update code for 31 and 32

Author: tyrchen

31_ffi/bzlib_sys/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "bzlib-sys"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+anyhow = "1"
+
+[build-dependencies]
+bindgen = "0.59"

31_ffi/bzlib_sys/build.rs

@@ -0,0 +1,19 @@
+fn main() {
+    // 告诉 rustc 需要 link bzip2
+    println!("cargo:rustc-link-lib=bz2");
+
+    // 告诉 cargo 当 wrapper.h 变化时重新运行
+    println!("cargo:rerun-if-changed=wrapper.h");
+
+    // 配置 bindgen，并生成 Bindings 结构
+    let bindings = bindgen::Builder::default()
+        .header("wrapper.h")
+        .parse_callbacks(Box::new(bindgen::CargoCallbacks))
+        .generate()
+        .expect("Unable to generate bindings");
+
+    // 生成 Rust 代码
+    bindings
+        .write_to_file("src/bindings.rs")
+        .expect("Failed to write bindings");
+}