diff --git a/Cargo.toml b/Cargo.toml
index 5ea09a2c79e2d1cbee23eed9d6e5491247177c72..71b9c28e770c26f24645ebd81797c65b256f963a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,8 +1,9 @@
[package]
-name = "goertzel"
+edition = "2021"
+name = "goertzel-nostd"
version = "0.2.0"
-authors = ["Matt McPherrin <matt@mcpherrin.ca>"]
+authors = ["Stephen D"]
repository = "https://github.com/mcpherrinm/goertzel.git"
keywords = ["dsp", "goertzel", "fft", "fourier"]
license = "MIT"
-description = "An implementation of Goertzel's Algoritm"
+description = "An nostd implementation of Goertzel's Algoritm"
diff --git a/README.md b/README.md
index e1ae2d5d692b60c3896f59bab32b831863a23848..4603bd788f0d207e0215dc9024eb4a956c909c9e 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,8 @@
-Goertzel
+Goertzel-nostd
--------
The Goertzel Algoritm is a single-bin discrete fourier transform, useful for
tone detection with a small number of tones. This has not yet been extensively
tested, but appears to basically work.
+
+This is a fork of [goertzel](https://github.com/mcpherrinm/goertzel).
diff --git a/rustfmt.toml b/rustfmt.toml
new file mode 100644
index 0000000000000000000000000000000000000000..a4f58761a21a7247aab2f84bbaea0f501ade6c81
--- /dev/null
+++ b/rustfmt.toml
@@ -0,0 +1,3 @@
+tab_spaces = 4
+hard_tabs = true
+edition = "2021"
diff --git a/src/lib.rs b/src/lib.rs
index ee7a171e8dfbe47010f2f878794ed4b878ae9cb4..64eb6f6dd57bf789ade85168f932087ed0d911f5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -6,95 +6,99 @@ use std::f32::consts::PI;
/// Set up parameters (and some precomputed values for those).
#[derive(Clone, Copy)]
pub struct Parameters {
- // Parameters we're working with
- window_size: usize,
- // Precomputed value:
- sine: f32,
- cosine: f32,
- term_coefficient: f32,
+ // Parameters we're working with
+ window_size: usize,
+ // Precomputed value:
+ sine: f32,
+ cosine: f32,
+ term_coefficient: f32,
}
pub struct Partial {
- params: Parameters,
- count: usize,
- prev: f32,
- prevprev: f32,
+ params: Parameters,
+ count: usize,
+ prev: f32,
+ prevprev: f32,
}
impl Parameters {
- pub fn new(target_freq: f32, sample_rate: u32, window_size: usize) -> Self {
- let k = target_freq * (window_size as f32) / (sample_rate as f32);
- let omega = (PI * 2. * k) / (window_size as f32);
- let cosine = omega.cos();
- Parameters {
- window_size: window_size,
- sine: omega.sin(),
- cosine: cosine,
- term_coefficient: 2. * cosine,
- }
- }
+ pub fn new(target_freq: f32, sample_rate: u32, window_size: usize) -> Self {
+ let k = target_freq * (window_size as f32) / (sample_rate as f32);
+ let omega = (PI * 2. * k) / (window_size as f32);
+ let cosine = omega.cos();
+ Parameters {
+ window_size: window_size,
+ sine: omega.sin(),
+ cosine: cosine,
+ term_coefficient: 2. * cosine,
+ }
+ }
- pub fn start(self) -> Partial {
- Partial{ params: self, count: 0, prev: 0., prevprev: 0. }
- }
+ pub fn start(self) -> Partial {
+ Partial {
+ params: self,
+ count: 0,
+ prev: 0.,
+ prevprev: 0.,
+ }
+ }
- pub fn mag(self, samples: &[i16]) -> f32 {
- self.start().add(samples).finish_mag()
- }
+ pub fn mag(self, samples: &[i16]) -> f32 {
+ self.start().add(samples).finish_mag()
+ }
}
impl Partial {
- pub fn add(mut self, samples: &[i16]) -> Self {
- for &sample in samples {
- let this = self.params.term_coefficient * self.prev - self.prevprev + (sample as f32);
- self.prevprev = self.prev;
- self.prev = this;
- }
- self.count += samples.len();
- self
- }
- pub fn finish(self) -> (f32, f32) {
- assert_eq!(self.count, self.params.window_size);
- let real = self.prev - self.prevprev * self.params.cosine;
- let imag = self.prevprev * self.params.sine;
- (real, imag)
- }
+ pub fn add(mut self, samples: &[i16]) -> Self {
+ for &sample in samples {
+ let this = self.params.term_coefficient * self.prev - self.prevprev + (sample as f32);
+ self.prevprev = self.prev;
+ self.prev = this;
+ }
+ self.count += samples.len();
+ self
+ }
+ pub fn finish(self) -> (f32, f32) {
+ assert_eq!(self.count, self.params.window_size);
+ let real = self.prev - self.prevprev * self.params.cosine;
+ let imag = self.prevprev * self.params.sine;
+ (real, imag)
+ }
- pub fn finish_mag(self) -> f32 {
- let (real, imag) = self.finish();
- (real*real + imag*imag).sqrt()
- }
+ pub fn finish_mag(self) -> f32 {
+ let (real, imag) = self.finish();
+ (real * real + imag * imag).sqrt()
+ }
}
#[test]
fn zero_data() {
- let p = Parameters::new(1800., 8000, 256);
- assert!(p.start().add(&[0; 256]).finish_mag() == 0.);
- assert!(p.start().add(&[0; 128]).add(&[0;128]).finish_mag() == 0.);
+ let p = Parameters::new(1800., 8000, 256);
+ assert!(p.start().add(&[0; 256]).finish_mag() == 0.);
+ assert!(p.start().add(&[0; 128]).add(&[0; 128]).finish_mag() == 0.);
}
#[test]
fn sine() {
- let mut buf = [0; 8000];
- for &freq in [697., 1200., 1800., 1633.].iter() {
- // Generate a 1 second sine wave at freq hz
- let step = 1. / 8000.;
- for sample in (0 .. 8000) {
- let time = sample as f32 * step;
- buf[sample] = ((time * freq * PI * 2.).sin() * std::i16::MAX as f32) as i16;
- }
+ let mut buf = [0; 8000];
+ for &freq in [697., 1200., 1800., 1633.].iter() {
+ // Generate a 1 second sine wave at freq hz
+ let step = 1. / 8000.;
+ for sample in (0..8000) {
+ let time = sample as f32 * step;
+ buf[sample] = ((time * freq * PI * 2.).sin() * std::i16::MAX as f32) as i16;
+ }
- let p = Parameters::new(freq, 8000, 8000);
- let mag = p.start().add(&buf[..]).finish_mag();
- for testfreq in (0 .. 30).map(|x| (x * 100) as f32) {
- let p = Parameters::new(testfreq, 8000, 8000);
- let testmag = p.mag(&buf[..]);
- println!("{:4}: {:12.3}", testfreq, testmag);
- if (freq-testfreq).abs() > 100. {
- println!("{} > 10*{}", mag, testmag);
- assert!(mag > 10.*testmag);
- }
- }
- }
+ let p = Parameters::new(freq, 8000, 8000);
+ let mag = p.start().add(&buf[..]).finish_mag();
+ for testfreq in (0..30).map(|x| (x * 100) as f32) {
+ let p = Parameters::new(testfreq, 8000, 8000);
+ let testmag = p.mag(&buf[..]);
+ println!("{:4}: {:12.3}", testfreq, testmag);
+ if (freq - testfreq).abs() > 100. {
+ println!("{} > 10*{}", mag, testmag);
+ assert!(mag > 10. * testmag);
+ }
+ }
+ }
}
-