refactor: make silk_corrVector_FLP safe

Author: DCNick3

Cargo.toml

@@ -29,7 +29,11 @@ bytemuck = "1.16.1"
 # for slicing arrays to other arrays
 arrayref = "0.3.7"
 const-chunks = "0.3.0"
+
+# better abstractions for multidimensional arrays
 ndarray = "0.15.6"
+# iterate over stuff
+itertools = "0.13.0"
 
 # for dumping data in ent-dump
 hex = { version = "0.4.3", optional = true }

src/silk/float/corrMatrix_FLP.rs

@@ -1,20 +1,25 @@
 use crate::silk::float::energy_FLP::silk_energy_FLP;
 use crate::silk::float::inner_product_FLP::silk_inner_product_FLP;
 
-pub unsafe fn silk_corrVector_FLP(x: *const f32, t: *const f32, L: i32, Order: i32, Xt: *mut f32) {
-    let mut lag: i32 = 0;
-    let mut ptr1: *const f32 = 0 as *const f32;
-    ptr1 = &*x.offset((Order - 1) as isize) as *const f32;
-    lag = 0;
-    while lag < Order {
-        *Xt.offset(lag as isize) = silk_inner_product_FLP(
-            std::slice::from_raw_parts(ptr1, L as usize),
-            std::slice::from_raw_parts(t, L as usize),
-        ) as f32;
-        ptr1 = ptr1.offset(-1);
-        lag += 1;
+// Correlation matrix computations for LS estimate.
+
+/// Calculates correlation vector X'*t
+///
+/// ```text
+/// x       I    x vector [L+order-1] used to create X
+/// t       I    Target vector [L]
+/// L       I    Length of vecors
+/// Order   I    Max lag for correlation
+/// *Xt     O    X'*t correlation vector [order]
+/// ```
+pub fn silk_corrVector_FLP(x: &[f32], t: &[f32], Xt: &mut [f32]) {
+    let L = t.len();
+
+    for (out, x) in itertools::zip_eq(Xt.iter_mut(), x.windows(L).rev()) {
+        *out = silk_inner_product_FLP(x, t) as f32;
     }
 }
+
 pub unsafe fn silk_corrMatrix_FLP(x: *const f32, L: i32, Order: i32, XX: *mut f32) {
     let mut j: i32 = 0;
     let mut lag: i32 = 0;

src/silk/float/find_LTP_FLP.rs

@@ -23,7 +23,11 @@ pub unsafe fn silk_find_LTP_FLP(
     while k < nb_subfr {
         lag_ptr = r_ptr.offset(-((*lag.offset(k as isize) + LTP_ORDER / 2) as isize));
         silk_corrMatrix_FLP(lag_ptr, subfr_length, LTP_ORDER, XX_ptr);
-        silk_corrVector_FLP(lag_ptr, r_ptr, subfr_length, LTP_ORDER, xX_ptr);
+        silk_corrVector_FLP(
+            std::slice::from_raw_parts(lag_ptr, (subfr_length + LTP_ORDER - 1) as usize),
+            std::slice::from_raw_parts(r_ptr, subfr_length as usize),
+            std::slice::from_raw_parts_mut(xX_ptr, LTP_ORDER as usize),
+        );
         xx = silk_energy_FLP(std::slice::from_raw_parts(
             r_ptr,
             (subfr_length + LTP_ORDER) as usize,