#![cfg_attr(feature = "benchmarks", feature(test))]
use std::error;
use std::fmt;
pub trait ToHex {
fn write_hex<W: fmt::Write>(&self, w: &mut W) -> fmt::Result;
fn write_hex_upper<W: fmt::Write>(&self, w: &mut W) -> fmt::Result;
}
fn hex_write<W: fmt::Write>(table: &[u8; 16], src: &[u8], w: &mut W) -> fmt::Result {
let hex = |byte: u8| table[byte as usize];
for &b in src.iter() {
w.write_char(hex((b >> 4) & 0xf) as char)?;
w.write_char(hex(b & 0xf) as char)?;
}
Ok(())
}
impl<T: AsRef<[u8]>> ToHex for T {
fn write_hex<W: fmt::Write>(&self, w: &mut W) -> fmt::Result {
static CHARS: &'static [u8; 16] = b"0123456789abcdef";
hex_write(&CHARS, self.as_ref(), w)
}
fn write_hex_upper<W: fmt::Write>(&self, w: &mut W) -> fmt::Result {
static CHARS: &'static [u8; 16] = b"0123456789ABCDEF";
hex_write(&CHARS, self.as_ref(), w)
}
}
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum FromHexError {
InvalidHexCharacter {
c: char,
index: usize,
},
OddLength,
InvalidStringLength,
}
impl error::Error for FromHexError {
fn description(&self) -> &str {
match *self {
FromHexError::InvalidHexCharacter { .. } => "invalid character",
FromHexError::OddLength => "odd number of digits",
FromHexError::InvalidStringLength => "invalid string length",
}
}
}
impl fmt::Display for FromHexError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
FromHexError::InvalidHexCharacter { c, index } =>
write!(f, "Invalid character '{}' at position {}", c, index),
FromHexError::OddLength =>
write!(f, "Odd number of digits"),
FromHexError::InvalidStringLength =>
write!(f, "Invalid string length"),
}
}
}
pub trait FromHex: Sized {
type Error;
fn from_hex<T: AsRef<[u8]>>(hex: T) -> Result<Self, Self::Error>;
}
fn val(c: u8, idx: usize) -> Result<u8, FromHexError> {
match c {
b'A'...b'F' => Ok(c - b'A' + 10),
b'a'...b'f' => Ok(c - b'a' + 10),
b'0'...b'9' => Ok(c - b'0'),
_ => {
Err(FromHexError::InvalidHexCharacter {
c: c as char,
index: idx,
})
}
}
}
impl FromHex for Vec<u8> {
type Error = FromHexError;
fn from_hex<T: AsRef<[u8]>>(hex: T) -> Result<Self, Self::Error> {
let hex = hex.as_ref();
if hex.len() % 2 != 0 {
return Err(FromHexError::OddLength);
}
hex.chunks(2).enumerate().map(|(i, pair)| {
Ok(val(pair[0], 2 * i)? << 4 | val(pair[1], 2 * i + 1)?)
}).collect()
}
}
macro_rules! from_hex_array_impl {
($($len:expr)+) => {$(
impl FromHex for [u8; $len] {
type Error = FromHexError;
fn from_hex<T: AsRef<[u8]>>(hex: T) -> Result<Self, Self::Error> {
let hex = hex.as_ref();
if hex.len() % 2 != 0 {
return Err(FromHexError::OddLength);
}
if hex.len() / 2 != $len {
return Err(FromHexError::InvalidStringLength);
}
let mut out = [0; $len];
for (i, byte) in out.iter_mut().enumerate() {
*byte = val(hex[2 * i], 2 * i)? << 4
| val(hex[2 * i + 1], 2 * i + 1)?;
}
Ok(out)
}
}
)+}
}
from_hex_array_impl! {
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48
49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64
65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80
81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96
97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112
113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128
160 192 200 224 256 384 512 768 1024 2048 4096 8192 16384 32768
}
#[cfg(any(target_pointer_width = "32", target_pointer_width = "64"))]
from_hex_array_impl! {
65536 131072 262144 524288 1048576 2097152 4194304 8388608
16777216 33554432 67108864 134217728 268435456 536870912
1073741824 2147483648
}
#[cfg(target_pointer_width = "64")]
from_hex_array_impl! {
4294967296
}
pub fn encode<T: AsRef<[u8]>>(data: T) -> String {
let mut s = String::with_capacity(data.as_ref().len() * 2);
data.write_hex(&mut s).unwrap();
s
}
pub fn encode_upper<T: AsRef<[u8]>>(data: T) -> String {
let mut s = String::with_capacity(data.as_ref().len() * 2);
data.write_hex_upper(&mut s).unwrap();
s
}
pub fn decode<T: AsRef<[u8]>>(data: T) -> Result<Vec<u8>, FromHexError> {
FromHex::from_hex(data)
}
#[cfg(test)]
mod test {
use super::{encode, decode, FromHex, FromHexError};
#[test]
fn test_encode() {
assert_eq!(encode("foobar"), "666f6f626172");
}
#[test]
fn test_decode() {
assert_eq!(decode("666f6f626172"), Ok("foobar".to_owned().into_bytes()));
}
#[test]
pub fn test_from_hex_okay_str() {
assert_eq!(
Vec::from_hex("666f6f626172").unwrap(),
b"foobar"
);
assert_eq!(
Vec::from_hex("666F6F626172").unwrap(),
b"foobar"
);
}
#[test]
pub fn test_from_hex_okay_bytes() {
assert_eq!(
Vec::from_hex(b"666f6f626172").unwrap(),
b"foobar"
);
assert_eq!(
Vec::from_hex(b"666F6F626172").unwrap(),
b"foobar"
);
}
#[test]
pub fn test_invalid_length() {
assert_eq!(
Vec::from_hex("1").unwrap_err(),
FromHexError::OddLength
);
assert_eq!(
Vec::from_hex("666f6f6261721").unwrap_err(),
FromHexError::OddLength
);
}
#[test]
pub fn test_invalid_char() {
assert_eq!(
Vec::from_hex("66ag").unwrap_err(),
FromHexError::InvalidHexCharacter {
c: 'g',
index: 3
}
);
}
#[test]
pub fn test_empty() {
assert_eq!(Vec::from_hex("").unwrap(), b"");
}
#[test]
pub fn test_from_hex_whitespace() {
assert_eq!(
Vec::from_hex("666f 6f62617").unwrap_err(),
FromHexError::InvalidHexCharacter {
c: ' ',
index: 4
}
);
}
#[test]
pub fn test_from_hex_array() {
assert_eq!(
<[u8; 6] as FromHex>::from_hex("666f6f626172"),
Ok([0x66, 0x6f, 0x6f, 0x62, 0x61, 0x72])
);
assert_eq!(
<[u8; 5] as FromHex>::from_hex("666f6f626172"),
Err(FromHexError::InvalidStringLength)
);
}
}
#[cfg(all(feature = "benchmarks", test))]
mod bench {
extern crate test;
use self::test::Bencher;
use super::*;
const MY_OWN_SOURCE: &[u8] = include_bytes!("lib.rs");
#[bench]
fn a_bench(b: &mut Bencher) {
b.bytes = MY_OWN_SOURCE.len() as u64;
b.iter(|| {
encode(MY_OWN_SOURCE)
});
}
}