45 lines
1.1 KiB
Rust
45 lines
1.1 KiB
Rust
pub struct FIRFilter<'a> {
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coeffs: Vec<f32>,
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state: Vec<f32>,
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pos: usize,
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iterator: Box<Iterator<Item=f32> + 'a>
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}
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impl<'a> FIRFilter<'a> {
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pub fn from<I>(iterator: I, coeffs: Vec<f32>) -> FIRFilter<'a> where I: Iterator<Item=f32> + 'a {
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let mut state = Vec::new();
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for _ in 0..coeffs.len() {
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state.push(0.0);
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}
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FIRFilter {
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coeffs: coeffs,
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state: state,
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pos: 0,
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iterator: Box::new(iterator)
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}
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}
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}
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impl<'a> Iterator for FIRFilter<'a> {
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type Item = f32;
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fn next(&mut self) -> Option<Self::Item> {
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let cur = match self.iterator.next() {
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Some(x) => x,
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None => return None
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};
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self.pos = (self.pos + 1) % self.coeffs.len();
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self.state[self.pos] = cur;
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let mut result = 0.0;
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for i in 0..self.coeffs.len() {
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let pos = (self.pos + self.coeffs.len() - i) % self.coeffs.len();
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result += self.state[pos] * self.coeffs[i];
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};
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Some(result)
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}
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}
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