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//! 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(())↩
}↩
}↩