serde_yaml 0.8.0

YAML support for Serde
Documentation
// Copyright 2017 Serde YAML Developers
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use error::Error;
use serde::de::{Unexpected, Visitor};
use serde::{Deserialize, Deserializer, Serialize, Serializer};
use std::fmt::{self, Debug, Display};
use std::hash::{Hash, Hasher};
use std::i64;

/// Represents a YAML number, whether integer or floating point.
#[derive(Clone, PartialEq, PartialOrd)]
pub struct Number {
    n: N,
}

// "N" is a prefix of "NegInt"... this is a false positive.
// https://github.com/Manishearth/rust-clippy/issues/1241
#[cfg_attr(feature = "cargo-clippy", allow(enum_variant_names))]
#[derive(Copy, Clone, Debug, PartialEq, PartialOrd)]
enum N {
    PosInt(u64),
    /// Always less than zero.
    NegInt(i64),
    /// May be infinite or NaN.
    Float(f64),
}

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.
    ///
    /// ```rust
    /// # #[macro_use]
    /// # extern crate serde_yaml;
    /// #
    /// # use std::i64;
    /// #
    /// # fn yaml(i: &str) -> serde_yaml::Value { serde_yaml::from_str(i).unwrap() }
    /// # fn main() {
    /// let big = i64::MAX as u64 + 10;
    /// let v = yaml(r#"
    /// a: 64
    /// b: 9223372036854775817
    /// 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]
    #[cfg_attr(feature = "cargo-clippy", allow(cast_sign_loss))]
    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.
    ///
    /// ```rust
    /// # #[macro_use]
    /// # extern crate serde_yaml;
    /// #
    /// # fn yaml(i: &str) -> serde_yaml::Value { serde_yaml::from_str(i).unwrap() }
    /// # fn main() {
    /// let v = yaml(r#"
    /// 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.
    ///
    /// ```rust
    /// # #[macro_use]
    /// # extern crate serde_yaml;
    /// #
    /// # fn yaml(i: &str) -> serde_yaml::Value { serde_yaml::from_str(i).unwrap() }
    /// # fn main() {
    /// let v = yaml(r#"
    /// ---
    /// 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.
    ///
    /// ```rust
    /// # #[macro_use]
    /// # extern crate serde_yaml;
    /// #
    /// # use std::i64;
    /// #
    /// # fn yaml(i: &str) -> serde_yaml::Value { serde_yaml::from_str(i).unwrap() }
    /// # fn main() {
    /// let big = i64::MAX as u64 + 10;
    /// let v = yaml(r#"
    /// ---
    /// a: 64
    /// b: 9223372036854775817
    /// 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.
    ///
    /// ```rust
    /// # #[macro_use]
    /// # extern crate serde_yaml;
    /// #
    /// # fn yaml(i: &str) -> serde_yaml::Value { serde_yaml::from_str(i).unwrap() }
    /// # fn main() {
    /// let v = yaml(r#"
    /// ---
    /// 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.
    ///
    /// ```rust
    /// # #[macro_use]
    /// # extern crate serde_yaml;
    /// #
    /// # fn main() {
    /// # fn yaml(i: &str) -> serde_yaml::Value { serde_yaml::from_str(i).unwrap() }
    /// let v = yaml(r#"
    /// ---
    /// 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));
    /// # }
    /// ```
    ///
    /// ```rust
    /// # use std::f64;
    /// # fn yaml(i: &str) -> serde_yaml::Value { serde_yaml::from_str(i).unwrap() }
    /// assert_eq!(yaml("inf").as_f64(), Some(f64::INFINITY));
    /// assert_eq!(yaml("-inf").as_f64(), Some(f64::NEG_INFINITY));
    /// assert!(yaml("NaN").as_f64().unwrap().is_nan());
    /// ```
    #[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),
        }
    }

    /// Returns true if this value is NaN and false otherwise.
    ///
    /// ```rust
    /// # use std::f64;
    /// #
    /// # use serde_yaml::Number;
    /// #
    /// assert!(!Number::from(256.0).is_nan());
    ///
    /// assert!(Number::from(f64::NAN).is_nan());
    ///
    /// assert!(!Number::from(f64::INFINITY).is_nan());
    ///
    /// assert!(!Number::from(f64::NEG_INFINITY).is_nan());
    ///
    /// assert!(!Number::from(1).is_nan());
    /// ```
    #[inline]
    pub fn is_nan(&self) -> bool {
        match self.n {
            N::PosInt(_) | N::NegInt(_) => false,
            N::Float(f) => f.is_nan(),
        }
    }

    /// Returns true if this value is positive infinity or negative infinity and
    /// false otherwise.
    ///
    /// ```rust
    /// # use std::f64;
    /// #
    /// # use serde_yaml::Number;
    /// #
    /// assert!(!Number::from(256.0).is_infinite());
    ///
    /// assert!(!Number::from(f64::NAN).is_infinite());
    ///
    /// assert!(Number::from(f64::INFINITY).is_infinite());
    ///
    /// assert!(Number::from(f64::NEG_INFINITY).is_infinite());
    ///
    /// assert!(!Number::from(1).is_infinite());
    /// ```
    #[inline]
    pub fn is_infinite(&self) -> bool {
        match self.n {
            N::PosInt(_) | N::NegInt(_) => false,
            N::Float(f) => f.is_infinite(),
        }
    }

    /// Returns true if this number is neither infinite nor NaN.
    ///
    /// ```rust
    /// # use std::f64;
    /// #
    /// # use serde_yaml::Number;
    /// #
    /// assert!(Number::from(256.0).is_finite());
    ///
    /// assert!(!Number::from(f64::NAN).is_finite());
    ///
    /// assert!(!Number::from(f64::INFINITY).is_finite());
    ///
    /// assert!(!Number::from(f64::NEG_INFINITY).is_finite());
    ///
    /// assert!(Number::from(1).is_finite());
    /// ```
    #[inline]
    pub fn is_finite(&self) -> bool {
        match self.n {
            N::PosInt(_) | N::NegInt(_) => true,
            N::Float(f) => f.is_finite(),
        }
    }
}

impl fmt::Display for Number {
    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        match self.n {
            N::PosInt(i) => Display::fmt(&i, formatter),
            N::NegInt(i) => Display::fmt(&i, formatter),
            N::Float(f) if f.is_nan() => formatter.write_str(".nan"),
            N::Float(f) if f.is_infinite() => {
                if f.is_sign_negative() {
                    formatter.write_str("-.inf")
                } else {
                    formatter.write_str(".inf")
                }
            }
            N::Float(f) => Display::fmt(&f, formatter),
        }
    }
}

impl Debug for Number {
    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        Debug::fmt(&self.n, formatter)
    }
}

impl Serialize for Number {
    #[inline]
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        match self.n {
            N::PosInt(i) => serializer.serialize_u64(i),
            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>,
    {
        struct NumberVisitor;

        impl<'de> Visitor<'de> for NumberVisitor {
            type Value = Number;

            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
                formatter.write_str("a number")
            }

            #[inline]
            fn visit_i64<E>(self, value: i64) -> Result<Number, E> {
                Ok(value.into())
            }

            #[inline]
            fn visit_u64<E>(self, value: u64) -> Result<Number, E> {
                Ok(value.into())
            }

            #[inline]
            fn visit_f64<E>(self, value: f64) -> Result<Number, E> {
                Ok(value.into())
            }
        }

        deserializer.deserialize_any(NumberVisitor)
    }
}

impl<'de> Deserializer<'de> for Number {
    type Error = Error;

    #[inline]
    fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Error>
    where
        V: Visitor<'de>,
    {
        match self.n {
            N::PosInt(i) => visitor.visit_u64(i),
            N::NegInt(i) => visitor.visit_i64(i),
            N::Float(f) => visitor.visit_f64(f),
        }
    }

    forward_to_deserialize_any! {
        bool i8 i16 i32 i64 u8 u16 u32 u64 f32 f64 char str string bytes
        byte_buf option unit unit_struct newtype_struct seq tuple
        tuple_struct map struct enum identifier ignored_any
    }
}

impl<'de, 'a> Deserializer<'de> for &'a Number {
    type Error = Error;

    #[inline]
    fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Error>
    where
        V: Visitor<'de>,
    {
        match self.n {
            N::PosInt(i) => visitor.visit_u64(i),
            N::NegInt(i) => visitor.visit_i64(i),
            N::Float(f) => visitor.visit_f64(f),
        }
    }

    forward_to_deserialize_any! {
        bool i8 i16 i32 i64 u8 u16 u32 u64 f32 f64 char str string bytes
        byte_buf option unit unit_struct newtype_struct seq tuple
        tuple_struct map struct enum identifier ignored_any
    }
}

macro_rules! from_signed {
    ($($signed_ty:ident)*) => {
        $(
            impl From<$signed_ty> for Number {
                #[inline]
                #[cfg_attr(feature = "cargo-clippy", allow(cast_sign_loss))]
                fn from(i: $signed_ty) -> Self {
                    if i < 0 {
                        Number { n: N::NegInt(i as i64) }
                    } else {
                        Number { n: N::PosInt(i as u64) }
                    }
                }
            }
        )*
    };
}

macro_rules! from_unsigned {
    ($($unsigned_ty:ident)*) => {
        $(
            impl From<$unsigned_ty> for Number {
                #[inline]
                fn from(u: $unsigned_ty) -> Self {
                    Number { n: N::PosInt(u as u64) }
                }
            }
        )*
    };
}

macro_rules! from_float {
    ($($float_ty:ident)*) => {
        $(
            impl From<$float_ty> for Number {
                #[inline]
                fn from(f: $float_ty) -> Self {
                    Number { n: N::Float(f as f64) }
                }
            }
        )*
    }
}

from_signed!(i8 i16 i32 i64 isize);
from_unsigned!(u8 u16 u32 u64 usize);
from_float!(f32 f64);

// This is fine, because we don't _really_ implement hash for floats
// all other hash functions should work as expected
#[cfg_attr(feature = "cargo-clippy", allow(derive_hash_xor_eq))]
impl Hash for Number {
    fn hash<H: Hasher>(&self, state: &mut H) {
        match self.n {
            N::Float(_) => {
                // you should feel bad for using f64 as a map key
                3.hash(state)
            }
            N::PosInt(u) => u.hash(state),
            N::NegInt(i) => i.hash(state),
        }
    }
}

impl Number {
    // Not public API. Should be pub(crate).
    #[doc(hidden)]
    pub fn unexpected(&self) -> Unexpected {
        match self.n {
            N::PosInt(u) => Unexpected::Unsigned(u),
            N::NegInt(i) => Unexpected::Signed(i),
            N::Float(f) => Unexpected::Float(f),
        }
    }
}