Vendor dependencies for 0.3.0 release

vendor/objc2/examples/encode_nsuinteger.rs

@@ -0,0 +1,30 @@
+use objc2::encode::{Encode, Encoding, RefEncode};
+
+// Note: In this case `NSUInteger` could be a type alias for `usize`, and
+// actually that's already available as `objc2::ffi::NSUInteger`.
+#[repr(transparent)]
+struct NSUInteger {
+    _inner: usize,
+}
+
+// SAFETY: `NSUInteger` has the same `repr` as `usize`.
+unsafe impl Encode for NSUInteger {
+    // Running `@encode(NSUInteger)` gives `Q` on 64-bit systems and `I` on
+    // 32-bit systems. This corresponds exactly to `usize`, which is also how
+    // we've defined our struct.
+    const ENCODING: Encoding = usize::ENCODING;
+}
+
+// SAFETY: `&NSUInteger` has the same representation as `&usize`.
+unsafe impl RefEncode for NSUInteger {
+    // Running `@encode(NSUInteger*)` gives `^Q` on 64-bit systems and `^I` on
+    // 32-bit systems. So implementing `RefEncode` as a plain pointer is
+    // correct.
+    const ENCODING_REF: Encoding = Encoding::Pointer(&NSUInteger::ENCODING);
+}
+
+fn main() {
+    assert!(NSUInteger::ENCODING.equivalent_to_str("Q"));
+    assert!(<&NSUInteger>::ENCODING.equivalent_to_str("^Q"));
+    assert!(<&NSUInteger>::ENCODING.equivalent_to_str("r^Q"));
+}