first steps towards a c lib

Cargo.toml

@@ -4,6 +4,9 @@ version = "0.1.0"
 edition = "2021"
 crate-type = ["rlib","staticlib", "cdylib"]
 
+[dependencies]
+libc = "0.2"
+
 [dev-dependencies]
 criterion = "0.5.1"
 walkdir = "2.3.1"

include/mbus_parser.h

@@ -9,4 +9,13 @@ extern "C" {
 }
 #endif
 
+
+typedef enum {
+    ParseOk,
+    ParseError,
+} ParseStatus;
+
+
+ParseStatus parse_mbus(const uint8_t* data, size_t length);
+
 #endif // MBUS_PARSER_H

src/ffi/mod.rs

@@ -0,0 +1,34 @@
+extern crate libc;
+use libc::{uint8_t, size_t};
+
+// Representing the C enum in Rust
+#[repr(C)]
+#[derive(Debug, PartialEq)]
+pub enum ParseStatus {
+    ParseOk = 0,
+    ParseError = 1,
+}
+
+extern "C" {
+    pub fn parse_mbus(data: *const uint8_t, length: size_t) -> ParseStatus;
+}
+
+
+#[no_mangle]
+pub extern "C" fn parse_mbus(data: *const uint8_t, length: size_t) -> ParseStatus {
+
+    if data.is_null() || length == 0 {
+        return ParseStatus::ParseError;
+    }
+
+    let slice = unsafe {
+        std::slice::from_raw_parts(data, length as usize)
+    };
+
+    /* dummy code */
+    if slice.len() == 5 {
+        ParseStatus::ParseOk
+    } else {
+        ParseStatus::ParseError
+    }
+}