Function FL_TEST_FILE

tests/fl/stl/ieee754_string.cpp:13–185

#include "fl/stl/string.h"

FL_TEST_FILE(FL_FILEPATH) {

using namespace fl;

// Convenience: parse a literal and reinterpret the result as a float for
// comparison against host strtof. The bit-cast itself does not anchor any
// libgcc soft-FP helper; the host `float` comparison does (cheap on host).
static float parse_as_float(const char* s) {
    u32 bits = ieee754_parse_decimal(s, fl::strlen(s));
    return fl::bit_cast<float>(bits);
}

FL_TEST_CASE("ieee754_parse_decimal -- well-known constants") {
    FL_SUBCASE("zero") {
        FL_CHECK(ieee754_parse_decimal("0", 1) == 0x00000000u);
        FL_CHECK(ieee754_parse_decimal("-0", 2) == 0x80000000u);
        FL_CHECK(ieee754_parse_decimal("0.0", 3) == 0x00000000u);
    }

    FL_SUBCASE("one") {
        FL_CHECK(ieee754_parse_decimal("1", 1) == 0x3F800000u);
        FL_CHECK(ieee754_parse_decimal("1.0", 3) == 0x3F800000u);
        FL_CHECK(ieee754_parse_decimal("-1", 2) == 0xBF800000u);
    }

    FL_SUBCASE("ten") {
        FL_CHECK(ieee754_parse_decimal("10", 2) == 0x41200000u);
        FL_CHECK(ieee754_parse_decimal("10.0", 4) == 0x41200000u);
    }

    FL_SUBCASE("half") {
        FL_CHECK(ieee754_parse_decimal("0.5", 3) == 0x3F000000u);
        FL_CHECK(ieee754_parse_decimal("-0.5", 4) == 0xBF000000u);
    }

    FL_SUBCASE("two") {
        FL_CHECK(ieee754_parse_decimal("2", 1) == 0x40000000u);
        FL_CHECK(ieee754_parse_decimal("2.0", 3) == 0x40000000u);
    }
}

FL_TEST_CASE("ieee754_parse_decimal -- within +/-1 ULP of strtof") {
    auto ulp_diff = [](u32 a, u32 b) -> u32 {
        return a > b ? (a - b) : (b - a);
    };

    auto roundtrip_check = [&](const char* s, float expected) {
        u32 got_bits = ieee754_parse_decimal(s, fl::strlen(s));
        u32 expected_bits = fl::bit_cast<u32>(expected);
        FL_CHECK(ulp_diff(got_bits, expected_bits) <= 1u);
    };

    roundtrip_check("3.14", 3.14f);
    roundtrip_check("3.14159", 3.14159f);
    roundtrip_check("0.001", 0.001f);
    roundtrip_check("0.0001", 0.0001f);
    roundtrip_check("100.0", 100.0f);
    roundtrip_check("1000.0", 1000.0f);