Permit multiple nuls in hdlr box name field.

`name` should be truncated after the first nul but we don't store the `name`
field so this change just lifts the restriction on multiple nul bytes.

Based on wording change drafted in MPEGGroup/FileFormat#35

Author: kinetiknz

mp4parse/src/lib.rs

@@ -203,7 +203,6 @@ pub enum Status {
     EsdsDecSpecificIntoTagQuantity,
     FtypBadSize,
     FtypNotFirst,
-    HdlrNameMultipleNul,
     HdlrNameNoNul,
     HdlrNameNotUtf8,
     HdlrNotFirst,
@@ -525,11 +524,6 @@ impl From<Status> for &str {
                 "The FileTypeBox shall be placed as early as possible in the file \
                  per ISOBMFF (ISO 14496-12:2020) § 4.3.1"
             }
-            Status::HdlrNameMultipleNul => {
-                "The HandlerBox 'name' field shall have a NUL byte \
-                 only in the final position \
-                 per ISOBMFF (ISO 14496-12:2020) § 8.4.3.2"
-            }
             Status::HdlrNameNoNul => {
                 "The HandlerBox 'name' field shall be null-terminated \
                  per ISOBMFF (ISO 14496-12:2020) § 8.4.3.2"
@@ -5522,21 +5516,14 @@ fn read_hdlr<T: Read>(src: &mut BMFFBox<T>, strictness: ParseStrictness) -> Resu
 
     match std::str::from_utf8(src.read_into_try_vec()?.as_slice()) {
         Ok(name) => {
-            match name.bytes().filter(|&b| b == b'\0').count() {
-                0 => fail_with_status_if(
+            match name.bytes().position(|b| b == b'\0') {
+                None => fail_with_status_if(
                     strictness != ParseStrictness::Permissive,
                     Status::HdlrNameNoNul,
                 )?,
-                1 => (),
-                n =>
+                // `name` must be nul-terminated and any trailing bytes after the first nul ignored.
                 // See https://github.com/MPEGGroup/FileFormat/issues/35
-                {
-                    error!("Found {} nul bytes in {:x?}", n, name);
-                    fail_with_status_if(
-                        strictness == ParseStrictness::Strict,
-                        Status::HdlrNameMultipleNul,
-                    )?
-                }
+                Some(_) => (),
             }
         }
         Err(_) => fail_with_status_if(

mp4parse/src/tests.rs

@@ -491,7 +491,7 @@ fn read_hdlr_multiple_nul_in_name() {
     assert_eq!(stream.head.size, 45);
     assert_eq!(
         super::Status::from(super::read_hdlr(&mut stream, ParseStrictness::Strict)),
-        super::Status::HdlrNameMultipleNul,
+        super::Status::Ok,
     );
 }
 

mp4parse/tests/public.rs

@@ -1051,7 +1051,7 @@ fn public_avif_hdlr_multiple_nul() {
     // This is a "should" despite the spec indicating a (somewhat ambiguous)
     // requirement about extra data in boxes
     // See comments in read_hdlr
-    assert_avif_should(IMAGE_AVIF_HDLR_MULTIPLE_NUL, Status::HdlrNameMultipleNul);
+    assert_avif_should(IMAGE_AVIF_HDLR_MULTIPLE_NUL, Status::Ok);
 }
 
 #[test]