handle edge case in reencode_samples

Project.toml

@@ -1,7 +1,7 @@
 name = "OndaEDF"
 uuid = "e3ed2cd1-99bf-415e-bb8f-38f4b42a544e"
 authors = ["Beacon Biosignals, Inc."]
-version = "0.12.2"
+version = "0.12.3"
 
 [deps]
 Compat = "34da2185-b29b-5c13-b0c7-acf172513d20"

src/export_edf.jl

@@ -155,6 +155,10 @@ function reencode_samples(samples::Samples, sample_type::Type{<:Integer}=Int16)
     # maximize the dynamic range of Int16 encoding.
     samples = decode(samples)
     smin, smax = extrema(samples.data)
+    # If the input is flat, normalize to zero and one
+    if smin == smax
+        smax = smin + one(smax)
+    end
 
     emin, emax = typemin(sample_type), typemax(sample_type)
 

test/export.jl

@@ -248,4 +248,21 @@
         end
     end
 
+    @testset "`reencode_samples` edge case: constant data" begin
+        # Weird encoding
+        info = SamplesInfoV2(; sensor_type="x",
+            channels=["x"],
+            sample_unit="microvolt",
+            sample_resolution_in_unit=0.001,
+            sample_offset_in_unit=0,
+            sample_type=Float64,
+            sample_rate=1)
+
+        data = zeros(UInt64, 1, 2) .+ 0x02
+        samples = Samples(data, info, false)
+        samples_reenc = OndaEDF.reencode_samples(samples)
+        @test samples_reenc isa Samples
+        @test decode(samples_reenc).data == data
+    end
+
 end