Bug 249771

Manage to have testcase - will try to do PR later today - https://jsfiddle.net/mwn0jy35/

<rdar://problem/103759613>

I am closing this PR for time being because I noted that we still have other pre-requisite bugs to fix in StepUp and StepDown and closing my PR for time being with following comment:

''

NOTE to myself - I am going to close this PR since there are still bugs in StepUp and StepDown, which we should fix since this might be causing this to fail. So I will look into this later, once I fix other bugs.

''


PR - https://github.com/WebKit/WebKit/pull/8045

Just copying that following compiles when added to 'Decimal.cpp' (for TestWebKit API):

// Simulate core/html/forms/StepRange
class DecimalStepRange {

public:
    Decimal maximum;
    Decimal minimum;
    Decimal step;

    DecimalStepRange(const Decimal& minimum, const Decimal& maximum, const Decimal& step)
        : maximum(maximum)
        , minimum(minimum)
        , step(step)
    {
    }

    Decimal clampValue(Decimal value) const
    {
        const Decimal result = minimum + ((value - minimum) / step).round() * step;
        ASSERT(result.isFinite());
        return result > maximum ? result - step : result;
    }
};

class Decimcal : public testing::Test {
protected:
    using Sign = Decimal::Sign;
    static constexpr Sign positive = Decimal::Positive;
    static constexpr Sign negative = Decimal::Negative;

    Decimal encode(uint64_t coefficient, int exponent, Sign sign)
    {
        return Decimal(sign, exponent, coefficient);
    }

    Decimal fromString(const String& string)
    {
        return Decimal::fromString(string);
    }

    Decimal stepDown(const String& minimum, const String& maximum, const String& step, const String& valueString, int numberOfStepTimes)
    {
        DecimalStepRange stepRange(fromString(minimum), fromString(maximum), fromString(step));
        Decimal value = fromString(valueString);

        for (int i = 0; i < numberOfStepTimes; ++i) {
            value -= stepRange.step;
            value = stepRange.clampValue(value);
        }
        return value;
    }

    Decimal stepUp(const String& minimum, const String& maximum, const String& step, const String& valueString, int numberOfStepTimes)
    {
        DecimalStepRange stepRange(fromString(minimum), fromString(maximum), fromString(step));
        Decimal value = fromString(valueString);

        for (int i = 0; i < numberOfStepTimes; ++i) {
            value += stepRange.step;
            value = stepRange.clampValue(value);
        }
        return value;
    }
};

Committed 280189@main (c79f2cd50054): <https://commits.webkit.org/280189@main>

Reviewed commits have been landed. Closing PR #29941 and removing active labels.