6, -1}, 1},
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{Number{5, -1}, 1},
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{Number{4, -1}, 1},
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{Number{-15, -1}, -1},
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{Number{-14, -1}, -1},
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{Number{-16, -1}, -1},
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{Number{-25, -1}, -2},
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{Number{-6, -1}, 0},
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{Number{-5, -1}, 0},
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{Number{-4, -1}, 0}};
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for (auto const& [x, y] : c)
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{
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auto j = static_cast<std::int64_t>(x);
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BEAST_EXPECT(j == y);
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}
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}
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bool caught = false;
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try
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