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use std::fmt::Write;
use std::num;
pub fn to_hex(bytes: &[u8]) -> String {
let mut s = String::new();
for byte in bytes {
write!(&mut s, "{:02x}", byte).expect("Unable to write");
}
s
}
pub fn from_hex(hex_str: String) -> Result<Vec<u8>, num::ParseIntError> {
if hex_str.len() % 2 == 1 {
let err = ("QQQ").parse::<u64>();
if let Err(e) = err {
return Err(e);
}
}
let hex_trim = if &hex_str[..2] == "0x" {
hex_str[2..].to_owned()
} else {
hex_str.clone()
};
split_n(&hex_trim.trim()[..], 2)
.iter()
.map(|b| u8::from_str_radix(b, 16))
.collect::<Result<Vec<u8>, _>>()
}
fn split_n(s: &str, n: usize) -> Vec<&str> {
(0..(s.len() - n + 1) / 2 + 1)
.map(|i| &s[2 * i..2 * i + n])
.collect()
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_to_hex() {
assert_eq!(to_hex(&[0, 0, 0, 0]), "00000000");
assert_eq!(to_hex(&[10, 11, 12, 13]), "0a0b0c0d");
assert_eq!(to_hex(&[0, 0, 0, 255]), "000000ff");
}
#[test]
fn test_from_hex() {
assert_eq!(from_hex("00000000".to_string()).unwrap(), &[0, 0, 0, 0]);
assert_eq!(
from_hex("0a0b0c0d".to_string()).unwrap(),
vec![10, 11, 12, 13]
);
assert_eq!(
from_hex("000000ff".to_string()).unwrap(),
vec![0, 0, 0, 255]
);
}
}