mytype.jl

using BenchmarkTools

struct MyType	
	x::Vector{Float64}
	y::Vector{Float64}
	_n::UInt16
	
	delta::Vector{Float64}
	
	function (::Type{MyType})(x::Vector{Float64}, y::Vector{Float64})
		if size(x, 1) != size(y, 1)
            err = "x and y must have same number of elements"
            throw(DimenmyonMismatch(err))
        end	
		delta=diff(y)./diff(x)
        new(x,y,length(x),delta)	
	end
end

function MyType(x::AbstractVector{T1}, y::AbstractVector{T2})  where {T1,T2<:Real}
    MyType(collect(x), collect(y))
end

function (my::MyType)(xp::T) where {T<:Real}
    ix::UInt16 = searchsortedfirst(my.x, xp)
	s::Float64 = 0.0
	value::Float64 = 0.0
	@inbounds begin	
		if ix==1
			s = xp-my.x[1]
			value = my.y[1] + s * my.delta[1] 
		elseif ix==my._n + 1
			s = xp-my.x[end]
			value = my.y[end] + s * my.delta[end]
		else
			s = xp-my.x[ix-1]
			value = my.y[ix-1] + s * my.delta[ix-1]
		end			
	end
	return value
end

function testit()
	x = 1.0:0.5:10.5
	y = log.(x)
	
	myty = MyType(x,y)
	
	@btime myty(5.0)
end