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// Copyright 2017 Serde 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 num_traits::NumCast;
use serde::de::{self, Visitor, Unexpected};
use serde::{Serialize, Serializer, Deserialize, Deserializer};
use std::fmt::{self, Debug, Display};
use std::i64;
/// Represents a JSON number, whether integer or floating point.
#[derive(Clone, PartialEq)]
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)]
enum N {
PosInt(u64),
/// Always less than zero.
NegInt(i64),
/// Always finite.
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_json;
/// #
/// # use std::i64;
/// #
/// # fn main() {
/// let big = i64::MAX 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 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_json;
/// #
/// # fn main() {
/// 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.
///
/// ```rust
/// # #[macro_use]
/// # extern crate serde_json;
/// #
/// # fn main() {
/// 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.
///
/// ```rust
/// # #[macro_use]
/// # extern crate serde_json;
/// #
/// # use std::i64;
/// #
/// # fn main() {
/// let big = i64::MAX 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) => NumCast::from(n),
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_json;
/// #
/// # fn main() {
/// 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) => NumCast::from(n),
N::Float(_) => None,
}
}
/// Represents the number as f64 if possible. Returns None otherwise.
///
/// ```rust
/// # #[macro_use]
/// # extern crate serde_json;
/// #
/// # fn main() {
/// 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) => NumCast::from(n),
N::NegInt(n) => NumCast::from(n),
N::Float(n) => Some(n),
}
}
/// Converts a finite `f64` to a `Number`. Infinite or NaN values are not JSON
/// numbers.
///
/// ```rust
/// # 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() {
Some(Number { n: N::Float(f) })
} else {
None
}
}
}
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) => 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>
where
E: de::Error,
{
Number::from_f64(value).ok_or_else(|| de::Error::custom("not a JSON number"))
}
}
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]
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) }
}
}
)*
};
}
from_signed!(i8 i16 i32 i64 isize);
from_unsigned!(u8 u16 u32 u64 usize);
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),
}
}
}