From 308edb5b5cd5ee6d2e2962f627612e3973f5b586 Mon Sep 17 00:00:00 2001
From: Justin Worthe <justin.worthe@gmail.com>
Date: Sun, 4 Dec 2016 22:45:54 +0200
Subject: Added sampling of a range

---
 src/num_traits.rs |  4 ++--
 src/sinusoid.rs   | 42 ++++++++++++++++++++++++++++++++++++------
 2 files changed, 38 insertions(+), 8 deletions(-)

(limited to 'src')

diff --git a/src/num_traits.rs b/src/num_traits.rs
index b6a2ac8..a754787 100644
--- a/src/num_traits.rs
+++ b/src/num_traits.rs
@@ -88,7 +88,7 @@ impl_int_pow!(u64);
 
 pub trait Float {
     fn recip(self) -> Self;
-    fn PI() -> Self;
+    fn pi() -> Self;
 }
 
 macro_rules! impl_float {
@@ -97,7 +97,7 @@ macro_rules! impl_float {
             fn recip(self) -> Self {
                 self.recip()
             }
-            fn PI() -> Self {
+            fn pi() -> Self {
                 $pi
             }
         }
diff --git a/src/sinusoid.rs b/src/sinusoid.rs
index 6ee5019..1f60b03 100644
--- a/src/sinusoid.rs
+++ b/src/sinusoid.rs
@@ -1,6 +1,6 @@
-use std;
-use std::ops::{Add, Sub, Mul, Div, Neg};
-use ::num_traits::{Trig, Pow, Float};
+use std::cmp::{PartialOrd};
+use std::ops::{Add, Sub, Mul, Div, Rem};
+use ::num_traits::{Trig, Float};
 
 // generic number type, but realistically it's only useful for
 // floats. Maybe also complex<float>
@@ -25,12 +25,28 @@ impl<T> Sinusoid<T> where T: Float + Copy {
         self.frequency.recip()
     }
 }
-impl<T> Sinusoid<T> where T: Float + Add<Output=T> + Mul<Output=T> + From<u8> + Trig + Copy + std::fmt::Display {
+impl<T> Sinusoid<T> where T: Float + Add<Output=T> + Sub<Output=T> + Mul<Output=T> + Div<Output=T> + From<u16> + Trig + Copy + PartialOrd + Rem<Output=T> {
     pub fn radial_frequency(&self) -> T {
-        (T::from(2))*T::PI()*self.frequency
+        (T::from(2))*T::pi()*self.frequency
     }
     pub fn sample(&self, t: T) -> T {
-        (self.radial_frequency()*t + self.phase).cos() * self.amplitude
+        (self.radial_frequency()*(t%self.period()) + self.phase).cos() * self.amplitude
+    }
+    //inclusive of start, exclusive of end
+    pub fn sample_range(&self, start: T, end: T, sample_rate: T) -> Vec<T> {
+        let sample_resolution = T::from(1) / sample_rate;
+        let mut result = Vec::new();
+        let mut i: u16 = 0;
+        loop {
+            let t = start + T::from(i)/sample_rate;
+            if t >= end {
+                break;
+            }
+            result.push(self.sample(t));
+            i += 1;
+        }
+        
+        result
     }
 }
 
@@ -60,4 +76,18 @@ mod tests {
         assert!((sinusoid.sample(0.75)+1.0) < f32::EPSILON);
         assert!((sinusoid.sample(1.0)-0.0) < f32::EPSILON);
     }
+
+    #[test]
+    fn sample_range() {
+        let sinusoid = Sinusoid::new(1.0 as f32, 1.0, -f32::consts::PI/2.0); //AKA sin
+        let samples = sinusoid.sample_range(0.0, 100.0, 4.0);
+        println!("Epsilon is {}", f32::EPSILON);
+        assert_eq!(samples.len(), 400);
+        for i in (0..100).map(|i| i*4) {
+            assert!((samples[i+0]-0.0) < f32::EPSILON, "Sample {} was {}", i+0, samples[i+0]);
+            assert!((samples[i+1]-1.0) < f32::EPSILON, "Sample {} was {}", i+1, samples[i+1]);
+            assert!((samples[i+2]-0.0) < f32::EPSILON, "Sample {} was {}", i+2, samples[i+2]);
+            assert!((samples[i+3]+1.0) < f32::EPSILON, "Sample {} was {}", i+3, samples[i+3]);
+        }
+    }
 }
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