der: add IntLike and UintLike traits

Author: dishmaker

der/src/asn1.rs

@@ -42,7 +42,7 @@ pub use self::{
     general_string::GeneralStringRef,
     generalized_time::GeneralizedTime,
     ia5_string::Ia5StringRef,
-    integer::{int::IntRef, uint::UintRef},
+    integer::{IntLike, UintLike, int::IntRef, uint::UintRef},
     null::Null,
     octet_string::OctetStringRef,
     printable_string::PrintableStringRef,

der/src/asn1/integer.rs

@@ -3,6 +3,11 @@
 pub(super) mod int;
 pub(super) mod uint;
 
+#[cfg(doc)]
+use int::IntRef;
+#[cfg(doc)]
+use uint::UintRef;
+
 use core::{cmp::Ordering, mem::size_of};
 
 use crate::{EncodeValue, Result, encode::encode_value_to_slice};
@@ -30,6 +35,22 @@ where
     Ok(buf1.cmp(buf2))
 }
 
+/// Borrow the inner byte slice of [`IntRef`], or an owned `Int`
+pub trait IntLike {
+    /// Borrow the inner byte slice which contains the least significant bytes
+    /// of a big endian integer value with all leading ones stripped.
+    #[must_use]
+    fn as_int_bytes(&self) -> &[u8];
+}
+
+/// Borrow the inner byte slice of [`UintRef`], or an owned `Uint`
+pub trait UintLike {
+    /// Borrow the inner byte slice which contains the least significant bytes
+    /// of a big endian integer value with all leading zeros stripped.
+    #[must_use]
+    fn as_uint_bytes(&self) -> &[u8];
+}
+
 #[cfg(test)]
 #[allow(clippy::unwrap_used)]
 pub(crate) mod tests {

der/src/asn1/integer/int.rs

@@ -3,7 +3,7 @@
 use super::{is_highest_bit_set, uint, value_cmp};
 use crate::{
     AnyRef, BytesRef, DecodeValue, EncodeValue, Error, ErrorKind, FixedTag, Header, Length, Reader,
-    Result, Tag, ValueOrd, Writer, ord::OrdIsValueOrd,
+    Result, Tag, ValueOrd, Writer, asn1::integer::IntLike, ord::OrdIsValueOrd,
 };
 use core::cmp::Ordering;
 
@@ -180,13 +180,19 @@ impl FixedTag for IntRef<'_> {
 
 impl OrdIsValueOrd for IntRef<'_> {}
 
+impl IntLike for IntRef<'_> {
+    fn as_int_bytes(&self) -> &[u8] {
+        self.inner.as_slice()
+    }
+}
+
 #[cfg(feature = "alloc")]
 mod allocating {
     use super::{IntRef, strip_leading_ones, validate_canonical};
     use crate::{
         BytesOwned, DecodeValue, EncodeValue, Error, ErrorKind, FixedTag, Header, Length, Reader,
         Result, Tag, Writer,
-        asn1::Uint,
+        asn1::{Uint, integer::IntLike},
         ord::OrdIsValueOrd,
         referenced::{OwnedToRef, RefToOwned},
     };
@@ -237,6 +243,12 @@ mod allocating {
         }
     }
 
+    impl IntLike for Int {
+        fn as_int_bytes(&self) -> &[u8] {
+            self.inner.as_slice()
+        }
+    }
+
     impl_any_conversions!(Int);
 
     impl<'a> DecodeValue<'a> for Int {

der/src/asn1/integer/uint.rs

@@ -3,7 +3,8 @@
 use super::value_cmp;
 use crate::{
     AnyRef, BytesRef, DecodeValue, EncodeValue, Error, ErrorKind, FixedTag, Header, Length, Reader,
-    Result, Tag, ValueOrd, Writer, ord::OrdIsValueOrd, referenced::OwnedToRef,
+    Result, Tag, ValueOrd, Writer, asn1::integer::UintLike, ord::OrdIsValueOrd,
+    referenced::OwnedToRef,
 };
 use core::cmp::Ordering;
 
@@ -179,12 +180,19 @@ impl<'a> OwnedToRef for UintRef<'a> {
     }
 }
 
+impl<'a> UintLike for UintRef<'a> {
+    fn as_uint_bytes(&self) -> &[u8] {
+        self.inner.as_slice()
+    }
+}
+
 #[cfg(feature = "alloc")]
 mod allocating {
     use super::{UintRef, decode_to_slice, encoded_len, strip_leading_zeroes};
     use crate::{
         BytesOwned, DecodeValue, EncodeValue, Error, ErrorKind, FixedTag, Header, Length, Reader,
         Result, Tag, Writer,
+        asn1::integer::UintLike,
         ord::OrdIsValueOrd,
         referenced::{OwnedToRef, RefToOwned},
     };
@@ -300,6 +308,12 @@ mod allocating {
         }
     }
 
+    impl UintLike for Uint {
+        fn as_uint_bytes(&self) -> &[u8] {
+            self.inner.as_slice()
+        }
+    }
+
     macro_rules! impl_from_traits {
         ($($uint:ty),+) => {
             $(