add from and to u32 scaffolding for U26 types

lib-bms-protocol/src/types.rs

@@ -44,6 +44,12 @@
 //! errors random errors in the transmission have a probabilty of 2**-6 = 0.015625 of matching the original messages CRC code.
 //! Meaning the chance of errors going undetected is <2%.
 
+const U26_VALUE_MASK: u32 = 0xFFFFFFc0;
+const U26_MAX_VALUE: u32 = 0x03FFFFFF;
+
+pub enum U26Error {
+    Overflow
+}
 
 #[derive(Debug)]
 /// this type is used for storing data on memory devices the concern here is mostly protecting against memory corruption
@@ -56,6 +62,24 @@
 /// | 26 bits u26 value | 5 hemming bits | 1 unused extrabit |
 pub struct Stored_U26(u32);
 
+impl From<Stored_U26> for u32 {
+    fn from(value: Stored_U26) -> Self {
+        value.0 & U26_VALUE_MASK >> 6
+    }
+}
+
+impl TryFrom<u32> for Stored_U26 {
+    type Error = U26Error;
+
+    fn try_from(value: u32) -> Result<Self, Self::Error> {
+        if value > U26_MAX_VALUE {
+            Err(U26Error::Overflow)
+        } else {
+            todo!()
+        }
+    }
+}
+
 #[derive(Debug)]
 /// this type is used for transmitting data, the concern here is protection against transmission errors which most likely occur
 /// as burst errors effecting multiple bits, hemming codes would be a waist of space here so instead a 6 bit crc code is used
@@ -64,6 +88,24 @@ pub struct Stored_U26(u32);
 /// | 26 bits u26 value | 6 bits crc value |
 pub struct Transit_U26(u32);
 
+impl From<Transit_U26> for u32 {
+    fn from(value: Transit_U26) -> Self {
+        value.0 & U26_VALUE_MASK >> 6
+    }
+}
+
+impl TryFrom<u32> for Transit_U26 {
+    type Error = U26Error;
+
+    fn try_from(value: u32) -> Result<Self, Self::Error> {
+        if value > U26_MAX_VALUE {
+            Err(U26Error::Overflow)
+        } else {
+            todo!()
+        }
+    }
+}
+
 // only calc hemming code for the first 24 data bits including the 5 hemming bits
 //  pos  |     | p1  | p2  | p3  | p4  | p5  |
 // 00001 | p1  |  o  |     |     |     |     |
@@ -182,7 +224,6 @@ fn calc_hemming(data_bits: u32) -> u8 {
     0x00 | (p1 as u8) << 0 | (p2 as u8) << 1 | (p3 as u8) << 2 | (p4 as u8) << 3 | (p5 as u8) << 5
 }
 
-
 #[cfg(test)]
 mod base_type_tests {
     use super::calc_hemming;