105 lines
3.6 KiB
Rust
105 lines
3.6 KiB
Rust
//! Generic array are commonly used as a return value for hash digests, so
|
|
//! it's a good idea to allow to hexlify them easily. This module implements
|
|
//! `std::fmt::LowerHex` and `std::fmt::UpperHex` traits.
|
|
//!
|
|
//! Example:
|
|
//!
|
|
//! ```rust
|
|
//! # #[macro_use]
|
|
//! # extern crate generic_array;
|
|
//! # extern crate typenum;
|
|
//! # fn main() {
|
|
//! let array = arr![u8; 10, 20, 30];
|
|
//! assert_eq!(format!("{:x}", array), "0a141e");
|
|
//! # }
|
|
//! ```
|
|
//!
|
|
|
|
use core::{fmt, str, ops::Add, cmp::min};
|
|
|
|
use typenum::*;
|
|
|
|
use crate::{ArrayLength, GenericArray};
|
|
|
|
static LOWER_CHARS: &'static [u8] = b"0123456789abcdef";
|
|
static UPPER_CHARS: &'static [u8] = b"0123456789ABCDEF";
|
|
|
|
impl<T: ArrayLength<u8>> fmt::LowerHex for GenericArray<u8, T>
|
|
where
|
|
T: Add<T>,
|
|
<T as Add<T>>::Output: ArrayLength<u8>,
|
|
{
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
let max_digits = f.precision().unwrap_or_else(|| self.len() * 2);
|
|
let max_hex = (max_digits >> 1) + (max_digits & 1);
|
|
|
|
if T::USIZE < 1024 {
|
|
// For small arrays use a stack allocated
|
|
// buffer of 2x number of bytes
|
|
let mut res = GenericArray::<u8, Sum<T, T>>::default();
|
|
|
|
self.iter().take(max_hex).enumerate().for_each(|(i, c)| {
|
|
res[i * 2] = LOWER_CHARS[(c >> 4) as usize];
|
|
res[i * 2 + 1] = LOWER_CHARS[(c & 0xF) as usize];
|
|
});
|
|
|
|
f.write_str(unsafe { str::from_utf8_unchecked(&res[..max_digits]) })?;
|
|
} else {
|
|
// For large array use chunks of up to 1024 bytes (2048 hex chars)
|
|
let mut buf = [0u8; 2048];
|
|
let mut digits_left = max_digits;
|
|
|
|
for chunk in self[..max_hex].chunks(1024) {
|
|
chunk.iter().enumerate().for_each(|(i, c)| {
|
|
buf[i * 2] = LOWER_CHARS[(c >> 4) as usize];
|
|
buf[i * 2 + 1] = LOWER_CHARS[(c & 0xF) as usize];
|
|
});
|
|
|
|
let n = min(chunk.len() * 2, digits_left);
|
|
f.write_str(unsafe { str::from_utf8_unchecked(&buf[..n]) })?;
|
|
digits_left -= n;
|
|
}
|
|
}
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
impl<T: ArrayLength<u8>> fmt::UpperHex for GenericArray<u8, T>
|
|
where
|
|
T: Add<T>,
|
|
<T as Add<T>>::Output: ArrayLength<u8>,
|
|
{
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
let max_digits = f.precision().unwrap_or_else(|| self.len() * 2);
|
|
let max_hex = (max_digits >> 1) + (max_digits & 1);
|
|
|
|
if T::USIZE < 1024 {
|
|
// For small arrays use a stack allocated
|
|
// buffer of 2x number of bytes
|
|
let mut res = GenericArray::<u8, Sum<T, T>>::default();
|
|
|
|
self.iter().take(max_hex).enumerate().for_each(|(i, c)| {
|
|
res[i * 2] = UPPER_CHARS[(c >> 4) as usize];
|
|
res[i * 2 + 1] = UPPER_CHARS[(c & 0xF) as usize];
|
|
});
|
|
|
|
f.write_str(unsafe { str::from_utf8_unchecked(&res[..max_digits]) })?;
|
|
} else {
|
|
// For large array use chunks of up to 1024 bytes (2048 hex chars)
|
|
let mut buf = [0u8; 2048];
|
|
let mut digits_left = max_digits;
|
|
|
|
for chunk in self[..max_hex].chunks(1024) {
|
|
chunk.iter().enumerate().for_each(|(i, c)| {
|
|
buf[i * 2] = UPPER_CHARS[(c >> 4) as usize];
|
|
buf[i * 2 + 1] = UPPER_CHARS[(c & 0xF) as usize];
|
|
});
|
|
|
|
let n = min(chunk.len() * 2, digits_left);
|
|
f.write_str(unsafe { str::from_utf8_unchecked(&buf[..n]) })?;
|
|
digits_left -= n;
|
|
}
|
|
}
|
|
Ok(())
|
|
}
|
|
}
|