From d55d764e10f57bf3dc938541d8796e983f977945 Mon Sep 17 00:00:00 2001
From: Alex van de Sandt <me@alexvds.com>
Date: Wed, 29 Apr 2026 15:34:44 -0500
Subject: [PATCH] Move BytesSplit to a module

---
 src/bytes_split.rs | 84 ++++++++++++++++++++++++++++++++++++++++++++++
 src/codec.rs       | 64 +++--------------------------------
 src/lib.rs         |  4 +--
 3 files changed, 91 insertions(+), 61 deletions(-)
 create mode 100644 src/bytes_split.rs

diff --git a/src/bytes_split.rs b/src/bytes_split.rs
new file mode 100644
index 0000000..d4e40b4
--- /dev/null
+++ b/src/bytes_split.rs
@@ -0,0 +1,84 @@
+use bytes::{Buf, Bytes};
+
+pub struct BytesSplit(Bytes, u8);
+
+impl BytesSplit {
+    pub fn new(inner: Bytes, split_at: u8) -> Self {
+        Self(inner, split_at)
+    }
+}
+
+impl Iterator for BytesSplit {
+    type Item = Bytes;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.0.is_empty() {
+            return None;
+        }
+
+        // find the index of the first delimiter
+        let Some(i) = self
+            .0
+            .iter()
+            .enumerate()
+            .find_map(|(i, b)| (*b == self.1).then_some(i))
+        else {
+            // we're on the last element
+            let last_elem = self.0.clone();
+            self.0.clear();
+            return Some(last_elem);
+        };
+
+        // extract the element
+        let elem = self.0.split_to(i);
+        // remove the comma
+        self.0.advance(1);
+
+        Some(elem)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #![allow(clippy::unwrap_used)]
+
+    use super::*;
+    use bytes::Bytes;
+
+    #[test]
+    fn splits_on_commas() {
+        let bytes = Bytes::from(b"foo,bar,baz".as_slice());
+        let mut split = BytesSplit::new(bytes, b',');
+
+        assert_eq!(split.next().unwrap().as_ref(), b"foo");
+        assert_eq!(split.next().unwrap().as_ref(), b"bar");
+        assert_eq!(split.next().unwrap().as_ref(), b"baz");
+        assert_eq!(split.next(), None);
+    }
+
+    #[test]
+    fn trailing_comma_returns_none() {
+        let bytes = Bytes::from(b"foo,".as_slice());
+        let mut split = BytesSplit::new(bytes, b',');
+
+        assert_eq!(split.next().unwrap().as_ref(), b"foo");
+        assert_eq!(split.next(), None);
+    }
+
+    #[test]
+    fn single_comma_returns_empty_then_none() {
+        let bytes = Bytes::from(b",".as_slice());
+        let mut split = BytesSplit::new(bytes, b',');
+
+        assert_eq!(split.next().unwrap().as_ref(), b"");
+        assert_eq!(split.next(), None);
+    }
+
+    #[test]
+    fn empty_string_returns_none() {
+        let bytes = Bytes::from(b"".as_slice());
+        let mut split = BytesSplit::new(bytes, b',');
+
+        assert_eq!(split.next(), None);
+    }
+}
diff --git a/src/codec.rs b/src/codec.rs
index ac45599..7901fc3 100644
--- a/src/codec.rs
+++ b/src/codec.rs
@@ -1,7 +1,10 @@
-use bytes::{Buf, BufMut, Bytes};
+use bytes::{BufMut, Bytes};
 use tokio_util::codec::{AnyDelimiterCodec, AnyDelimiterCodecError, Decoder, Encoder};
 
-use crate::command::{Command, ParamSet, Response};
+use crate::{
+    bytes_split::BytesSplit,
+    command::{Command, ParamSet, Response},
+};
 
 #[derive(Clone, Debug)]
 pub struct Codec {
@@ -116,60 +119,3 @@ impl Decoder for Codec {
         Ok(Some(RawResponse { cmd, raw_values }))
     }
 }
-
-struct BytesSplit(Bytes, u8);
-
-impl BytesSplit {
-    fn new(inner: Bytes, split_at: u8) -> Self {
-        Self(inner, split_at)
-    }
-}
-
-impl Iterator for BytesSplit {
-    type Item = Bytes;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        if self.0.is_empty() {
-            return None;
-        }
-
-        // find the index of the first delimiter
-        let Some(i) = self
-            .0
-            .iter()
-            .enumerate()
-            .find_map(|(i, b)| (*b == self.1).then_some(i))
-        else {
-            // we're on the last element
-            let last_elem = self.0.clone();
-            self.0.clear();
-            return Some(last_elem);
-        };
-
-        // extract the element
-        let elem = self.0.split_to(i);
-        // remove the comma
-        self.0.advance(1);
-
-        Some(elem)
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    #![allow(clippy::unwrap_used)]
-
-    use super::*;
-    use bytes::Bytes;
-
-    #[test]
-    fn split_works() {
-        let bytes = Bytes::from(b"foo,bar,baz".as_slice());
-        let mut split = BytesSplit::new(bytes, b',');
-
-        assert_eq!(split.next().unwrap().as_ref(), b"foo");
-        assert_eq!(split.next().unwrap().as_ref(), b"bar");
-        assert_eq!(split.next().unwrap().as_ref(), b"baz");
-        assert_eq!(split.next(), None);
-    }
-}
diff --git a/src/lib.rs b/src/lib.rs
index 0fa1f0c..54350cb 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,7 +1,7 @@
+mod bytes_split;
 mod codec;
-mod scanner;
-
 mod command;
+mod scanner;
 
 pub use crate::command::bc125at;
 pub use crate::command::{Command, Param, ParamSet, Response};
-- 
2.51.2