pub use self::FromHexError::*;
use std::fmt;
use std::error;
pub trait ToHex {
fn to_hex(&self) -> String;
}
const CHARS: &[u8] = b"0123456789abcdef";
impl ToHex for [u8] {
fn to_hex(&self) -> String {
let mut v = Vec::with_capacity(self.len() * 2);
for &byte in self {
v.push(CHARS[(byte >> 4) as usize]);
v.push(CHARS[(byte & 0xf) as usize]);
}
unsafe {
String::from_utf8_unchecked(v)
}
}
}
pub trait FromHex {
fn from_hex(&self) -> Result<Vec<u8>, FromHexError>;
}
#[derive(Copy, Clone, Debug)]
pub enum FromHexError {
InvalidHexCharacter(char, usize),
InvalidHexLength,
}
impl fmt::Display for FromHexError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
InvalidHexCharacter(ch, idx) =>
write!(f, "Invalid character '{}' at position {}", ch, idx),
InvalidHexLength => write!(f, "Invalid input length"),
}
}
}
impl error::Error for FromHexError {
fn description(&self) -> &str {
match *self {
InvalidHexCharacter(..) => "invalid character",
InvalidHexLength => "invalid length",
}
}
}
impl FromHex for str {
fn from_hex(&self) -> Result<Vec<u8>, FromHexError> {
let mut b = Vec::with_capacity(self.len() / 2);
let mut modulus = 0;
let mut buf = 0;
for (idx, byte) in self.bytes().enumerate() {
buf <<= 4;
match byte {
b'A'..=b'F' => buf |= byte - b'A' + 10,
b'a'..=b'f' => buf |= byte - b'a' + 10,
b'0'..=b'9' => buf |= byte - b'0',
b' '|b'\r'|b'\n'|b'\t' => {
buf >>= 4;
continue
}
_ => {
let ch = self[idx..].chars().next().unwrap();
return Err(InvalidHexCharacter(ch, idx))
}
}
modulus += 1;
if modulus == 2 {
modulus = 0;
b.push(buf);
}
}
match modulus {
0 => Ok(b),
_ => Err(InvalidHexLength),
}
}
}
#[cfg(test)]
mod tests {
extern crate test;
use self::test::Bencher;
use hex::{FromHex, ToHex};
#[test]
pub fn test_to_hex() {
assert_eq!("foobar".as_bytes().to_hex(), "666f6f626172");
}
#[test]
pub fn test_from_hex_okay() {
assert_eq!("666f6f626172".from_hex().unwrap(),
b"foobar");
assert_eq!("666F6F626172".from_hex().unwrap(),
b"foobar");
}
#[test]
pub fn test_from_hex_odd_len() {
assert!("666".from_hex().is_err());
assert!("66 6".from_hex().is_err());
}
#[test]
pub fn test_from_hex_invalid_char() {
assert!("66y6".from_hex().is_err());
}
#[test]
pub fn test_from_hex_ignores_whitespace() {
assert_eq!("666f 6f6\r\n26172 ".from_hex().unwrap(),
b"foobar");
}
#[test]
pub fn test_to_hex_all_bytes() {
for i in 0..256 {
assert_eq!([i as u8].to_hex(), format!("{:02x}", i as usize));
}
}
#[test]
pub fn test_from_hex_all_bytes() {
for i in 0..256 {
let ii: &[u8] = &[i as u8];
assert_eq!(format!("{:02x}", i as usize).from_hex()
.unwrap(),
ii);
assert_eq!(format!("{:02X}", i as usize).from_hex()
.unwrap(),
ii);
}
}
#[bench]
pub fn bench_to_hex(b: &mut Bencher) {
let s = "イロハニホヘト チリヌルヲ ワカヨタレソ ツネナラム \
ウヰノオクヤマ ケフコエテ アサキユメミシ ヱヒモセスン";
b.iter(|| {
s.as_bytes().to_hex();
});
b.bytes = s.len() as u64;
}
#[bench]
pub fn bench_from_hex(b: &mut Bencher) {
let s = "イロハニホヘト チリヌルヲ ワカヨタレソ ツネナラム \
ウヰノオクヤマ ケフコエテ アサキユメミシ ヱヒモセスン";
let sb = s.as_bytes().to_hex();
b.iter(|| {
sb.from_hex().unwrap();
});
b.bytes = sb.len() as u64;
}
}