From 6b1387515040b0c8c46ef7ccdc51c25a6cee9c0a Mon Sep 17 00:00:00 2001
From: Rafael Caricio <rafael@caricio.com>
Date: Tue, 10 May 2022 23:05:48 +0200
Subject: [PATCH] Use Deku crate for serialization

Using the Deku library we can implement a `no_std` compatible read and
write structs/enums. We don't need to write manually encoding code and
rely completely on the Deku derive macros to do the right job.

I've implemented the SpliceTime part of the spec as a proof of concept
of the use of Deku. It worked great for this small structure.
---
 Cargo.toml  |  4 ++-
 src/data.rs | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs  |  1 +
 src/time.rs | 27 ++++++++++++++++++++
 4 files changed, 102 insertions(+), 1 deletion(-)
 create mode 100644 src/data.rs

diff --git a/Cargo.toml b/Cargo.toml
index a07bf62..c125c01 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,8 +7,9 @@ edition = "2021"
 license = "MIT"
 
 [dependencies]
-base64 = "0.13"
+base64 = { version = "0.13", default-features = false, features = ["alloc"] }
 bitstream-io = "1.3"
+deku = { version = "0.13", default-features = false, features = ["alloc"] }
 crc = "3.0"
 thiserror = "1"
 serde = { version = "1", features = ["derive"], optional = true }
@@ -19,3 +20,4 @@ ascii = "1"
 [dev-dependencies]
 serde_json = "1"
 assert-json-diff = "2"
+hexlit = "0.5"
diff --git a/src/data.rs b/src/data.rs
new file mode 100644
index 0000000..09af197
--- /dev/null
+++ b/src/data.rs
@@ -0,0 +1,71 @@
+use deku::prelude::*;
+
+#[derive(Debug, Clone, PartialEq, DekuRead, DekuWrite)]
+#[deku(endian = "big", type="u8", bits = "1")]
+pub(crate) enum SpliceTime {
+
+    #[deku(id = "1")]
+    TimeSpecified {
+
+        #[deku(bits = "6", assert_eq = "0x3f")]
+        reserved: u8,
+
+        #[deku(bits = "33")]
+        pts_time: u64,
+
+    },
+
+    #[deku(id = "0")]
+    NoTimeSpecified {
+
+        #[deku(bits = "7", assert_eq = "0x7f")]
+        reserved: u8,
+
+    }
+}
+
+impl Default for SpliceTime {
+    fn default() -> Self {
+        Self::NoTimeSpecified {
+            reserved: 0x7f
+        }
+    }
+}
+
+impl SpliceTime {
+    fn new(pts_time: u64) -> Self {
+        Self::TimeSpecified {
+            reserved: 0x3f,
+            pts_time
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn write_splice_time() {
+        let st = SpliceTime::default();
+        let data: Vec<u8> = st.try_into().unwrap();
+
+        assert_eq!(hex::encode(data.as_slice()), "7f");
+    }
+
+    #[test]
+    fn write_splice_time_with_pts_time() {
+        let st = SpliceTime::new(0x072bd0050);
+        let encoded: Vec<u8> = st.try_into().unwrap();
+
+        assert_eq!(hex::encode(encoded.as_slice()), "fe72bd0050");
+    }
+
+    #[test]
+    fn read_splice_time_with_pts_time() {
+        let data = hex::decode("fe72bd0050").unwrap();
+        let st = SpliceTime::try_from(data.as_slice()).unwrap();
+
+        assert_eq!(st, SpliceTime::new(0x072bd0050));
+    }
+}
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
index 73cbca3..20b6374 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -4,6 +4,7 @@ use std::time::Duration;
 use thiserror::Error;
 
 mod commands;
+mod data;
 mod descriptors;
 mod info;
 mod time;
diff --git a/src/time.rs b/src/time.rs
index e56fe9d..7f48633 100644
--- a/src/time.rs
+++ b/src/time.rs
@@ -80,3 +80,30 @@ where
         t
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn encode_time_signal() {
+
+        let mut st = SpliceTime::default();
+
+        let mut data = Vec::new();
+        st.write_to(&mut data).unwrap();
+
+        assert_eq!(hex::encode(data.as_slice()), "7f")
+    }
+
+    #[test]
+    fn encode_time_signal_with_time() {
+
+        let mut st = SpliceTime::from(0x072bd0050);
+
+        let mut data = Vec::new();
+        st.write_to(&mut data).unwrap();
+
+        assert_eq!(hex::encode(data.as_slice()), "fe72bd0050")
+    }
+}
\ No newline at end of file