split nihav-codec-support crate from nihav-core

[nihav.git] / nihav-core / src / dsp / window.rs

diff --git a/nihav-core/src/dsp/window.rs b/nihav-core/src/dsp/window.rs
deleted file mode 100644 (file)
index eb350e3..0000000
--- a/nihav-core/src/dsp/window.rs
+++ /dev/null
@@ -1,59 +0,0 @@
-//! Window generating functions.
-use std::f32::consts;
-
-/// Known window types.
-#[derive(Debug,Clone,Copy,PartialEq)]
-pub enum WindowType {
-    /// Simple square window.
-    Square,
-    /// Simple sine window.
-    Sine,
-    /// Kaiser-Bessel derived window.
-    KaiserBessel(f32),
-}
-
-/// Calculates window coefficients for the requested window type and size.
-///
-/// Set `half` flag to calculate only the first half of the window.
-pub fn generate_window(mode: WindowType, scale: f32, size: usize, half: bool, dst: &mut [f32]) {
-    match mode {
-        WindowType::Square => {
-                for n in 0..size { dst[n] = scale; }
-            },
-        WindowType::Sine => {
-                let param = if half {
-                        consts::PI / ((2 * size) as f32)
-                    } else {
-                        consts::PI / (size as f32)
-                    };
-                for n in 0..size {
-                    dst[n] = (((n as f32) + 0.5) * param).sin() * scale;
-                }
-            },
-        WindowType::KaiserBessel(alpha) => {
-                let dlen = if half { size as f32 } else { (size as f32) * 0.5 };
-                let alpha2 = f64::from((alpha * consts::PI / dlen) * (alpha * consts::PI / dlen));
-
-                let mut kb: Vec<f64> = Vec::with_capacity(size);
-                let mut sum = 0.0;
-                for n in 0..size {
-                    let b = bessel_i0(((n * (size - n)) as f64) * alpha2);
-                    sum += b;
-                    kb.push(sum);
-                }
-                sum += 1.0;
-                for n in 0..size {
-                    dst[n] = (kb[n] / sum).sqrt() as f32;
-                }
-            },
-    };
-}
-
-fn bessel_i0(inval: f64) -> f64 {
-    let mut val: f64 = 1.0;
-    for n in (1..64).rev() {
-        val *= inval / f64::from(n * n);
-        val += 1.0;
-    }
-    val
-}