From fb8b4c069547eef95aacca3fc9382b8e9ec745e1 Mon Sep 17 00:00:00 2001
From: Luca Cominardi <luca.cominardi@gmail.com>
Date: Mon, 26 Feb 2024 09:47:12 +0100
Subject: [PATCH] Encoding suffix bitflag

---
 Cargo.lock                                  |  4 +-
 commons/zenoh-codec/src/core/encoding.rs    | 44 ++++++++++++++++-----
 commons/zenoh-protocol/src/core/encoding.rs | 14 +++++++
 commons/zenoh-protocol/src/core/mod.rs      |  2 +-
 commons/zenoh-protocol/src/zenoh/mod.rs     |  4 +-
 5 files changed, 54 insertions(+), 14 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 7ceb5dbc39..ab79dfcd15 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2221,9 +2221,9 @@ dependencies = [
 
 [[package]]
 name = "num-traits"
-version = "0.2.16"
+version = "0.2.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f30b0abd723be7e2ffca1272140fac1a2f084c77ec3e123c192b66af1ee9e6c2"
+checksum = "da0df0e5185db44f69b44f26786fe401b6c293d1907744beaa7fa62b2e5a517a"
 dependencies = [
  "autocfg",
  "libm",
diff --git a/commons/zenoh-codec/src/core/encoding.rs b/commons/zenoh-codec/src/core/encoding.rs
index 4b2e2248c9..b14710f48f 100644
--- a/commons/zenoh-codec/src/core/encoding.rs
+++ b/commons/zenoh-codec/src/core/encoding.rs
@@ -17,11 +17,19 @@ use zenoh_buffers::{
     reader::{DidntRead, Reader},
     writer::{DidntWrite, Writer},
 };
-use zenoh_protocol::core::{Encoding, EncodingPrefix};
+use zenoh_protocol::{
+    common::imsg,
+    core::encoding::{flag, Encoding, EncodingPrefix},
+};
 
 impl LCodec<&Encoding> for Zenoh080 {
     fn w_len(self, x: &Encoding) -> usize {
-        self.w_len(x.prefix()) + self.w_len(x.suffix())
+        let (prefix, suffix) = (x.prefix(), x.suffix());
+        let mut len = self.w_len((prefix as u32) << 1);
+        if !suffix.is_empty() {
+            len += self.w_len(x.suffix());
+        }
+        len
     }
 }
 
@@ -32,10 +40,18 @@ where
     type Output = Result<(), DidntWrite>;
 
     fn write(self, writer: &mut W, x: &Encoding) -> Self::Output {
-        let zodec = Zenoh080Bounded::<EncodingPrefix>::new();
-        zodec.write(&mut *writer, x.prefix())?;
-        let zodec = Zenoh080Bounded::<u8>::new();
-        zodec.write(&mut *writer, x.suffix())?;
+        let mut prefix = (x.prefix() as u32) << 1;
+        let suffix = x.suffix();
+
+        if !suffix.is_empty() {
+            prefix |= flag::S;
+        }
+        let zodec = Zenoh080Bounded::<u32>::new();
+        zodec.write(&mut *writer, prefix)?;
+        if !suffix.is_empty() {
+            let zodec = Zenoh080Bounded::<u8>::new();
+            zodec.write(&mut *writer, suffix)?;
+        }
         Ok(())
     }
 }
@@ -47,10 +63,18 @@ where
     type Error = DidntRead;
 
     fn read(self, reader: &mut R) -> Result<Encoding, Self::Error> {
-        let zodec = Zenoh080Bounded::<EncodingPrefix>::new();
-        let prefix: EncodingPrefix = zodec.read(&mut *reader)?;
-        let zodec = Zenoh080Bounded::<u8>::new();
-        let suffix: String = zodec.read(&mut *reader)?;
+        let zodec = Zenoh080Bounded::<u32>::new();
+        let prefix: u32 = zodec.read(&mut *reader)?;
+        let (prefix, has_suffix) = (
+            (prefix >> 1) as EncodingPrefix,
+            imsg::has_flag(prefix as u8, flag::S as u8),
+        );
+
+        let mut suffix = String::new();
+        if has_suffix {
+            let zodec = Zenoh080Bounded::<u8>::new();
+            suffix = zodec.read(&mut *reader)?;
+        }
 
         let mut encoding: Encoding = Encoding::new(prefix);
         if !suffix.is_empty() {
diff --git a/commons/zenoh-protocol/src/core/encoding.rs b/commons/zenoh-protocol/src/core/encoding.rs
index c49b315b21..620d6e2b66 100644
--- a/commons/zenoh-protocol/src/core/encoding.rs
+++ b/commons/zenoh-protocol/src/core/encoding.rs
@@ -31,6 +31,20 @@ pub struct Encoding {
     suffix: CowStr<'static>,
 }
 
+/// # Encoding field
+///
+/// ```text
+///  7 6 5 4 3 2 1 0
+/// +-+-+-+-+-+-+-+-+
+/// ~ prefix: z16 |S~
+/// +---------------+
+/// ~suffix: <u8;z8>~  -- if S==1
+/// +---------------+
+/// ```
+pub mod flag {
+    pub const S: u32 = 1; // 0x01 Suffix    if S==1 then suffix is present
+}
+
 impl Encoding {
     /// Returns a new [`Encoding`] object provided the prefix ID.
     pub const fn new(prefix: EncodingPrefix) -> Self {
diff --git a/commons/zenoh-protocol/src/core/mod.rs b/commons/zenoh-protocol/src/core/mod.rs
index 55e57d5d81..c2218a7f84 100644
--- a/commons/zenoh-protocol/src/core/mod.rs
+++ b/commons/zenoh-protocol/src/core/mod.rs
@@ -42,7 +42,7 @@ pub use wire_expr::*;
 
 mod cowstr;
 pub use cowstr::CowStr;
-mod encoding;
+pub mod encoding;
 pub use encoding::{Encoding, EncodingPrefix};
 
 pub mod locator;
diff --git a/commons/zenoh-protocol/src/zenoh/mod.rs b/commons/zenoh-protocol/src/zenoh/mod.rs
index e67576e673..686e9f8ec5 100644
--- a/commons/zenoh-protocol/src/zenoh/mod.rs
+++ b/commons/zenoh-protocol/src/zenoh/mod.rs
@@ -220,12 +220,14 @@ pub mod ext {
         }
     }
 
+    /// ```text
     ///   7 6 5 4 3 2 1 0
     ///  +-+-+-+-+-+-+-+-+
     ///  ~   encoding    ~
     ///  +---------------+
-    ///  ~ pl: [u8;z32]  ~  -- Payload
+    ///  ~ pl: <u8;z32>  ~  -- Payload
     ///  +---------------+
+    /// ```
     #[derive(Debug, Clone, PartialEq, Eq)]
     pub struct ValueType<const VID: u8, const SID: u8> {
         #[cfg(feature = "shared-memory")]