Merge pull request #232 from mozilla/checked-integer

Add a CheckedInteger type to ensure checked arithmetic

Author: baumanj

mp4parse/src/lib.rs

@@ -975,16 +975,16 @@ pub struct TrackTimeScale<T: Num>(pub T, pub usize);
 /// A time to be scaled by the track's local (mdhd) timescale.
 /// Members are time in scale units and the track id.
 #[derive(Debug, Copy, Clone, PartialEq)]
-pub struct TrackScaledTime<T: Num>(pub T, pub usize);
+pub struct TrackScaledTime<T>(pub T, pub usize);
 
 impl<T> std::ops::Add for TrackScaledTime<T>
 where
-    T: Num,
+    T: num_traits::CheckedAdd,
 {
-    type Output = TrackScaledTime<T>;
+    type Output = Option<Self>;
 
-    fn add(self, other: TrackScaledTime<T>) -> TrackScaledTime<T> {
-        TrackScaledTime::<T>(self.0 + other.0, self.1)
+    fn add(self, other: TrackScaledTime<T>) -> Self::Output {
+        self.0.checked_add(&other.0).map(|sum| Self(sum, self.1))
     }
 }
 

mp4parse_capi/Cargo.toml

@@ -26,7 +26,7 @@ travis-ci = { repository = "https://github.com/mozilla/mp4parse-rust" }
 byteorder = "1.2.1"
 log = "0.4"
 mp4parse = {version = "0.11.2", path = "../mp4parse"}
-num-traits = "0.2.0"
+num = "0.3.0"
 
 [dev-dependencies]
 env_logger = "0.7.1"

mp4parse_capi/examples/dump.rs

@@ -62,9 +62,7 @@ fn dump_file(filename: &str) {
         for i in 0..counts {
             let mut track_info = Mp4parseTrackInfo {
                 track_type: Mp4parseTrackType::Audio,
-                track_id: 0,
-                duration: 0,
-                media_time: 0,
+                ..Default::default()
             };
             match mp4parse_get_track_info(parser, i, &mut track_info) {
                 Mp4parseStatus::Ok => {