/rust/registry/src/index.crates.io-1949cf8c6b5b557f/noisy_float-0.2.0/src/lib.rs

Source
// Copyright 2016-2021 Matthew D. Michelotti
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! This crate contains floating point types that panic if they are set
//! to an illegal value, such as NaN.
//!
//! The name "Noisy Float" comes from
//! the terms "quiet NaN" and "signaling NaN"; "signaling" was too long
//! to put in a struct/crate name, so "noisy" is used instead, being the opposite
//! of "quiet."
//!
//! The standard types defined in `noisy_float::types` follow the principle
//! demonstrated by Rust's handling of integer overflow:
//! a bad arithmetic operation is considered an error,
//! but it is too costly to check everywhere in optimized builds.
//! For each floating point number that is created, a `debug_assert!` invocation is used
//! to check if it is valid or not.
//! This way, there are guarantees when developing code that floating point
//! numbers have valid values,
//! but during a release run there is *no overhead* for using these floating
//! point types compared to using `f32` or `f64` directly.
//!
//! This crate makes use of the num, bounded, signed and floating point traits
//! in the popular `num_traits` crate.
//! This crate can be compiled with no_std.
//!
//! # Examples
//! An example using the `R64` type, which corresponds to *finite* `f64` values.
//!
//! ```
//! use noisy_float::prelude::*;
//!
//! fn geometric_mean(a: R64, b: R64) -> R64 {
//!     (a * b).sqrt() //used just like regular floating point numbers
//! }
//!
//! fn mean(a: R64, b: R64) -> R64 {
//!     (a + b) * 0.5 //the RHS of ops can be the underlying float type
//! }
//!
//! println!(
//!     "geometric_mean(10.0, 20.0) = {}",
//!     geometric_mean(r64(10.0), r64(20.0))
//! );
//! //prints 14.142...
//! assert!(mean(r64(10.0), r64(20.0)) == 15.0);
//! ```
//!
//! An example using the `N32` type, which corresponds to *non-NaN* `f32` values.
//! The float types in this crate are able to implement `Eq` and `Ord` properly,
//! since NaN is not allowed.
//!
//! ```
//! use noisy_float::prelude::*;
//!
//! let values = vec![n32(3.0), n32(-1.5), n32(71.3), N32::infinity()];
//! assert!(values.iter().cloned().min() == Some(n32(-1.5)));
//! assert!(values.iter().cloned().max() == Some(N32::infinity()));
//! ```
//!
//! An example converting from R64 to primitive types.
//!
//! ```
//! use noisy_float::prelude::*;
//! use num_traits::cast::ToPrimitive;
//!
//! let value_r64: R64 = r64(1.0);
//! let value_f64_a: f64 = value_r64.into();
//! let value_f64_b: f64 = value_r64.raw();
//! let value_u64: u64 = value_r64.to_u64().unwrap();
//!
//! assert!(value_f64_a == value_f64_b);
//! assert!(value_f64_a as u64 == value_u64);
//! ```
//!
//! # Features
//!
//! This crate has the following cargo features:
//!
//! - `serde`: Enable serialization for all `NoisyFloats` using serde 1.0 and
//!   will transparently serialize then as floats
//! - `approx`: Adds implementations to use `NoisyFloat` with the `approx`
//!   crate

#![no_std]

#[cfg(feature = "serde")]
use serde::{Deserialize, Deserializer, Serialize, Serializer, de::Error};

pub mod checkers;
mod float_impl;
pub mod types;

/// Prelude for the `noisy_float` crate.
///
/// This includes all of the types defined in the `noisy_float::types` module,
/// as well as a re-export of the `Float` trait from the `num_traits` crate.
/// It is important to have this re-export here, because it allows the user
/// to access common floating point methods like `abs()`, `sqrt()`, etc.
pub mod prelude {
    pub use crate::types::*;

    #[doc(no_inline)]
    pub use num_traits::Float;
}

use core::{fmt, marker::PhantomData};
use num_traits::Float;

/// Trait for checking whether a floating point number is *valid*.
///
/// The implementation defines its own criteria for what constitutes a *valid* value.
pub trait FloatChecker<F> {
    /// Returns `true` if (and only if) the given floating point number is *valid*
    /// according to this checker's criteria.
    ///
    /// The only hard requirement is that NaN *must* be considered *invalid*
    /// for all implementations of `FloatChecker`.
    fn check(value: F) -> bool;

    /// A function that may panic if the floating point number is *invalid*.
    ///
    /// Should either call `assert!(check(value), ...)` or `debug_assert!(check(value), ...)`.
    fn assert(value: F);
}

/// A floating point number with a restricted set of legal values.
///
/// Typical users will not need to access this struct directly, but
/// can instead use the type aliases found in the module `noisy_float::types`.
/// However, this struct together with a `FloatChecker` implementation can be used
/// to define custom behavior.
///
/// The underlying float type is `F`, usually `f32` or `f64`.
/// Valid values for the float are determined by the float checker `C`.
/// If an invalid value would ever be returned from a method on this type,
/// the method will panic instead, using either `assert!` or `debug_assert!`
/// as defined by the float checker.
/// The exception to this rule is for methods that return an `Option` containing
/// a `NoisyFloat`, in which case the result would be `None` if the value is invalid.
#[repr(transparent)]
pub struct NoisyFloat<F: Float, C: FloatChecker<F>> {
    value: F,
    checker: PhantomData<C>,
}

impl<F: Float, C: FloatChecker<F>> NoisyFloat<F, C> {
    /// Constructs a `NoisyFloat` with the given value.
    ///
    /// Uses the `FloatChecker` to assert that the value is valid.
    #[inline]
    pub fn new(value: F) -> Self {
        C::assert(value);
        Self::unchecked_new_generic(value)
    }

    #[inline]
    fn unchecked_new_generic(value: F) -> Self {
        NoisyFloat {
            value,
            checker: PhantomData,
        }
    }

    /// Tries to construct a `NoisyFloat` with the given value.
    ///
    /// Returns `None` if the value is invalid.
    #[inline]
    pub fn try_new(value: F) -> Option<Self> {
        if C::check(value) {
            Some(NoisyFloat {
                value,
                checker: PhantomData,
            })
        } else {
            None
        }
    }

    /// Converts the value in-place to a reference to a `NoisyFloat`.
    ///
    /// Uses the `FloatChecker` to assert that the value is valid.
    #[inline]
    pub fn borrowed(value: &F) -> &Self {
        C::assert(*value);
        Self::unchecked_borrowed(value)
    }

    #[inline]
    fn unchecked_borrowed(value: &F) -> &Self {
        // This is safe because `NoisyFloat` is a thin wrapper around the
        // floating-point type.
        unsafe { &*(value as *const F as *const Self) }
    }

    /// Tries to convert the value in-place to a reference to a `NoisyFloat`.
    ///
    /// Returns `None` if the value is invalid.
    #[inline]
    pub fn try_borrowed(value: &F) -> Option<&Self> {
        if C::check(*value) {
            Some(Self::unchecked_borrowed(value))
        } else {
            None
        }
    }

    /// Converts the value in-place to a mutable reference to a `NoisyFloat`.
    ///
    /// Uses the `FloatChecker` to assert that the value is valid.
    #[inline]
    pub fn borrowed_mut(value: &mut F) -> &mut Self {
        C::assert(*value);
        Self::unchecked_borrowed_mut(value)
    }

    #[inline]
    fn unchecked_borrowed_mut(value: &mut F) -> &mut Self {
        // This is safe because `NoisyFloat` is a thin wrapper around the
        // floating-point type.
        unsafe { &mut *(value as *mut F as *mut Self) }
    }

    /// Tries to convert the value in-place to a mutable reference to a `NoisyFloat`.
    ///
    /// Returns `None` if the value is invalid.
    #[inline]
    pub fn try_borrowed_mut(value: &mut F) -> Option<&mut Self> {
        if C::check(*value) {
            Some(Self::unchecked_borrowed_mut(value))
        } else {
            None
        }
    }

    /// Constructs a `NoisyFloat` with the given `f32` value.
    ///
    /// May panic not only by the `FloatChecker` but also
    /// by unwrapping the result of a `NumCast` invocation for type `F`,
    /// although the later should not occur in normal situations.
    #[inline]
    pub fn from_f32(value: f32) -> Self {
        Self::new(F::from(value).unwrap())
    }

    /// Constructs a `NoisyFloat` with the given `f64` value.
    ///
    /// May panic not only by the `FloatChecker` but also
    /// by unwrapping the result of a `NumCast` invocation for type `F`,
    /// although the later should not occur in normal situations.
    #[inline]
    pub fn from_f64(value: f64) -> Self {
        Self::new(F::from(value).unwrap())
    }

    /// Returns the underlying float value.
    #[inline]
    pub fn raw(self) -> F {
        self.value
    }

    /// Compares and returns the minimum of two values.
    ///
    /// This method exists to disambiguate between `num_traits::Float.min` and `std::cmp::Ord.min`.
    #[inline]
    pub fn min(self, other: Self) -> Self {
        Ord::min(self, other)
    }

    /// Compares and returns the maximum of two values.
    ///
    /// This method exists to disambiguate between `num_traits::Float.max` and `std::cmp::Ord.max`.
    #[inline]
    pub fn max(self, other: Self) -> Self {
        Ord::max(self, other)
    }
}

impl<F: Float + Default, C: FloatChecker<F>> Default for NoisyFloat<F, C> {
    #[inline]
    fn default() -> Self {
        Self::new(F::default())
    }
}

impl<F: Float + fmt::Debug, C: FloatChecker<F>> fmt::Debug for NoisyFloat<F, C> {
    #[inline]
    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
        fmt::Debug::fmt(&self.value, f)
    }
}

impl<F: Float + fmt::Display, C: FloatChecker<F>> fmt::Display for NoisyFloat<F, C> {
    #[inline]
    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
        fmt::Display::fmt(&self.value, f)
    }
}

impl<F: Float + fmt::LowerExp, C: FloatChecker<F>> fmt::LowerExp for NoisyFloat<F, C> {
    #[inline]
    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
        fmt::LowerExp::fmt(&self.value, f)
    }
}

impl<F: Float + fmt::UpperExp, C: FloatChecker<F>> fmt::UpperExp for NoisyFloat<F, C> {
    #[inline]
    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
        fmt::UpperExp::fmt(&self.value, f)
    }
}

#[cfg(feature = "serde")]
impl<F: Float + Serialize, C: FloatChecker<F>> Serialize for NoisyFloat<F, C> {
    fn serialize<S: Serializer>(&self, ser: S) -> Result<S::Ok, S::Error> {
        self.value.serialize(ser)
    }
}

#[cfg(feature = "serde")]
impl<'de, F: Float + Deserialize<'de>, C: FloatChecker<F>> Deserialize<'de> for NoisyFloat<F, C> {
    fn deserialize<D: Deserializer<'de>>(de: D) -> Result<Self, D::Error> {
        let value = F::deserialize(de)?;
        Self::try_new(value).ok_or_else(|| D::Error::custom("invalid NoisyFloat"))
    }
}

#[cfg(test)]
mod tests {
    extern crate std;
    use std::prelude::v1::*;

    use crate::prelude::*;
    #[cfg(feature = "serde")]
    use serde_derive::{Deserialize, Serialize};
    #[cfg(feature = "serde")]
    use serde_json;
    use std::{
        f32,
        f64::{self, consts},
        hash::{Hash, Hasher},
        mem::{align_of, size_of},
    };

    #[test]
    fn smoke_test() {
        assert_eq!(n64(1.0) + 2.0, 3.0);
        assert_ne!(n64(3.0), n64(2.9));
        assert!(r64(1.0) < 2.0);
        let mut value = n64(18.0);
        value %= n64(5.0);
        assert_eq!(-value, n64(-3.0));
        assert_eq!(r64(1.0).exp(), consts::E);
        assert_eq!((N64::try_new(1.0).unwrap() / N64::infinity()), 0.0);
        assert_eq!(N64::from_f32(f32::INFINITY), N64::from_f64(f64::INFINITY));
        assert_eq!(R64::try_new(f64::NEG_INFINITY), None);
        assert_eq!(N64::try_new(f64::NAN), None);
        assert_eq!(R64::try_new(f64::NAN), None);
        assert_eq!(N64::try_borrowed(&f64::NAN), None);
        let mut nan = f64::NAN;
        assert_eq!(N64::try_borrowed_mut(&mut nan), None);
    }

    #[test]
    fn ensure_layout() {
        assert_eq!(size_of::<N32>(), size_of::<f32>());
        assert_eq!(align_of::<N32>(), align_of::<f32>());

        assert_eq!(size_of::<N64>(), size_of::<f64>());
        assert_eq!(align_of::<N64>(), align_of::<f64>());
    }

    #[test]
    fn borrowed_casts() {
        assert_eq!(R64::borrowed(&3.14), &3.14);
        assert_eq!(N64::borrowed(&[f64::INFINITY; 2][0]), &f64::INFINITY);
        assert_eq!(N64::borrowed_mut(&mut 2.72), &mut 2.72);
    }

    #[test]
    fn test_convert() {
        assert_eq!(f32::from(r32(3.0)), 3.0f32);
        assert_eq!(f64::from(r32(5.0)), 5.0f64);
        assert_eq!(f64::from(r64(7.0)), 7.0f64);
    }

    #[test]
    #[cfg(debug_assertions)]
    #[should_panic]
    fn n64_nan() {
        let _ = n64(0.0) / n64(0.0);
    }

    #[test]
    #[cfg(debug_assertions)]
    #[should_panic]
    fn r64_nan() {
        let _ = r64(0.0) / r64(0.0);
    }

    #[test]
    #[cfg(debug_assertions)]
    #[should_panic]
    fn r64_infinity() {
        let _ = r64(1.0) / r64(0.0);
    }

    #[test]
    fn resolves_min_max() {
        assert_eq!(r64(1.0).min(r64(3.0)), r64(1.0));
        assert_eq!(r64(1.0).max(r64(3.0)), r64(3.0));
    }

    #[test]
    fn epsilon() {
        assert_eq!(R32::epsilon(), f32::EPSILON);
        assert_eq!(R64::epsilon(), f64::EPSILON);
    }

    #[test]
    fn test_try_into() {
        use std::convert::{TryFrom, TryInto};
        let _: R64 = 1.0.try_into().unwrap();
        let _ = R64::try_from(f64::INFINITY).unwrap_err();
    }

    struct TestHasher {
        bytes: Vec<u8>,
    }

    impl Hasher for TestHasher {
        fn finish(&self) -> u64 {
            panic!("unexpected Hasher.finish invocation")
        }
        fn write(&mut self, bytes: &[u8]) {
            self.bytes.extend_from_slice(bytes)
        }
    }

    fn hash_bytes<T: Hash>(value: T) -> Vec<u8> {
        let mut hasher = TestHasher { bytes: Vec::new() };
        value.hash(&mut hasher);
        hasher.bytes
    }

    #[test]
    fn test_hash() {
        assert_eq!(hash_bytes(r64(10.3)), hash_bytes(10.3f64.to_bits()));
        assert_ne!(hash_bytes(r64(10.3)), hash_bytes(10.4f64.to_bits()));
        assert_eq!(hash_bytes(r32(10.3)), hash_bytes(10.3f32.to_bits()));
        assert_ne!(hash_bytes(r32(10.3)), hash_bytes(10.4f32.to_bits()));

        assert_eq!(
            hash_bytes(N64::infinity()),
            hash_bytes(f64::INFINITY.to_bits())
        );
        assert_eq!(
            hash_bytes(N64::neg_infinity()),
            hash_bytes(f64::NEG_INFINITY.to_bits())
        );

        // positive and negative zero should have the same hashes
        assert_eq!(hash_bytes(r64(0.0)), hash_bytes(0.0f64.to_bits()));
        assert_eq!(hash_bytes(r64(-0.0)), hash_bytes(0.0f64.to_bits()));
        assert_eq!(hash_bytes(r32(0.0)), hash_bytes(0.0f32.to_bits()));
        assert_eq!(hash_bytes(r32(-0.0)), hash_bytes(0.0f32.to_bits()));
    }

    #[cfg(feature = "serde")]
    #[test]
    fn serialize_transparently_as_float() {
        let num = R32::new(3.14);
        let should_be = "3.14";

        let got = serde_json::to_string(&num).unwrap();
        assert_eq!(got, should_be);
    }

    #[cfg(feature = "serde")]
    #[test]
    fn deserialize_transparently_as_float() {
        let src = "3.14";
        let should_be = R32::new(3.14);

        let got: R32 = serde_json::from_str(src).unwrap();
        assert_eq!(got, should_be);
    }

    #[cfg(feature = "serde")]
    #[test]
    fn deserialize_invalid_float() {
        use crate::{FloatChecker, NoisyFloat};
        struct PositiveChecker;
        impl FloatChecker<f64> for PositiveChecker {
            fn check(value: f64) -> bool {
                value > 0.
            }
            fn assert(value: f64) {
                debug_assert!(Self::check(value))
            }
        }

        let src = "-1.0";
        let got: Result<NoisyFloat<f64, PositiveChecker>, _> = serde_json::from_str(src);
        assert!(got.is_err());
    }

    // Make sure you can use serde_derive with noisy floats.
    #[cfg(feature = "serde")]
    #[derive(Debug, PartialEq, Serialize, Deserialize)]
    struct Dummy {
        value: N64,
    }

    #[cfg(feature = "serde")]
    #[test]
    fn deserialize_struct_containing_n64() {
        let src = r#"{ "value": 3.14 }"#;
        let should_be = Dummy { value: n64(3.14) };

        let got: Dummy = serde_json::from_str(src).unwrap();
        assert_eq!(got, should_be);
    }

    #[cfg(feature = "serde")]
    #[test]
    fn serialize_struct_containing_n64() {
        let src = Dummy { value: n64(3.14) };
        let should_be = r#"{"value":3.14}"#;

        let got = serde_json::to_string(&src).unwrap();
        assert_eq!(got, should_be);
    }

    #[cfg(feature = "approx")]
    #[test]
    fn approx_assert_eq() {
        use approx::{assert_abs_diff_eq, assert_relative_eq, assert_ulps_eq};

        let lhs = r64(0.1000000000000001);
        let rhs = r64(0.1);

        assert_abs_diff_eq!(lhs, rhs);
        assert_relative_eq!(lhs, rhs);
        assert_ulps_eq!(lhs, rhs);
    }

    #[test]
    fn const_functions() {
        const A: N32 = N32::unchecked_new(1.0);
        const B: N64 = N64::unchecked_new(2.0);
        const C: R32 = R32::unchecked_new(3.0);
        const D: R64 = R64::unchecked_new(4.0);

        const A_RAW: f32 = A.const_raw();
        const B_RAW: f64 = B.const_raw();
        const C_RAW: f32 = C.const_raw();
        const D_RAW: f64 = D.const_raw();

        assert_eq!(A_RAW, 1.0);
        assert_eq!(B_RAW, 2.0);
        assert_eq!(C_RAW, 3.0);
        assert_eq!(D_RAW, 4.0);
    }
}

Coverage Report

Created: 2025-11-28 06:44

Line	Count	Source
1		// Copyright 2016-2021 Matthew D. Michelotti
2		//
3		// Licensed under the Apache License, Version 2.0 (the "License");
4		// you may not use this file except in compliance with the License.
5		// You may obtain a copy of the License at
6		//
7		// http://www.apache.org/licenses/LICENSE-2.0
8		//
9		// Unless required by applicable law or agreed to in writing, software
10		// distributed under the License is distributed on an "AS IS" BASIS,
11		// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12		// See the License for the specific language governing permissions and
13		// limitations under the License.
14
15		//! This crate contains floating point types that panic if they are set
16		//! to an illegal value, such as NaN.
17		//!
18		//! The name "Noisy Float" comes from
19		//! the terms "quiet NaN" and "signaling NaN"; "signaling" was too long
20		//! to put in a struct/crate name, so "noisy" is used instead, being the opposite
21		//! of "quiet."
22		//!
23		//! The standard types defined in `noisy_float::types` follow the principle
24		//! demonstrated by Rust's handling of integer overflow:
25		//! a bad arithmetic operation is considered an error,
26		//! but it is too costly to check everywhere in optimized builds.
27		//! For each floating point number that is created, a `debug_assert!` invocation is used
28		//! to check if it is valid or not.
29		//! This way, there are guarantees when developing code that floating point
30		//! numbers have valid values,
31		//! but during a release run there is no overhead for using these floating
32		//! point types compared to using `f32` or `f64` directly.
33		//!
34		//! This crate makes use of the num, bounded, signed and floating point traits
35		//! in the popular `num_traits` crate.
36		//! This crate can be compiled with no_std.
37		//!
38		//! # Examples
39		//! An example using the `R64` type, which corresponds to finite `f64` values.
40		//!
41		//! ```
42		//! use noisy_float::prelude::*;
43		//!
44		//! fn geometric_mean(a: R64, b: R64) -> R64 {
45		//! (a * b).sqrt() //used just like regular floating point numbers
46		//! }
47		//!
48		//! fn mean(a: R64, b: R64) -> R64 {
49		//! (a + b) * 0.5 //the RHS of ops can be the underlying float type
50		//! }
51		//!
52		//! println!(
53		//! "geometric_mean(10.0, 20.0) = {}",
54		//! geometric_mean(r64(10.0), r64(20.0))
55		//! );
56		//! //prints 14.142...
57		//! assert!(mean(r64(10.0), r64(20.0)) == 15.0);
58		//! ```
59		//!
60		//! An example using the `N32` type, which corresponds to non-NaN `f32` values.
61		//! The float types in this crate are able to implement `Eq` and `Ord` properly,
62		//! since NaN is not allowed.
63		//!
64		//! ```
65		//! use noisy_float::prelude::*;
66		//!
67		//! let values = vec![n32(3.0), n32(-1.5), n32(71.3), N32::infinity()];
68		//! assert!(values.iter().cloned().min() == Some(n32(-1.5)));
69		//! assert!(values.iter().cloned().max() == Some(N32::infinity()));
70		//! ```
71		//!
72		//! An example converting from R64 to primitive types.
73		//!
74		//! ```
75		//! use noisy_float::prelude::*;
76		//! use num_traits::cast::ToPrimitive;
77		//!
78		//! let value_r64: R64 = r64(1.0);
79		//! let value_f64_a: f64 = value_r64.into();
80		//! let value_f64_b: f64 = value_r64.raw();
81		//! let value_u64: u64 = value_r64.to_u64().unwrap();
82		//!
83		//! assert!(value_f64_a == value_f64_b);
84		//! assert!(value_f64_a as u64 == value_u64);
85		//! ```
86		//!
87		//! # Features
88		//!
89		//! This crate has the following cargo features:
90		//!
91		//! - `serde`: Enable serialization for all `NoisyFloats` using serde 1.0 and
92		//! will transparently serialize then as floats
93		//! - `approx`: Adds implementations to use `NoisyFloat` with the `approx`
94		//! crate
95
96		#![no_std]
97
98		#[cfg(feature = "serde")]
99		use serde::{Deserialize, Deserializer, Serialize, Serializer, de::Error};
100
101		pub mod checkers;
102		mod float_impl;
103		pub mod types;
104
105		/// Prelude for the `noisy_float` crate.
106		///
107		/// This includes all of the types defined in the `noisy_float::types` module,
108		/// as well as a re-export of the `Float` trait from the `num_traits` crate.
109		/// It is important to have this re-export here, because it allows the user
110		/// to access common floating point methods like `abs()`, `sqrt()`, etc.
111		pub mod prelude {
112		pub use crate::types::*;
113
114		#[doc(no_inline)]
115		pub use num_traits::Float;
116		}
117
118		use core::{fmt, marker::PhantomData};
119		use num_traits::Float;
120
121		/// Trait for checking whether a floating point number is valid.
122		///
123		/// The implementation defines its own criteria for what constitutes a valid value.
124		pub trait FloatChecker<F> {
125		/// Returns `true` if (and only if) the given floating point number is valid
126		/// according to this checker's criteria.
127		///
128		/// The only hard requirement is that NaN must be considered invalid
129		/// for all implementations of `FloatChecker`.
130		fn check(value: F) -> bool;
131
132		/// A function that may panic if the floating point number is invalid.
133		///
134		/// Should either call `assert!(check(value), ...)` or `debug_assert!(check(value), ...)`.
135		fn assert(value: F);
136		}
137
138		/// A floating point number with a restricted set of legal values.
139		///
140		/// Typical users will not need to access this struct directly, but
141		/// can instead use the type aliases found in the module `noisy_float::types`.
142		/// However, this struct together with a `FloatChecker` implementation can be used
143		/// to define custom behavior.
144		///
145		/// The underlying float type is `F`, usually `f32` or `f64`.
146		/// Valid values for the float are determined by the float checker `C`.
147		/// If an invalid value would ever be returned from a method on this type,
148		/// the method will panic instead, using either `assert!` or `debug_assert!`
149		/// as defined by the float checker.
150		/// The exception to this rule is for methods that return an `Option` containing
151		/// a `NoisyFloat`, in which case the result would be `None` if the value is invalid.
152		#[repr(transparent)]
153		pub struct NoisyFloat<F: Float, C: FloatChecker<F>> {
154		value: F,
155		checker: PhantomData<C>,
156		}
157
158		impl<F: Float, C: FloatChecker<F>> NoisyFloat<F, C> {
159		/// Constructs a `NoisyFloat` with the given value.
160		///
161		/// Uses the `FloatChecker` to assert that the value is valid.
162		#[inline]
163	0	pub fn new(value: F) -> Self {
164	0	C::assert(value);
165	0	Self::unchecked_new_generic(value)
166	0	}
167
168		#[inline]
169	0	fn unchecked_new_generic(value: F) -> Self {
170	0	NoisyFloat {
171	0	value,
172	0	checker: PhantomData,
173	0	}
174	0	}
175
176		/// Tries to construct a `NoisyFloat` with the given value.
177		///
178		/// Returns `None` if the value is invalid.
179		#[inline]
180		pub fn try_new(value: F) -> Option<Self> {
181		if C::check(value) {
182		Some(NoisyFloat {
183		value,
184		checker: PhantomData,
185		})
186		} else {
187		None
188		}
189		}
190
191		/// Converts the value in-place to a reference to a `NoisyFloat`.
192		///
193		/// Uses the `FloatChecker` to assert that the value is valid.
194		#[inline]
195		pub fn borrowed(value: &F) -> &Self {
196		C::assert(*value);
197		Self::unchecked_borrowed(value)
198		}
199
200		#[inline]
201	0	fn unchecked_borrowed(value: &F) -> &Self {
202		// This is safe because `NoisyFloat` is a thin wrapper around the
203		// floating-point type.
204	0	unsafe { &(value as const F as *const Self) }
205	0	} Unexecuted instantiation: <noisy_float::NoisyFloat<f64, noisy_float::checkers::NumChecker>>::unchecked_borrowed Unexecuted instantiation: <noisy_float::NoisyFloat<f32, noisy_float::checkers::NumChecker>>::unchecked_borrowed
206
207		/// Tries to convert the value in-place to a reference to a `NoisyFloat`.
208		///
209		/// Returns `None` if the value is invalid.
210		#[inline]
211	0	pub fn try_borrowed(value: &F) -> Option<&Self> {
212	0	if C::check(*value) {
213	0	Some(Self::unchecked_borrowed(value))
214		} else {
215	0	None
216		}
217	0	} Unexecuted instantiation: <noisy_float::NoisyFloat<f64, noisy_float::checkers::NumChecker>>::try_borrowed Unexecuted instantiation: <noisy_float::NoisyFloat<f32, noisy_float::checkers::NumChecker>>::try_borrowed
218
219		/// Converts the value in-place to a mutable reference to a `NoisyFloat`.
220		///
221		/// Uses the `FloatChecker` to assert that the value is valid.
222		#[inline]
223		pub fn borrowed_mut(value: &mut F) -> &mut Self {
224		C::assert(*value);
225		Self::unchecked_borrowed_mut(value)
226		}
227
228		#[inline]
229		fn unchecked_borrowed_mut(value: &mut F) -> &mut Self {
230		// This is safe because `NoisyFloat` is a thin wrapper around the
231		// floating-point type.
232		unsafe { &mut (value as mut F as *mut Self) }
233		}
234
235		/// Tries to convert the value in-place to a mutable reference to a `NoisyFloat`.
236		///
237		/// Returns `None` if the value is invalid.
238		#[inline]
239		pub fn try_borrowed_mut(value: &mut F) -> Option<&mut Self> {
240		if C::check(*value) {
241		Some(Self::unchecked_borrowed_mut(value))
242		} else {
243		None
244		}
245		}
246
247		/// Constructs a `NoisyFloat` with the given `f32` value.
248		///
249		/// May panic not only by the `FloatChecker` but also
250		/// by unwrapping the result of a `NumCast` invocation for type `F`,
251		/// although the later should not occur in normal situations.
252		#[inline]
253		pub fn from_f32(value: f32) -> Self {
254		Self::new(F::from(value).unwrap())
255		}
256
257		/// Constructs a `NoisyFloat` with the given `f64` value.
258		///
259		/// May panic not only by the `FloatChecker` but also
260		/// by unwrapping the result of a `NumCast` invocation for type `F`,
261		/// although the later should not occur in normal situations.
262		#[inline]
263		pub fn from_f64(value: f64) -> Self {
264		Self::new(F::from(value).unwrap())
265		}
266
267		/// Returns the underlying float value.
268		#[inline]
269	0	pub fn raw(self) -> F {
270	0	self.value
271	0	} Unexecuted instantiation: <noisy_float::NoisyFloat<f64, noisy_float::checkers::NumChecker>>::raw Unexecuted instantiation: <noisy_float::NoisyFloat<f32, noisy_float::checkers::NumChecker>>::raw
272
273		/// Compares and returns the minimum of two values.
274		///
275		/// This method exists to disambiguate between `num_traits::Float.min` and `std::cmp::Ord.min`.
276		#[inline]
277		pub fn min(self, other: Self) -> Self {
278		Ord::min(self, other)
279		}
280
281		/// Compares and returns the maximum of two values.
282		///
283		/// This method exists to disambiguate between `num_traits::Float.max` and `std::cmp::Ord.max`.
284		#[inline]
285		pub fn max(self, other: Self) -> Self {
286		Ord::max(self, other)
287		}
288		}
289
290		impl<F: Float + Default, C: FloatChecker<F>> Default for NoisyFloat<F, C> {
291		#[inline]
292		fn default() -> Self {
293		Self::new(F::default())
294		}
295		}
296
297		impl<F: Float + fmt::Debug, C: FloatChecker<F>> fmt::Debug for NoisyFloat<F, C> {
298		#[inline]
299		fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
300		fmt::Debug::fmt(&self.value, f)
301		}
302		}
303
304		impl<F: Float + fmt::Display, C: FloatChecker<F>> fmt::Display for NoisyFloat<F, C> {
305		#[inline]
306	0	fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
307	0	fmt::Display::fmt(&self.value, f)
308	0	}
309		}
310
311		impl<F: Float + fmt::LowerExp, C: FloatChecker<F>> fmt::LowerExp for NoisyFloat<F, C> {
312		#[inline]
313		fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
314		fmt::LowerExp::fmt(&self.value, f)
315		}
316		}
317
318		impl<F: Float + fmt::UpperExp, C: FloatChecker<F>> fmt::UpperExp for NoisyFloat<F, C> {
319		#[inline]
320		fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
321		fmt::UpperExp::fmt(&self.value, f)
322		}
323		}
324
325		#[cfg(feature = "serde")]
326		impl<F: Float + Serialize, C: FloatChecker<F>> Serialize for NoisyFloat<F, C> {
327		fn serialize<S: Serializer>(&self, ser: S) -> Result<S::Ok, S::Error> {
328		self.value.serialize(ser)
329		}
330		}
331
332		#[cfg(feature = "serde")]
333		impl<'de, F: Float + Deserialize<'de>, C: FloatChecker<F>> Deserialize<'de> for NoisyFloat<F, C> {
334		fn deserialize<D: Deserializer<'de>>(de: D) -> Result<Self, D::Error> {
335		let value = F::deserialize(de)?;
336		Self::try_new(value).ok_or_else(\|\| D::Error::custom("invalid NoisyFloat"))
337		}
338		}
339
340		#[cfg(test)]
341		mod tests {
342		extern crate std;
343		use std::prelude::v1::*;
344
345		use crate::prelude::*;
346		#[cfg(feature = "serde")]
347		use serde_derive::{Deserialize, Serialize};
348		#[cfg(feature = "serde")]
349		use serde_json;
350		use std::{
351		f32,
352		f64::{self, consts},
353		hash::{Hash, Hasher},
354		mem::{align_of, size_of},
355		};
356
357		#[test]
358		fn smoke_test() {
359		assert_eq!(n64(1.0) + 2.0, 3.0);
360		assert_ne!(n64(3.0), n64(2.9));
361		assert!(r64(1.0) < 2.0);
362		let mut value = n64(18.0);
363		value %= n64(5.0);
364		assert_eq!(-value, n64(-3.0));
365		assert_eq!(r64(1.0).exp(), consts::E);
366		assert_eq!((N64::try_new(1.0).unwrap() / N64::infinity()), 0.0);
367		assert_eq!(N64::from_f32(f32::INFINITY), N64::from_f64(f64::INFINITY));
368		assert_eq!(R64::try_new(f64::NEG_INFINITY), None);
369		assert_eq!(N64::try_new(f64::NAN), None);
370		assert_eq!(R64::try_new(f64::NAN), None);
371		assert_eq!(N64::try_borrowed(&f64::NAN), None);
372		let mut nan = f64::NAN;
373		assert_eq!(N64::try_borrowed_mut(&mut nan), None);
374		}
375
376		#[test]
377		fn ensure_layout() {
378		assert_eq!(size_of::<N32>(), size_of::<f32>());
379		assert_eq!(align_of::<N32>(), align_of::<f32>());
380
381		assert_eq!(size_of::<N64>(), size_of::<f64>());
382		assert_eq!(align_of::<N64>(), align_of::<f64>());
383		}
384
385		#[test]
386		fn borrowed_casts() {
387		assert_eq!(R64::borrowed(&3.14), &3.14);
388		assert_eq!(N64::borrowed(&[f64::INFINITY; 2][0]), &f64::INFINITY);
389		assert_eq!(N64::borrowed_mut(&mut 2.72), &mut 2.72);
390		}
391
392		#[test]
393		fn test_convert() {
394		assert_eq!(f32::from(r32(3.0)), 3.0f32);
395		assert_eq!(f64::from(r32(5.0)), 5.0f64);
396		assert_eq!(f64::from(r64(7.0)), 7.0f64);
397		}
398
399		#[test]
400		#[cfg(debug_assertions)]
401		#[should_panic]
402		fn n64_nan() {
403		let _ = n64(0.0) / n64(0.0);
404		}
405
406		#[test]
407		#[cfg(debug_assertions)]
408		#[should_panic]
409		fn r64_nan() {
410		let _ = r64(0.0) / r64(0.0);
411		}
412
413		#[test]
414		#[cfg(debug_assertions)]
415		#[should_panic]
416		fn r64_infinity() {
417		let _ = r64(1.0) / r64(0.0);
418		}
419
420		#[test]
421		fn resolves_min_max() {
422		assert_eq!(r64(1.0).min(r64(3.0)), r64(1.0));
423		assert_eq!(r64(1.0).max(r64(3.0)), r64(3.0));
424		}
425
426		#[test]
427		fn epsilon() {
428		assert_eq!(R32::epsilon(), f32::EPSILON);
429		assert_eq!(R64::epsilon(), f64::EPSILON);
430		}
431
432		#[test]
433		fn test_try_into() {
434		use std::convert::{TryFrom, TryInto};
435		let _: R64 = 1.0.try_into().unwrap();
436		let _ = R64::try_from(f64::INFINITY).unwrap_err();
437		}
438
439		struct TestHasher {
440		bytes: Vec<u8>,
441		}
442
443		impl Hasher for TestHasher {
444		fn finish(&self) -> u64 {
445		panic!("unexpected Hasher.finish invocation")
446		}
447		fn write(&mut self, bytes: &[u8]) {
448		self.bytes.extend_from_slice(bytes)
449		}
450		}
451
452		fn hash_bytes<T: Hash>(value: T) -> Vec<u8> {
453		let mut hasher = TestHasher { bytes: Vec::new() };
454		value.hash(&mut hasher);
455		hasher.bytes
456		}
457
458		#[test]
459		fn test_hash() {
460		assert_eq!(hash_bytes(r64(10.3)), hash_bytes(10.3f64.to_bits()));
461		assert_ne!(hash_bytes(r64(10.3)), hash_bytes(10.4f64.to_bits()));
462		assert_eq!(hash_bytes(r32(10.3)), hash_bytes(10.3f32.to_bits()));
463		assert_ne!(hash_bytes(r32(10.3)), hash_bytes(10.4f32.to_bits()));
464
465		assert_eq!(
466		hash_bytes(N64::infinity()),
467		hash_bytes(f64::INFINITY.to_bits())
468		);
469		assert_eq!(
470		hash_bytes(N64::neg_infinity()),
471		hash_bytes(f64::NEG_INFINITY.to_bits())
472		);
473
474		// positive and negative zero should have the same hashes
475		assert_eq!(hash_bytes(r64(0.0)), hash_bytes(0.0f64.to_bits()));
476		assert_eq!(hash_bytes(r64(-0.0)), hash_bytes(0.0f64.to_bits()));
477		assert_eq!(hash_bytes(r32(0.0)), hash_bytes(0.0f32.to_bits()));
478		assert_eq!(hash_bytes(r32(-0.0)), hash_bytes(0.0f32.to_bits()));
479		}
480
481		#[cfg(feature = "serde")]
482		#[test]
483		fn serialize_transparently_as_float() {
484		let num = R32::new(3.14);
485		let should_be = "3.14";
486
487		let got = serde_json::to_string(&num).unwrap();
488		assert_eq!(got, should_be);
489		}
490
491		#[cfg(feature = "serde")]
492		#[test]
493		fn deserialize_transparently_as_float() {
494		let src = "3.14";
495		let should_be = R32::new(3.14);
496
497		let got: R32 = serde_json::from_str(src).unwrap();
498		assert_eq!(got, should_be);
499		}
500
501		#[cfg(feature = "serde")]
502		#[test]
503		fn deserialize_invalid_float() {
504		use crate::{FloatChecker, NoisyFloat};
505		struct PositiveChecker;
506		impl FloatChecker<f64> for PositiveChecker {
507		fn check(value: f64) -> bool {
508		value > 0.
509		}
510		fn assert(value: f64) {
511		debug_assert!(Self::check(value))
512		}
513		}
514
515		let src = "-1.0";
516		let got: Result<NoisyFloat<f64, PositiveChecker>, _> = serde_json::from_str(src);
517		assert!(got.is_err());
518		}
519
520		// Make sure you can use serde_derive with noisy floats.
521		#[cfg(feature = "serde")]
522		#[derive(Debug, PartialEq, Serialize, Deserialize)]
523		struct Dummy {
524		value: N64,
525		}
526
527		#[cfg(feature = "serde")]
528		#[test]
529		fn deserialize_struct_containing_n64() {
530		let src = r#"{ "value": 3.14 }"#;
531		let should_be = Dummy { value: n64(3.14) };
532
533		let got: Dummy = serde_json::from_str(src).unwrap();
534		assert_eq!(got, should_be);
535		}
536
537		#[cfg(feature = "serde")]
538		#[test]
539		fn serialize_struct_containing_n64() {
540		let src = Dummy { value: n64(3.14) };
541		let should_be = r#"{"value":3.14}"#;
542
543		let got = serde_json::to_string(&src).unwrap();
544		assert_eq!(got, should_be);
545		}
546
547		#[cfg(feature = "approx")]
548		#[test]
549		fn approx_assert_eq() {
550		use approx::{assert_abs_diff_eq, assert_relative_eq, assert_ulps_eq};
551
552		let lhs = r64(0.1000000000000001);
553		let rhs = r64(0.1);
554
555		assert_abs_diff_eq!(lhs, rhs);
556		assert_relative_eq!(lhs, rhs);
557		assert_ulps_eq!(lhs, rhs);
558		}
559
560		#[test]
561		fn const_functions() {
562		const A: N32 = N32::unchecked_new(1.0);
563		const B: N64 = N64::unchecked_new(2.0);
564		const C: R32 = R32::unchecked_new(3.0);
565		const D: R64 = R64::unchecked_new(4.0);
566
567		const A_RAW: f32 = A.const_raw();
568		const B_RAW: f64 = B.const_raw();
569		const C_RAW: f32 = C.const_raw();
570		const D_RAW: f64 = D.const_raw();
571
572		assert_eq!(A_RAW, 1.0);
573		assert_eq!(B_RAW, 2.0);
574		assert_eq!(C_RAW, 3.0);
575		assert_eq!(D_RAW, 4.0);
576		}
577		}