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#![cfg_attr(not(feature = "std"), no_std)]
#![cfg_attr(not(feature = "std"), feature(alloc))]
#[cfg(not(feature = "std"))]
extern crate alloc;
#[cfg(feature = "std")]
use std::fmt::Write;
#[cfg(not(feature = "std"))]
use core::fmt::Write;
#[cfg(not(feature = "std"))]
use alloc::{String, Vec};
#[cfg(not(feature = "std"))]
use alloc::string::ToString;
#[derive(Debug)]
pub enum ParseHexError {
InvalidCharacter,
TooLong,
TooShort,
Other
}
pub fn clean_0x(s: &str) -> &str {
if s.starts_with("0x") {
&s[2..]
} else {
s
}
}
pub fn read_hex(s: &str) -> Result<Vec<u8>, ParseHexError> {
if s.starts_with("0x") {
return read_hex(&s[2..s.len()]);
}
if s.len() & 1 == 1 {
let mut new_s = "0".to_string();
new_s.push_str(s);
return read_hex(&new_s);
}
let mut res = Vec::<u8>::new();
let mut cur = 0;
let mut len = 0;
for c in s.chars() {
len += 1;
let v_option = c.to_digit(16);
if v_option.is_none() {
return Err(ParseHexError::InvalidCharacter);
}
let v = v_option.unwrap();
if len == 1 {
cur += v * 16;
} else {
cur += v;
}
if len == 2 {
res.push(cur as u8);
cur = 0;
len = 0;
}
}
return Ok(res);
}
pub fn to_hex(a: &[u8]) -> String {
let mut s = String::new();
write!(s, "0x").unwrap();
for v in a {
write!(s, "{:02x}", *v).unwrap();
}
s
}
#[cfg(test)]
mod tests {
use super::read_hex;
#[test]
fn read_hex_zero() {
assert_eq!(read_hex("0x0").unwrap(), vec![0u8]);
assert_eq!(read_hex("0").unwrap(), vec![0u8]);
}
}