Fix reading small or empty slices

Cargo.toml

@@ -3,7 +3,7 @@ name = "tl-proto"
 description = "A collection of traits for working with TL serialization/deserialization"
 authors = ["Ivan Kalinin <[email protected]>"]
 repository = "https://github.com/broxus/tl-proto"
-version = "0.4.10"
+version = "0.4.11"
 edition = "2021"
 include = ["src/**/*.rs", "README.md"]
 license = "MIT"

scheme/src/tokens.rs

@@ -164,7 +164,7 @@ pub struct Constructor<'a> {
     pub output: OutputType<'a>,
 }
 
-impl<'a> Constructor<'a> {
+impl Constructor<'_> {
     pub fn as_normalized(&self) -> String {
         NormalizedConstructor(self).to_string()
     }

src/hasher.rs

@@ -68,7 +68,7 @@ where
 
 struct HashWriter<'a>(pub &'a mut dyn Hasher);
 
-impl<'a> TlPacket for HashWriter<'a> {
+impl TlPacket for HashWriter<'_> {
     const TARGET: TlTarget = TlTarget::Hasher;
 
     #[inline(always)]

src/seq.rs

@@ -730,7 +730,7 @@ fn read_bytes<'a>(packet: &'a [u8], offset: &mut usize) -> TlResult<&'a [u8]> {
 #[inline(always)]
 fn compute_bytes_meta(packet: &[u8], offset: usize) -> TlResult<(usize, usize, usize)> {
     let packet_len = packet.len();
-    if unlikely(packet_len <= offset + 4) {
+    if unlikely(packet_len < offset + 4) {
         return Err(TlError::UnexpectedEof);
     }
 
@@ -750,3 +750,16 @@ fn compute_bytes_meta(packet: &[u8], offset: usize) -> TlResult<(usize, usize, u
 }
 
 const SIZE_MAGIC: u8 = 254;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn read_small_slice() {
+        assert_eq!(read_bytes(&[0, 0, 0, 0], &mut 0).unwrap(), &[]);
+        assert_eq!(read_bytes(&[1, 123, 0, 0], &mut 0).unwrap(), &[123]);
+        assert_eq!(read_bytes(&[2, 123, 3, 0], &mut 0).unwrap(), &[123, 3]);
+        assert_eq!(read_bytes(&[3, 123, 3, 2], &mut 0).unwrap(), &[123, 3, 2]);
+    }
+}