1 files changed, 124 insertions, 0 deletions
diff --git a/vendor/image/src/codecs/pnm/autobreak.rs b/vendor/image/src/codecs/pnm/autobreak.rs
new file mode 100644
index 0000000..cea2cd8
--- /dev/null
+++ b/vendor/image/src/codecs/pnm/autobreak.rs
@@ -0,0 +1,124 @@
+//! Insert line breaks between written buffers when they would overflow the line length.
+use std::io;
+
+// The pnm standard says to insert line breaks after 70 characters. Assumes that no line breaks
+// are actually written. We have to be careful to fully commit buffers or not commit them at all,
+// otherwise we might insert a newline in the middle of a token.
+pub(crate) struct AutoBreak<W: io::Write> {
+    wrapped: W,
+    line_capacity: usize,
+    line: Vec<u8>,
+    has_newline: bool,
+    panicked: bool, // see https://github.com/rust-lang/rust/issues/30888
+}
+
+impl<W: io::Write> AutoBreak<W> {
+    pub(crate) fn new(writer: W, line_capacity: usize) -> Self {
+        AutoBreak {
+            wrapped: writer,
+            line_capacity,
+            line: Vec::with_capacity(line_capacity + 1),
+            has_newline: false,
+            panicked: false,
+        }
+    }
+
+    fn flush_buf(&mut self) -> io::Result<()> {
+        // from BufWriter
+        let mut written = 0;
+        let len = self.line.len();
+        let mut ret = Ok(());
+        while written < len {
+            self.panicked = true;
+            let r = self.wrapped.write(&self.line[written..]);
+            self.panicked = false;
+            match r {
+                Ok(0) => {
+                    ret = Err(io::Error::new(
+                        io::ErrorKind::WriteZero,
+                        "failed to write the buffered data",
+                    ));
+                    break;
+                }
+                Ok(n) => written += n,
+                Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
+                Err(e) => {
+                    ret = Err(e);
+                    break;
+                }
+            }
+        }
+        if written > 0 {
+            self.line.drain(..written);
+        }
+        ret
+    }
+}
+
+impl<W: io::Write> io::Write for AutoBreak<W> {
+    fn write(&mut self, buffer: &[u8]) -> io::Result<usize> {
+        if self.has_newline {
+            self.flush()?;
+            self.has_newline = false;
+        }
+
+        if !self.line.is_empty() && self.line.len() + buffer.len() > self.line_capacity {
+            self.line.push(b'\n');
+            self.has_newline = true;
+            self.flush()?;
+            self.has_newline = false;
+        }
+
+        self.line.extend_from_slice(buffer);
+        Ok(buffer.len())
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        self.flush_buf()?;
+        self.wrapped.flush()
+    }
+}
+
+impl<W: io::Write> Drop for AutoBreak<W> {
+    fn drop(&mut self) {
+        if !self.panicked {
+            let _r = self.flush_buf();
+            // internal writer flushed automatically by Drop
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::io::Write;
+
+    #[test]
+    fn test_aligned_writes() {
+        let mut output = Vec::new();
+
+        {
+            let mut writer = AutoBreak::new(&mut output, 10);
+            writer.write_all(b"0123456789").unwrap();
+            writer.write_all(b"0123456789").unwrap();
+        }
+
+        assert_eq!(output.as_slice(), b"0123456789\n0123456789");
+    }
+
+    #[test]
+    fn test_greater_writes() {
+        let mut output = Vec::new();
+
+        {
+            let mut writer = AutoBreak::new(&mut output, 10);
+            writer.write_all(b"012").unwrap();
+            writer.write_all(b"345").unwrap();
+            writer.write_all(b"0123456789").unwrap();
+            writer.write_all(b"012345678910").unwrap();
+            writer.write_all(b"_").unwrap();
+        }
+
+        assert_eq!(output.as_slice(), b"012345\n0123456789\n012345678910\n_");
+    }
+}