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Diffstat (limited to 'src/libserialize/hex.rs')
| -rw-r--r-- | src/libserialize/hex.rs | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/src/libserialize/hex.rs b/src/libserialize/hex.rs new file mode 100644 index 00000000000..409bf4af809 --- /dev/null +++ b/src/libserialize/hex.rs @@ -0,0 +1,210 @@ +// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +//! Hex binary-to-text encoding +use std::str; +use std::vec; + +/// 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) -> ~str; +} + +static CHARS: &'static[u8] = bytes!("0123456789abcdef"); + +impl<'a> ToHex for &'a [u8] { + /** + * Turn a vector of `u8` bytes into a hexadecimal string. + * + * # Example + * + * ```rust + * extern mod serialize; + * use serialize::hex::ToHex; + * + * fn main () { + * let str = [52,32].to_hex(); + * println!("{}", str); + * } + * ``` + */ + fn to_hex(&self) -> ~str { + let mut v = vec::with_capacity(self.len() * 2); + for &byte in self.iter() { + v.push(CHARS[byte >> 4]); + v.push(CHARS[byte & 0xf]); + } + + unsafe { + str::raw::from_utf8_owned(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<~[u8], FromHexError>; +} + +/// Errors that can occur when decoding a hex encoded string +pub enum FromHexError { + /// The input contained a character not part of the hex format + InvalidHexCharacter(char, uint), + /// The input had an invalid length + InvalidHexLength, +} + +impl ToStr for FromHexError { + fn to_str(&self) -> ~str { + match *self { + InvalidHexCharacter(ch, idx) => + format!("Invalid character '{}' at position {}", ch, idx), + InvalidHexLength => ~"Invalid input length", + } + } +} + +impl<'a> FromHex for &'a str { + /** + * Convert any hexadecimal encoded string (literal, `@`, `&`, or `~`) + * to the byte values it encodes. + * + * You can use the `from_utf8_owned` function in `std::str` + * to turn a `[u8]` into a string with characters corresponding to those + * values. + * + * # Example + * + * This converts a string literal to hexadecimal and back. + * + * ```rust + * extern mod serialize; + * use serialize::hex::{FromHex, ToHex}; + * use std::str; + * + * 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 = str::from_utf8_owned(bytes).unwrap(); + * println!("{}", result_str); + * } + * ``` + */ + fn from_hex(&self) -> Result<~[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 = 0u8; + + for (idx, byte) in self.bytes().enumerate() { + buf <<= 4; + + match byte as char { + 'A'..'F' => buf |= byte - ('A' as u8) + 10, + 'a'..'f' => buf |= byte - ('a' as u8) + 10, + '0'..'9' => buf |= byte - ('0' as u8), + ' '|'\r'|'\n'|'\t' => { + buf >>= 4; + continue + } + _ => return Err(InvalidHexCharacter(self.char_at(idx), idx)), + } + + modulus += 1; + if modulus == 2 { + modulus = 0; + b.push(buf); + } + } + + match modulus { + 0 => Ok(b), + _ => Err(InvalidHexLength), + } + } +} + +#[cfg(test)] +mod tests { + use extra::test::BenchHarness; + 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(), + "foobar".as_bytes().to_owned()); + assert_eq!("666F6F626172".from_hex().unwrap(), + "foobar".as_bytes().to_owned()); + } + + #[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(), + "foobar".as_bytes().to_owned()); + } + + #[test] + pub fn test_to_hex_all_bytes() { + for i in range(0, 256) { + assert_eq!([i as u8].to_hex(), format!("{:02x}", i as uint)); + } + } + + #[test] + pub fn test_from_hex_all_bytes() { + for i in range(0, 256) { + assert_eq!(format!("{:02x}", i as uint).from_hex().unwrap(), ~[i as u8]); + assert_eq!(format!("{:02X}", i as uint).from_hex().unwrap(), ~[i as u8]); + } + } + + #[bench] + pub fn bench_to_hex(bh: & mut BenchHarness) { + 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"; + bh.iter(|| { + s.as_bytes().to_hex(); + }); + bh.bytes = s.len() as u64; + } + + #[bench] + pub fn bench_from_hex(bh: & mut BenchHarness) { + 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 b = s.as_bytes().to_hex(); + bh.iter(|| { + b.from_hex().unwrap(); + }); + bh.bytes = b.len() as u64; + } +} |