-
Notifications
You must be signed in to change notification settings - Fork 134
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Adds initial support for a Basic Multilingual Plane (a.k.a. UCS-2) string type.
- Loading branch information
Showing
3 changed files
with
173 additions
and
0 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,164 @@ | ||
//! ASN.1 `BMPString` support. | ||
|
||
use crate::{ | ||
BytesOwned, DecodeValue, EncodeValue, Error, FixedTag, Header, Length, Reader, Result, Tag, | ||
Writer, | ||
}; | ||
use alloc::{boxed::Box, vec::Vec}; | ||
use core::{fmt, str::FromStr}; | ||
|
||
/// ASN.1 `BMPString` type. | ||
/// | ||
/// Encodes Basic Multilingual Plane (BMP) subset of Unicode (ISO 10646), | ||
/// a.k.a. UCS-2. | ||
#[derive(Clone, Eq, PartialEq, PartialOrd, Ord)] | ||
pub struct BmpString { | ||
bytes: BytesOwned, | ||
} | ||
|
||
impl BmpString { | ||
/// Create a new [`BmpString`] from its UCS-2 encoding. | ||
pub fn from_ucs2(bytes: impl Into<Box<[u8]>>) -> Result<Self> { | ||
let bytes = bytes.into(); | ||
|
||
if bytes.len() % 2 != 0 { | ||
return Err(Tag::BmpString.length_error()); | ||
} | ||
|
||
let ret = Self { | ||
bytes: bytes.try_into()?, | ||
}; | ||
|
||
for maybe_char in char::decode_utf16(ret.codepoints()) { | ||
match maybe_char { | ||
// All surrogates paired and character is in the Basic Multilingual Plane | ||
Ok(c) if (c as u64) < u64::from(u16::MAX) => (), | ||
// Unpaired surrogates or characters outside Basic Multilingual Plane | ||
_ => return Err(Tag::BmpString.value_error()), | ||
} | ||
} | ||
|
||
Ok(ret) | ||
} | ||
|
||
/// Create a new [`BmpString`] from a UTF-8 string. | ||
pub fn from_utf8(utf8: &str) -> Result<Self> { | ||
let capacity = utf8 | ||
.len() | ||
.checked_mul(2) | ||
.ok_or_else(|| Tag::BmpString.length_error())?; | ||
|
||
let mut bytes = Vec::with_capacity(capacity); | ||
|
||
for code_point in utf8.encode_utf16() { | ||
bytes.extend(code_point.to_be_bytes()); | ||
} | ||
|
||
Self::from_ucs2(bytes) | ||
} | ||
|
||
/// Borrow the encoded UCS-2 as bytes. | ||
pub fn as_bytes(&self) -> &[u8] { | ||
self.bytes.as_ref() | ||
} | ||
|
||
/// Obtain the inner bytes. | ||
#[inline] | ||
pub fn into_bytes(self) -> Box<[u8]> { | ||
self.bytes.into() | ||
} | ||
|
||
/// Get an iterator over characters in the string. | ||
pub fn chars(&self) -> impl Iterator<Item = char> + '_ { | ||
char::decode_utf16(self.codepoints()) | ||
.map(|maybe_char| maybe_char.expect("unpaired surrogates checked in constructor")) | ||
} | ||
|
||
/// Get an iterator over the `u16` codepoints. | ||
pub fn codepoints(&self) -> impl Iterator<Item = u16> + '_ { | ||
// TODO(tarcieri): use `array_chunks` | ||
self.as_bytes() | ||
.chunks_exact(2) | ||
.map(|chunk| u16::from_be_bytes(chunk.try_into().expect("two bytes"))) | ||
} | ||
} | ||
|
||
impl AsRef<[u8]> for BmpString { | ||
fn as_ref(&self) -> &[u8] { | ||
self.as_bytes() | ||
} | ||
} | ||
|
||
impl<'a> DecodeValue<'a> for BmpString { | ||
fn decode_value<R: Reader<'a>>(reader: &mut R, header: Header) -> Result<Self> { | ||
Self::from_ucs2(reader.read_vec(header.length)?) | ||
} | ||
} | ||
|
||
impl EncodeValue for BmpString { | ||
fn value_len(&self) -> Result<Length> { | ||
Ok(self.bytes.len()) | ||
} | ||
|
||
fn encode_value(&self, writer: &mut impl Writer) -> Result<()> { | ||
writer.write(self.as_bytes()) | ||
} | ||
} | ||
|
||
impl FixedTag for BmpString { | ||
const TAG: Tag = Tag::BmpString; | ||
} | ||
|
||
impl FromStr for BmpString { | ||
type Err = Error; | ||
|
||
fn from_str(s: &str) -> Result<Self> { | ||
Self::from_utf8(s) | ||
} | ||
} | ||
|
||
impl fmt::Debug for BmpString { | ||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | ||
write!(f, "BmpString(\"{}\")", self) | ||
} | ||
} | ||
|
||
impl fmt::Display for BmpString { | ||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | ||
for c in self.chars() { | ||
write!(f, "{}", c)?; | ||
} | ||
Ok(()) | ||
} | ||
} | ||
|
||
#[cfg(test)] | ||
mod tests { | ||
use super::BmpString; | ||
use crate::{Decode, Encode}; | ||
use alloc::string::ToString; | ||
use hex_literal::hex; | ||
|
||
const EXAMPLE_BYTES: &[u8] = &hex!( | ||
"1e 26 00 43 00 65 00 72 00 74" | ||
" 00 69 00 66 00 69 00 63" | ||
" 00 61 00 74 00 65 00 54" | ||
" 00 65 00 6d 00 70 00 6c" | ||
" 00 61 00 74 00 65" | ||
); | ||
|
||
const EXAMPLE_UTF8: &str = "CertificateTemplate"; | ||
|
||
#[test] | ||
fn decode() { | ||
let bmp_string = BmpString::from_der(EXAMPLE_BYTES).unwrap(); | ||
assert_eq!(bmp_string.to_string(), EXAMPLE_UTF8); | ||
} | ||
|
||
#[test] | ||
fn encode() { | ||
let bmp_string = BmpString::from_utf8(EXAMPLE_UTF8).unwrap(); | ||
let encoded = bmp_string.to_der().unwrap(); | ||
assert_eq!(encoded, EXAMPLE_BYTES); | ||
} | ||
} |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters