fix(organize): normalize rotations before adding so large quarter turns cannot overflow (#1512)

* Contributors: credit webdevtodayjason as Jason Brashear

* fix(organize): normalize rotations before adding so large quarter turns cannot overflow

contributors/people.toml

@@ -126,3 +126,6 @@ sync_github_name = true
 real_name = "Jeremy Yao"
 display_name = "Jeremy Yao"
 sync_github_name = false
+
+[people.webdevtodayjason]
+display_name = "Jason Brashear"

crates/organize/src/lib.rs

@@ -158,11 +158,11 @@ pub fn rotate_pages(doc: &mut Document, indices: &[usize], degrees: i64) -> Resu
     }
     let all = walk(doc)?;
     check(indices, all.len())?;
-    let delta = (degrees / 90) * 90;
+    let delta = degrees.rem_euclid(360);
     for &i in indices {
         let (page, inherited) = &all[i];
         let current = doc.get(*page).as_dict().and_then(|d| d.int(b"Rotate")).or_else(|| inherited.int(b"Rotate")).unwrap_or(0);
-        let new = (current + delta).rem_euclid(360);
+        let new = (current.rem_euclid(360) + delta).rem_euclid(360);
         doc.update_dict(*page, |d| d.set(b"Rotate".to_vec(), Object::Int(new)))?;
     }
     Ok(())

crates/organize/src/tests.rs

@@ -28,6 +28,20 @@ fn rotate_rejects_angles_that_are_not_multiples_of_90() {
     assert_eq!(page_rotation(&doc, 0).unwrap(), 0);
 }
 
+#[test]
+fn rotate_handles_large_quarter_turns() {
+    let large = i64::MAX - i64::MAX % 90;
+    for (current, degrees, expected) in [(90, large, 90), (-90, -large, 270), (large, 90, 90), (-large, -90, 270), (180, large - 90, 90)] {
+        for inherited in [false, true] {
+            let mut doc = open(fixture());
+            let target = if inherited { pages_root(&doc).unwrap() } else { pages(&doc).unwrap()[0].obj };
+            doc.update_dict(target, |d| d.set(b"Rotate".to_vec(), Object::Int(current))).unwrap();
+            rotate_pages(&mut doc, &[0], degrees).unwrap();
+            assert_eq!(page_rotation(&doc, 0).unwrap(), expected);
+        }
+    }
+}
+
 /// A 3-page document with a nested page tree. MediaBox and Rotate are inherited from the root,
 /// Resources from an intermediate node; each page's content says which page it is.
 fn fixture() -> Vec<u8> {