From 6769872b397e28c6a8023b45bd6766e351fae4a2 Mon Sep 17 00:00:00 2001
From: Ahmet Inan <inan@aicodix.de>
Date: Thu, 3 Jan 2019 19:50:18 +0100
Subject: [PATCH] moved sinc() to utils

---
 README.md    | 1 +
 resampler.hh | 6 +-----
 utils.hh     | 6 ++++++
 window.hh    | 6 +-----
 4 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/README.md b/README.md
index cb4627f..1e16bdb 100644
--- a/README.md
+++ b/README.md
@@ -56,6 +56,7 @@ Some everyday helpers:
 * [signum function](https://en.wikipedia.org/wiki/Sign_function)
 * [lerp function](https://en.wikipedia.org/wiki/Linear_interpolation)
 * [probability density function](https://en.wikipedia.org/wiki/Probability_density_function) of the [normal distribution](https://en.wikipedia.org/wiki/Normal_distribution)
+* [sinc function](https://en.wikipedia.org/wiki/Sinc_function)
 
 ### [resampler.hh](resampler.hh)
 
diff --git a/resampler.hh b/resampler.hh
index 753be93..4353135 100644
--- a/resampler.hh
+++ b/resampler.hh
@@ -10,6 +10,7 @@ Copyright 2018 Ahmet Inan <inan@aicodix.de>
 
 #include "window.hh"
 #include "spline.hh"
+#include "utils.hh"
 #include "const.hh"
 
 namespace DSP {
@@ -19,11 +20,6 @@ class Resampler
 {
 	typedef DSP::UniformNaturalCubicSpline<TAPS * OVER, TYPE, TYPE> spline_type;
 	spline_type lpf;
-
-	static TYPE sinc(TYPE x)
-	{
-		return TYPE(0) == x ? TYPE(1) : std::sin(DSP::Const<TYPE>::Pi() * x) / (DSP::Const<TYPE>::Pi() * x);
-	}
 public:
 	Resampler(TYPE cutoff, TYPE alpha)
 	{
diff --git a/utils.hh b/utils.hh
index ff987b3..c155ee2 100644
--- a/utils.hh
+++ b/utils.hh
@@ -29,6 +29,12 @@ TYPE normal_pdf(TYPE x, TYPE m, TYPE s)
 	return std::exp(-std::pow((x - m) / s, TYPE(2)) / TYPE(2)) / (Const<TYPE>::SqrtTwoPi() * s);
 }
 
+template <typename TYPE>
+TYPE sinc(TYPE x)
+{
+	return TYPE(0) == x ? TYPE(1) : std::sin(Const<TYPE>::Pi() * x) / (Const<TYPE>::Pi() * x);
+}
+
 }
 
 #endif
diff --git a/window.hh b/window.hh
index c01bf88..f8cd512 100644
--- a/window.hh
+++ b/window.hh
@@ -9,6 +9,7 @@ Copyright 2018 Ahmet Inan <inan@aicodix.de>
 
 #include "const.hh"
 #include "kahan.hh"
+#include "utils.hh"
 #include "coeffs.hh"
 
 namespace DSP {
@@ -40,11 +41,6 @@ struct Hamming : public CoeffsFunc<TYPE>
 template <typename TYPE>
 class Lanczos : public CoeffsFunc<TYPE>
 {
-	static TYPE sinc(TYPE x)
-	{
-		return TYPE(0) == x ? TYPE(1) : std::sin(Const<TYPE>::Pi() * x) / (Const<TYPE>::Pi() * x);
-	}
-public:
 	TYPE operator () (int n, int N)
 	{
 		return sinc(TYPE(2 * n) / TYPE(N - 1) - TYPE(1));