Number type

crates/air-lib/interpreter-value/src/lib.rs

@@ -34,6 +34,7 @@ macro_rules! tri {
     };
 }
 
+mod number;
 mod value;
 
 pub use value::JValue;

crates/air-lib/interpreter-value/src/number.rs

@@ -0,0 +1,298 @@
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+
+use std::{
+    fmt::{self, Debug, Display},
+    hash::{Hash, Hasher},
+};
+
+/// Represents a JSON number, whether integer or floating point.
+#[derive(Clone, PartialEq, Eq, Hash, rkyv::Archive, rkyv::Serialize, rkyv::Deserialize)]
+#[archive(check_bytes)]
+pub struct Number {
+    n: N,
+}
+
+#[derive(Copy, Clone, rkyv::Archive, rkyv::Serialize, rkyv::Deserialize)]
+#[archive(check_bytes)]
+enum N {
+    PosInt(u64),
+    /// Always less than zero.
+    NegInt(i64),
+    /// Always finite.
+    // TODO bytecheck that deserialized value is finite
+    Float(f64),
+}
+
+impl PartialEq for N {
+    fn eq(&self, other: &Self) -> bool {
+        match (self, other) {
+            (N::PosInt(a), N::PosInt(b)) => a == b,
+            (N::NegInt(a), N::NegInt(b)) => a == b,
+            (N::Float(a), N::Float(b)) => a == b,
+            _ => false,
+        }
+    }
+}
+
+// Implementing Eq is fine since any float values are always finite.
+impl Eq for N {}
+
+impl Hash for N {
+    fn hash<H: Hasher>(&self, h: &mut H) {
+        match *self {
+            N::PosInt(i) => i.hash(h),
+            N::NegInt(i) => i.hash(h),
+            N::Float(f) => {
+                if f == 0.0f64 {
+                    // There are 2 zero representations, +0 and -0, which
+                    // compare equal but have different bits. We use the +0 hash
+                    // for both so that hash(+0) == hash(-0).
+                    0.0f64.to_bits().hash(h);
+                } else {
+                    f.to_bits().hash(h);
+                }
+            }
+        }
+    }
+}
+
+impl Number {
+    /// Returns true if the `Number` is an integer between `i64::MIN` and
+    /// `i64::MAX`.
+    ///
+    /// For any Number on which `is_i64` returns true, `as_i64` is guaranteed to
+    /// return the integer value.
+    ///
+    /// ```
+    /// # use serde_json::json;
+    /// #
+    /// let big = i64::max_value() as u64 + 10;
+    /// let v = json!({ "a": 64, "b": big, "c": 256.0 });
+    ///
+    /// assert!(v["a"].is_i64());
+    ///
+    /// // Greater than i64::MAX.
+    /// assert!(!v["b"].is_i64());
+    ///
+    /// // Numbers with a decimal point are not considered integers.
+    /// assert!(!v["c"].is_i64());
+    /// ```
+    #[inline]
+    pub fn is_i64(&self) -> bool {
+        match self.n {
+            N::PosInt(v) => v <= i64::max_value() as u64,
+            N::NegInt(_) => true,
+            N::Float(_) => false,
+        }
+    }
+
+    /// Returns true if the `Number` is an integer between zero and `u64::MAX`.
+    ///
+    /// For any Number on which `is_u64` returns true, `as_u64` is guaranteed to
+    /// return the integer value.
+    ///
+    /// ```
+    /// # use serde_json::json;
+    /// #
+    /// let v = json!({ "a": 64, "b": -64, "c": 256.0 });
+    ///
+    /// assert!(v["a"].is_u64());
+    ///
+    /// // Negative integer.
+    /// assert!(!v["b"].is_u64());
+    ///
+    /// // Numbers with a decimal point are not considered integers.
+    /// assert!(!v["c"].is_u64());
+    /// ```
+    #[inline]
+    pub fn is_u64(&self) -> bool {
+        match self.n {
+            N::PosInt(_) => true,
+            N::NegInt(_) | N::Float(_) => false,
+        }
+    }
+
+    /// Returns true if the `Number` can be represented by f64.
+    ///
+    /// For any Number on which `is_f64` returns true, `as_f64` is guaranteed to
+    /// return the floating point value.
+    ///
+    /// Currently this function returns true if and only if both `is_i64` and
+    /// `is_u64` return false but this is not a guarantee in the future.
+    ///
+    /// ```
+    /// # use serde_json::json;
+    /// #
+    /// let v = json!({ "a": 256.0, "b": 64, "c": -64 });
+    ///
+    /// assert!(v["a"].is_f64());
+    ///
+    /// // Integers.
+    /// assert!(!v["b"].is_f64());
+    /// assert!(!v["c"].is_f64());
+    /// ```
+    #[inline]
+    pub fn is_f64(&self) -> bool {
+        match self.n {
+            N::Float(_) => true,
+            N::PosInt(_) | N::NegInt(_) => false,
+        }
+    }
+
+    /// If the `Number` is an integer, represent it as i64 if possible. Returns
+    /// None otherwise.
+    ///
+    /// ```
+    /// # use serde_json::json;
+    /// #
+    /// let big = i64::max_value() as u64 + 10;
+    /// let v = json!({ "a": 64, "b": big, "c": 256.0 });
+    ///
+    /// assert_eq!(v["a"].as_i64(), Some(64));
+    /// assert_eq!(v["b"].as_i64(), None);
+    /// assert_eq!(v["c"].as_i64(), None);
+    /// ```
+    #[inline]
+    pub fn as_i64(&self) -> Option<i64> {
+        match self.n {
+            N::PosInt(n) => {
+                if n <= i64::max_value() as u64 {
+                    Some(n as i64)
+                } else {
+                    None
+                }
+            }
+            N::NegInt(n) => Some(n),
+            N::Float(_) => None,
+        }
+    }
+
+    /// If the `Number` is an integer, represent it as u64 if possible. Returns
+    /// None otherwise.
+    ///
+    /// ```
+    /// # use serde_json::json;
+    /// #
+    /// let v = json!({ "a": 64, "b": -64, "c": 256.0 });
+    ///
+    /// assert_eq!(v["a"].as_u64(), Some(64));
+    /// assert_eq!(v["b"].as_u64(), None);
+    /// assert_eq!(v["c"].as_u64(), None);
+    /// ```
+    #[inline]
+    pub fn as_u64(&self) -> Option<u64> {
+        match self.n {
+            N::PosInt(n) => Some(n),
+            N::NegInt(_) | N::Float(_) => None,
+        }
+    }
+
+    /// Represents the number as f64 if possible. Returns None otherwise.
+    ///
+    /// ```
+    /// # use serde_json::json;
+    /// #
+    /// let v = json!({ "a": 256.0, "b": 64, "c": -64 });
+    ///
+    /// assert_eq!(v["a"].as_f64(), Some(256.0));
+    /// assert_eq!(v["b"].as_f64(), Some(64.0));
+    /// assert_eq!(v["c"].as_f64(), Some(-64.0));
+    /// ```
+    #[inline]
+    pub fn as_f64(&self) -> Option<f64> {
+        match self.n {
+            N::PosInt(n) => Some(n as f64),
+            N::NegInt(n) => Some(n as f64),
+            N::Float(n) => Some(n),
+        }
+    }
+
+    /// Converts a finite `f64` to a `Number`. Infinite or NaN values are not JSON
+    /// numbers.
+    ///
+    /// ```
+    /// # use std::f64;
+    /// #
+    /// # use serde_json::Number;
+    /// #
+    /// assert!(Number::from_f64(256.0).is_some());
+    ///
+    /// assert!(Number::from_f64(f64::NAN).is_none());
+    /// ```
+    #[inline]
+    pub fn from_f64(f: f64) -> Option<Number> {
+        if f.is_finite() {
+            let n = {
+                {
+                    N::Float(f)
+                }
+            };
+            Some(Number { n })
+        } else {
+            None
+        }
+    }
+}
+
+impl Display for Number {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        write!(formatter, "{}", serde_json::Number::from(self.clone()))
+    }
+}
+
+impl From<Number> for serde_json::Number {
+    fn from(value: Number) -> Self {
+        match value.n {
+            N::PosInt(n) => n.into(),
+            N::NegInt(n) => n.into(),
+            // input is always finite, so unwrap is never triggered
+            N::Float(f) => serde_json::Number::from_f64(f).unwrap(),
+        }
+    }
+}
+
+impl From<serde_json::Number> for Number {
+    fn from(value: serde_json::Number) -> Self {
+        if let Some(f) = value.as_f64() {
+            return Number::from_f64(f).unwrap();
+        }
+        if let Some(n) = value.as_u64() {
+            return Number { n: N::PosInt(n) };
+        }
+        if let Some(n) = value.as_i64() {
+            return Number { n: N::NegInt(n) };
+        }
+        unreachable!()
+    }
+}
+
+impl Debug for Number {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        write!(formatter, "Number({})", self)
+    }
+}
+
+impl Serialize for Number {
+    #[inline]
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        match self.n {
+            N::PosInt(u) => serializer.serialize_u64(u),
+            N::NegInt(i) => serializer.serialize_i64(i),
+            N::Float(f) => serializer.serialize_f64(f),
+        }
+    }
+}
+
+impl<'de> Deserialize<'de> for Number {
+    #[inline]
+    fn deserialize<D>(deserializer: D) -> Result<Number, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let n: serde_json::Number = serde_json::Number::deserialize(deserializer)?;
+        Ok(n.into())
+    }
+}