add c_export

c_export/src/lib.rs

@@ -0,0 +1,17 @@
+extern crate libc;
+
+use std::ffi::CStr;
+use libc::c_char;
+
+#[no_mangle]
+pub extern "C" fn count_substrings(value: *const c_char, substr: *const c_char) -> i32 {
+    let c_value = unsafe { CStr::from_ptr(value) };
+    let c_substr = unsafe { CStr::from_ptr(substr) };
+    match c_value.to_str() {
+        Ok(value) => match c_substr.to_str() {
+            Ok(substr) => value.match_indices(substr).count() as i32,
+            Err(_) => -1,
+        },
+        Err(_) => -1,
+    }
+}