82 lines
2.0 KiB
Rust
82 lines
2.0 KiB
Rust
use num::traits::Num;
|
|
|
|
use super::error::DspError;
|
|
|
|
pub struct FIRFilter<'a, NumType>
|
|
where
|
|
NumType: Num + Copy,
|
|
{
|
|
coeffs: &'a [NumType],
|
|
state: Vec<NumType>,
|
|
pos: usize,
|
|
iterator: Box<dyn Iterator<Item = Result<NumType, DspError>> + 'a>,
|
|
}
|
|
|
|
impl<'a, NumType> FIRFilter<'a, NumType>
|
|
where
|
|
NumType: Num + Copy,
|
|
{
|
|
pub fn from<I>(iterator: I, coeffs: &'a [NumType]) -> FIRFilter<'a, NumType>
|
|
where
|
|
I: Iterator<Item = Result<NumType, DspError>> + 'a,
|
|
{
|
|
let mut state = Vec::new();
|
|
for _ in 0..coeffs.len() {
|
|
state.push(NumType::zero());
|
|
}
|
|
|
|
FIRFilter {
|
|
coeffs: coeffs,
|
|
state: state,
|
|
pos: 0,
|
|
iterator: Box::new(iterator),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a, NumType> Iterator for FIRFilter<'a, NumType>
|
|
where
|
|
NumType: Num + Copy,
|
|
{
|
|
type Item = Result<NumType, DspError>;
|
|
|
|
fn next(&mut self) -> Option<Self::Item> {
|
|
let cur = match self.iterator.next() {
|
|
Some(Ok(x)) => x,
|
|
Some(Err(e)) => return Some(Err(e)),
|
|
None => return None,
|
|
};
|
|
|
|
self.pos = (self.pos + 1) % self.coeffs.len();
|
|
self.state[self.pos] = cur;
|
|
|
|
let mut result = NumType::zero();
|
|
for i in 0..self.coeffs.len() {
|
|
let pos = (self.pos + self.coeffs.len() - i) % self.coeffs.len();
|
|
result = result + (self.state[pos] * self.coeffs[i]);
|
|
}
|
|
|
|
Some(Ok(result))
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use super::*;
|
|
|
|
#[test]
|
|
fn fir_avg_test() {
|
|
let test_data = vec![0_f32, 1_f32, 2_f32, 3_f32, 4_f32, 5_f32, 6_f32, 7_f32];
|
|
|
|
let upsampler = FIRFilter::from(test_data.into_iter().map(|x| Ok(x)), &[0.5_f32, 0.5_f32]);
|
|
|
|
let result_data: Result<Vec<f32>, DspError> = upsampler.collect();
|
|
assert_eq!(
|
|
result_data,
|
|
Ok(vec![
|
|
0.0_f32, 0.5_f32, 1.5_f32, 2.5_f32, 3.5_f32, 4.5_f32, 5.5_f32, 6.5_f32
|
|
]),
|
|
);
|
|
}
|
|
}
|