use core::mem::size_of; use core::num::Wrapping; use core::{f32, f64}; #[cfg(has_i128)] use core::{i128, u128}; use core::{i16, i32, i64, i8, isize}; use core::{u16, u32, u64, u8, usize}; /// A generic trait for converting a value to a number. /// /// A value can be represented by the target type when it lies within /// the range of scalars supported by the target type. /// For example, a negative integer cannot be represented by an unsigned /// integer type, and an `i64` with a very high magnitude might not be /// convertible to an `i32`. /// On the other hand, conversions with possible precision loss or truncation /// are admitted, like an `f32` with a decimal part to an integer type, or /// even a large `f64` saturating to `f32` infinity. pub trait ToPrimitive { /// Converts the value of `self` to an `isize`. If the value cannot be /// represented by an `isize`, then `None` is returned. #[inline] fn to_isize(&self) -> Option { self.to_i64().as_ref().and_then(ToPrimitive::to_isize) } /// Converts the value of `self` to an `i8`. If the value cannot be /// represented by an `i8`, then `None` is returned. #[inline] fn to_i8(&self) -> Option { self.to_i64().as_ref().and_then(ToPrimitive::to_i8) } /// Converts the value of `self` to an `i16`. If the value cannot be /// represented by an `i16`, then `None` is returned. #[inline] fn to_i16(&self) -> Option { self.to_i64().as_ref().and_then(ToPrimitive::to_i16) } /// Converts the value of `self` to an `i32`. If the value cannot be /// represented by an `i32`, then `None` is returned. #[inline] fn to_i32(&self) -> Option { self.to_i64().as_ref().and_then(ToPrimitive::to_i32) } /// Converts the value of `self` to an `i64`. If the value cannot be /// represented by an `i64`, then `None` is returned. fn to_i64(&self) -> Option; /// Converts the value of `self` to an `i128`. If the value cannot be /// represented by an `i128` (`i64` under the default implementation), then /// `None` is returned. /// /// This method is only available with feature `i128` enabled on Rust >= 1.26. /// /// The default implementation converts through `to_i64()`. Types implementing /// this trait should override this method if they can represent a greater range. #[inline] #[cfg(has_i128)] fn to_i128(&self) -> Option { self.to_i64().map(From::from) } /// Converts the value of `self` to a `usize`. If the value cannot be /// represented by a `usize`, then `None` is returned. #[inline] fn to_usize(&self) -> Option { self.to_u64().as_ref().and_then(ToPrimitive::to_usize) } /// Converts the value of `self` to a `u8`. If the value cannot be /// represented by a `u8`, then `None` is returned. #[inline] fn to_u8(&self) -> Option { self.to_u64().as_ref().and_then(ToPrimitive::to_u8) } /// Converts the value of `self` to a `u16`. If the value cannot be /// represented by a `u16`, then `None` is returned. #[inline] fn to_u16(&self) -> Option { self.to_u64().as_ref().and_then(ToPrimitive::to_u16) } /// Converts the value of `self` to a `u32`. If the value cannot be /// represented by a `u32`, then `None` is returned. #[inline] fn to_u32(&self) -> Option { self.to_u64().as_ref().and_then(ToPrimitive::to_u32) } /// Converts the value of `self` to a `u64`. If the value cannot be /// represented by a `u64`, then `None` is returned. fn to_u64(&self) -> Option; /// Converts the value of `self` to a `u128`. If the value cannot be /// represented by a `u128` (`u64` under the default implementation), then /// `None` is returned. /// /// This method is only available with feature `i128` enabled on Rust >= 1.26. /// /// The default implementation converts through `to_u64()`. Types implementing /// this trait should override this method if they can represent a greater range. #[inline] #[cfg(has_i128)] fn to_u128(&self) -> Option { self.to_u64().map(From::from) } /// Converts the value of `self` to an `f32`. Overflows may map to positive /// or negative inifinity, otherwise `None` is returned if the value cannot /// be represented by an `f32`. #[inline] fn to_f32(&self) -> Option { self.to_f64().as_ref().and_then(ToPrimitive::to_f32) } /// Converts the value of `self` to an `f64`. Overflows may map to positive /// or negative inifinity, otherwise `None` is returned if the value cannot /// be represented by an `f64`. /// /// The default implementation tries to convert through `to_i64()`, and /// failing that through `to_u64()`. Types implementing this trait should /// override this method if they can represent a greater range. #[inline] fn to_f64(&self) -> Option { match self.to_i64() { Some(i) => i.to_f64(), None => self.to_u64().as_ref().and_then(ToPrimitive::to_f64), } } } macro_rules! impl_to_primitive_int_to_int { ($SrcT:ident : $( $(#[$cfg:meta])* fn $method:ident -> $DstT:ident ; )*) => {$( #[inline] $(#[$cfg])* fn $method(&self) -> Option<$DstT> { let min = $DstT::MIN as $SrcT; let max = $DstT::MAX as $SrcT; if size_of::<$SrcT>() <= size_of::<$DstT>() || (min <= *self && *self <= max) { Some(*self as $DstT) } else { None } } )*} } macro_rules! impl_to_primitive_int_to_uint { ($SrcT:ident : $( $(#[$cfg:meta])* fn $method:ident -> $DstT:ident ; )*) => {$( #[inline] $(#[$cfg])* fn $method(&self) -> Option<$DstT> { let max = $DstT::MAX as $SrcT; if 0 <= *self && (size_of::<$SrcT>() <= size_of::<$DstT>() || *self <= max) { Some(*self as $DstT) } else { None } } )*} } macro_rules! impl_to_primitive_int { ($T:ident) => { impl ToPrimitive for $T { impl_to_primitive_int_to_int! { $T: fn to_isize -> isize; fn to_i8 -> i8; fn to_i16 -> i16; fn to_i32 -> i32; fn to_i64 -> i64; #[cfg(has_i128)] fn to_i128 -> i128; } impl_to_primitive_int_to_uint! { $T: fn to_usize -> usize; fn to_u8 -> u8; fn to_u16 -> u16; fn to_u32 -> u32; fn to_u64 -> u64; #[cfg(has_i128)] fn to_u128 -> u128; } #[inline] fn to_f32(&self) -> Option { Some(*self as f32) } #[inline] fn to_f64(&self) -> Option { Some(*self as f64) } } }; } impl_to_primitive_int!(isize); impl_to_primitive_int!(i8); impl_to_primitive_int!(i16); impl_to_primitive_int!(i32); impl_to_primitive_int!(i64); #[cfg(has_i128)] impl_to_primitive_int!(i128); macro_rules! impl_to_primitive_uint_to_int { ($SrcT:ident : $( $(#[$cfg:meta])* fn $method:ident -> $DstT:ident ; )*) => {$( #[inline] $(#[$cfg])* fn $method(&self) -> Option<$DstT> { let max = $DstT::MAX as $SrcT; if size_of::<$SrcT>() < size_of::<$DstT>() || *self <= max { Some(*self as $DstT) } else { None } } )*} } macro_rules! impl_to_primitive_uint_to_uint { ($SrcT:ident : $( $(#[$cfg:meta])* fn $method:ident -> $DstT:ident ; )*) => {$( #[inline] $(#[$cfg])* fn $method(&self) -> Option<$DstT> { let max = $DstT::MAX as $SrcT; if size_of::<$SrcT>() <= size_of::<$DstT>() || *self <= max { Some(*self as $DstT) } else { None } } )*} } macro_rules! impl_to_primitive_uint { ($T:ident) => { impl ToPrimitive for $T { impl_to_primitive_uint_to_int! { $T: fn to_isize -> isize; fn to_i8 -> i8; fn to_i16 -> i16; fn to_i32 -> i32; fn to_i64 -> i64; #[cfg(has_i128)] fn to_i128 -> i128; } impl_to_primitive_uint_to_uint! { $T: fn to_usize -> usize; fn to_u8 -> u8; fn to_u16 -> u16; fn to_u32 -> u32; fn to_u64 -> u64; #[cfg(has_i128)] fn to_u128 -> u128; } #[inline] fn to_f32(&self) -> Option { Some(*self as f32) } #[inline] fn to_f64(&self) -> Option { Some(*self as f64) } } }; } impl_to_primitive_uint!(usize); impl_to_primitive_uint!(u8); impl_to_primitive_uint!(u16); impl_to_primitive_uint!(u32); impl_to_primitive_uint!(u64); #[cfg(has_i128)] impl_to_primitive_uint!(u128); macro_rules! impl_to_primitive_float_to_float { ($SrcT:ident : $( fn $method:ident -> $DstT:ident ; )*) => {$( #[inline] fn $method(&self) -> Option<$DstT> { // We can safely cast all values, whether NaN, +-inf, or finite. // Finite values that are reducing size may saturate to +-inf. Some(*self as $DstT) } )*} } #[cfg(has_to_int_unchecked)] macro_rules! float_to_int_unchecked { // SAFETY: Must not be NaN or infinite; must be representable as the integer after truncating. // We already checked that the float is in the exclusive range `(MIN-1, MAX+1)`. ($float:expr => $int:ty) => { unsafe { $float.to_int_unchecked::<$int>() } }; } #[cfg(not(has_to_int_unchecked))] macro_rules! float_to_int_unchecked { ($float:expr => $int:ty) => { $float as $int }; } macro_rules! impl_to_primitive_float_to_signed_int { ($f:ident : $( $(#[$cfg:meta])* fn $method:ident -> $i:ident ; )*) => {$( #[inline] $(#[$cfg])* fn $method(&self) -> Option<$i> { // Float as int truncates toward zero, so we want to allow values // in the exclusive range `(MIN-1, MAX+1)`. if size_of::<$f>() > size_of::<$i>() { // With a larger size, we can represent the range exactly. const MIN_M1: $f = $i::MIN as $f - 1.0; const MAX_P1: $f = $i::MAX as $f + 1.0; if *self > MIN_M1 && *self < MAX_P1 { return Some(float_to_int_unchecked!(*self => $i)); } } else { // We can't represent `MIN-1` exactly, but there's no fractional part // at this magnitude, so we can just use a `MIN` inclusive boundary. const MIN: $f = $i::MIN as $f; // We can't represent `MAX` exactly, but it will round up to exactly // `MAX+1` (a power of two) when we cast it. const MAX_P1: $f = $i::MAX as $f; if *self >= MIN && *self < MAX_P1 { return Some(float_to_int_unchecked!(*self => $i)); } } None } )*} } macro_rules! impl_to_primitive_float_to_unsigned_int { ($f:ident : $( $(#[$cfg:meta])* fn $method:ident -> $u:ident ; )*) => {$( #[inline] $(#[$cfg])* fn $method(&self) -> Option<$u> { // Float as int truncates toward zero, so we want to allow values // in the exclusive range `(-1, MAX+1)`. if size_of::<$f>() > size_of::<$u>() { // With a larger size, we can represent the range exactly. const MAX_P1: $f = $u::MAX as $f + 1.0; if *self > -1.0 && *self < MAX_P1 { return Some(float_to_int_unchecked!(*self => $u)); } } else { // We can't represent `MAX` exactly, but it will round up to exactly // `MAX+1` (a power of two) when we cast it. // (`u128::MAX as f32` is infinity, but this is still ok.) const MAX_P1: $f = $u::MAX as $f; if *self > -1.0 && *self < MAX_P1 { return Some(float_to_int_unchecked!(*self => $u)); } } None } )*} } macro_rules! impl_to_primitive_float { ($T:ident) => { impl ToPrimitive for $T { impl_to_primitive_float_to_signed_int! { $T: fn to_isize -> isize; fn to_i8 -> i8; fn to_i16 -> i16; fn to_i32 -> i32; fn to_i64 -> i64; #[cfg(has_i128)] fn to_i128 -> i128; } impl_to_primitive_float_to_unsigned_int! { $T: fn to_usize -> usize; fn to_u8 -> u8; fn to_u16 -> u16; fn to_u32 -> u32; fn to_u64 -> u64; #[cfg(has_i128)] fn to_u128 -> u128; } impl_to_primitive_float_to_float! { $T: fn to_f32 -> f32; fn to_f64 -> f64; } } }; } impl_to_primitive_float!(f32); impl_to_primitive_float!(f64); /// A generic trait for converting a number to a value. /// /// A value can be represented by the target type when it lies within /// the range of scalars supported by the target type. /// For example, a negative integer cannot be represented by an unsigned /// integer type, and an `i64` with a very high magnitude might not be /// convertible to an `i32`. /// On the other hand, conversions with possible precision loss or truncation /// are admitted, like an `f32` with a decimal part to an integer type, or /// even a large `f64` saturating to `f32` infinity. pub trait FromPrimitive: Sized { /// Converts an `isize` to return an optional value of this type. If the /// value cannot be represented by this type, then `None` is returned. #[inline] fn from_isize(n: isize) -> Option { n.to_i64().and_then(FromPrimitive::from_i64) } /// Converts an `i8` to return an optional value of this type. If the /// value cannot be represented by this type, then `None` is returned. #[inline] fn from_i8(n: i8) -> Option { FromPrimitive::from_i64(From::from(n)) } /// Converts an `i16` to return an optional value of this type. If the /// value cannot be represented by this type, then `None` is returned. #[inline] fn from_i16(n: i16) -> Option { FromPrimitive::from_i64(From::from(n)) } /// Converts an `i32` to return an optional value of this type. If the /// value cannot be represented by this type, then `None` is returned. #[inline] fn from_i32(n: i32) -> Option { FromPrimitive::from_i64(From::from(n)) } /// Converts an `i64` to return an optional value of this type. If the /// value cannot be represented by this type, then `None` is returned. fn from_i64(n: i64) -> Option; /// Converts an `i128` to return an optional value of this type. If the /// value cannot be represented by this type, then `None` is returned. /// /// This method is only available with feature `i128` enabled on Rust >= 1.26. /// /// The default implementation converts through `from_i64()`. Types implementing /// this trait should override this method if they can represent a greater range. #[inline] #[cfg(has_i128)] fn from_i128(n: i128) -> Option { n.to_i64().and_then(FromPrimitive::from_i64) } /// Converts a `usize` to return an optional value of this type. If the /// value cannot be represented by this type, then `None` is returned. #[inline] fn from_usize(n: usize) -> Option { n.to_u64().and_then(FromPrimitive::from_u64) } /// Converts an `u8` to return an optional value of this type. If the /// value cannot be represented by this type, then `None` is returned. #[inline] fn from_u8(n: u8) -> Option { FromPrimitive::from_u64(From::from(n)) } /// Converts an `u16` to return an optional value of this type. If the /// value cannot be represented by this type, then `None` is returned. #[inline] fn from_u16(n: u16) -> Option { FromPrimitive::from_u64(From::from(n)) } /// Converts an `u32` to return an optional value of this type. If the /// value cannot be represented by this type, then `None` is returned. #[inline] fn from_u32(n: u32) -> Option { FromPrimitive::from_u64(From::from(n)) } /// Converts an `u64` to return an optional value of this type. If the /// value cannot be represented by this type, then `None` is returned. fn from_u64(n: u64) -> Option; /// Converts an `u128` to return an optional value of this type. If the /// value cannot be represented by this type, then `None` is returned. /// /// This method is only available with feature `i128` enabled on Rust >= 1.26. /// /// The default implementation converts through `from_u64()`. Types implementing /// this trait should override this method if they can represent a greater range. #[inline] #[cfg(has_i128)] fn from_u128(n: u128) -> Option { n.to_u64().and_then(FromPrimitive::from_u64) } /// Converts a `f32` to return an optional value of this type. If the /// value cannot be represented by this type, then `None` is returned. #[inline] fn from_f32(n: f32) -> Option { FromPrimitive::from_f64(From::from(n)) } /// Converts a `f64` to return an optional value of this type. If the /// value cannot be represented by this type, then `None` is returned. /// /// The default implementation tries to convert through `from_i64()`, and /// failing that through `from_u64()`. Types implementing this trait should /// override this method if they can represent a greater range. #[inline] fn from_f64(n: f64) -> Option { match n.to_i64() { Some(i) => FromPrimitive::from_i64(i), None => n.to_u64().and_then(FromPrimitive::from_u64), } } } macro_rules! impl_from_primitive { ($T:ty, $to_ty:ident) => { #[allow(deprecated)] impl FromPrimitive for $T { #[inline] fn from_isize(n: isize) -> Option<$T> { n.$to_ty() } #[inline] fn from_i8(n: i8) -> Option<$T> { n.$to_ty() } #[inline] fn from_i16(n: i16) -> Option<$T> { n.$to_ty() } #[inline] fn from_i32(n: i32) -> Option<$T> { n.$to_ty() } #[inline] fn from_i64(n: i64) -> Option<$T> { n.$to_ty() } #[cfg(has_i128)] #[inline] fn from_i128(n: i128) -> Option<$T> { n.$to_ty() } #[inline] fn from_usize(n: usize) -> Option<$T> { n.$to_ty() } #[inline] fn from_u8(n: u8) -> Option<$T> { n.$to_ty() } #[inline] fn from_u16(n: u16) -> Option<$T> { n.$to_ty() } #[inline] fn from_u32(n: u32) -> Option<$T> { n.$to_ty() } #[inline] fn from_u64(n: u64) -> Option<$T> { n.$to_ty() } #[cfg(has_i128)] #[inline] fn from_u128(n: u128) -> Option<$T> { n.$to_ty() } #[inline] fn from_f32(n: f32) -> Option<$T> { n.$to_ty() } #[inline] fn from_f64(n: f64) -> Option<$T> { n.$to_ty() } } }; } impl_from_primitive!(isize, to_isize); impl_from_primitive!(i8, to_i8); impl_from_primitive!(i16, to_i16); impl_from_primitive!(i32, to_i32); impl_from_primitive!(i64, to_i64); #[cfg(has_i128)] impl_from_primitive!(i128, to_i128); impl_from_primitive!(usize, to_usize); impl_from_primitive!(u8, to_u8); impl_from_primitive!(u16, to_u16); impl_from_primitive!(u32, to_u32); impl_from_primitive!(u64, to_u64); #[cfg(has_i128)] impl_from_primitive!(u128, to_u128); impl_from_primitive!(f32, to_f32); impl_from_primitive!(f64, to_f64); macro_rules! impl_to_primitive_wrapping { ($( $(#[$cfg:meta])* fn $method:ident -> $i:ident ; )*) => {$( #[inline] $(#[$cfg])* fn $method(&self) -> Option<$i> { (self.0).$method() } )*} } impl ToPrimitive for Wrapping { impl_to_primitive_wrapping! { fn to_isize -> isize; fn to_i8 -> i8; fn to_i16 -> i16; fn to_i32 -> i32; fn to_i64 -> i64; #[cfg(has_i128)] fn to_i128 -> i128; fn to_usize -> usize; fn to_u8 -> u8; fn to_u16 -> u16; fn to_u32 -> u32; fn to_u64 -> u64; #[cfg(has_i128)] fn to_u128 -> u128; fn to_f32 -> f32; fn to_f64 -> f64; } } macro_rules! impl_from_primitive_wrapping { ($( $(#[$cfg:meta])* fn $method:ident ( $i:ident ); )*) => {$( #[inline] $(#[$cfg])* fn $method(n: $i) -> Option { T::$method(n).map(Wrapping) } )*} } impl FromPrimitive for Wrapping { impl_from_primitive_wrapping! { fn from_isize(isize); fn from_i8(i8); fn from_i16(i16); fn from_i32(i32); fn from_i64(i64); #[cfg(has_i128)] fn from_i128(i128); fn from_usize(usize); fn from_u8(u8); fn from_u16(u16); fn from_u32(u32); fn from_u64(u64); #[cfg(has_i128)] fn from_u128(u128); fn from_f32(f32); fn from_f64(f64); } } /// Cast from one machine scalar to another. /// /// # Examples /// /// ``` /// # use num_traits as num; /// let twenty: f32 = num::cast(0x14).unwrap(); /// assert_eq!(twenty, 20f32); /// ``` /// #[inline] pub fn cast(n: T) -> Option { NumCast::from(n) } /// An interface for casting between machine scalars. pub trait NumCast: Sized + ToPrimitive { /// Creates a number from another value that can be converted into /// a primitive via the `ToPrimitive` trait. If the source value cannot be /// represented by the target type, then `None` is returned. /// /// A value can be represented by the target type when it lies within /// the range of scalars supported by the target type. /// For example, a negative integer cannot be represented by an unsigned /// integer type, and an `i64` with a very high magnitude might not be /// convertible to an `i32`. /// On the other hand, conversions with possible precision loss or truncation /// are admitted, like an `f32` with a decimal part to an integer type, or /// even a large `f64` saturating to `f32` infinity. fn from(n: T) -> Option; } macro_rules! impl_num_cast { ($T:ty, $conv:ident) => { impl NumCast for $T { #[inline] #[allow(deprecated)] fn from(n: N) -> Option<$T> { // `$conv` could be generated using `concat_idents!`, but that // macro seems to be broken at the moment n.$conv() } } }; } impl_num_cast!(u8, to_u8); impl_num_cast!(u16, to_u16); impl_num_cast!(u32, to_u32); impl_num_cast!(u64, to_u64); #[cfg(has_i128)] impl_num_cast!(u128, to_u128); impl_num_cast!(usize, to_usize); impl_num_cast!(i8, to_i8); impl_num_cast!(i16, to_i16); impl_num_cast!(i32, to_i32); impl_num_cast!(i64, to_i64); #[cfg(has_i128)] impl_num_cast!(i128, to_i128); impl_num_cast!(isize, to_isize); impl_num_cast!(f32, to_f32); impl_num_cast!(f64, to_f64); impl NumCast for Wrapping { fn from(n: U) -> Option { T::from(n).map(Wrapping) } } /// A generic interface for casting between machine scalars with the /// `as` operator, which admits narrowing and precision loss. /// Implementers of this trait `AsPrimitive` should behave like a primitive /// numeric type (e.g. a newtype around another primitive), and the /// intended conversion must never fail. /// /// # Examples /// /// ``` /// # use num_traits::AsPrimitive; /// let three: i32 = (3.14159265f32).as_(); /// assert_eq!(three, 3); /// ``` /// /// # Safety /// /// **In Rust versions before 1.45.0**, some uses of the `as` operator were not entirely safe. /// In particular, it was undefined behavior if /// a truncated floating point value could not fit in the target integer /// type ([#10184](https://github.com/rust-lang/rust/issues/10184)). /// /// ```ignore /// # use num_traits::AsPrimitive; /// let x: u8 = (1.04E+17).as_(); // UB /// ``` /// pub trait AsPrimitive: 'static + Copy where T: 'static + Copy, { /// Convert a value to another, using the `as` operator. fn as_(self) -> T; } macro_rules! impl_as_primitive { (@ $T: ty => $(#[$cfg:meta])* impl $U: ty ) => { $(#[$cfg])* impl AsPrimitive<$U> for $T { #[inline] fn as_(self) -> $U { self as $U } } }; (@ $T: ty => { $( $U: ty ),* } ) => {$( impl_as_primitive!(@ $T => impl $U); )*}; ($T: ty => { $( $U: ty ),* } ) => { impl_as_primitive!(@ $T => { $( $U ),* }); impl_as_primitive!(@ $T => { u8, u16, u32, u64, usize }); impl_as_primitive!(@ $T => #[cfg(has_i128)] impl u128); impl_as_primitive!(@ $T => { i8, i16, i32, i64, isize }); impl_as_primitive!(@ $T => #[cfg(has_i128)] impl i128); }; } impl_as_primitive!(u8 => { char, f32, f64 }); impl_as_primitive!(i8 => { f32, f64 }); impl_as_primitive!(u16 => { f32, f64 }); impl_as_primitive!(i16 => { f32, f64 }); impl_as_primitive!(u32 => { f32, f64 }); impl_as_primitive!(i32 => { f32, f64 }); impl_as_primitive!(u64 => { f32, f64 }); impl_as_primitive!(i64 => { f32, f64 }); #[cfg(has_i128)] impl_as_primitive!(u128 => { f32, f64 }); #[cfg(has_i128)] impl_as_primitive!(i128 => { f32, f64 }); impl_as_primitive!(usize => { f32, f64 }); impl_as_primitive!(isize => { f32, f64 }); impl_as_primitive!(f32 => { f32, f64 }); impl_as_primitive!(f64 => { f32, f64 }); impl_as_primitive!(char => { char }); impl_as_primitive!(bool => {});