C Interface

.github/workflows/build.yml

@@ -18,4 +18,4 @@ jobs:
         run: curl https://drager.github.io/wasm-pack/installer/init.sh -sSf | bash
 
       - name: Build library
-        run: wasm-pack build --scope libresplit --target web --release
+        run: wasm-pack build --scope libresplit --target web --release --features wasm

.github/workflows/publish.yml

@@ -26,7 +26,7 @@ jobs:
         run: curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
 
       - name: Build WASM library
-        run: wasm-pack build --scope libresplit --target web --release
+        run: wasm-pack build --scope libresplit --target web --release --features wasm
 
       - name: Set up Node.js
         uses: actions/setup-node@v4
@@ -36,4 +36,4 @@ jobs:
 
       - name: Publish to npm
         run: npm install -g npm@latest 
-      - run: wasm-pack publish --target web --access public
+      - run: wasm-pack publish ./pkg --access public

Cargo.toml

@@ -10,11 +10,15 @@ version = "1.0.0"
 edition = "2024"
 
 [lib]
-crate-type = ["cdylib"]
+crate-type = ["cdylib", "staticlib", "rlib"]
 
 [dependencies]
-wasm-bindgen = "0.2.104"
+wasm-bindgen = { version = "0.2.123", optional = true }
 
 serde = { version = "1.0.215", features = ["derive"] }
 serde_json = "1.0.133"
 spex = "0.2.2"
+
+[features]
+default = []
+wasm = ["wasm-bindgen"]

README.md

@@ -1,6 +1,6 @@
 # converter
 
-A WASM library for converting [LiveSplit](https://livesplit.org) `.lss` files into the [LibreSplit](https://libresplit.org) `.json` format.
+A library for converting [LiveSplit](https://livesplit.org) `.lss` files into the [LibreSplit](https://libresplit.org) `.json` format.
 
 An online converter using this library is available at [libresplit.org/converter](https://libresplit.org/converter).
 
@@ -27,6 +27,13 @@ wasm-pack build --scope libresplit --target web --release
 
 This outputs a compiled WASM package under `pkg/`.
 
+### Building (for C ABI)
+```sh
+git clone https://github.com/LibreSplit/converter
+cd converter
+cargo build --release
+```
+
 ---
 
 Published as an npm package under [`@libresplit/converter`](https://npmjs.com/package/@libresplit/converter).

src/lib.rs

@@ -1,15 +1,65 @@
-use std::io::Cursor;
+use std::{
+    ffi::{CStr, CString},
+    io::Cursor,
+    os::raw::c_char,
+    ptr::null_mut,
+};
 
 use spex::parsing::XmlReader;
-use wasm_bindgen::prelude::*;
 
 mod libresplit;
 mod livesplit;
 
-#[wasm_bindgen]
-pub fn convert(file: String) -> String {
+// Shared logic for both interfaces.
+fn convert_inner(file: &str) -> Result<String, String> {
     let cursor = Cursor::new(file);
-    let xml = XmlReader::parse_auto(cursor).unwrap();
+    let xml = XmlReader::parse_auto(cursor).map_err(|e| e.to_string())?;
     let livesplit_data = livesplit::LiveSplitFile::new(xml);
-    libresplit::LibreSplitFile::from_livesplit(livesplit_data).get()
+    Ok(libresplit::LibreSplitFile::from_livesplit(livesplit_data).get())
+}
+
+// Build the library for WASM targets.
+// Used on the LibreSplit website, for converting splits.
+// Accepts a LiveSplit XML file as a string and returns LibreSplit JSON.
+
+#[cfg(feature = "wasm")]
+use wasm_bindgen::prelude::*;
+
+#[cfg_attr(feature = "wasm", wasm_bindgen)]
+pub fn convert(file: String) -> String {
+    convert_inner(&file).unwrap_or_else(|e| format!("{{\"error\":\"{}\"}}", e))
+}
+
+// C FFI entrypoints used by the split editor.
+
+// 'converter_convert' takes a null-terminated UTF-8 string and returns an owned C string.
+#[unsafe(no_mangle)]
+pub extern "C" fn converter_convert(input: *const c_char) -> *mut c_char {
+    if input.is_null() {
+        return null_mut();
+    }
+
+    let input = unsafe {
+        match CStr::from_ptr(input).to_str() {
+            Ok(s) => s,
+            Err(_) => return null_mut(),
+        }
+    };
+
+    match convert_inner(input) {
+        Ok(output) => CString::new(output).unwrap().into_raw(),
+        Err(error) => CString::new(format!("{{\"error\":\"{}\"}}", error))
+            .unwrap()
+            .into_raw(),
+    }
+}
+
+// The caller must free the returned pointer with 'converter_free_string'.
+#[unsafe(no_mangle)]
+pub extern "C" fn converter_free_string(ptr: *mut c_char) {
+    if !ptr.is_null() {
+        unsafe {
+            let _ = CString::from_raw(ptr);
+        }
+    }
 }