FFT: throw for inputs with fewer than 16 values

swharden · swharden · commit ff6205ca2fff · 2022-06-15T23:21:35.000-04:00
diff --git a/src/FftSharp/Transform.cs b/src/FftSharp/Transform.cs
@@ -23,8 +23,8 @@ public static void FFT(Complex[] buffer)
         /// <param name="buffer">Data to transform in-place. Length must be a power of 2.</param>
         public static void FFT(Span<Complex> buffer)
         {
-            if (buffer.Length == 0)
-                throw new ArgumentException("Buffer must not be empty");
+            if (buffer.Length < 16)
+                throw new ArgumentException("Buffer must contain at least 16 values");
 
             if (!IsPowerOfTwo(buffer.Length))
                 throw new ArgumentException("Buffer length must be a power of 2");
@@ -74,8 +74,8 @@ public static void IFFT(Complex[] buffer)
             if (buffer is null)
                 throw new ArgumentNullException(nameof(buffer));
 
-            if (buffer.Length == 0)
-                throw new ArgumentException("Buffer must not be empty");
+            if (buffer.Length < 16)
+                throw new ArgumentException("Buffer must contain at least 16 values");
 
             if (!IsPowerOfTwo(buffer.Length))
                 throw new ArgumentException("Buffer length must be a power of 2");
@@ -213,8 +213,8 @@ public static Complex[] FFT(double[] input)
             if (input is null)
                 throw new ArgumentNullException(nameof(input));
 
-            if (input.Length == 0)
-                throw new ArgumentException("Input must not be empty");
+            if (input.Length < 16)
+                throw new ArgumentException("Input must have at least 16 values");
 
             if (!IsPowerOfTwo(input.Length))
                 throw new ArgumentException("Input length must be an even power of 2");
@@ -234,8 +234,8 @@ public static Complex[] RFFT(double[] input)
             if (input is null)
                 throw new ArgumentNullException(nameof(input));
 
-            if (input.Length == 0)
-                throw new ArgumentException("Input must not be empty");
+            if (input.Length < 16)
+                throw new ArgumentException("Input must have at least 16 values");
 
             if (!IsPowerOfTwo(input.Length))
                 throw new ArgumentException("Input length must be an even power of 2");
