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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157
use std::error; use std::fmt; pub trait ToHex { fn to_hex(&self) -> String; fn write_hex<W: fmt::Write>(&self, w: &mut W) -> fmt::Result { w.write_str(&self.to_hex()) } } impl<T: AsRef<[u8]>> ToHex for T { fn to_hex(&self) -> String { static CHARS: &'static [u8] = b"0123456789abcdef"; let bytes = self.as_ref(); let mut v = Vec::with_capacity(bytes.len() * 2); for &byte in bytes.iter() { v.push(CHARS[(byte >> 4) as usize]); v.push(CHARS[(byte & 0xf) as usize]); } unsafe { String::from_utf8_unchecked(v) } } } #[derive(Debug, Clone, Copy, PartialEq)] pub enum FromHexError { InvalidHexCharacter { c: char, index: usize, }, InvalidHexLength, } impl error::Error for FromHexError { fn description(&self) -> &str { match *self { FromHexError::InvalidHexCharacter{ .. } => "invalid character", FromHexError::InvalidHexLength => "invalid 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::InvalidHexLength => write!(f, "Invalid string length"), } } } pub trait FromHex: Sized { type Error; fn from_hex<T: AsRef<[u8]>>(s: T) -> Result<Self, Self::Error>; } impl FromHex for Vec<u8> { type Error = FromHexError; fn from_hex<T: AsRef<[u8]>>(s: T) -> Result<Self, Self::Error> { let bytes = s.as_ref(); let mut b = Vec::with_capacity(bytes.len() / 2); let mut modulus = 0; let mut buf = 08; for (idx, byte) in bytes.iter().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', _ => { return Err(FromHexError::InvalidHexCharacter { c: bytes[idx] as char, index: idx, }) } } modulus += 1; if modulus == 2 { modulus = 0; b.push(buf); } } match modulus { 0 => Ok(b.into_iter().collect()), _ => Err(FromHexError::InvalidHexLength), } } } #[cfg(test)] mod test { use super::{FromHex, FromHexError, ToHex}; #[test] fn test_to_hex() { assert_eq!("foobar".to_hex(), "666f6f626172"); } #[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::InvalidHexLength); assert_eq!(Vec::from_hex("666f6f6261721").unwrap_err(), FromHexError::InvalidHexLength); } #[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 6f626172").unwrap_err(), FromHexError::InvalidHexCharacter { c: ' ', index: 4 }); } }