add ffi module

source/durandal/ffi.rs

@@ -0,0 +1,61 @@
+//! Foreign function interface utilities.
+
+use crate::durandal::err::*;
+pub use std::{ffi::*, os::raw::*, ptr::{null, null_mut}};
+
+/// Creates a C string from a literal.
+#[macro_export]
+macro_rules! c_str {
+   ($s:expr) => {concat!($s, "\0").as_ptr() as *const c_char};
+}
+
+impl CStringVec
+{
+   /// Creates a new empty CStringVec.
+   pub fn new() -> Self
+   {
+      Self::default()
+   }
+
+   /// Creates a new `CStringVec` from an iterator.
+   pub fn new_from_iter<'a, I: Iterator<Item = &'a str>>(it: I)
+      -> ResultS<Self>
+   {
+      let mut v = Self::new();
+
+      for st in it {
+         v.push(CString::new(st)?);
+      }
+
+      Ok(v)
+   }
+
+   /// Pushes a new `CString`.
+   pub fn push(&mut self, st: CString)
+   {
+      self.cv.push(st.as_c_str().as_ptr());
+      self.sv.push(st);
+   }
+
+   /// Returns the FFI pointer.
+   pub fn as_ptr(&self) -> *const *const c_char
+   {
+      self.cv.as_ptr()
+   }
+
+   /// Returns the FFI pointer mutably.
+   pub fn as_mut_ptr(&mut self) -> *mut *const c_char
+   {
+      self.cv.as_mut_ptr()
+   }
+}
+
+/// An owned FFI-compatible string vector.
+#[derive(Default)]
+pub struct CStringVec
+{
+   sv: Vec<CString>,
+   cv: Vec<*const c_char>,
+}
+
+// EOF

source/durandal/mod.rs

@@ -1,5 +1,7 @@
 //! Library for utilities.
 
+#[macro_use]
+pub mod ffi;
 #[macro_use]
 pub mod err;
 #[macro_use]