Removed Nix and the sample-main, added a CI/CD pipeline and updated the README.md

src/record.rs

@@ -0,0 +1,122 @@
+use chrono::{DateTime, Local, TimeZone};
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, Copy, Default, Eq, PartialEq, Ord, PartialOrd, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub enum Clock {
+    #[default]
+    FirstIn,
+    FirstOut,
+    SecondIn,
+    SecondOut,
+}
+
+// unsafe impl Send for Clock {}
+// unsafe impl Sync for Clock {}
+
+#[derive(Debug, Clone, Copy, Default, Eq, PartialEq, Ord, PartialOrd, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+pub struct Record {
+    pub employee_id: u32,
+    pub clock: Clock,
+    pub datetime: DateTime<Local>,
+}
+
+// unsafe impl Send for Record {}
+// unsafe impl Sync for Record {}
+
+impl TryFrom<&[u8]> for Record {
+    type Error = &'static str;
+
+    fn try_from(record_bytes: &[u8]) -> Result<Self, Self::Error> {
+        // Return an error if the slice length is less than 12
+        if record_bytes.len() != 12 {
+            return Err("Slice must be of length 12 to be converted into Record");
+        }
+
+        // Extract the employee ID from the central 4 bytes of the record in
+        // little endian
+        let mut employee_id = [0u8; 4];
+        employee_id.clone_from_slice(&record_bytes[4..8]);
+        let employee_id = u32::from_le_bytes(employee_id);
+
+        // Extract the DateTime from the last 4 bytes of the record in little
+        // endian
+        let mut datetime = [0u8; 4];
+        datetime.clone_from_slice(&record_bytes[8..12]);
+        let datetime = u32::from_le_bytes(datetime);
+
+        // Return a new Record
+        #[allow(clippy::cast_possible_wrap)]
+        Ok(Self {
+            employee_id,
+            clock: match record_bytes[1] >> 6 {
+                0 => Clock::FirstIn,
+                1 => Clock::FirstOut,
+                2 => Clock::SecondIn,
+                3 => Clock::SecondOut,
+                _ => unreachable!("Math has broken"),
+            },
+            datetime: Local
+                .with_ymd_and_hms(
+                    // DateTime data is in this format:
+                    //
+                    // mmmmmmhh hhhddddd MMMMyyyy yyyyyyyy
+                    //
+                    // Using some bitshifts and some bitwise operations we can
+                    // extract the data and put it into a DateTime struct
+                    (datetime & 0x0fff) as i32,
+                    (datetime >> 12) & 0x0f,
+                    (datetime >> 16) & 0x1f,
+                    (datetime >> 21) & 0x1f,
+                    (datetime >> 26) & 0x3f,
+                    0,
+                )
+                .single()
+                .ok_or("DateTime conversion error")?,
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn valid_record_conversion() {
+        let record_bytes: &[u8] = &[0x10, 0x23, 0x0b, 0x1d, 0x01, 0, 0, 0, 0xb2, 0x17, 0x01, 0];
+
+        assert_eq!(
+            record_bytes.try_into(),
+            Ok(Record {
+                employee_id: 1,
+                clock: Clock::FirstIn,
+                datetime: Local
+                    .with_ymd_and_hms(1970, 1, 1, 0, 0, 0)
+                    .single()
+                    .expect("Datetime is not unique!"),
+            })
+        );
+    }
+
+    #[test]
+    fn invalid_length() {
+        let record_bytes: &[u8] = &[0u8; 11];
+
+        assert_eq!(
+            record_bytes.try_into(),
+            Err::<Record, &str>("Slice must be at least of length 12 to be converted into Record")
+        );
+    }
+
+    #[test]
+    fn invalid_datetime() {
+        let record_bytes: &[u8] = &[0x10, 0x23, 0x0b, 0x1d, 0x01, 0, 0, 0, 0xb2, 0x17, 0x20, 0];
+
+        assert_eq!(
+            record_bytes.try_into(),
+            Err::<Record, &str>("DateTime conversion error")
+        );
+    }
+}