we can now read c style string arrays

.gitignore

@@ -1,2 +1,3 @@
 /target
 Cargo.lock
+/ctest/test

Cargo.toml

@@ -4,11 +4,16 @@ version = "0.1.0"
 authors = ["Nathan Eikermann <tensazangetsu1990@googlemail.com>"]
 description = "A rust library providing various utilities. To be used via FFI"
 edition = "2018"
-#build = "build.rs"
+build = "build.rs"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+libc = "0.2"
+ffi-convert = "0.5"
+
+[build-dependencies]
+cbindgen = "0.19.0"
 
 [lib]
 crate-type = ["cdylib", "lib"]

Makefile

@@ -0,0 +1,6 @@
+DEBUG=target/debug/libmd_util_rs.so 
+FILE=ctest/test.c
+OUTPUT=ctest/test
+test:
+	 gcc -o ${OUTPUT} ${FILE} -Isrc  -L. -l:${DEBUG}
+	 ./ctest/test

build.rs

@@ -0,0 +1,14 @@
+extern crate cbindgen;
+
+use std::env;
+
+fn main() {
+    let crate_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
+
+    cbindgen::Builder::new()
+        .with_crate(crate_dir)
+        .with_language(cbindgen::Language::C)
+        .generate()
+        .expect("Unable to generate bindings")
+        .write_to_file("./ctest/bindings.h");
+}

ctest/bindings.h

@@ -0,0 +1,6 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+void files_exist(const char *const *f, size_t len);

ctest/test.c

@@ -0,0 +1,15 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+extern void files_exist(const char *const *f, size_t len);
+
+int main(int argc, char const* argv[])
+{
+    const char *a[2];
+    a[0] = "Hello";
+    a[1] = "World!";
+    files_exist(a, 2);
+    return 0;
+}

src/lib.rs

@@ -1,7 +1,35 @@
+extern crate ffi_convert;
+extern crate libc;
+
+use ffi_convert::{AsRust, CReprOf, CStringArray};
+use libc::c_char;
+use libc::size_t;
+//use std::ffi::CStr;
+//use std::ffi::CString;
+use std::path::Path;
+//use std::slice;
+
+fn file_exists(file_path: &str) -> bool {
+    return Path::new(file_path).is_file();
+}
+
+#[no_mangle]
+pub extern "C" fn files_exist(f: *const *const c_char, len: size_t) -> () {
+    let files = unsafe {
+        assert!(!f.is_null());
+        CStringArray { data: f, size: len }
+    };
+
+    println!("{:?}", files.as_rust().unwrap());
+    std::mem::forget(files);
+}
+
 #[cfg(test)]
 mod tests {
+    use super::*;
+
     #[test]
     fn it_works() {
-        assert_eq!(2 + 2, 4);
+        assert_eq!(file_exists("/home/nathan/Downloads/cert.sh"), true);
     }
 }