Line data    Source code

       1              : /// Useful type for asserting that expected bytes match reporting the bytes more readable
       2              : /// array-syntax compatible hex bytes.
       3              : ///
       4              : /// # Usage
       5              : ///
       6              : /// ```
       7              : /// use utils::Hex;
       8              : ///
       9              : /// let actual = serialize_something();
      10              : /// let expected = [0x68, 0x65, 0x6c, 0x6c, 0x6f, 0x20, 0x77, 0x6f, 0x72, 0x6c, 0x64];
      11              : ///
      12              : /// // the type implements PartialEq and on mismatch, both sides are printed in 16 wide multiline
      13              : /// // output suffixed with an array style length for easier comparisons.
      14              : /// assert_eq!(Hex(&actual), Hex(&expected));
      15              : ///
      16              : /// // with `let expected = [0x68];` the error would had been:
      17              : /// // assertion `left == right` failed
      18              : /// //  left: [0x68, 0x65, 0x6c, 0x6c, 0x6f, 0x20, 0x77, 0x6f, 0x72, 0x6c, 0x64; 11]
      19              : /// // right: [0x68; 1]
      20              : /// # fn serialize_something() -> Vec<u8> { "hello world".as_bytes().to_vec() }
      21              : /// ```
      22           20 : #[derive(PartialEq)]
      23              : pub struct Hex<'a>(pub &'a [u8]);
      24              : 
      25              : impl std::fmt::Debug for Hex<'_> {
      26            0 :     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
      27            0 :         write!(f, "[")?;
      28            0 :         for (i, c) in self.0.chunks(16).enumerate() {
      29            0 :             if i > 0 && !c.is_empty() {
      30            0 :                 writeln!(f, ", ")?;
      31            0 :             }
      32            0 :             for (j, b) in c.iter().enumerate() {
      33            0 :                 if j > 0 {
      34            0 :                     write!(f, ", ")?;
      35            0 :                 }
      36            0 :                 write!(f, "0x{b:02x}")?;
      37              :             }
      38              :         }
      39            0 :         write!(f, "; {}]", self.0.len())
      40            0 :     }
      41              : }