issue #262

Alexander-Barth · Aug 26, 2024 · 968ebbf · 968ebbf · Alexander-Barth · Aug 30, 2024
1 parent 35991a8
commit 968ebbf
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diff --git a/src/netcdf_c.jl b/src/netcdf_c.jl
@@ -1026,7 +1026,26 @@ end
 
 function nc_get_vars!(ncid::Integer,varid::Integer,startp,countp,stridep,ip)
     @debug "nc_get_vars!: $startp,$countp,$stridep"
-    check(ccall((:nc_get_vars,libnetcdf),Cint,(Cint,Cint,Ptr{Csize_t},Ptr{Csize_t},Ptr{Cint},Ptr{Nothing}),ncid,varid,startp,countp,stridep,ip))
+
+    if any(<(0),stridep)
+        reverse_dim = stridep .< 0
+        strider = copy(stridep)
+        startr = copy(startp)
+
+        for i = 1:length(stridep)
+            if reverse_dim[i]
+                strider[i] = -stridep[i]
+                startr[i] = startp[i] + (countp[i]-1)*stridep[i]
+            end
+        end
+
+        check(ccall((:nc_get_vars,libnetcdf),Cint,(Cint,Cint,Ptr{Csize_t},Ptr{Csize_t},Ptr{Cint},Ptr{Nothing}),ncid,varid,startr,countp,strider,ip))
+
+        # reverse(reverse_dim) is necessary because stride uses the C ordering
+        reverse!(ip,dims=Tuple(findall(reverse(reverse_dim))))
+    else
+        check(ccall((:nc_get_vars,libnetcdf),Cint,(Cint,Cint,Ptr{Csize_t},Ptr{Csize_t},Ptr{Cint},Ptr{Nothing}),ncid,varid,startp,countp,stridep,ip))
+    end
 end
 
 

diff --git a/test/test_variable.jl b/test/test_variable.jl
@@ -310,3 +310,21 @@ vv = [1.0f0]
 NCDatasets.load!(variable(ds, "temperature"), vv, CartesianIndex(5,5))
 @test vv[1] == data[CartesianIndex(5,5)]
 close(ds)
+
+# issue 262
+fname = tempname()
+ds = NCDataset(fname,"c")
+defDim(ds,"lon",10)
+defDim(ds,"lat",11)
+data = [Float32(i+j) for i = 1:10, j = 1:11];
+data2 = similar(data)
+v = defVar(ds,"temperature",data,("lon","lat"))
+
+@test v[:,end:-1:1] == data[:,end:-1:1]
+@test v[:,end:-2:1] == data[:,end:-2:1]
+@test v[:,5:-1:1] == data[:,5:-1:1]
+@test v[:,5:-1:3] == data[:,5:-1:3]
+@test v[end:-1:1,:] == data[end:-1:1,:]
+
+NCDatasets.load!(variable(ds, "temperature"), data2, :,11:-1:1)
+@test data2 == data[:,end:-1:1]