grin/util/src/hex.rs
Yeastplume 8440aad7ea
Retrieve header by output commit (#1388)
* Add get_header_for_output function to chain

* add api call to retrieve associated header for a given output

* rustfmt
2018-08-20 19:02:44 +01:00

80 lines
2.2 KiB
Rust

// Copyright 2018 The Grin Developers
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/// Implements hex-encoding from bytes to string and decoding of strings
/// to bytes. Given that rustc-serialize is deprecated and serde doesn't
/// provide easy hex encoding, hex is a bit in limbo right now in Rust-
/// land. It's simple enough that we can just have our own.
use std::fmt::Write;
use std::num;
/// Encode the provided bytes into a hex string
pub fn to_hex(bytes: Vec<u8>) -> String {
let mut s = String::new();
for byte in bytes {
write!(&mut s, "{:02x}", byte).expect("Unable to write");
}
s
}
/// Decode a hex string into bytes.
pub fn from_hex(hex_str: String) -> Result<Vec<u8>, num::ParseIntError> {
if hex_str.len() % 2 == 1 {
// TODO: other way to instantiate a ParseIntError?
let err = ("QQQ").parse::<u64>();
if let Err(e) = err {
return Err(e);
}
}
let hex_trim = if &hex_str[..2] == "0x" {
hex_str[2..].to_owned()
} else {
hex_str.clone()
};
split_n(&hex_trim.trim()[..], 2)
.iter()
.map(|b| u8::from_str_radix(b, 16))
.collect::<Result<Vec<u8>, _>>()
}
fn split_n(s: &str, n: usize) -> Vec<&str> {
(0..(s.len() - n + 1) / 2 + 1)
.map(|i| &s[2 * i..2 * i + n])
.collect()
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_to_hex() {
assert_eq!(to_hex(vec![0, 0, 0, 0]), "00000000");
assert_eq!(to_hex(vec![10, 11, 12, 13]), "0a0b0c0d");
assert_eq!(to_hex(vec![0, 0, 0, 255]), "000000ff");
}
#[test]
fn test_from_hex() {
assert_eq!(from_hex("00000000".to_string()).unwrap(), vec![0, 0, 0, 0]);
assert_eq!(
from_hex("0a0b0c0d".to_string()).unwrap(),
vec![10, 11, 12, 13]
);
assert_eq!(
from_hex("000000ff".to_string()).unwrap(),
vec![0, 0, 0, 255]
);
}
}