fix mis-align problem when converting &[u8] to &[f32] (#9986)

* fix: windows, improve audio buffer (#9770)

* .

* fix statics does not record

and avoid channel changing when drio audio when audio is stero

* add some commence

* fix mis-align problem when converting &[u8] to &[f32]

* add safety commence

* revert client.rs

* avoid tmp lifetime extends

* avoid move in loop

* avoid use after drop

* another use after free

* another use after free

* make code more reasonable

---------

Co-authored-by: zylthinking <zhaoyulong@qianxin.com>

libs/hbb_common/src/lib.rs

@@ -27,6 +27,7 @@ pub use anyhow::{self, bail};
 pub use futures_util;
 pub mod config;
 pub mod fs;
+pub mod mem;
 pub use lazy_static;
 #[cfg(not(any(target_os = "android", target_os = "ios")))]
 pub use mac_address;

libs/hbb_common/src/mem.rs

@@ -0,0 +1,14 @@
+/// SAFETY: the returned Vec must not be resized or reserverd
+pub unsafe fn aligned_u8_vec(cap: usize, align: usize) -> Vec<u8> {
+    use std::alloc::*;
+
+    let layout =
+        Layout::from_size_align(cap, align).expect("invalid aligned value, must be power of 2");
+    unsafe {
+        let ptr = alloc(layout);
+        if ptr.is_null() {
+            panic!("failed to allocate {} bytes", cap);
+        }
+        Vec::from_raw_parts(ptr, 0, cap)
+    }
+}

src/server/audio_service.rs

@@ -78,6 +78,19 @@ pub fn restart() {
 #[cfg(any(target_os = "linux", target_os = "android"))]
 mod pa_impl {
     use super::*;
+
+    // SAFETY: constrains of hbb_common::mem::aligned_u8_vec must be held
+    unsafe fn align_to_32(data: Vec<u8>) -> Vec<u8> {
+        if (data.as_ptr() as usize & 3) == 0 {
+            return data;
+        }
+
+        let mut buf = vec![];
+        buf = unsafe { hbb_common::mem::aligned_u8_vec(data.len(), 4) };
+        buf.extend_from_slice(data.as_ref());
+        buf
+    }
+
     #[tokio::main(flavor = "current_thread")]
     pub async fn run(sp: EmptyExtraFieldService) -> ResultType<()> {
         hbb_common::sleep(0.1).await; // one moment to wait for _pa ipc
@@ -106,23 +119,29 @@ mod pa_impl {
                 sps.send(create_format_msg(crate::platform::PA_SAMPLE_RATE, 2));
                 Ok(())
             })?;
+
             #[cfg(target_os = "linux")]
             if let Ok(data) = stream.next_raw().await {
                 if data.len() == 0 {
                     send_f32(&zero_audio_frame, &mut encoder, &sp);
                     continue;
                 }
+
                 if data.len() != AUDIO_DATA_SIZE_U8 {
                     continue;
                 }
+
+                let data = unsafe { align_to_32(data.into()) };
                 let data = unsafe {
                     std::slice::from_raw_parts::<f32>(data.as_ptr() as _, data.len() / 4)
                 };
                 send_f32(data, &mut encoder, &sp);
             }
+
             #[cfg(target_os = "android")]
             if scrap::android::ffi::get_audio_raw(&mut android_data, &mut vec![]).is_some() {
                 let data = unsafe {
+                    android_data = align_to_32(android_data);
                     std::slice::from_raw_parts::<f32>(
                         android_data.as_ptr() as _,
                         android_data.len() / 4,