Grab current sample rate from mixer control

src/main.rs

@@ -144,14 +144,29 @@ fn main() {
     let io = pcm.io_i16().unwrap();
 
     let hwp = pcm.hw_params_current().unwrap();
-    let sample_rate = hwp.get_rate().unwrap();
 
-    info!("Sample rate: {}", sample_rate);
+    let mut sample_rate_elem = types::Elem::new(
+        "Speaker Sample Rate".to_string(),
+        &ctl,
+        alsa::ctl::ElemType::Integer,
+    );
+    let mut sample_rate = sample_rate_elem.read_int(&ctl);
 
     loop {
         // Block while we're reading into the buffer
         io.readi(&mut buf).unwrap();
 
+        let cur_sample_rate = sample_rate_elem.read_int(&ctl);
+
+        if cur_sample_rate != 0 {
+            sample_rate = cur_sample_rate;
+        }
+
+        if (sample_rate == 0) {
+            panic!("Invalid sample rate");
+        }
+
+        info!("Sample rate: {}", sample_rate);
         for (idx, group) in groups.iter_mut() {
             let gain = group
                 .speakers

src/types.rs

@@ -14,14 +14,14 @@ use crate::helpers;
     The val field is created using a wrapper so that we can handle
     any errors.
 */
-struct Elem {
+pub struct Elem {
     elem_name: String,
     id: alsa::ctl::ElemId,
     val: alsa::ctl::ElemValue,
 }
 
 impl Elem {
-    fn new(name: String, card: &Ctl, t: alsa::ctl::ElemType) -> Elem {
+    pub fn new(name: String, card: &Ctl, t: alsa::ctl::ElemType) -> Elem {
         // CString::new() cannot borrow a String. We want name for the elem
         // for error identification though, so it can't consume name directly.
         let borrow: String = name.clone();
@@ -43,6 +43,14 @@ impl Elem {
 
         return new_elem;
     }
+
+    pub fn read_int(&mut self, card: &Ctl) -> i32 {
+        helpers::read_ev(card, &mut self.val, &self.elem_name);
+
+        self.val
+            .get_integer(0)
+            .expect(&format!("Could not read {}", self.elem_name))
+    }
 }
 
 /**