From 439dc00d1ce9ff3e5dc05f32a0426152fc5fab89 Mon Sep 17 00:00:00 2001
From: metamuffin <metamuffin@disroot.org>
Date: Sat, 14 Jan 2023 21:37:40 +0100
Subject: reproduction *almost* perfect

---
 ebml/src/write.rs | 34 +++++++++++++++++++++++-----------
 1 file changed, 23 insertions(+), 11 deletions(-)

(limited to 'ebml/src/write.rs')

diff --git a/ebml/src/write.rs b/ebml/src/write.rs
index 89268d5..2191693 100644
--- a/ebml/src/write.rs
+++ b/ebml/src/write.rs
@@ -23,20 +23,12 @@ impl EbmlWriter {
     }
 
     pub fn write_tag(&mut self, tag: &MatroskaTag) -> Result<()> {
-        self.write_tag_id(tag.id())?;
         let mut buf = vec![];
-        tag.write(&mut buf)?;
+        tag.write_full(&mut buf)?;
         self.write(&buf)?;
         Ok(())
     }
 
-    pub fn write_tag_id(&mut self, id: u64) -> Result<()> {
-        for n in id.to_be_bytes().iter().skip_while(|&v| *v == 0u8) {
-            self.write(&[*n])?;
-        }
-        Ok(())
-    }
-
     pub fn write_vint(&mut self, i: u64) -> Result<()> {
         if i > (1 << 56) - 1 {
             bail!("vint does not fit");
@@ -55,6 +47,17 @@ impl EbmlWriter {
     }
 }
 
+impl MatroskaTag {
+    pub fn write_full(&self, w: &mut Vec<u8>) -> Result<()> {
+        let mut buf = vec![];
+        buf.extend(self.id().to_be_bytes().iter().skip_while(|&v| *v == 0u8));
+        // note: it is relevant here, to pass the buffer with the id, such that closing tags, can clear it
+        self.write(&mut buf)?;
+        w.extend_from_slice(&buf);
+        Ok(())
+    }
+}
+
 pub trait WriteValue {
     fn write_to(&self, w: &mut Vec<u8>) -> Result<()>;
 }
@@ -138,8 +141,17 @@ impl WriteValue for EbmlSize {
 impl WriteValue for Master {
     fn write_to(&self, w: &mut Vec<u8>) -> Result<()> {
         match self {
-            Master::Start(size) => size.write_to(w),
-            Master::End => Ok(()),
+            Master::Start => EbmlSize::Unknown.write_to(w),
+            Master::End => Ok(w.clear()),
+            Master::Collected(c) => {
+                let mut ib = vec![];
+                for c in c {
+                    c.write_full(&mut ib)?;
+                }
+                EbmlSize::Exact(ib.len()).write_to(w);
+                w.extend_from_slice(&ib);
+                Ok(())
+            }
         }
     }
 }
-- 
cgit v1.2.3-70-g09d2