146 lines
4 KiB
Rust
146 lines
4 KiB
Rust
//! Hex binary-to-text encoding
|
|
|
|
pub use self::FromHexError::*;
|
|
|
|
use std::fmt;
|
|
use std::error;
|
|
|
|
/// A trait for converting a value to hexadecimal encoding
|
|
pub trait ToHex {
|
|
/// Converts the value of `self` to a hex value, returning the owned
|
|
/// string.
|
|
fn to_hex(&self) -> String;
|
|
}
|
|
|
|
const CHARS: &[u8] = b"0123456789abcdef";
|
|
|
|
impl ToHex for [u8] {
|
|
/// Turn a vector of `u8` bytes into a hexadecimal string.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(rustc_private)]
|
|
///
|
|
/// extern crate serialize;
|
|
/// use serialize::hex::ToHex;
|
|
///
|
|
/// fn main () {
|
|
/// let str = [52,32].to_hex();
|
|
/// println!("{}", str);
|
|
/// }
|
|
/// ```
|
|
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)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// A trait for converting hexadecimal encoded values
|
|
pub trait FromHex {
|
|
/// Converts the value of `self`, interpreted as hexadecimal encoded data,
|
|
/// into an owned vector of bytes, returning the vector.
|
|
fn from_hex(&self) -> Result<Vec<u8>, FromHexError>;
|
|
}
|
|
|
|
/// Errors that can occur when decoding a hex encoded string
|
|
#[derive(Copy, Clone, Debug)]
|
|
pub enum FromHexError {
|
|
/// The input contained a character not part of the hex format
|
|
InvalidHexCharacter(char, usize),
|
|
/// The input had an invalid length
|
|
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 {
|
|
/// Converts any hexadecimal encoded string (literal, `@`, `&`, or `~`)
|
|
/// to the byte values it encodes.
|
|
///
|
|
/// You can use the `String::from_utf8` function to turn a
|
|
/// `Vec<u8>` into a string with characters corresponding to those values.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// This converts a string literal to hexadecimal and back.
|
|
///
|
|
/// ```
|
|
/// #![feature(rustc_private)]
|
|
///
|
|
/// extern crate serialize;
|
|
/// use serialize::hex::{FromHex, ToHex};
|
|
///
|
|
/// fn main () {
|
|
/// let hello_str = "Hello, World".as_bytes().to_hex();
|
|
/// println!("{}", hello_str);
|
|
/// let bytes = hello_str.from_hex().unwrap();
|
|
/// println!("{:?}", bytes);
|
|
/// let result_str = String::from_utf8(bytes).unwrap();
|
|
/// println!("{}", result_str);
|
|
/// }
|
|
/// ```
|
|
fn from_hex(&self) -> Result<Vec<u8>, FromHexError> {
|
|
// This may be an overestimate if there is any whitespace
|
|
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;
|