mapnik/test/unit/numerics/safe_cast.cpp

#include "catch.hpp"
#include <mapnik/safe_cast.hpp>

#define CAST_ASSERT(numeric_type)                                                                                      \
    using limit = std::numeric_limits<numeric_type>;                                                                   \
    auto min_value = static_cast<std::intmax_t>(limit::min()) - 1;                                                     \
    auto max_value = static_cast<std::intmax_t>(limit::max()) + 1;                                                     \
    CHECK(limit::min() == mapnik::safe_cast<numeric_type>(min_value));                                                 \
    CHECK(limit::max() == mapnik::safe_cast<numeric_type>(max_value));

#define CAST_ASSERT2(numeric_type)                                                                                     \
    using limit = std::numeric_limits<numeric_type>;                                                                   \
    auto min_value = static_cast<std::intmax_t>(limit::min());                                                         \
    auto max_value = static_cast<std::intmax_t>(limit::max());                                                         \
    CHECK(limit::min() == mapnik::safe_cast<numeric_type>(min_value));                                                 \
    CHECK(limit::max() == mapnik::safe_cast<numeric_type>(max_value));

#define CAST_ASSERT3(numeric_type)                                                                                     \
    using limit = std::numeric_limits<numeric_type>;                                                                   \
    auto min_value = static_cast<std::intmax_t>(limit::min()) - 1;                                                     \
    auto max_value = static_cast<std::uintmax_t>(limit::max());                                                        \
    CHECK(limit::min() == mapnik::safe_cast<numeric_type>(min_value));                                                 \
    CHECK(limit::max() == mapnik::safe_cast<numeric_type>(max_value));

#define CAST_ASSERT4(numeric_type)                                                                                     \
    using limit = std::numeric_limits<numeric_type>;                                                                   \
    auto min_value = static_cast<double>(-limit::max()) - 1;                                                           \
    auto max_value = static_cast<double>(limit::max());                                                                \
    CHECK(-limit::max() == mapnik::safe_cast<numeric_type>(min_value));                                                \
    CHECK(limit::max() == mapnik::safe_cast<numeric_type>(max_value));

TEST_CASE("saturated cast")
{
    SECTION("int8") { CAST_ASSERT(std::int8_t); }
    SECTION("int16") { CAST_ASSERT(std::int16_t); }
    SECTION("int32") { CAST_ASSERT(std::int32_t); }

    SECTION("int64") { CAST_ASSERT2(std::int64_t); }
    SECTION("intmax") { CAST_ASSERT2(std::intmax_t); }
    SECTION("intptr") { CAST_ASSERT2(std::intptr_t); }

    SECTION("uint8") { CAST_ASSERT(std::uint8_t); }
    SECTION("uint16") { CAST_ASSERT(std::uint16_t); }
    SECTION("uint32") { CAST_ASSERT(std::uint32_t); }

    SECTION("uint64") { CAST_ASSERT3(std::uint64_t); }
    SECTION("uintmax") { CAST_ASSERT3(std::uintmax_t); }
    SECTION("uintptr") { CAST_ASSERT3(std::uintptr_t); }

    SECTION("float") { CAST_ASSERT4(float); }

    SECTION("freeform")
    {
        CHECK(static_cast<std::size_t>(0) == mapnik::safe_cast<std::size_t>(-1));
        CHECK(static_cast<std::uint64_t>(0) == mapnik::safe_cast<std::uint64_t>(-1));
        CHECK(static_cast<unsigned long long>(0) == mapnik::safe_cast<unsigned long long>(-1));
    }
}