1 files changed, 69 insertions, 0 deletions
diff --git a/vendor/crypto-bigint/src/uint/encoding/der.rs b/vendor/crypto-bigint/src/uint/encoding/der.rs
new file mode 100644
index 000000000..cf1b9c31e
--- /dev/null
+++ b/vendor/crypto-bigint/src/uint/encoding/der.rs
@@ -0,0 +1,69 @@
+//! Support for decoding/encoding [`UInt`] as an ASN.1 DER `INTEGER`.
+
+use crate::{generic_array::GenericArray, ArrayEncoding, UInt};
+use ::der::{
+    asn1::{AnyRef, UIntRef},
+    DecodeValue, EncodeValue, FixedTag, Length, Tag,
+};
+
+#[cfg_attr(docsrs, doc(cfg(feature = "der")))]
+impl<'a, const LIMBS: usize> TryFrom<AnyRef<'a>> for UInt<LIMBS>
+where
+    UInt<LIMBS>: ArrayEncoding,
+{
+    type Error = der::Error;
+
+    fn try_from(any: AnyRef<'a>) -> der::Result<UInt<LIMBS>> {
+        UIntRef::try_from(any)?.try_into()
+    }
+}
+
+#[cfg_attr(docsrs, doc(cfg(feature = "der")))]
+impl<'a, const LIMBS: usize> TryFrom<UIntRef<'a>> for UInt<LIMBS>
+where
+    UInt<LIMBS>: ArrayEncoding,
+{
+    type Error = der::Error;
+
+    fn try_from(bytes: UIntRef<'a>) -> der::Result<UInt<LIMBS>> {
+        let mut array = GenericArray::default();
+        let offset = array.len().saturating_sub(bytes.len().try_into()?);
+        array[offset..].copy_from_slice(bytes.as_bytes());
+        Ok(UInt::from_be_byte_array(array))
+    }
+}
+
+#[cfg_attr(docsrs, doc(cfg(feature = "der")))]
+impl<'a, const LIMBS: usize> DecodeValue<'a> for UInt<LIMBS>
+where
+    UInt<LIMBS>: ArrayEncoding,
+{
+    fn decode_value<R: der::Reader<'a>>(reader: &mut R, header: der::Header) -> der::Result<Self> {
+        UIntRef::decode_value(reader, header)?.try_into()
+    }
+}
+
+#[cfg_attr(docsrs, doc(cfg(feature = "der")))]
+impl<const LIMBS: usize> EncodeValue for UInt<LIMBS>
+where
+    UInt<LIMBS>: ArrayEncoding,
+{
+    fn value_len(&self) -> der::Result<Length> {
+        // TODO(tarcieri): more efficient length calculation
+        let array = self.to_be_byte_array();
+        UIntRef::new(&array)?.value_len()
+    }
+
+    fn encode_value(&self, encoder: &mut dyn der::Writer) -> der::Result<()> {
+        let array = self.to_be_byte_array();
+        UIntRef::new(&array)?.encode_value(encoder)
+    }
+}
+
+#[cfg_attr(docsrs, doc(cfg(feature = "der")))]
+impl<const LIMBS: usize> FixedTag for UInt<LIMBS>
+where
+    UInt<LIMBS>: ArrayEncoding,
+{
+    const TAG: Tag = Tag::Integer;
+}