der: add owned Any and OctetString types

der/src/asn1.rs

@@ -43,7 +43,7 @@ pub use self::{
 
 #[cfg(feature = "alloc")]
 #[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
-pub use self::{bit_string::BitString, set_of::SetOfVec};
+pub use self::{any::Any, bit_string::BitString, octet_string::OctetString, set_of::SetOfVec};
 
 #[cfg(feature = "oid")]
 #[cfg_attr(docsrs, doc(cfg(feature = "oid")))]

der/src/asn1/any.rs

@@ -6,6 +6,9 @@ use crate::{
 };
 use core::cmp::Ordering;
 
+#[cfg(feature = "alloc")]
+use alloc::vec::Vec;
+
 #[cfg(feature = "oid")]
 use crate::asn1::ObjectIdentifier;
 
@@ -36,7 +39,7 @@ impl<'a> AnyRef<'a> {
         value: ByteSlice::EMPTY,
     };
 
-    /// Create a new [`AnyRef`] from the provided [`Tag`] and byte slice.
+    /// Create a new [`AnyRef`] from the provided [`Tag`] and DER bytes.
     pub fn new(tag: Tag, bytes: &'a [u8]) -> Result<Self> {
         let value = ByteSlice::new(bytes).map_err(|_| ErrorKind::Length { tag })?;
         Ok(Self { tag, value })
@@ -200,3 +203,72 @@ impl<'a> TryFrom<&'a [u8]> for AnyRef<'a> {
         AnyRef::from_der(bytes)
     }
 }
+
+/// ASN.1 `ANY`: represents any explicitly tagged ASN.1 value.
+///
+/// This type provides the same functionality as [`AnyRef`] but owns the
+/// backing data.
+#[cfg(feature = "alloc")]
+#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
+#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
+pub struct Any {
+    /// Tag representing the type of the encoded value.
+    tag: Tag,
+
+    /// Inner value encoded as bytes.
+    value: Vec<u8>,
+}
+
+#[cfg(feature = "alloc")]
+impl Any {
+    /// Create a new [`Any`] from the provided [`Tag`] and DER bytes.
+    pub fn new(tag: Tag, bytes: impl Into<Vec<u8>>) -> Result<Self> {
+        let value = bytes.into();
+
+        // Ensure the tag and value are a valid `AnyRef`.
+        AnyRef::new(tag, &value)?;
+        Ok(Self { tag, value })
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl Choice<'_> for Any {
+    fn can_decode(_: Tag) -> bool {
+        true
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl<'a> Decode<'a> for Any {
+    fn decode<R: Reader<'a>>(reader: &mut R) -> Result<Self> {
+        let header = Header::decode(reader)?;
+        let value = reader.read_vec(header.length)?;
+        Self::new(header.tag, value)
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl EncodeValue for Any {
+    fn value_len(&self) -> Result<Length> {
+        self.value.len().try_into()
+    }
+
+    fn encode_value(&self, writer: &mut dyn Writer) -> Result<()> {
+        writer.write(&self.value)
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl<'a> From<&'a Any> for AnyRef<'a> {
+    fn from(any: &'a Any) -> AnyRef<'a> {
+        // Ensured to parse successfully in constructor
+        AnyRef::new(any.tag, &any.value).expect("invalid ANY")
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl Tagged for Any {
+    fn tag(&self) -> Tag {
+        self.tag
+    }
+}

der/src/asn1/bit_string.rs

@@ -198,6 +198,145 @@ impl<'a> FixedTag for BitStringRef<'a> {
     const TAG: Tag = Tag::BitString;
 }
 
+/// Owned form of ASN.1 `BIT STRING` type.
+///
+/// This type provides the same functionality as [`BitStringRef`] but owns the
+/// backing data.
+#[cfg(feature = "alloc")]
+#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
+#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
+pub struct BitString {
+    /// Number of unused bits in the final octet.
+    unused_bits: u8,
+
+    /// Length of this `BIT STRING` in bits.
+    bit_length: usize,
+
+    /// Bitstring represented as a slice of bytes.
+    inner: Vec<u8>,
+}
+
+#[cfg(feature = "alloc")]
+impl BitString {
+    /// Maximum number of unused bits allowed.
+    pub const MAX_UNUSED_BITS: u8 = 7;
+
+    /// Create a new ASN.1 `BIT STRING` from a byte slice.
+    ///
+    /// Accepts an optional number of "unused bits" (0-7) which are omitted
+    /// from the final octet. This number is 0 if the value is octet-aligned.
+    pub fn new(unused_bits: u8, bytes: impl Into<Vec<u8>>) -> Result<Self> {
+        let inner = bytes.into();
+
+        // Ensure parameters parse successfully as a `BitStringRef`.
+        let bit_length = BitStringRef::new(unused_bits, &inner)?.bit_length;
+
+        Ok(BitString {
+            unused_bits,
+            bit_length,
+            inner,
+        })
+    }
+
+    /// Create a new ASN.1 `BIT STRING` from the given bytes.
+    ///
+    /// The "unused bits" are set to 0.
+    pub fn from_bytes(bytes: &[u8]) -> Result<Self> {
+        Self::new(0, bytes)
+    }
+
+    /// Get the number of unused bits in the octet serialization of this
+    /// `BIT STRING`.
+    pub fn unused_bits(&self) -> u8 {
+        self.unused_bits
+    }
+
+    /// Is the number of unused bits a value other than 0?
+    pub fn has_unused_bits(&self) -> bool {
+        self.unused_bits != 0
+    }
+
+    /// Get the length of this `BIT STRING` in bits.
+    pub fn bit_len(&self) -> usize {
+        self.bit_length
+    }
+
+    /// Is the inner byte slice empty?
+    pub fn is_empty(&self) -> bool {
+        self.inner.is_empty()
+    }
+
+    /// Borrow the inner byte slice.
+    ///
+    /// Returns `None` if the number of unused bits is *not* equal to zero,
+    /// i.e. if the `BIT STRING` is not octet aligned.
+    ///
+    /// Use [`BitString::raw_bytes`] to obtain access to the raw value
+    /// regardless of the presence of unused bits.
+    pub fn as_bytes(&self) -> Option<&[u8]> {
+        if self.has_unused_bits() {
+            None
+        } else {
+            Some(self.raw_bytes())
+        }
+    }
+
+    /// Borrow the raw bytes of this `BIT STRING`.
+    pub fn raw_bytes(&self) -> &[u8] {
+        self.inner.as_slice()
+    }
+
+    /// Iterator over the bits of this `BIT STRING`.
+    pub fn bits(&self) -> BitStringIter<'_> {
+        BitStringRef::from(self).bits()
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl<'a> DecodeValue<'a> for BitString {
+    fn decode_value<R: Reader<'a>>(reader: &mut R, header: Header) -> Result<Self> {
+        let inner_len = (header.length - Length::ONE)?;
+        let unused_bits = reader.read_byte()?;
+        let inner = reader.read_vec(inner_len)?;
+        Self::new(unused_bits, inner)
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl EncodeValue for BitString {
+    fn value_len(&self) -> Result<Length> {
+        Length::ONE + Length::try_from(self.inner.len())?
+    }
+
+    fn encode_value(&self, writer: &mut dyn Writer) -> Result<()> {
+        writer.write_byte(self.unused_bits)?;
+        writer.write(&self.inner)
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl FixedTag for BitString {
+    const TAG: Tag = Tag::BitString;
+}
+
+#[cfg(feature = "alloc")]
+impl<'a> From<&'a BitString> for BitStringRef<'a> {
+    fn from(bit_string: &'a BitString) -> BitStringRef<'a> {
+        // Ensured to parse successfully in constructor
+        BitStringRef::new(bit_string.unused_bits, &bit_string.inner).expect("invalid BIT STRING")
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl ValueOrd for BitString {
+    fn value_cmp(&self, other: &Self) -> Result<Ordering> {
+        match self.unused_bits.cmp(&other.unused_bits) {
+            Ordering::Equal => self.inner.der_cmp(&other.inner),
+            ordering => Ok(ordering),
+        }
+    }
+}
+
 /// Iterator over the bits of a [`BitString`].
 pub struct BitStringIter<'a> {
     /// [`BitString`] being iterated over.
@@ -302,95 +441,6 @@ where
     }
 }
 
-/// Owned form of ASN.1 `BIT STRING` type.
-///
-/// This type provides the same functionality as [`BitString`] but owns the
-/// backing data.
-#[cfg(feature = "alloc")]
-#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
-#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
-pub struct BitString {
-    /// Number of unused bits in the final octet.
-    unused_bits: u8,
-
-    /// Length of this `BIT STRING` in bits.
-    bit_length: usize,
-
-    /// Bitstring represented as a slice of bytes.
-    inner: Vec<u8>,
-}
-
-#[cfg(feature = "alloc")]
-impl BitString {
-    /// Get the number of unused bits in the octet serialization of this
-    /// `BIT STRING`.
-    pub fn unused_bits(&self) -> u8 {
-        self.unused_bits
-    }
-
-    /// Borrow the raw bytes of this `BIT STRING`.
-    pub fn raw_bytes(&self) -> &[u8] {
-        self.inner.as_slice()
-    }
-}
-
-#[cfg(feature = "alloc")]
-impl<'a> DecodeValue<'a> for BitString {
-    fn decode_value<R: Reader<'a>>(reader: &mut R, header: Header) -> Result<Self> {
-        let unused_bits = reader.read_byte()?;
-        let inner_len: usize = (header.length - Length::ONE)?.try_into()?;
-
-        if (unused_bits > BitStringRef::MAX_UNUSED_BITS) || (unused_bits != 0 && inner_len == 0) {
-            return Err(Self::TAG.value_error());
-        }
-
-        let bit_length = inner_len
-            .checked_mul(8)
-            .and_then(|n| n.checked_sub(usize::from(unused_bits)))
-            .ok_or(ErrorKind::Overflow)?;
-
-        let mut inner = vec![0u8; inner_len];
-        let actual_len = reader.read_into(&mut inner)?.len();
-
-        if inner_len == actual_len {
-            Ok(Self {
-                unused_bits,
-                bit_length,
-                inner,
-            })
-        } else {
-            Err(Self::TAG.length_error())
-        }
-    }
-}
-
-#[cfg(feature = "alloc")]
-impl EncodeValue for BitString {
-    fn value_len(&self) -> Result<Length> {
-        Length::ONE + Length::try_from(self.inner.len())?
-    }
-
-    fn encode_value(&self, writer: &mut dyn Writer) -> Result<()> {
-        writer.write_byte(self.unused_bits)?;
-        writer.write(&self.inner)
-    }
-}
-
-#[cfg(feature = "alloc")]
-impl FixedTag for BitString {
-    const TAG: Tag = Tag::BitString;
-}
-
-#[cfg(feature = "alloc")]
-impl ValueOrd for BitString {
-    fn value_cmp(&self, other: &Self) -> Result<Ordering> {
-        match self.unused_bits.cmp(&other.unused_bits) {
-            Ordering::Equal => self.inner.der_cmp(&other.inner),
-            ordering => Ok(ordering),
-        }
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::{BitStringRef, Result, Tag};