| use std::mem::size_of; |
| use std::num::Wrapping; |
| |
| use identities::Zero; |
| use bounds::Bounded; |
| |
| /// A generic trait for converting a value to a number. |
| pub trait ToPrimitive { |
| /// Converts the value of `self` to an `isize`. |
| #[inline] |
| fn to_isize(&self) -> Option<isize> { |
| self.to_i64().and_then(|x| x.to_isize()) |
| } |
| |
| /// Converts the value of `self` to an `i8`. |
| #[inline] |
| fn to_i8(&self) -> Option<i8> { |
| self.to_i64().and_then(|x| x.to_i8()) |
| } |
| |
| /// Converts the value of `self` to an `i16`. |
| #[inline] |
| fn to_i16(&self) -> Option<i16> { |
| self.to_i64().and_then(|x| x.to_i16()) |
| } |
| |
| /// Converts the value of `self` to an `i32`. |
| #[inline] |
| fn to_i32(&self) -> Option<i32> { |
| self.to_i64().and_then(|x| x.to_i32()) |
| } |
| |
| /// Converts the value of `self` to an `i64`. |
| fn to_i64(&self) -> Option<i64>; |
| |
| /// Converts the value of `self` to a `usize`. |
| #[inline] |
| fn to_usize(&self) -> Option<usize> { |
| self.to_u64().and_then(|x| x.to_usize()) |
| } |
| |
| /// Converts the value of `self` to an `u8`. |
| #[inline] |
| fn to_u8(&self) -> Option<u8> { |
| self.to_u64().and_then(|x| x.to_u8()) |
| } |
| |
| /// Converts the value of `self` to an `u16`. |
| #[inline] |
| fn to_u16(&self) -> Option<u16> { |
| self.to_u64().and_then(|x| x.to_u16()) |
| } |
| |
| /// Converts the value of `self` to an `u32`. |
| #[inline] |
| fn to_u32(&self) -> Option<u32> { |
| self.to_u64().and_then(|x| x.to_u32()) |
| } |
| |
| /// Converts the value of `self` to an `u64`. |
| #[inline] |
| fn to_u64(&self) -> Option<u64>; |
| |
| /// Converts the value of `self` to an `f32`. |
| #[inline] |
| fn to_f32(&self) -> Option<f32> { |
| self.to_f64().and_then(|x| x.to_f32()) |
| } |
| |
| /// Converts the value of `self` to an `f64`. |
| #[inline] |
| fn to_f64(&self) -> Option<f64> { |
| self.to_i64().and_then(|x| x.to_f64()) |
| } |
| } |
| |
| macro_rules! impl_to_primitive_int_to_int { |
| ($SrcT:ty, $DstT:ty, $slf:expr) => ( |
| { |
| if size_of::<$SrcT>() <= size_of::<$DstT>() { |
| Some($slf as $DstT) |
| } else { |
| let n = $slf as i64; |
| let min_value: $DstT = Bounded::min_value(); |
| let max_value: $DstT = Bounded::max_value(); |
| if min_value as i64 <= n && n <= max_value as i64 { |
| Some($slf as $DstT) |
| } else { |
| None |
| } |
| } |
| } |
| ) |
| } |
| |
| macro_rules! impl_to_primitive_int_to_uint { |
| ($SrcT:ty, $DstT:ty, $slf:expr) => ( |
| { |
| let zero: $SrcT = Zero::zero(); |
| let max_value: $DstT = Bounded::max_value(); |
| if zero <= $slf && $slf as u64 <= max_value as u64 { |
| Some($slf as $DstT) |
| } else { |
| None |
| } |
| } |
| ) |
| } |
| |
| macro_rules! impl_to_primitive_int { |
| ($T:ty) => ( |
| impl ToPrimitive for $T { |
| #[inline] |
| fn to_isize(&self) -> Option<isize> { impl_to_primitive_int_to_int!($T, isize, *self) } |
| #[inline] |
| fn to_i8(&self) -> Option<i8> { impl_to_primitive_int_to_int!($T, i8, *self) } |
| #[inline] |
| fn to_i16(&self) -> Option<i16> { impl_to_primitive_int_to_int!($T, i16, *self) } |
| #[inline] |
| fn to_i32(&self) -> Option<i32> { impl_to_primitive_int_to_int!($T, i32, *self) } |
| #[inline] |
| fn to_i64(&self) -> Option<i64> { impl_to_primitive_int_to_int!($T, i64, *self) } |
| |
| #[inline] |
| fn to_usize(&self) -> Option<usize> { impl_to_primitive_int_to_uint!($T, usize, *self) } |
| #[inline] |
| fn to_u8(&self) -> Option<u8> { impl_to_primitive_int_to_uint!($T, u8, *self) } |
| #[inline] |
| fn to_u16(&self) -> Option<u16> { impl_to_primitive_int_to_uint!($T, u16, *self) } |
| #[inline] |
| fn to_u32(&self) -> Option<u32> { impl_to_primitive_int_to_uint!($T, u32, *self) } |
| #[inline] |
| fn to_u64(&self) -> Option<u64> { impl_to_primitive_int_to_uint!($T, u64, *self) } |
| |
| #[inline] |
| fn to_f32(&self) -> Option<f32> { Some(*self as f32) } |
| #[inline] |
| fn to_f64(&self) -> Option<f64> { Some(*self as f64) } |
| } |
| ) |
| } |
| |
| impl_to_primitive_int!(isize); |
| impl_to_primitive_int!(i8); |
| impl_to_primitive_int!(i16); |
| impl_to_primitive_int!(i32); |
| impl_to_primitive_int!(i64); |
| |
| macro_rules! impl_to_primitive_uint_to_int { |
| ($DstT:ty, $slf:expr) => ( |
| { |
| let max_value: $DstT = Bounded::max_value(); |
| if $slf as u64 <= max_value as u64 { |
| Some($slf as $DstT) |
| } else { |
| None |
| } |
| } |
| ) |
| } |
| |
| macro_rules! impl_to_primitive_uint_to_uint { |
| ($SrcT:ty, $DstT:ty, $slf:expr) => ( |
| { |
| if size_of::<$SrcT>() <= size_of::<$DstT>() { |
| Some($slf as $DstT) |
| } else { |
| let zero: $SrcT = Zero::zero(); |
| let max_value: $DstT = Bounded::max_value(); |
| if zero <= $slf && $slf as u64 <= max_value as u64 { |
| Some($slf as $DstT) |
| } else { |
| None |
| } |
| } |
| } |
| ) |
| } |
| |
| macro_rules! impl_to_primitive_uint { |
| ($T:ty) => ( |
| impl ToPrimitive for $T { |
| #[inline] |
| fn to_isize(&self) -> Option<isize> { impl_to_primitive_uint_to_int!(isize, *self) } |
| #[inline] |
| fn to_i8(&self) -> Option<i8> { impl_to_primitive_uint_to_int!(i8, *self) } |
| #[inline] |
| fn to_i16(&self) -> Option<i16> { impl_to_primitive_uint_to_int!(i16, *self) } |
| #[inline] |
| fn to_i32(&self) -> Option<i32> { impl_to_primitive_uint_to_int!(i32, *self) } |
| #[inline] |
| fn to_i64(&self) -> Option<i64> { impl_to_primitive_uint_to_int!(i64, *self) } |
| |
| #[inline] |
| fn to_usize(&self) -> Option<usize> { |
| impl_to_primitive_uint_to_uint!($T, usize, *self) |
| } |
| #[inline] |
| fn to_u8(&self) -> Option<u8> { impl_to_primitive_uint_to_uint!($T, u8, *self) } |
| #[inline] |
| fn to_u16(&self) -> Option<u16> { impl_to_primitive_uint_to_uint!($T, u16, *self) } |
| #[inline] |
| fn to_u32(&self) -> Option<u32> { impl_to_primitive_uint_to_uint!($T, u32, *self) } |
| #[inline] |
| fn to_u64(&self) -> Option<u64> { impl_to_primitive_uint_to_uint!($T, u64, *self) } |
| |
| #[inline] |
| fn to_f32(&self) -> Option<f32> { Some(*self as f32) } |
| #[inline] |
| fn to_f64(&self) -> Option<f64> { 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); |
| |
| macro_rules! impl_to_primitive_float_to_float { |
| ($SrcT:ident, $DstT:ident, $slf:expr) => ( |
| if size_of::<$SrcT>() <= size_of::<$DstT>() { |
| Some($slf as $DstT) |
| } else { |
| // Make sure the value is in range for the cast. |
| // NaN and +-inf are cast as they are. |
| let n = $slf as f64; |
| let max_value: $DstT = ::std::$DstT::MAX; |
| if !n.is_finite() || (-max_value as f64 <= n && n <= max_value as f64) { |
| Some($slf as $DstT) |
| } else { |
| None |
| } |
| } |
| ) |
| } |
| |
| macro_rules! impl_to_primitive_float { |
| ($T:ident) => ( |
| impl ToPrimitive for $T { |
| #[inline] |
| fn to_isize(&self) -> Option<isize> { Some(*self as isize) } |
| #[inline] |
| fn to_i8(&self) -> Option<i8> { Some(*self as i8) } |
| #[inline] |
| fn to_i16(&self) -> Option<i16> { Some(*self as i16) } |
| #[inline] |
| fn to_i32(&self) -> Option<i32> { Some(*self as i32) } |
| #[inline] |
| fn to_i64(&self) -> Option<i64> { Some(*self as i64) } |
| |
| #[inline] |
| fn to_usize(&self) -> Option<usize> { Some(*self as usize) } |
| #[inline] |
| fn to_u8(&self) -> Option<u8> { Some(*self as u8) } |
| #[inline] |
| fn to_u16(&self) -> Option<u16> { Some(*self as u16) } |
| #[inline] |
| fn to_u32(&self) -> Option<u32> { Some(*self as u32) } |
| #[inline] |
| fn to_u64(&self) -> Option<u64> { Some(*self as u64) } |
| |
| #[inline] |
| fn to_f32(&self) -> Option<f32> { impl_to_primitive_float_to_float!($T, f32, *self) } |
| #[inline] |
| fn to_f64(&self) -> Option<f64> { impl_to_primitive_float_to_float!($T, f64, *self) } |
| } |
| ) |
| } |
| |
| impl_to_primitive_float!(f32); |
| impl_to_primitive_float!(f64); |
| |
| /// A generic trait for converting a number to a value. |
| pub trait FromPrimitive: Sized { |
| /// Convert an `isize` to return an optional value of this type. If the |
| /// value cannot be represented by this value, the `None` is returned. |
| #[inline] |
| fn from_isize(n: isize) -> Option<Self> { |
| FromPrimitive::from_i64(n as i64) |
| } |
| |
| /// Convert an `i8` to return an optional value of this type. If the |
| /// type cannot be represented by this value, the `None` is returned. |
| #[inline] |
| fn from_i8(n: i8) -> Option<Self> { |
| FromPrimitive::from_i64(n as i64) |
| } |
| |
| /// Convert an `i16` to return an optional value of this type. If the |
| /// type cannot be represented by this value, the `None` is returned. |
| #[inline] |
| fn from_i16(n: i16) -> Option<Self> { |
| FromPrimitive::from_i64(n as i64) |
| } |
| |
| /// Convert an `i32` to return an optional value of this type. If the |
| /// type cannot be represented by this value, the `None` is returned. |
| #[inline] |
| fn from_i32(n: i32) -> Option<Self> { |
| FromPrimitive::from_i64(n as i64) |
| } |
| |
| /// Convert an `i64` to return an optional value of this type. If the |
| /// type cannot be represented by this value, the `None` is returned. |
| fn from_i64(n: i64) -> Option<Self>; |
| |
| /// Convert a `usize` to return an optional value of this type. If the |
| /// type cannot be represented by this value, the `None` is returned. |
| #[inline] |
| fn from_usize(n: usize) -> Option<Self> { |
| FromPrimitive::from_u64(n as u64) |
| } |
| |
| /// Convert an `u8` to return an optional value of this type. If the |
| /// type cannot be represented by this value, the `None` is returned. |
| #[inline] |
| fn from_u8(n: u8) -> Option<Self> { |
| FromPrimitive::from_u64(n as u64) |
| } |
| |
| /// Convert an `u16` to return an optional value of this type. If the |
| /// type cannot be represented by this value, the `None` is returned. |
| #[inline] |
| fn from_u16(n: u16) -> Option<Self> { |
| FromPrimitive::from_u64(n as u64) |
| } |
| |
| /// Convert an `u32` to return an optional value of this type. If the |
| /// type cannot be represented by this value, the `None` is returned. |
| #[inline] |
| fn from_u32(n: u32) -> Option<Self> { |
| FromPrimitive::from_u64(n as u64) |
| } |
| |
| /// Convert an `u64` to return an optional value of this type. If the |
| /// type cannot be represented by this value, the `None` is returned. |
| fn from_u64(n: u64) -> Option<Self>; |
| |
| /// Convert a `f32` to return an optional value of this type. If the |
| /// type cannot be represented by this value, the `None` is returned. |
| #[inline] |
| fn from_f32(n: f32) -> Option<Self> { |
| FromPrimitive::from_f64(n as f64) |
| } |
| |
| /// Convert a `f64` to return an optional value of this type. If the |
| /// type cannot be represented by this value, the `None` is returned. |
| #[inline] |
| fn from_f64(n: f64) -> Option<Self> { |
| FromPrimitive::from_i64(n as i64) |
| } |
| } |
| |
| macro_rules! impl_from_primitive { |
| ($T:ty, $to_ty:ident) => ( |
| #[allow(deprecated)] |
| impl FromPrimitive for $T { |
| #[inline] fn from_i8(n: i8) -> Option<$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.$to_ty() } |
| |
| #[inline] fn from_u8(n: u8) -> Option<$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.$to_ty() } |
| |
| #[inline] fn from_f32(n: f32) -> Option<$T> { n.$to_ty() } |
| #[inline] fn from_f64(n: f64) -> Option<$T> { n.$to_ty() } |
| } |
| ) |
| } |
| |
| impl_from_primitive!(isize, to_isize); |
| impl_from_primitive!(i8, to_i8); |
| impl_from_primitive!(i16, to_i16); |
| impl_from_primitive!(i32, to_i32); |
| impl_from_primitive!(i64, to_i64); |
| impl_from_primitive!(usize, to_usize); |
| impl_from_primitive!(u8, to_u8); |
| impl_from_primitive!(u16, to_u16); |
| impl_from_primitive!(u32, to_u32); |
| impl_from_primitive!(u64, to_u64); |
| impl_from_primitive!(f32, to_f32); |
| impl_from_primitive!(f64, to_f64); |
| |
| |
| impl<T: ToPrimitive> ToPrimitive for Wrapping<T> { |
| fn to_i64(&self) -> Option<i64> { self.0.to_i64() } |
| fn to_u64(&self) -> Option<u64> { self.0.to_u64() } |
| } |
| impl<T: FromPrimitive> FromPrimitive for Wrapping<T> { |
| fn from_u64(n: u64) -> Option<Self> { T::from_u64(n).map(Wrapping) } |
| fn from_i64(n: i64) -> Option<Self> { T::from_i64(n).map(Wrapping) } |
| } |
| |
| |
| /// Cast from one machine scalar to another. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// # use num_traits as num; |
| /// let twenty: f32 = num::cast(0x14).unwrap(); |
| /// assert_eq!(twenty, 20f32); |
| /// ``` |
| /// |
| #[inline] |
| pub fn cast<T: NumCast, U: NumCast>(n: T) -> Option<U> { |
| NumCast::from(n) |
| } |
| |
| /// An interface for casting between machine scalars. |
| pub trait NumCast: Sized + ToPrimitive { |
| /// Creates a number from another value that can be converted into |
| /// a primitive via the `ToPrimitive` trait. |
| fn from<T: ToPrimitive>(n: T) -> Option<Self>; |
| } |
| |
| macro_rules! impl_num_cast { |
| ($T:ty, $conv:ident) => ( |
| impl NumCast for $T { |
| #[inline] |
| #[allow(deprecated)] |
| fn from<N: ToPrimitive>(n: N) -> Option<$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); |
| 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); |
| impl_num_cast!(isize, to_isize); |
| impl_num_cast!(f32, to_f32); |
| impl_num_cast!(f64, to_f64); |
| |
| impl<T: NumCast> NumCast for Wrapping<T> { |
| fn from<U: ToPrimitive>(n: U) -> Option<Self> { |
| T::from(n).map(Wrapping) |
| } |
| } |
| |
| #[test] |
| fn to_primitive_float() { |
| use std::f32; |
| use std::f64; |
| |
| let f32_toolarge = 1e39f64; |
| assert_eq!(f32_toolarge.to_f32(), None); |
| assert_eq!((f32::MAX as f64).to_f32(), Some(f32::MAX)); |
| assert_eq!((-f32::MAX as f64).to_f32(), Some(-f32::MAX)); |
| assert_eq!(f64::INFINITY.to_f32(), Some(f32::INFINITY)); |
| assert_eq!((f64::NEG_INFINITY).to_f32(), Some(f32::NEG_INFINITY)); |
| assert!((f64::NAN).to_f32().map_or(false, |f| f.is_nan())); |
| } |
| |
| #[test] |
| fn wrapping_to_primitive() { |
| macro_rules! test_wrapping_to_primitive { |
| ($($t:ty)+) => { |
| $({ |
| let i: $t = 0; |
| let w = Wrapping(i); |
| assert_eq!(i.to_u8(), w.to_u8()); |
| assert_eq!(i.to_u16(), w.to_u16()); |
| assert_eq!(i.to_u32(), w.to_u32()); |
| assert_eq!(i.to_u64(), w.to_u64()); |
| assert_eq!(i.to_usize(), w.to_usize()); |
| assert_eq!(i.to_i8(), w.to_i8()); |
| assert_eq!(i.to_i16(), w.to_i16()); |
| assert_eq!(i.to_i32(), w.to_i32()); |
| assert_eq!(i.to_i64(), w.to_i64()); |
| assert_eq!(i.to_isize(), w.to_isize()); |
| assert_eq!(i.to_f32(), w.to_f32()); |
| assert_eq!(i.to_f64(), w.to_f64()); |
| })+ |
| }; |
| } |
| |
| test_wrapping_to_primitive!(usize u8 u16 u32 u64 isize i8 i16 i32 i64); |
| } |
| |
| #[test] |
| fn wrapping_is_toprimitive() { |
| fn require_toprimitive<T: ToPrimitive>(_: &T) {} |
| require_toprimitive(&Wrapping(42)); |
| } |
| |
| #[test] |
| fn wrapping_is_fromprimitive() { |
| fn require_fromprimitive<T: FromPrimitive>(_: &T) {} |
| require_fromprimitive(&Wrapping(42)); |
| } |
| |
| #[test] |
| fn wrapping_is_numcast() { |
| fn require_numcast<T: NumCast>(_: &T) {} |
| require_numcast(&Wrapping(42)); |
| } |