another byte positioning bug

Author: rudib

packed_struct_codegen/src/pack_parse_attributes.rs

@@ -162,11 +162,15 @@ pub fn parse_position_val(v: &str, multiplier: usize) -> BitsPositionParsed {
         if s.len() == 2 {
             let start = parse_num(s[0]);
             let end = parse_num(s[1]);
-            return BitsPositionParsed::Range(start * multiplier, end * multiplier);
+            if multiplier > 1 {
+                return BitsPositionParsed::Range(start * multiplier, ((end+1) * multiplier)-1);
+            } else {
+                return BitsPositionParsed::Range(start * multiplier, end * multiplier);
+            }
         }
     } else {
         let start = parse_num(v);
-        if multiplier > 1 {
+        if multiplier > 1 {            
             return BitsPositionParsed::Range(start * multiplier, ((start+1) * multiplier)-1);
         } else {
             return BitsPositionParsed::Range(start * multiplier, start * multiplier);

packed_struct_tests/tests/packing_bit_positioning.rs

@@ -61,3 +61,32 @@ fn test_packing_bit_positions_lsb() {
     let unpacked = SmallIntsLsb::unpack(&packed).unwrap();
     assert_eq!(a, unpacked);
 }
+
+
+
+#[test]
+fn test_packing_byte_position() {
+    #[derive(Copy, Clone, Debug, PartialEq, PackedStruct)]
+    #[packed_struct(bit_numbering="msb0", endian="msb")]
+    pub struct BufferChecksum {
+        #[packed_field(bytes="0")]
+        pub version: u8,
+        #[packed_field(bytes="1..4")]
+        pub size: u32,
+        #[packed_field(bytes="5..")]
+        pub checksum: u64
+    }
+
+    let b = BufferChecksum {
+        version: 101,
+        size: 52748273,
+        checksum: 869034217895
+    };
+    
+    let packed = b.pack();
+    assert_eq!(packed.len(), 13);
+
+    let unpacked = BufferChecksum::unpack(&packed).unwrap();
+
+    assert_eq!(b, unpacked);
+}