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chacha20stream/src/ext.rs

125 lines
2.5 KiB

use std::{
mem,
iter::{
self,
ExactSizeIterator,
FusedIterator,
},
slice,
fmt,
};
#[derive(Debug, Clone)]
pub struct HexStringIter<I>(I, [u8; 2]);
impl<I: Iterator<Item = u8>> HexStringIter<I>
{
/// Write this hex string iterator to a formattable buffer
pub fn consume<F>(self, f: &mut F) -> fmt::Result
where F: std::fmt::Write
{
if self.1[0] != 0 {
write!(f, "{}", self.1[0] as char)?;
}
if self.1[1] != 0 {
write!(f, "{}", self.1[1] as char)?;
}
for x in self.0 {
write!(f, "{:02x}", x)?;
}
Ok(())
}
/// Consume into a string
pub fn into_string(self) -> String
{
let mut output = match self.size_hint() {
(0, None) => String::new(),
(_, Some(x)) |
(x, None) => String::with_capacity(x),
};
self.consume(&mut output).unwrap();
output
}
}
pub trait HexStringIterExt<I>: Sized
{
fn into_hex(self) -> HexStringIter<I>;
}
pub type HexStringSliceIter<'a> = HexStringIter<iter::Copied<slice::Iter<'a, u8>>>;
pub trait HexStringSliceIterExt
{
fn hex(&self) -> HexStringSliceIter<'_>;
}
impl<S> HexStringSliceIterExt for S
where S: AsRef<[u8]>
{
fn hex(&self) -> HexStringSliceIter<'_>
{
self.as_ref().iter().copied().into_hex()
}
}
impl<I: IntoIterator<Item=u8>> HexStringIterExt<I::IntoIter> for I
{
#[inline] fn into_hex(self) -> HexStringIter<I::IntoIter> {
HexStringIter(self.into_iter(), [0u8; 2])
}
}
impl<I: Iterator<Item = u8>> Iterator for HexStringIter<I>
{
type Item = char;
fn next(&mut self) -> Option<Self::Item>
{
match self.1 {
[_, 0] => {
use std::io::Write;
write!(&mut self.1[..], "{:02x}", self.0.next()?).unwrap();
Some(mem::replace(&mut self.1[0], 0) as char)
},
[0, _] => Some(mem::replace(&mut self.1[1], 0) as char),
_ => unreachable!(),
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
let (l, h) = self.0.size_hint();
(l * 2, h.map(|x| x*2))
}
}
impl<I: Iterator<Item = u8> + ExactSizeIterator> ExactSizeIterator for HexStringIter<I>{}
impl<I: Iterator<Item = u8> + FusedIterator> FusedIterator for HexStringIter<I>{}
impl<I: Iterator<Item = u8>> From<HexStringIter<I>> for String
{
fn from(from: HexStringIter<I>) -> Self
{
from.into_string()
}
}
impl<I: Iterator<Item = u8> + Clone> fmt::Display for HexStringIter<I>
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
{
self.clone().consume(f)
}
}
/*
#[macro_export] macro_rules! prog1 {
($first:expr, $($rest:expr);+ $(;)?) => {
($first, $( $rest ),+).0
}
}
*/