util/dictionary: add Dictionary

src/lib.rs

@@ -7,3 +7,4 @@ extern crate ffmpeg_sys as ffi;
 
 pub mod util;
 pub use util::error::Error;
+pub use util::dictionary::Dictionary;

src/util/dictionary.rs

@@ -0,0 +1,36 @@
+use std::marker::PhantomData;
+use std::ptr;
+
+use ffi::*;
+
+pub struct Dictionary<'a> {
+	pub ptr: *mut AVDictionary,
+
+	own:     bool,
+	_marker: PhantomData<&'a i32>,
+}
+
+impl<'a> Dictionary<'a> {
+	pub fn new() -> Self {
+		Dictionary { ptr: ptr::null_mut(), own: true, _marker: PhantomData }
+	}
+
+	pub fn wrap(ptr: *mut AVDictionary) -> Self {
+		Dictionary { ptr: ptr, own: false, _marker: PhantomData }
+	}
+
+	pub fn take(&mut self) -> *mut AVDictionary {
+		self.own = false;
+		self.ptr
+	}
+}
+
+impl<'a> Drop for Dictionary<'a> {
+	fn drop(&mut self) {
+		unsafe {
+			if self.own && self.ptr != ptr::null_mut() {
+				av_dict_free(&mut self.ptr);
+			}
+		}
+	}
+}

src/util/mod.rs

@@ -1,3 +1,4 @@
+pub mod dictionary;
 pub mod error;
 
 use std::ffi::CStr;