fix: Support aarch64 Linux (#40)

Author: kanarus

README.md

@@ -6,7 +6,7 @@
 
 <br>
 
-- Offers safe, direct Rust wrappers for the entire MuJoCo API.
+- Offers safe, low-level Rust wrappers for the entire MuJoCo API.
 - Provides getters for all struct fields and setters for user-modifiable fields,
   instead of allowing direct field access.
 - Implements automatic resource management via Rust's RAII pattern.

src/helper.rs

@@ -7,12 +7,12 @@ pub(crate) fn array_flatslice<T, const M: usize, const N: usize>(
 
 pub(crate) fn copy_str_to_c_chararray<const N: usize>(
     s: &str,
-    c_array: &mut [i8; N],
+    c_array: &mut [std::ffi::c_char; N],
 ) {
     let c_str = std::ffi::CString::new(s).expect("string must not contain internal null bytes");
     let bytes = c_str.into_bytes_with_nul();
     assert!(bytes.len() <= N, "string must be less than {N} bytes long");
-    bytes.iter().enumerate().for_each(|(i, &b)| {c_array[i] = b as i8});
+    bytes.iter().enumerate().for_each(|(i, &b)| {c_array[i] = b as std::ffi::c_char});
     c_array[bytes.len()..].fill(0); // fill the rest with zeros
 }
 

src/types/visualization.rs

@@ -456,7 +456,7 @@ macro_rules! chars {
                     let bytes = $name.as_bytes();
                     let (len, limit) = (bytes.len(), self.$name.len() - 1);
                     assert!(len <= limit, "{}: `{len}` is too long, max {limit} bytes", stringify!($name));
-                    bytes.iter().enumerate().for_each(|(i, &b)| self.$name[i] = b as i8);
+                    bytes.iter().enumerate().for_each(|(i, &b)| self.$name[i] = b as std::ffi::c_char);
                     self.$name[bytes.len()] = 0; // null-terminate
                     self
                 }
@@ -481,7 +481,7 @@ impl mjvFigure {
         assert!(index < mjMAXLINE, "`set_linename`: too large index `{index}`, must be index < {mjMAXLINE}");
         let (len, limit) = (name.as_bytes().len(), self.linename[index].len() - 1);
         assert!(len <= limit, "Line name `{name}` is too long, max {limit} bytes");
-        name.as_bytes().iter().enumerate().for_each(|(i, &b)| self.linename[index][i] = b as i8);
+        name.as_bytes().iter().enumerate().for_each(|(i, &b)| self.linename[index][i] = b as std::ffi::c_char);
         self.linename[index][len] = 0; // null-terminate
         self
     }