130 lines
3.3 KiB
Rust
130 lines
3.3 KiB
Rust
use core::ops::Mul;
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use super::{atan2, cossin};
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#[derive(Copy, Clone, Default, PartialEq, Debug)]
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pub struct Complex<T>(pub T, pub T);
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impl<T: Copy> Complex<T> {
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pub fn map<F>(&self, func: F) -> Self
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where
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F: Fn(T) -> T,
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{
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Complex(func(self.0), func(self.1))
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}
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}
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impl Complex<i32> {
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/// Return a Complex on the unit circle given an angle.
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///
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/// Example:
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///
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/// ```
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/// use dsp::Complex;
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/// Complex::<i32>::from_angle(0);
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/// Complex::<i32>::from_angle(1 << 30); // pi/2
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/// Complex::<i32>::from_angle(-1 << 30); // -pi/2
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/// ```
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pub fn from_angle(angle: i32) -> Self {
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let (c, s) = cossin(angle);
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Self(c, s)
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}
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/// Return the absolute square (the squared magnitude).
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///
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/// Note: Normalization is `1 << 32`, i.e. U0.32.
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///
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/// Note(panic): This will panic for `Complex(i32::MIN, i32::MIN)`
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///
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/// Example:
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///
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/// ```
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/// use dsp::Complex;
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/// assert_eq!(Complex(i32::MIN, 0).abs_sqr(), 1 << 31);
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/// assert_eq!(Complex(i32::MAX, i32::MAX).abs_sqr(), u32::MAX - 3);
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/// ```
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pub fn abs_sqr(&self) -> u32 {
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(((self.0 as i64) * (self.0 as i64)
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+ (self.1 as i64) * (self.1 as i64))
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>> 31) as u32
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}
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/// log2(power) re full scale approximation
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///
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/// TODO: scale up, interpolate
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///
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/// Panic:
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/// This will panic for `Complex(i32::MIN, i32::MIN)`
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///
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/// Example:
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///
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/// ```
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/// use dsp::Complex;
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/// assert_eq!(Complex(i32::MAX, i32::MAX).log2(), -1);
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/// assert_eq!(Complex(i32::MAX, 0).log2(), -2);
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/// assert_eq!(Complex(1, 0).log2(), -63);
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/// assert_eq!(Complex(0, 0).log2(), -64);
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/// ```
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pub fn log2(&self) -> i32 {
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let a = (self.0 as i64) * (self.0 as i64)
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+ (self.1 as i64) * (self.1 as i64);
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-(a.leading_zeros() as i32)
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}
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/// Return the angle.
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///
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/// Note: Normalization is `1 << 31 == pi`.
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///
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/// Example:
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///
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/// ```
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/// use dsp::Complex;
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/// assert_eq!(Complex(1, 0).arg(), 0);
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/// assert_eq!(Complex(-i32::MAX, 1).arg(), i32::MAX);
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/// assert_eq!(Complex(-i32::MAX, -1).arg(), -i32::MAX);
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/// assert_eq!(Complex(0, -1).arg(), -i32::MAX >> 1);
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/// assert_eq!(Complex(0, 1).arg(), (i32::MAX >> 1) + 1);
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/// assert_eq!(Complex(1, 1).arg(), (i32::MAX >> 2) + 1);
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/// ```
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pub fn arg(&self) -> i32 {
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atan2(self.1, self.0)
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}
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}
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impl Mul for Complex<i32> {
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type Output = Self;
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fn mul(self, other: Self) -> Self {
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let a = self.0 as i64;
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let b = self.1 as i64;
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let c = other.0 as i64;
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let d = other.1 as i64;
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Complex(
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((a * c - b * d + (1 << 31)) >> 32) as i32,
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((b * c + a * d + (1 << 31)) >> 32) as i32,
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)
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}
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}
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impl Mul<i32> for Complex<i32> {
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type Output = Self;
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fn mul(self, other: i32) -> Self {
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Complex(
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((other as i64 * self.0 as i64 + (1 << 31)) >> 32) as i32,
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((other as i64 * self.1 as i64 + (1 << 31)) >> 32) as i32,
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)
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}
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}
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impl Mul<i16> for Complex<i32> {
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type Output = Self;
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fn mul(self, other: i16) -> Self {
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Complex(
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(other as i32 * (self.0 >> 16) + (1 << 15)) >> 16,
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(other as i32 * (self.1 >> 16) + (1 << 15)) >> 16,
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)
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}
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}
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