From 0b5dc724549c48a9f59324dc2e22547e197f50d3 Mon Sep 17 00:00:00 2001
From: "A. Molzer" <5550310+197g@users.noreply.github.com>
Date: Fri, 7 Nov 2025 22:09:41 +0100
Subject: [PATCH 1/2] Fix: uncompressed encoder doing short writes

---
 src/encoder/compression/uncompressed.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/encoder/compression/uncompressed.rs b/src/encoder/compression/uncompressed.rs
index f414403..2385d9e 100644
--- a/src/encoder/compression/uncompressed.rs
+++ b/src/encoder/compression/uncompressed.rs
@@ -14,7 +14,7 @@ impl Compression for Uncompressed {
 
 impl CompressionAlgorithm for Uncompressed {
     fn write_to<W: Write>(&mut self, writer: &mut W, bytes: &[u8]) -> Result<u64, io::Error> {
-        writer.write(bytes).map(|byte_count| byte_count as u64)
+        writer.write_all(bytes).map(|()| bytes.len() as u64)
     }
 }
 

From 02118620e2a002992b77a3bcdb94cdf547b48b70 Mon Sep 17 00:00:00 2001
From: "A. Molzer" <5550310+197g@users.noreply.github.com>
Date: Sat, 8 Nov 2025 11:16:09 +0100
Subject: [PATCH 2/2] Verify handling of a blocked writer

---
 src/encoder/writer.rs | 55 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/src/encoder/writer.rs b/src/encoder/writer.rs
index f45038b..e3585cc 100644
--- a/src/encoder/writer.rs
+++ b/src/encoder/writer.rs
@@ -190,3 +190,58 @@ impl<W: Seek> TiffWriter<W> {
         Ok(())
     }
 }
+
+#[test]
+fn encoder_on_short_writes() {
+    struct ShortWriter<T> {
+        inner: T,
+    }
+
+    impl<T: std::io::Write> std::io::Write for ShortWriter<T> {
+        fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+            let lower_bound = buf.len().min(1);
+            let lower = buf.len().saturating_sub(1).max(lower_bound);
+
+            self.inner.write(&buf[..lower])
+        }
+
+        fn flush(&mut self) -> std::io::Result<()> {
+            self.inner.flush()
+        }
+    }
+
+    impl<T: std::io::Seek> std::io::Seek for ShortWriter<T> {
+        fn seek(&mut self, pos: std::io::SeekFrom) -> std::io::Result<u64> {
+            self.inner.seek(pos)
+        }
+    }
+
+    let mut write = ShortWriter {
+        inner: std::io::Cursor::new(vec![0u8; 0]),
+    };
+
+    let imgdata = vec![42u8; 100 * 100];
+    for comp in [
+        super::Compression::Uncompressed,
+        super::Compression::Packbits,
+    ] {
+        write.inner.set_position(0);
+        write.inner.get_mut().clear();
+
+        {
+            let mut tiff_writer = super::TiffEncoder::new(&mut write)
+                .unwrap()
+                .with_compression(comp);
+
+            tiff_writer
+                .write_image::<super::Gray8>(100, 100, &imgdata)
+                .unwrap();
+        }
+
+        write.inner.set_position(0);
+        let mut tiff_reader = crate::decoder::Decoder::new(&mut write.inner).unwrap();
+        let data = tiff_reader.read_image().unwrap();
+
+        assert!(matches!(data, crate::decoder::DecodingResult::U8(v) if v == imgdata));
+    }
+}