[RFC PATCH v2 05/12] ipa: libipa: vector: Generalize arithmetic operators

[Laurent Pinchart]

On Mon, Nov 18, 2024 at 01:44:07PM +0100, Milan Zamazal wrote:
> Laurent Pinchart <laurent.pinchart at ideasonboard.com> writes:
> 
> > Instead of hand-coding all arithmetic operators, implement them based on
> > a generic apply() function that takes an operator-specific
> > std::function. This will simplify adding missing arithmetic operators.
> 
> I always welcome deduplication!
> 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> >  src/ipa/libipa/vector.h | 48 ++++++++++++++++++++++++-----------------
> >  1 file changed, 28 insertions(+), 20 deletions(-)
> >
> > diff --git a/src/ipa/libipa/vector.h b/src/ipa/libipa/vector.h
> > index 9dabdc28a540..8c4edfbaf85f 100644
> > --- a/src/ipa/libipa/vector.h
> > +++ b/src/ipa/libipa/vector.h
> > @@ -74,36 +74,24 @@ public:
> >  		return ret;
> >  	}
> >  
> > -	constexpr Vector<T, Rows> operator-(const Vector<T, Rows> &other) const
> > +	constexpr Vector operator-(const Vector &other) const
> >  	{
> > -		Vector<T, Rows> ret;
> > -		for (unsigned int i = 0; i < Rows; i++)
> > -			ret[i] = data_[i] - other[i];
> > -		return ret;
> > +		return apply(*this, other, [](T a, T b) { return a - b; });
> >  	}
> 
> Could std::minus be used here (and similarly for the other methods)?

Yes it can. I'll fix that.

> With or without this:
> 
> Reviewed-by: Milan Zamazal <mzamazal at redhat.com>
> 
> > -	constexpr Vector<T, Rows> operator+(const Vector<T, Rows> &other) const
> > +	constexpr Vector operator+(const Vector &other) const
> >  	{
> > -		Vector<T, Rows> ret;
> > -		for (unsigned int i = 0; i < Rows; i++)
> > -			ret[i] = data_[i] + other[i];
> > -		return ret;
> > +		return apply(*this, other, [](T a, T b) { return a + b; });
> >  	}
> >  
> > -	constexpr Vector<T, Rows> operator*(T factor) const
> > +	constexpr Vector operator*(T factor) const
> >  	{
> > -		Vector<T, Rows> ret;
> > -		for (unsigned int i = 0; i < Rows; i++)
> > -			ret[i] = data_[i] * factor;
> > -		return ret;
> > +		return apply(*this, factor, [](T a, T b) { return a * b; });
> >  	}
> >  
> > -	constexpr Vector<T, Rows> operator/(T factor) const
> > +	constexpr Vector operator/(T factor) const
> >  	{
> > -		Vector<T, Rows> ret;
> > -		for (unsigned int i = 0; i < Rows; i++)
> > -			ret[i] = data_[i] / factor;
> > -		return ret;
> > +		return apply(*this, factor, [](T a, T b) { return a / b; });
> >  	}
> >  
> >  	constexpr T dot(const Vector<T, Rows> &other) const
> > @@ -178,6 +166,26 @@ public:
> >  	}
> >  
> >  private:
> > +	static constexpr Vector apply(const Vector &lhs, const Vector &rhs, std::function<T(T, T)> func)
> > +	{
> > +		Vector result;
> > +		std::transform(lhs.data_.begin(), lhs.data_.end(),
> > +			       rhs.data_.begin(), result.data_.begin(),
> > +			       func);
> > +
> > +		return result;
> > +	}
> > +
> > +	static constexpr Vector apply(const Vector &lhs, T rhs, std::function<T(T, T)> func)
> > +	{
> > +		Vector result;
> > +		std::transform(lhs.data_.begin(), lhs.data_.end(),
> > +			       result.data_.begin(),
> > +			       [&func, rhs](T v) { return func(v, rhs); });
> > +
> > +		return result;
> > +	}
> > +
> >  	std::array<T, Rows> data_;
> >  };

-- 
Regards,

Laurent Pinchart