fix: use c_char instead of i8 when handling C strings

Author: bguo068

.github/workflows/tests.yml

@@ -13,7 +13,7 @@ jobs:
     #  image: ubuntu:20.10
     strategy:
       matrix:
-        os: [ubuntu-24.04, macos-latest]
+        os: [ubuntu-24.04, ubuntu-24.04-arm,  macos-latest]
         rust:
           - stable
     steps:
@@ -32,7 +32,7 @@ jobs:
       - uses: Swatinem/[email protected]
       - uses: taiki-e/install-action@cargo-hack
       - run: sudo apt-get update -y
-        if: matrix.os == 'ubuntu-24.04'
+        if: (matrix.os == 'ubuntu-24.04') || (matrix.os == 'ubuntu-24.04-arm')
       - name: update toolchain
         run: rustup toolchain install
       - name: cargo check (powerset)

src/metadata.rs

@@ -239,13 +239,14 @@ pub use crate::sys::MetadataError;
 #[cfg(test)]
 mod tests {
     use super::*;
+    use std::ffi::c_char;
 
     #[test]
     fn test_vec8_cast_to_c_string() {
         let v: Vec<u8> = vec![0, 1, b'\0', 2, 3];
         let c = v.as_ptr() as *const libc::c_char;
         for (i, vi) in v.iter().enumerate() {
-            assert_eq!(*vi as i8, unsafe { *c.add(i) });
+            assert_eq!(*vi as c_char, unsafe { *c.add(i) });
         }
 
         let _ = match Some(&v) {

src/sys/edge_table.rs

@@ -1,3 +1,4 @@
+use std::ffi::c_char;
 use std::ptr::NonNull;
 
 use super::newtypes::EdgeId;
@@ -64,7 +65,7 @@ impl EdgeTable {
                 right,
                 parent,
                 child,
-                metadata.as_ptr().cast::<i8>(),
+                metadata.as_ptr().cast::<c_char>(),
                 metadata.len() as u64,
             ))
         }

src/sys/individual_table.rs

@@ -1,3 +1,4 @@
+use std::ffi::c_char;
 use std::ptr::NonNull;
 
 use super::bindings::tsk_size_t;
@@ -65,7 +66,7 @@ impl IndividualTable {
                 location.len() as u64,
                 parents.as_ptr(),
                 parents.len() as u64,
-                metadata.as_ptr().cast::<i8>(),
+                metadata.as_ptr().cast::<c_char>(),
                 metadata.len() as u64,
             ))
         }

src/sys/migration_table.rs

@@ -1,3 +1,4 @@
+use std::ffi::c_char;
 use std::ptr::NonNull;
 
 use super::newtypes::MigrationId;
@@ -71,7 +72,7 @@ impl MigrationTable {
                 source,
                 dest,
                 time,
-                metadata.as_ptr().cast::<i8>(),
+                metadata.as_ptr().cast::<c_char>(),
                 metadata.len() as u64,
             ))
         }

src/sys/mutation_table.rs

@@ -1,3 +1,4 @@
+use std::ffi::c_char;
 use std::ptr::NonNull;
 
 use super::newtypes::MutationId;
@@ -70,14 +71,14 @@ impl MutationTable {
                 parent,
                 time,
                 match derived_state {
-                    Some(d) => d.as_ptr() as *const i8,
+                    Some(d) => d.as_ptr() as *const c_char,
                     None => std::ptr::null(),
                 },
                 match derived_state {
                     Some(d) => d.len() as u64,
                     None => 0,
                 },
-                metadata.as_ptr().cast::<i8>(),
+                metadata.as_ptr().cast::<c_char>(),
                 metadata.len() as u64,
             ))
         }

src/sys/node_table.rs

@@ -1,3 +1,4 @@
+use std::ffi::c_char;
 use std::ptr::NonNull;
 
 use super::flags::NodeFlags;
@@ -80,7 +81,7 @@ impl NodeTable {
                 time.into().into(),
                 population.into().into(),
                 individual.into().into(),
-                metadata.as_ptr().cast::<i8>(),
+                metadata.as_ptr().cast::<c_char>(),
                 metadata.len() as u64,
             )
         } {

src/sys/population_table.rs

@@ -1,3 +1,4 @@
+use std::ffi::c_char;
 use std::ptr::NonNull;
 
 use super::bindings::tsk_id_t;
@@ -44,7 +45,7 @@ impl PopulationTable {
         unsafe {
             Ok(tsk_population_table_add_row(
                 self.as_mut(),
-                metadata.as_ptr().cast::<i8>(),
+                metadata.as_ptr().cast::<c_char>(),
                 metadata.len() as u64,
             ))
         }

src/sys/provenance_table.rs

@@ -10,6 +10,7 @@ use super::bindings::tsk_provenance_table_t;
 use super::bindings::tsk_size_t;
 use super::tskbox::TskBox;
 use super::TskitError;
+use std::ffi::c_char;
 
 #[derive(Debug)]
 pub struct ProvenanceTable(TskBox<tsk_provenance_table_t>);
@@ -49,9 +50,9 @@ impl ProvenanceTable {
         let rv = unsafe {
             tsk_provenance_table_add_row(
                 self.as_mut(),
-                timestamp.as_ptr() as *mut i8,
+                timestamp.as_ptr() as *const c_char,
                 timestamp.len() as tsk_size_t,
-                record.as_ptr() as *mut i8,
+                record.as_ptr() as *const c_char,
                 record.len() as tsk_size_t,
             )
         };

src/sys/site_table.rs

@@ -1,3 +1,4 @@
+use std::ffi::c_char;
 use std::ptr::NonNull;
 
 use super::bindings::tsk_size_t;
@@ -58,14 +59,14 @@ impl SiteTable {
                 self.as_mut(),
                 position,
                 match ancestral_state {
-                    Some(d) => d.as_ptr() as *const i8,
+                    Some(d) => d.as_ptr() as *const c_char,
                     None => std::ptr::null(),
                 },
                 match ancestral_state {
                     Some(d) => d.len() as u64,
                     None => 0,
                 },
-                metadata.as_ptr().cast::<i8>(),
+                metadata.as_ptr().cast::<c_char>(),
                 metadata.len() as u64,
             ))
         }