Simplify fft's API

fft/src/fftwrap.rs

@@ -1,5 +1,3 @@
-use crate::smallft::*;
-
 /* Copyright (C) 2005-2006 Jean-Marc Valin
    File: fftwrap.c
 
@@ -33,46 +31,94 @@ use crate::smallft::*;
    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 */
-pub fn spx_fft_init(size: usize) -> DrftLookup {
-    DrftLookup::new(size)
+
+use crate::smallft::*;
+
+#[derive(Clone)]
+pub struct DrftLookup {
+    pub n: usize,
+    pub trigcache: Vec<f32>,
+    pub splitcache: Vec<i32>,
 }
 
-pub fn spx_fft(table: &mut DrftLookup, in_0: &mut [f32], out: &mut [f32]) {
-    let scale = (1.0f64 / table.n as f64) as f32;
-    if in_0 == out {
-        eprintln!("FFT should not be done in-place");
+impl DrftLookup {
+    pub fn new(n: usize) -> Self {
+        let mut drft = Self {
+            n: n,
+            trigcache: vec![0.0; 3 * n],
+            splitcache: vec![0; 32],
+        };
+
+        fdrffti(n, &mut drft.trigcache, &mut drft.splitcache);
+
+        drft
     }
 
-    out.iter_mut()
-        .zip(in_0.iter())
-        .take(table.n as usize)
-        .for_each(|(o, i)| *o = scale * *i);
+    pub fn spx_fft(&mut self, in_0: &[f32], out: &mut [f32]) {
+        let scale = (1.0f64 / self.n as f64) as f32;
+        if in_0 == out {
+            eprintln!("FFT should not be done in-place");
+        }
 
-    spx_drft_forward(table, out);
-}
+        out.iter_mut()
+            .zip(in_0.iter())
+            .take(self.n as usize)
+            .for_each(|(o, i)| *o = scale * *i);
 
-pub fn spx_ifft(table: &mut DrftLookup, in_0: &mut [f32], out: &mut [f32]) {
-    if in_0 == out {
-        eprintln!("FFT should not be done in-place");
-    } else {
-        out.copy_from_slice(&in_0[..table.n as usize]);
+        self.spx_drft_forward(out);
     }
 
-    spx_drft_backward(table, out);
-}
+    pub fn spx_ifft(&mut self, in_0: &[f32], out: &mut [f32]) {
+        if in_0 == out {
+            eprintln!("FFT should not be done in-place");
+        } else {
+            out.copy_from_slice(&in_0[..self.n as usize]);
+        }
 
-pub fn spx_fft_float(
-    table: &mut DrftLookup,
-    in_0: &mut [f32],
-    out: &mut [f32],
-) {
-    spx_fft(table, in_0, out);
-}
+        self.spx_drft_backward(out);
+    }
+
+    pub fn spx_fft_float(&mut self, in_0: &[f32], out: &mut [f32]) {
+        self.spx_fft(in_0, out);
+    }
+
+    pub fn spx_ifft_float(&mut self, in_0: &[f32], out: &mut [f32]) {
+        self.spx_ifft(in_0, out);
+    }
+
+    pub fn spx_drft_forward(&mut self, data: &mut [f32]) {
+        if self.n == 1 {
+            return;
+        }
+
+        let mut trigcache_temp = self.trigcache[self.n as usize..].to_vec();
+
+        drftf1(
+            self.n as i32,
+            data,
+            &mut self.trigcache,
+            &mut trigcache_temp,
+            &mut self.splitcache,
+        );
 
-pub fn spx_ifft_float(
-    table: &mut DrftLookup,
-    in_0: &mut [f32],
-    out: &mut [f32],
-) {
-    spx_ifft(table, in_0, out);
+        self.trigcache[self.n as usize..].copy_from_slice(&trigcache_temp);
+    }
+
+    pub fn spx_drft_backward(&mut self, data: &mut [f32]) {
+        if self.n == 1 {
+            return;
+        }
+
+        let mut trigcache_temp = self.trigcache[self.n as usize..].to_vec();
+
+        drftb1(
+            self.n as i32,
+            data,
+            &mut self.trigcache,
+            &mut trigcache_temp,
+            &mut self.splitcache,
+        );
+
+        self.trigcache[self.n as usize..].copy_from_slice(&trigcache_temp);
+    }
 }

fft/src/lib.rs

@@ -4,4 +4,3 @@ mod fftwrap;
 mod smallft;
 
 pub use crate::fftwrap::*;
-pub use crate::smallft::*;

fft/src/smallft.rs

@@ -1,27 +1,6 @@
 use crate::dradb::*;
 use crate::dradf::*;
 
-#[derive(Clone)]
-pub struct DrftLookup {
-    pub n: usize,
-    pub trigcache: Vec<f32>,
-    pub splitcache: Vec<i32>,
-}
-
-impl DrftLookup {
-    pub fn new(n: usize) -> Self {
-        let mut drft = Self {
-            n: n,
-            trigcache: vec![0.0; 3 * n],
-            splitcache: vec![0; 32],
-        };
-
-        fdrffti(n, &mut drft.trigcache, &mut drft.splitcache);
-
-        drft
-    }
-}
-
 #[inline(always)]
 fn drfti1_c_10244(ifac: &mut [i32], n: i32, nf: &mut i32) {
     const NTRYH: [i32; 4] = [4, 2, 3, 5];
@@ -62,7 +41,7 @@ fn drfti1_c_10244(ifac: &mut [i32], n: i32, nf: &mut i32) {
     }
 }
 
-fn drfti1(wa: &mut [f32], ifac: &mut [i32]) {
+pub(crate) fn drfti1(wa: &mut [f32], ifac: &mut [i32]) {
     const TPI: f32 = 6.283_185_307_179_586_48;
 
     let n = wa.len() as i32;
@@ -112,7 +91,7 @@ fn drfti1(wa: &mut [f32], ifac: &mut [i32]) {
     }
 }
 
-fn fdrffti(n: usize, wsave: &mut [f32], ifac: &mut [i32]) {
+pub(crate) fn fdrffti(n: usize, wsave: &mut [f32], ifac: &mut [i32]) {
     if n == 1 {
         return;
     }
@@ -152,7 +131,7 @@ fn drftf1_l102(
     }
 }
 
-fn drftf1(
+pub(crate) fn drftf1(
     n: i32,
     c: &mut [f32],
     ch: &mut [f32],
@@ -254,7 +233,7 @@ fn drftb1_l102(
     }
 }
 
-fn drftb1(
+pub(crate) fn drftb1(
     n: i32,
     c: &mut [f32],
     ch: &mut [f32],
@@ -312,42 +291,6 @@ fn drftb1(
     c[..n as usize].copy_from_slice(&ch[..n as usize]);
 }
 
-pub fn spx_drft_forward(l: &mut DrftLookup, data: &mut [f32]) {
-    if l.n == 1 {
-        return;
-    }
-
-    let mut trigcache_temp = l.trigcache[l.n as usize..].to_vec();
-
-    drftf1(
-        l.n as i32,
-        data,
-        &mut l.trigcache,
-        &mut trigcache_temp,
-        &mut l.splitcache,
-    );
-
-    l.trigcache[l.n as usize..].copy_from_slice(&trigcache_temp);
-}
-
-pub fn spx_drft_backward(l: &mut DrftLookup, data: &mut [f32]) {
-    if l.n == 1 {
-        return;
-    }
-
-    let mut trigcache_temp = l.trigcache[l.n as usize..].to_vec();
-
-    drftb1(
-        l.n as i32,
-        data,
-        &mut l.trigcache,
-        &mut trigcache_temp,
-        &mut l.splitcache,
-    );
-
-    l.trigcache[l.n as usize..].copy_from_slice(&trigcache_temp);
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;