Minor performance improvements to the BaseUnits class (v5)

[lipchev]

• avoid storing the IsFullyDefined value to a field (the property is only used when constructing a UnitSystem)
• add a reference check to the Equals method (improves the == Undefined)
• use the HashCode class for the GetHashCode method (note that the result would be different between Framework and NET projects)

[lipchev]

If you think the 3rd point is a "breaker", I could switch it over to v6 but I find it very unlikely that this would affect anyone (I'm frankly not even sure if the same code would produce the same result on both targets 🤷 ).
I have one more change I want to make- but that's more likely (although it shouldn't) to surprise somebody:

I'd like to change the ToString format:

        public override string ToString()
        {
            if (Equals(Undefined))
            {
                return "Undefined";
            }

            return string.Join(", ", GetUnitsDefined());

            IEnumerable<string> GetUnitsDefined()
            {
                if (Length is not null)
                {
                    yield return $"[Length]: {Length}";
                }
                if (Mass is not null)
                {
                    yield return $"[Mass]: {Mass}";
                }
                if (Time is not null)
                {
                    yield return $"[Time]: {Time}";
                }
                if (Current is not null)
                {
                    yield return $"[Current]: {Current}";
                }
                if (Temperature is not null)
                {
                    yield return $"[Temperature]: {Temperature}";
                }
                if (Amount is not null)
                {
                    yield return $"[Amount]: {Amount}";
                }
                if (LuminousIntensity is not null)
                {
                    yield return $"[LuminousIntensity]: {LuminousIntensity}";
                }
            }
        }

The difference is that we're not using the UnitAbbreviations - which removes the potential side effects that this could have when "configuring" the UnitsNetSetup.

[angularsen]

Looks fine to me, I don't think this should break anyone or at least extremely few.

Regarding the ToString change, beware that yield return and enumerable are not really performant if that is the goal. No source right now, but if I recall correctly using StringBuilder is the way to go to construct strings performantly.

Of course, we're talking micro optimizations here, but also no real downside to that approach.

[angularsen]

Release UnitsNet/5.62.0 · angularsen/UnitsNet