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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:47:55 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:47:55 +0000 |
commit | 2aadc03ef15cb5ca5cc2af8a7c08e070742f0ac4 (patch) | |
tree | 033cc839730fda84ff08db877037977be94e5e3a /vendor/der/src/encode.rs | |
parent | Initial commit. (diff) | |
download | cargo-2aadc03ef15cb5ca5cc2af8a7c08e070742f0ac4.tar.xz cargo-2aadc03ef15cb5ca5cc2af8a7c08e070742f0ac4.zip |
Adding upstream version 0.70.1+ds1.upstream/0.70.1+ds1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'vendor/der/src/encode.rs')
-rw-r--r-- | vendor/der/src/encode.rs | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/vendor/der/src/encode.rs b/vendor/der/src/encode.rs new file mode 100644 index 0000000..28d7cba --- /dev/null +++ b/vendor/der/src/encode.rs @@ -0,0 +1,158 @@ +//! Trait definition for [`Encode`]. + +use crate::{Header, Length, Result, SliceWriter, Tagged, Writer}; +use core::marker::PhantomData; + +#[cfg(feature = "alloc")] +use {alloc::boxed::Box, alloc::vec::Vec, core::iter}; + +#[cfg(feature = "pem")] +use { + crate::PemWriter, + alloc::string::String, + pem_rfc7468::{self as pem, LineEnding, PemLabel}, +}; + +#[cfg(any(feature = "alloc", feature = "pem"))] +use crate::ErrorKind; + +#[cfg(doc)] +use crate::Tag; + +/// Encoding trait. +pub trait Encode { + /// Compute the length of this value in bytes when encoded as ASN.1 DER. + fn encoded_len(&self) -> Result<Length>; + + /// Encode this value as ASN.1 DER using the provided [`Writer`]. + fn encode(&self, encoder: &mut impl Writer) -> Result<()>; + + /// Encode this value to the provided byte slice, returning a sub-slice + /// containing the encoded message. + fn encode_to_slice<'a>(&self, buf: &'a mut [u8]) -> Result<&'a [u8]> { + let mut writer = SliceWriter::new(buf); + self.encode(&mut writer)?; + writer.finish() + } + + /// Encode this message as ASN.1 DER, appending it to the provided + /// byte vector. + #[cfg(feature = "alloc")] + fn encode_to_vec(&self, buf: &mut Vec<u8>) -> Result<Length> { + let expected_len = usize::try_from(self.encoded_len()?)?; + buf.reserve(expected_len); + buf.extend(iter::repeat(0).take(expected_len)); + + let mut writer = SliceWriter::new(buf); + self.encode(&mut writer)?; + let actual_len = writer.finish()?.len(); + + if expected_len != actual_len { + return Err(ErrorKind::Incomplete { + expected_len: expected_len.try_into()?, + actual_len: actual_len.try_into()?, + } + .into()); + } + + actual_len.try_into() + } + + /// Encode this type as DER, returning a byte vector. + #[cfg(feature = "alloc")] + fn to_der(&self) -> Result<Vec<u8>> { + let mut buf = Vec::new(); + self.encode_to_vec(&mut buf)?; + Ok(buf) + } +} + +impl<T> Encode for T +where + T: EncodeValue + Tagged, +{ + /// Compute the length of this value in bytes when encoded as ASN.1 DER. + fn encoded_len(&self) -> Result<Length> { + self.value_len().and_then(|len| len.for_tlv()) + } + + /// Encode this value as ASN.1 DER using the provided [`Writer`]. + fn encode(&self, writer: &mut impl Writer) -> Result<()> { + self.header()?.encode(writer)?; + self.encode_value(writer) + } +} + +/// Dummy implementation for [`PhantomData`] which allows deriving +/// implementations on structs with phantom fields. +impl<T> Encode for PhantomData<T> +where + T: ?Sized, +{ + fn encoded_len(&self) -> Result<Length> { + Ok(Length::ZERO) + } + + fn encode(&self, _writer: &mut impl Writer) -> Result<()> { + Ok(()) + } +} + +/// PEM encoding trait. +/// +/// This trait is automatically impl'd for any type which impls both +/// [`Encode`] and [`PemLabel`]. +#[cfg(feature = "pem")] +pub trait EncodePem: Encode + PemLabel { + /// Try to encode this type as PEM. + fn to_pem(&self, line_ending: LineEnding) -> Result<String>; +} + +#[cfg(feature = "pem")] +impl<T: Encode + PemLabel> EncodePem for T { + fn to_pem(&self, line_ending: LineEnding) -> Result<String> { + let der_len = usize::try_from(self.encoded_len()?)?; + let pem_len = pem::encapsulated_len(Self::PEM_LABEL, line_ending, der_len)?; + + let mut buf = vec![0u8; pem_len]; + let mut writer = PemWriter::new(Self::PEM_LABEL, line_ending, &mut buf)?; + self.encode(&mut writer)?; + + let actual_len = writer.finish()?; + buf.truncate(actual_len); + Ok(String::from_utf8(buf)?) + } +} + +/// Encode the value part of a Tag-Length-Value encoded field, sans the [`Tag`] +/// and [`Length`]. +pub trait EncodeValue { + /// Get the [`Header`] used to encode this value. + fn header(&self) -> Result<Header> + where + Self: Tagged, + { + Header::new(self.tag(), self.value_len()?) + } + + /// Compute the length of this value (sans [`Tag`]+[`Length`] header) when + /// encoded as ASN.1 DER. + fn value_len(&self) -> Result<Length>; + + /// Encode value (sans [`Tag`]+[`Length`] header) as ASN.1 DER using the + /// provided [`Writer`]. + fn encode_value(&self, encoder: &mut impl Writer) -> Result<()>; +} + +#[cfg(feature = "alloc")] +impl<T> EncodeValue for Box<T> +where + T: EncodeValue, +{ + fn value_len(&self) -> Result<Length> { + T::value_len(self) + } + fn encode_value(&self, writer: &mut impl Writer) -> Result<()> { + T::encode_value(self, writer) + } +} |