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use crate::base::octets::{EmptyBuilder, FromBuilder, OctetsBuilder};
use core::fmt;
#[cfg(feature = "std")]
use std::string::String;
pub use super::base64::DecodeError;
pub fn decode<Octets>(s: &str) -> Result<Octets, DecodeError>
where
Octets: FromBuilder,
<Octets as FromBuilder>::Builder:
OctetsBuilder<Octets = Octets> + EmptyBuilder,
{
let mut decoder = Decoder::<<Octets as FromBuilder>::Builder>::new();
for ch in s.chars() {
decoder.push(ch)?;
}
decoder.finalize()
}
pub fn display<Octets, Target>(octets: &Octets, f: &mut Target) -> fmt::Result
where
Octets: AsRef<[u8]> + ?Sized,
Target: fmt::Write,
{
for octet in octets.as_ref() {
f.write_char(ENCODE_ALPHABET[(octet >> 4) as usize])?;
f.write_char(ENCODE_ALPHABET[(octet & 0x0F) as usize])?;
}
Ok(())
}
#[cfg(feature = "std")]
pub fn encode_string<B: AsRef<[u8]> + ?Sized>(bytes: &B) -> String {
let mut res = String::with_capacity(bytes.as_ref().len() * 2);
display(bytes, &mut res).unwrap();
res
}
pub fn encode_display<Octets: AsRef<[u8]>>(
octets: &Octets,
) -> impl fmt::Display + '_ {
struct Display<'a>(&'a [u8]);
impl<'a> fmt::Display for Display<'a> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
display(self.0, f)
}
}
Display(octets.as_ref())
}
#[cfg(feature = "serde")]
pub mod serde {
use crate::base::octets::{
DeserializeOctets, EmptyBuilder, FromBuilder, OctetsBuilder,
SerializeOctets,
};
use core::fmt;
pub fn serialize<Octets, S>(
octets: &Octets,
serializer: S,
) -> Result<S::Ok, S::Error>
where
Octets: AsRef<[u8]> + SerializeOctets,
S: serde::Serializer,
{
if serializer.is_human_readable() {
serializer.collect_str(&super::encode_display(octets))
} else {
octets.serialize_octets(serializer)
}
}
pub fn deserialize<'de, Octets, D: serde::Deserializer<'de>>(
deserializer: D,
) -> Result<Octets, D::Error>
where
Octets: FromBuilder + DeserializeOctets<'de>,
<Octets as FromBuilder>::Builder: EmptyBuilder,
{
struct Visitor<'de, Octets: DeserializeOctets<'de>>(Octets::Visitor);
impl<'de, Octets> serde::de::Visitor<'de> for Visitor<'de, Octets>
where
Octets: FromBuilder + DeserializeOctets<'de>,
<Octets as FromBuilder>::Builder:
OctetsBuilder<Octets = Octets> + EmptyBuilder,
{
type Value = Octets;
fn expecting(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.write_str("an Base16-encoded string")
}
fn visit_str<E: serde::de::Error>(
self,
v: &str,
) -> Result<Self::Value, E> {
super::decode(v).map_err(E::custom)
}
fn visit_borrowed_bytes<E: serde::de::Error>(
self,
value: &'de [u8],
) -> Result<Self::Value, E> {
self.0.visit_borrowed_bytes(value)
}
#[cfg(feature = "std")]
fn visit_byte_buf<E: serde::de::Error>(
self,
value: std::vec::Vec<u8>,
) -> Result<Self::Value, E> {
self.0.visit_byte_buf(value)
}
}
if deserializer.is_human_readable() {
deserializer.deserialize_str(Visitor(Octets::visitor()))
} else {
Octets::deserialize_with_visitor(
deserializer,
Visitor(Octets::visitor()),
)
}
}
}
pub struct Decoder<Builder> {
buf: Option<u8>,
target: Result<Builder, DecodeError>,
}
impl<Builder: EmptyBuilder> Decoder<Builder> {
pub fn new() -> Self {
Decoder {
buf: None,
target: Ok(Builder::empty()),
}
}
}
impl<Builder: OctetsBuilder> Decoder<Builder> {
pub fn finalize(self) -> Result<Builder::Octets, DecodeError> {
if self.buf.is_some() {
return Err(DecodeError::ShortInput);
}
self.target.map(OctetsBuilder::freeze)
}
pub fn push(&mut self, ch: char) -> Result<(), DecodeError> {
let value = match ch.to_digit(16) {
Some(value) => value as u8,
None => {
self.target = Err(DecodeError::IllegalChar(ch));
return Err(DecodeError::IllegalChar(ch));
}
};
if let Some(upper) = self.buf.take() {
self.append(upper | value);
} else {
self.buf = Some(value << 4)
}
match self.target {
Ok(_) => Ok(()),
Err(err) => Err(err),
}
}
fn append(&mut self, value: u8) {
let target = match self.target.as_mut() {
Ok(target) => target,
Err(_) => return,
};
if let Err(err) = target.append_slice(&[value]) {
self.target = Err(err.into());
}
}
}
impl<Builder: EmptyBuilder> Default for Decoder<Builder> {
fn default() -> Self {
Self::new()
}
}
const ENCODE_ALPHABET: [char; 16] = [
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', ];
#[cfg(test)]
#[cfg(feature = "std")]
mod test {
use super::*;
use std::string::String;
#[test]
#[cfg(feature = "bytes")]
fn decode_str() {
use super::DecodeError;
fn decode(s: &str) -> Result<std::vec::Vec<u8>, DecodeError> {
super::decode(s)
}
assert_eq!(&decode("").unwrap(), b"");
assert_eq!(&decode("F0").unwrap(), b"\xF0");
assert_eq!(&decode("F00f").unwrap(), b"\xF0\x0F");
}
#[test]
fn test_display() {
fn fmt(s: &[u8]) -> String {
let mut out = String::new();
display(s, &mut out).unwrap();
out
}
assert_eq!(fmt(b""), "");
assert_eq!(fmt(b"\xf0"), "F0");
assert_eq!(fmt(b"\xf0\x0f"), "F00F");
}
}