pico_common/
utils.rs

1use std::{ffi::CString, str};
2
3/// Pico drivers require strings as *mut i8. This converts from Rust
4/// to Pico string format
5pub trait ToPicoStr {
6    /// Converts Rust strings to Pico null terminated Vec<i8> format
7    fn into_pico_i8_string(self) -> Vec<i8>;
8}
9
10impl<'a> ToPicoStr for &'a str {
11    fn into_pico_i8_string(self) -> Vec<i8> {
12        CString::new(self)
13            .expect("invalid CString")
14            .into_bytes_with_nul()
15            .iter()
16            .map(|&x| x as i8)
17            .collect()
18    }
19}
20
21/// Pico drivers return strings as *i8. This converts from Pico to Rust string
22/// formats
23pub trait FromPicoStr {
24    /// Converts from Pico null terminated Vec<i8> string format to Rust Strings
25    #[allow(clippy::wrong_self_convention)]
26    fn from_pico_i8_string(self, buf_len: usize) -> String;
27}
28
29impl FromPicoStr for &[i8] {
30    fn from_pico_i8_string(self, buf_len: usize) -> String {
31        let serial_vec: Vec<u8> = self[..(buf_len - 1)].iter().map(|&x| x as u8).collect();
32
33        str::from_utf8(&serial_vec)
34            .expect("invalid utf8 string")
35            // This should not be required but older versions of the 5000a
36            // driver return the wrong buf_len for the driver version string.
37            // This trims the extra nulls that we get in the buffer
38            .trim_matches(char::from(0))
39            .to_string()
40    }
41}
42
43#[cfg(test)]
44mod tests {
45    use super::*;
46
47    #[test]
48    fn pico_strings() {
49        let s1 = "something here";
50        let ps = s1.into_pico_i8_string();
51
52        assert_eq!(
53            ps,
54            vec![115, 111, 109, 101, 116, 104, 105, 110, 103, 32, 104, 101, 114, 101, 0]
55        );
56
57        let s2 = ps.from_pico_i8_string(ps.len());
58        assert_eq!(s1, s2)
59    }
60
61    #[test]
62    fn pico_strings_ps5000a_bug() {
63        let s1 = "something here";
64        // Add a load of nulls on the end
65        let ps = [s1.into_pico_i8_string(), vec![0; 200]].concat();
66        let s2 = ps.from_pico_i8_string(ps.len());
67        assert_eq!(s1, s2)
68    }
69}
pico_common/utils.rs

pico_common/
utils.rs
