move c++ bindings definition and usage to lib file

build.rs

@@ -1,7 +1,7 @@
 fn main() -> miette::Result<()> {
     let path = std::path::PathBuf::from("src/cpp"); // include path
 
-    let mut b = autocxx_build::Builder::new("src/main.rs", &[&path]).build()?;
+    let mut b = autocxx_build::Builder::new("src/lib.rs", &[&path]).build()?;
     // This assumes all your C++ bindings are in main.rs
     b.flag_if_supported("-std=c++14")
         .flag("-fopenmp")

src/lib.rs

@@ -0,0 +1,24 @@
+use autocxx::prelude::*;
+
+include_cpp! {
+    #include "data.hpp"
+    safety!(unsafe)
+    generate!("Data")
+}
+
+use ffi::Data as Data_;
+
+pub fn generate_data(samples: &[i8]) -> UniquePtr<Data_> {
+    let samples_length = samples.len() as i32;
+    let bits_per_symbol = 8;
+
+    unsafe {
+        ffi::Data::new2(
+            samples.as_ptr(),
+            samples_length.into(),
+            bits_per_symbol.into(),
+            false,
+        )
+        .within_unique_ptr()
+    }
+}

src/main.rs

@@ -1,29 +1,16 @@
-use autocxx::prelude::*;
+use SP800_90B_rs::generate_data;
 use rand::Rng;
 
-include_cpp! {
-    #include "data.hpp"
-    safety!(unsafe)
-    generate!("Data")
-}
+
 
 fn main() {
     // println!("Hello, world!");
 
     let mut rng = rand::thread_rng();
     let samples: [i8; 1_000_000] = rng.gen();
-    let samples_length = samples.len() as i32;
-    let bits_per_symbol = 8;
+    
+    let data = generate_data(&samples);
 
-    let data = unsafe {
-        ffi::Data::new2(
-            samples.as_ptr(),
-            samples_length.into(),
-            bits_per_symbol.into(),
-            false,
-        )
-        .within_unique_ptr()
-    };
     let a = data.iid_tests();
 
     println!("{a:?}");