229 lines
6.5 KiB
Rust
229 lines
6.5 KiB
Rust
// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//
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// ignore-lexer-test FIXME #15679
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//! Hex binary-to-text encoding
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pub use self::FromHexError::*;
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use std::fmt;
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use std::error;
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/// A trait for converting a value to hexadecimal encoding
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pub trait ToHex {
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/// Converts the value of `self` to a hex value, returning the owned
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/// string.
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fn to_hex(&self) -> String;
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}
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const CHARS: &'static [u8] = b"0123456789abcdef";
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impl ToHex for [u8] {
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/// Turn a vector of `u8` bytes into a hexadecimal string.
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///
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/// # Examples
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///
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/// ```
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/// # #![feature(rustc_private)]
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/// extern crate serialize;
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/// use serialize::hex::ToHex;
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///
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/// fn main () {
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/// let str = [52,32].to_hex();
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/// println!("{}", str);
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/// }
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/// ```
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fn to_hex(&self) -> String {
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let mut v = Vec::with_capacity(self.len() * 2);
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for &byte in self {
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v.push(CHARS[(byte >> 4) as usize]);
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v.push(CHARS[(byte & 0xf) as usize]);
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}
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unsafe {
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String::from_utf8_unchecked(v)
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}
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}
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}
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/// A trait for converting hexadecimal encoded values
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pub trait FromHex {
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/// Converts the value of `self`, interpreted as hexadecimal encoded data,
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/// into an owned vector of bytes, returning the vector.
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fn from_hex(&self) -> Result<Vec<u8>, FromHexError>;
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}
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/// Errors that can occur when decoding a hex encoded string
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#[derive(Copy, Debug)]
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pub enum FromHexError {
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/// The input contained a character not part of the hex format
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InvalidHexCharacter(char, usize),
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/// The input had an invalid length
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InvalidHexLength,
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}
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impl fmt::Display for FromHexError {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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match *self {
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InvalidHexCharacter(ch, idx) =>
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write!(f, "Invalid character '{}' at position {}", ch, idx),
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InvalidHexLength => write!(f, "Invalid input length"),
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}
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}
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}
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impl error::Error for FromHexError {
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fn description(&self) -> &str {
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match *self {
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InvalidHexCharacter(_, _) => "invalid character",
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InvalidHexLength => "invalid length",
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}
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}
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}
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impl FromHex for str {
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/// Convert any hexadecimal encoded string (literal, `@`, `&`, or `~`)
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/// to the byte values it encodes.
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///
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/// You can use the `String::from_utf8` function to turn a
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/// `Vec<u8>` into a string with characters corresponding to those values.
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///
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/// # Examples
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///
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/// This converts a string literal to hexadecimal and back.
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///
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/// ```
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/// # #![feature(rustc_private)]
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/// extern crate serialize;
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/// use serialize::hex::{FromHex, ToHex};
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///
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/// fn main () {
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/// let hello_str = "Hello, World".as_bytes().to_hex();
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/// println!("{}", hello_str);
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/// let bytes = hello_str.from_hex().unwrap();
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/// println!("{:?}", bytes);
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/// let result_str = String::from_utf8(bytes).unwrap();
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/// println!("{}", result_str);
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/// }
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/// ```
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fn from_hex(&self) -> Result<Vec<u8>, FromHexError> {
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// This may be an overestimate if there is any whitespace
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let mut b = Vec::with_capacity(self.len() / 2);
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let mut modulus = 0;
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let mut buf = 0;
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for (idx, byte) in self.bytes().enumerate() {
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buf <<= 4;
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match byte {
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b'A'...b'F' => buf |= byte - b'A' + 10,
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b'a'...b'f' => buf |= byte - b'a' + 10,
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b'0'...b'9' => buf |= byte - b'0',
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b' '|b'\r'|b'\n'|b'\t' => {
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buf >>= 4;
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continue
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}
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_ => return Err(InvalidHexCharacter(self.char_at(idx), idx)),
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}
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modulus += 1;
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if modulus == 2 {
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modulus = 0;
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b.push(buf);
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}
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}
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match modulus {
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0 => Ok(b.into_iter().collect()),
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_ => Err(InvalidHexLength),
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}
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}
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}
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#[cfg(test)]
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mod tests {
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extern crate test;
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use self::test::Bencher;
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use hex::{FromHex, ToHex};
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#[test]
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pub fn test_to_hex() {
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assert_eq!("foobar".as_bytes().to_hex(), "666f6f626172");
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}
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#[test]
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pub fn test_from_hex_okay() {
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assert_eq!("666f6f626172".from_hex().unwrap(),
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b"foobar");
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assert_eq!("666F6F626172".from_hex().unwrap(),
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b"foobar");
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}
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#[test]
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pub fn test_from_hex_odd_len() {
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assert!("666".from_hex().is_err());
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assert!("66 6".from_hex().is_err());
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}
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#[test]
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pub fn test_from_hex_invalid_char() {
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assert!("66y6".from_hex().is_err());
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}
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#[test]
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pub fn test_from_hex_ignores_whitespace() {
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assert_eq!("666f 6f6\r\n26172 ".from_hex().unwrap(),
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b"foobar");
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}
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#[test]
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pub fn test_to_hex_all_bytes() {
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for i in 0..256 {
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assert_eq!([i as u8].to_hex(), format!("{:02x}", i as usize));
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}
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}
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#[test]
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pub fn test_from_hex_all_bytes() {
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for i in 0..256 {
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let ii: &[u8] = &[i as u8];
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assert_eq!(format!("{:02x}", i as usize).from_hex()
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.unwrap(),
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ii);
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assert_eq!(format!("{:02X}", i as usize).from_hex()
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.unwrap(),
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ii);
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}
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}
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#[bench]
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pub fn bench_to_hex(b: &mut Bencher) {
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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 \
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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";
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b.iter(|| {
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s.as_bytes().to_hex();
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});
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b.bytes = s.len() as u64;
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}
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#[bench]
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pub fn bench_from_hex(b: &mut Bencher) {
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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 \
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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";
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let sb = s.as_bytes().to_hex();
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b.iter(|| {
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sb.from_hex().unwrap();
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});
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b.bytes = sb.len() as u64;
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}
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}
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