test dimension and readme

README.md

@@ -20,8 +20,7 @@ Convert the ndims-dimensional coordinates `p` into the linear index `d` :
 
 `d = hilbert(p::Vector{T}, ndims, nbits = 32) where T <: Integer`
 
-The number of bits `nbits` determines the precision of the curve, and the algorithm work
-under the constrain:
+All coordinates are positive integers (zero included). The number of bits `nbits` determines the precision of the curve, and the algorithm work under the constrain:
 
 - `ndims * nbits <= 64`
 

src/HilbertSpaceFillingCurve.jl

@@ -14,15 +14,17 @@ module HilbertSpaceFillingCurve
     global const bits_per_byte = 8
 
     function hilbert(d::T, ndims, nbits = 32) where T <: Integer
-
         @assert ndims*nbits <= sizeof(bitmask_t) * bits_per_byte
+
         p = bitmask_t.(zeros(ndims))
         ccall((:hilbert_i2c, libhilbert), Void, (Int,Int,bitmask_t,Ptr{bitmask_t}),ndims,nbits,d,p) 
         Int.(p)
     end
 
     function hilbert(p::Vector{T}, ndims, nbits = 32) where T <: Integer
         @assert ndims*nbits <= sizeof(bitmask_t) * bits_per_byte
+        @assert length(p) == ndims
+
         Int(ccall((:hilbert_c2i, libhilbert), bitmask_t, (Int,Int,Ptr{bitmask_t}),ndims,nbits, bitmask_t.(p)))
     end