feat!: Add basic support for REAL using f32/f64 with JER/OER rules (#406

)

Co-authored-by: Magnus Sjöstrand <magnus.sjostrand@ead.nu>

Cargo.toml

@@ -28,7 +28,10 @@ chrono = { version = "0.4.38", default-features = false, features = ["alloc"] }
 bitvec = { version = "1.0.1", default-features = false, features = ["alloc"] }
 
 [features]
+default = ["f32", "f64"]
 std = []
+f32 = []
+f64 = []
 backtraces = ["std", "snafu/backtrace"]
 compiler = ["rasn-compiler"]
 

src/ber/de.rs

@@ -410,6 +410,14 @@ impl<'input> crate::Decoder for Decoder<'input> {
         }
     }
 
+    fn decode_real<R: types::RealType>(
+        &mut self,
+        _: Tag,
+        _: Constraints,
+    ) -> Result<R, Self::Error> {
+        Err(DecodeError::real_not_supported(self.codec()))
+    }
+
     fn decode_octet_string<'b, T: From<&'b [u8]> + From<Vec<u8>>>(
         &'b mut self,
         tag: Tag,

src/ber/enc.rs

@@ -395,6 +395,15 @@ impl crate::Encoder<'_> for Encoder {
         Ok(())
     }
 
+    fn encode_real<R: types::RealType>(
+        &mut self,
+        _: Tag,
+        _: Constraints,
+        _: &R,
+    ) -> Result<Self::Ok, Self::Error> {
+        Err(EncodeError::real_not_supported(self.codec()))
+    }
+
     fn encode_null(&mut self, tag: Tag) -> Result<Self::Ok, Self::Error> {
         self.encode_primitive(tag, &[]);
         Ok(())

src/de.rs

@@ -93,6 +93,14 @@ pub trait Decoder<const RCL: usize = 0, const ECL: usize = 0>: Sized {
         tag: Tag,
         constraints: Constraints,
     ) -> Result<I, Self::Error>;
+
+    /// Decode a `REAL` identified by `tag` from the available input.
+    fn decode_real<R: types::RealType>(
+        &mut self,
+        tag: Tag,
+        constraints: Constraints,
+    ) -> Result<R, Self::Error>;
+
     /// Decode `NULL` identified by `tag` from the available input.
     fn decode_null(&mut self, tag: Tag) -> Result<(), Self::Error>;
     /// Decode a `OBJECT IDENTIFIER` identified by `tag` from the available input.
@@ -534,6 +542,28 @@ impl Decode for types::Integer {
     }
 }
 
+#[cfg(feature = "f32")]
+impl Decode for f32 {
+    fn decode_with_tag_and_constraints<D: Decoder>(
+        decoder: &mut D,
+        tag: Tag,
+        _: Constraints,
+    ) -> Result<Self, D::Error> {
+        decoder.decode_real::<f32>(tag, Constraints::default())
+    }
+}
+
+#[cfg(feature = "f64")]
+impl Decode for f64 {
+    fn decode_with_tag_and_constraints<D: Decoder>(
+        decoder: &mut D,
+        tag: Tag,
+        _: Constraints,
+    ) -> Result<Self, D::Error> {
+        decoder.decode_real::<f64>(tag, Constraints::default())
+    }
+}
+
 impl<T: Decode> Decode for Box<T> {
     fn decode<D: Decoder>(decoder: &mut D) -> Result<Self, D::Error> {
         T::decode(decoder).map(Box::new)

src/enc.rs

@@ -2,6 +2,8 @@
 
 use crate::types::{self, AsnType, Constraints, Enumerated, IntegerType, SetOf, Tag};
 
+use crate::types::RealType;
+
 use num_bigint::BigInt;
 pub use rasn_derive::Encode;
 
@@ -117,6 +119,14 @@ pub trait Encoder<'encoder, const RCL: usize = 0, const ECL: usize = 0> {
         value: &I,
     ) -> Result<Self::Ok, Self::Error>;
 
+    /// Encode a `REAL` value.
+    fn encode_real<R: RealType>(
+        &mut self,
+        tag: Tag,
+        constraints: Constraints,
+        value: &R,
+    ) -> Result<Self::Ok, Self::Error>;
+
     /// Encode a `NULL` value.
     fn encode_null(&mut self, tag: Tag) -> Result<Self::Ok, Self::Error>;
 
@@ -576,6 +586,30 @@ impl Encode for types::Integer {
     }
 }
 
+#[cfg(feature = "f32")]
+impl Encode for f32 {
+    fn encode_with_tag_and_constraints<'b, E: Encoder<'b>>(
+        &self,
+        encoder: &mut E,
+        tag: Tag,
+        constraints: Constraints,
+    ) -> Result<(), E::Error> {
+        encoder.encode_real(tag, constraints, self).map(drop)
+    }
+}
+
+#[cfg(feature = "f64")]
+impl Encode for f64 {
+    fn encode_with_tag_and_constraints<'b, E: Encoder<'b>>(
+        &self,
+        encoder: &mut E,
+        tag: Tag,
+        constraints: Constraints,
+    ) -> Result<(), E::Error> {
+        encoder.encode_real(tag, constraints, self).map(drop)
+    }
+}
+
 impl Encode for types::OctetString {
     fn encode_with_tag_and_constraints<'b, E: Encoder<'b>>(
         &self,

src/error/decode.rs

@@ -276,6 +276,12 @@ impl DecodeError {
         DecodeError::from_kind(DecodeErrorKind::Parser { msg }, codec)
     }
 
+    /// Creates a wrapper around using `REAL` with unsupported codecs.
+    #[must_use]
+    pub fn real_not_supported(codec: Codec) -> Self {
+        DecodeError::from_kind(DecodeErrorKind::RealNotSupported, codec)
+    }
+
     /// Creates a wrapper around a missing required extension error from a given codec.
     #[must_use]
     pub fn required_extension_not_present(tag: Tag, codec: Codec) -> Self {
@@ -553,6 +559,14 @@ pub enum DecodeErrorKind {
         msg: alloc::string::String,
     },
 
+    /// Real conversion failure.
+    #[snafu(display("Invalid real encoding"))]
+    InvalidRealEncoding,
+
+    /// Decoder doesn't support REAL
+    #[snafu(display("Decoder doesn't support REAL types"))]
+    RealNotSupported,
+
     /// BitString contains an invalid amount of unused bits.
     #[snafu(display("BitString contains an invalid amount of unused bits: {}", bits))]
     InvalidBitString {

src/error/encode.rs

@@ -212,6 +212,12 @@ impl EncodeError {
         Self::from_kind(EncodeErrorKind::VariantNotInChoice, codec)
     }
 
+    /// Returns an encode error when the encoder doesn't support `REAL` type.
+    #[must_use]
+    pub fn real_not_supported(codec: crate::Codec) -> Self {
+        Self::from_kind(EncodeErrorKind::RealNotSuppored, codec)
+    }
+
     /// A helper function to construct an `EncodeError` from the given `kind` and `codec`.
     #[must_use]
     pub fn from_kind(kind: EncodeErrorKind, codec: crate::Codec) -> Self {
@@ -328,6 +334,10 @@ pub enum EncodeErrorKind {
     /// Error when the selected variant is not found in the choice.
     #[snafu(display("Selected Variant not found from Choice"))]
     VariantNotInChoice,
+
+    /// Error when we try to encode a `REAL` type with an unspported codec.
+    #[snafu(display("Encoder doesn't support `REAL` type"))]
+    RealNotSuppored,
 }
 /// `EncodeError` kinds of `Kind::CodecSpecific` which are specific for BER.
 #[derive(Snafu, Debug)]
@@ -392,6 +402,9 @@ pub enum JerEncodeErrorKind {
         /// value failed to encode
         value: BigInt,
     },
+    /// Error to be thrown when encoding real values that exceed the supported range
+    #[snafu(display("Exceeds supported real value range"))]
+    ExceedsSupportedRealRange,
     /// Error to be thrown when some character from the input data is not valid UTF-8
     #[snafu(display("Invalid character: {:?}", error))]
     InvalidCharacter {

src/jer.rs

@@ -24,6 +24,13 @@ pub fn encode<T: crate::Encode>(
 #[cfg(test)]
 mod tests {
     macro_rules! round_trip_jer {
+        ($typ:ty, $value:expr, $expected:expr) => {{
+            let value: $typ = $value;
+            pretty_assertions::assert_eq!(value, round_trip_value!($typ, $value, $expected));
+        }};
+    }
+
+    macro_rules! round_trip_value {
         ($typ:ty, $value:expr, $expected:expr) => {{
             let value: $typ = $value;
             let expected: &'static str = $expected;
@@ -32,8 +39,7 @@ mod tests {
             pretty_assertions::assert_eq!(expected, &*actual_encoding);
 
             let decoded_value: $typ = crate::jer::decode(&actual_encoding).unwrap();
-
-            pretty_assertions::assert_eq!(value, decoded_value);
+            decoded_value
         }};
     }
 
@@ -187,6 +193,36 @@ mod tests {
         round_trip_jer!(ConstrainedInt, ConstrainedInt(1.into()), "1");
     }
 
+    #[test]
+    #[cfg(feature = "f32")]
+    fn real_f32() {
+        round_trip_jer!(f32, 0.0, "0.0");
+        round_trip_jer!(f32, -0.0, "\"-0\"");
+
+        round_trip_jer!(f32, f32::INFINITY, "\"INF\"");
+        round_trip_jer!(f32, f32::NEG_INFINITY, "\"-INF\"");
+
+        assert!(round_trip_value!(f32, f32::NAN, "\"NAN\"").is_nan());
+
+        round_trip_jer!(f32, 1.0, "1.0");
+        round_trip_jer!(f32, -1.0, "-1.0");
+    }
+
+    #[test]
+    #[cfg(feature = "f64")]
+    fn real_f64() {
+        round_trip_jer!(f64, 0.0, "0.0");
+        round_trip_jer!(f64, -0.0, "\"-0\"");
+
+        round_trip_jer!(f64, f64::INFINITY, "\"INF\"");
+        round_trip_jer!(f64, f64::NEG_INFINITY, "\"-INF\"");
+
+        assert!(round_trip_value!(f64, f64::NAN, "\"NAN\"").is_nan());
+
+        round_trip_jer!(f64, 1.0, "1.0");
+        round_trip_jer!(f64, -1.0, "-1.0");
+    }
+
     #[test]
     fn bit_string() {
         round_trip_jer!(

src/jer/de.rs

@@ -142,6 +142,14 @@ impl crate::Decoder for Decoder {
         decode_jer_value!(Self::integer_from_value::<I>, self.stack)
     }
 
+    fn decode_real<R: crate::types::RealType>(
+        &mut self,
+        _t: Tag,
+        _c: Constraints,
+    ) -> Result<R, Self::Error> {
+        decode_jer_value!(Self::real_from_value::<R>, self.stack)
+    }
+
     fn decode_null(&mut self, _t: Tag) -> Result<(), Self::Error> {
         decode_jer_value!(Self::null_from_value, self.stack)
     }
@@ -496,6 +504,35 @@ impl Decoder {
             .map_err(|_| DecodeError::integer_overflow(I::WIDTH, crate::Codec::Jer))
     }
 
+    fn real_from_value<R: crate::types::RealType>(value: Value) -> Result<R, DecodeError> {
+        if let Some(as_f64) = value.as_f64() {
+            return R::try_from_float(as_f64).ok_or_else(|| {
+                JerDecodeErrorKind::TypeMismatch {
+                    needed: "number (double precision floating point)",
+                    found: alloc::format!("{value}"),
+                }
+                .into()
+            });
+        }
+
+        value
+            .as_str()
+            .and_then(|s| match s {
+                "-0" => R::try_from_float(-0.0),
+                "INF" => R::try_from_float(f64::INFINITY),
+                "-INF" => R::try_from_float(f64::NEG_INFINITY),
+                "NAN" => R::try_from_float(f64::NAN),
+                _ => None,
+            })
+            .ok_or_else(|| {
+                JerDecodeErrorKind::TypeMismatch {
+                    needed: "number (double precision floating point)",
+                    found: alloc::format!("{value}"),
+                }
+                .into()
+            })
+    }
+
     fn null_from_value(value: Value) -> Result<(), DecodeError> {
         Ok(value
             .is_null()

src/jer/enc.rs

@@ -11,6 +11,8 @@ use crate::{
     types::{variants, Constraints, IntegerType, Tag},
 };
 
+use crate::types::RealType;
+
 /// Encodes Rust structures into JSON Encoding Rules data.
 pub struct Encoder {
     stack: alloc::vec::Vec<&'static str>,
@@ -149,6 +151,35 @@ impl crate::Encoder<'_> for Encoder {
         }
     }
 
+    fn encode_real<R: RealType>(
+        &mut self,
+        _t: Tag,
+        _c: Constraints,
+        value: &R,
+    ) -> Result<Self::Ok, Self::Error> {
+        use num_traits::{float::FloatCore, ToPrimitive, Zero};
+
+        let as_float = value
+            .try_to_float()
+            .ok_or(JerEncodeErrorKind::ExceedsSupportedRealRange)?;
+
+        if as_float.is_infinite() {
+            if as_float.is_sign_positive() {
+                self.update_root_or_constructed(Value::String("INF".into()))
+            } else {
+                self.update_root_or_constructed(Value::String("-INF".into()))
+            }
+        } else if as_float.is_nan() {
+            self.update_root_or_constructed(Value::String("NAN".into()))
+        } else if as_float.is_zero() && as_float.is_sign_negative() {
+            self.update_root_or_constructed(Value::String("-0".into()))
+        } else if let Some(number) = as_float.to_f64().and_then(serde_json::Number::from_f64) {
+            self.update_root_or_constructed(number.into())
+        } else {
+            Err(JerEncodeErrorKind::ExceedsSupportedRealRange.into())
+        }
+    }
+
     fn encode_null(&mut self, _: Tag) -> Result<Self::Ok, Self::Error> {
         self.update_root_or_constructed(Value::Null)
     }