| use super::{From, TryFrom}; |
| use crate::num::TryFromIntError; |
| |
| mod private { |
| /// This trait being unreachable from outside the crate |
| /// prevents other implementations of the `FloatToInt` trait, |
| /// which allows potentially adding more trait methods after the trait is `#[stable]`. |
| #[unstable(feature = "convert_float_to_int", issue = "67057")] |
| pub trait Sealed {} |
| } |
| |
| /// Supporting trait for inherent methods of `f32` and `f64` such as `round_unchecked_to`. |
| /// Typically doesn’t need to be used directly. |
| #[unstable(feature = "convert_float_to_int", issue = "67057")] |
| pub trait FloatToInt<Int>: private::Sealed + Sized { |
| #[cfg(not(bootstrap))] |
| #[unstable(feature = "float_approx_unchecked_to", issue = "67058")] |
| #[doc(hidden)] |
| unsafe fn approx_unchecked(self) -> Int; |
| } |
| |
| macro_rules! impl_float_to_int { |
| ( $Float: ident => $( $Int: ident )+ ) => { |
| #[unstable(feature = "convert_float_to_int", issue = "67057")] |
| impl private::Sealed for $Float {} |
| $( |
| #[unstable(feature = "convert_float_to_int", issue = "67057")] |
| impl FloatToInt<$Int> for $Float { |
| #[cfg(not(bootstrap))] |
| #[doc(hidden)] |
| #[inline] |
| unsafe fn approx_unchecked(self) -> $Int { |
| crate::intrinsics::float_to_int_approx_unchecked(self) |
| } |
| } |
| )+ |
| } |
| } |
| |
| impl_float_to_int!(f32 => u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize); |
| impl_float_to_int!(f64 => u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize); |
| |
| // Conversion traits for primitive integer and float types |
| // Conversions T -> T are covered by a blanket impl and therefore excluded |
| // Some conversions from and to usize/isize are not implemented due to portability concerns |
| macro_rules! impl_from { |
| ($Small: ty, $Large: ty, #[$attr:meta], $doc: expr) => { |
| #[$attr] |
| #[doc = $doc] |
| impl From<$Small> for $Large { |
| #[inline] |
| fn from(small: $Small) -> $Large { |
| small as $Large |
| } |
| } |
| }; |
| ($Small: ty, $Large: ty, #[$attr:meta]) => { |
| impl_from!($Small, |
| $Large, |
| #[$attr], |
| concat!("Converts `", |
| stringify!($Small), |
| "` to `", |
| stringify!($Large), |
| "` losslessly.")); |
| } |
| } |
| |
| macro_rules! impl_from_bool { |
| ($target: ty, #[$attr:meta]) => { |
| impl_from!(bool, $target, #[$attr], concat!("Converts a `bool` to a `", |
| stringify!($target), "`. The resulting value is `0` for `false` and `1` for `true` |
| values. |
| |
| # Examples |
| |
| ``` |
| assert_eq!(", stringify!($target), "::from(true), 1); |
| assert_eq!(", stringify!($target), "::from(false), 0); |
| ```")); |
| }; |
| } |
| |
| // Bool -> Any |
| impl_from_bool! { u8, #[stable(feature = "from_bool", since = "1.28.0")] } |
| impl_from_bool! { u16, #[stable(feature = "from_bool", since = "1.28.0")] } |
| impl_from_bool! { u32, #[stable(feature = "from_bool", since = "1.28.0")] } |
| impl_from_bool! { u64, #[stable(feature = "from_bool", since = "1.28.0")] } |
| impl_from_bool! { u128, #[stable(feature = "from_bool", since = "1.28.0")] } |
| impl_from_bool! { usize, #[stable(feature = "from_bool", since = "1.28.0")] } |
| impl_from_bool! { i8, #[stable(feature = "from_bool", since = "1.28.0")] } |
| impl_from_bool! { i16, #[stable(feature = "from_bool", since = "1.28.0")] } |
| impl_from_bool! { i32, #[stable(feature = "from_bool", since = "1.28.0")] } |
| impl_from_bool! { i64, #[stable(feature = "from_bool", since = "1.28.0")] } |
| impl_from_bool! { i128, #[stable(feature = "from_bool", since = "1.28.0")] } |
| impl_from_bool! { isize, #[stable(feature = "from_bool", since = "1.28.0")] } |
| |
| // Unsigned -> Unsigned |
| impl_from! { u8, u16, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { u8, u32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { u8, u64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { u8, u128, #[stable(feature = "i128", since = "1.26.0")] } |
| impl_from! { u8, usize, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { u16, u32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { u16, u64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { u16, u128, #[stable(feature = "i128", since = "1.26.0")] } |
| impl_from! { u32, u64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { u32, u128, #[stable(feature = "i128", since = "1.26.0")] } |
| impl_from! { u64, u128, #[stable(feature = "i128", since = "1.26.0")] } |
| |
| // Signed -> Signed |
| impl_from! { i8, i16, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { i8, i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { i8, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { i8, i128, #[stable(feature = "i128", since = "1.26.0")] } |
| impl_from! { i8, isize, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { i16, i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { i16, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { i16, i128, #[stable(feature = "i128", since = "1.26.0")] } |
| impl_from! { i32, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { i32, i128, #[stable(feature = "i128", since = "1.26.0")] } |
| impl_from! { i64, i128, #[stable(feature = "i128", since = "1.26.0")] } |
| |
| // Unsigned -> Signed |
| impl_from! { u8, i16, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { u8, i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { u8, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { u8, i128, #[stable(feature = "i128", since = "1.26.0")] } |
| impl_from! { u16, i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { u16, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { u16, i128, #[stable(feature = "i128", since = "1.26.0")] } |
| impl_from! { u32, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] } |
| impl_from! { u32, i128, #[stable(feature = "i128", since = "1.26.0")] } |
| impl_from! { u64, i128, #[stable(feature = "i128", since = "1.26.0")] } |
| |
| // The C99 standard defines bounds on INTPTR_MIN, INTPTR_MAX, and UINTPTR_MAX |
| // which imply that pointer-sized integers must be at least 16 bits: |
| // https://port70.net/~nsz/c/c99/n1256.html#7.18.2.4 |
| impl_from! { u16, usize, #[stable(feature = "lossless_iusize_conv", since = "1.26.0")] } |
| impl_from! { u8, isize, #[stable(feature = "lossless_iusize_conv", since = "1.26.0")] } |
| impl_from! { i16, isize, #[stable(feature = "lossless_iusize_conv", since = "1.26.0")] } |
| |
| // RISC-V defines the possibility of a 128-bit address space (RV128). |
| |
| // CHERI proposes 256-bit “capabilities”. Unclear if this would be relevant to usize/isize. |
| // https://www.cl.cam.ac.uk/research/security/ctsrd/pdfs/20171017a-cheri-poster.pdf |
| // http://www.csl.sri.com/users/neumann/2012resolve-cheri.pdf |
| |
| |
| // Note: integers can only be represented with full precision in a float if |
| // they fit in the significand, which is 24 bits in f32 and 53 bits in f64. |
| // Lossy float conversions are not implemented at this time. |
| |
| // Signed -> Float |
| impl_from! { i8, f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")] } |
| impl_from! { i8, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] } |
| impl_from! { i16, f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")] } |
| impl_from! { i16, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] } |
| impl_from! { i32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] } |
| |
| // Unsigned -> Float |
| impl_from! { u8, f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")] } |
| impl_from! { u8, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] } |
| impl_from! { u16, f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")] } |
| impl_from! { u16, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] } |
| impl_from! { u32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] } |
| |
| // Float -> Float |
| impl_from! { f32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] } |
| |
| // no possible bounds violation |
| macro_rules! try_from_unbounded { |
| ($source:ty, $($target:ty),*) => {$( |
| #[stable(feature = "try_from", since = "1.34.0")] |
| impl TryFrom<$source> for $target { |
| type Error = TryFromIntError; |
| |
| /// Try to create the target number type from a source |
| /// number type. This returns an error if the source value |
| /// is outside of the range of the target type. |
| #[inline] |
| fn try_from(value: $source) -> Result<Self, Self::Error> { |
| Ok(value as $target) |
| } |
| } |
| )*} |
| } |
| |
| // only negative bounds |
| macro_rules! try_from_lower_bounded { |
| ($source:ty, $($target:ty),*) => {$( |
| #[stable(feature = "try_from", since = "1.34.0")] |
| impl TryFrom<$source> for $target { |
| type Error = TryFromIntError; |
| |
| /// Try to create the target number type from a source |
| /// number type. This returns an error if the source value |
| /// is outside of the range of the target type. |
| #[inline] |
| fn try_from(u: $source) -> Result<$target, TryFromIntError> { |
| if u >= 0 { |
| Ok(u as $target) |
| } else { |
| Err(TryFromIntError(())) |
| } |
| } |
| } |
| )*} |
| } |
| |
| // unsigned to signed (only positive bound) |
| macro_rules! try_from_upper_bounded { |
| ($source:ty, $($target:ty),*) => {$( |
| #[stable(feature = "try_from", since = "1.34.0")] |
| impl TryFrom<$source> for $target { |
| type Error = TryFromIntError; |
| |
| /// Try to create the target number type from a source |
| /// number type. This returns an error if the source value |
| /// is outside of the range of the target type. |
| #[inline] |
| fn try_from(u: $source) -> Result<$target, TryFromIntError> { |
| if u > (<$target>::max_value() as $source) { |
| Err(TryFromIntError(())) |
| } else { |
| Ok(u as $target) |
| } |
| } |
| } |
| )*} |
| } |
| |
| // all other cases |
| macro_rules! try_from_both_bounded { |
| ($source:ty, $($target:ty),*) => {$( |
| #[stable(feature = "try_from", since = "1.34.0")] |
| impl TryFrom<$source> for $target { |
| type Error = TryFromIntError; |
| |
| /// Try to create the target number type from a source |
| /// number type. This returns an error if the source value |
| /// is outside of the range of the target type. |
| #[inline] |
| fn try_from(u: $source) -> Result<$target, TryFromIntError> { |
| let min = <$target>::min_value() as $source; |
| let max = <$target>::max_value() as $source; |
| if u < min || u > max { |
| Err(TryFromIntError(())) |
| } else { |
| Ok(u as $target) |
| } |
| } |
| } |
| )*} |
| } |
| |
| macro_rules! rev { |
| ($mac:ident, $source:ty, $($target:ty),*) => {$( |
| $mac!($target, $source); |
| )*} |
| } |
| |
| // intra-sign conversions |
| try_from_upper_bounded!(u16, u8); |
| try_from_upper_bounded!(u32, u16, u8); |
| try_from_upper_bounded!(u64, u32, u16, u8); |
| try_from_upper_bounded!(u128, u64, u32, u16, u8); |
| |
| try_from_both_bounded!(i16, i8); |
| try_from_both_bounded!(i32, i16, i8); |
| try_from_both_bounded!(i64, i32, i16, i8); |
| try_from_both_bounded!(i128, i64, i32, i16, i8); |
| |
| // unsigned-to-signed |
| try_from_upper_bounded!(u8, i8); |
| try_from_upper_bounded!(u16, i8, i16); |
| try_from_upper_bounded!(u32, i8, i16, i32); |
| try_from_upper_bounded!(u64, i8, i16, i32, i64); |
| try_from_upper_bounded!(u128, i8, i16, i32, i64, i128); |
| |
| // signed-to-unsigned |
| try_from_lower_bounded!(i8, u8, u16, u32, u64, u128); |
| try_from_lower_bounded!(i16, u16, u32, u64, u128); |
| try_from_lower_bounded!(i32, u32, u64, u128); |
| try_from_lower_bounded!(i64, u64, u128); |
| try_from_lower_bounded!(i128, u128); |
| try_from_both_bounded!(i16, u8); |
| try_from_both_bounded!(i32, u16, u8); |
| try_from_both_bounded!(i64, u32, u16, u8); |
| try_from_both_bounded!(i128, u64, u32, u16, u8); |
| |
| // usize/isize |
| try_from_upper_bounded!(usize, isize); |
| try_from_lower_bounded!(isize, usize); |
| |
| #[cfg(target_pointer_width = "16")] |
| mod ptr_try_from_impls { |
| use super::TryFromIntError; |
| use crate::convert::TryFrom; |
| |
| try_from_upper_bounded!(usize, u8); |
| try_from_unbounded!(usize, u16, u32, u64, u128); |
| try_from_upper_bounded!(usize, i8, i16); |
| try_from_unbounded!(usize, i32, i64, i128); |
| |
| try_from_both_bounded!(isize, u8); |
| try_from_lower_bounded!(isize, u16, u32, u64, u128); |
| try_from_both_bounded!(isize, i8); |
| try_from_unbounded!(isize, i16, i32, i64, i128); |
| |
| rev!(try_from_upper_bounded, usize, u32, u64, u128); |
| rev!(try_from_lower_bounded, usize, i8, i16); |
| rev!(try_from_both_bounded, usize, i32, i64, i128); |
| |
| rev!(try_from_upper_bounded, isize, u16, u32, u64, u128); |
| rev!(try_from_both_bounded, isize, i32, i64, i128); |
| } |
| |
| #[cfg(target_pointer_width = "32")] |
| mod ptr_try_from_impls { |
| use super::TryFromIntError; |
| use crate::convert::TryFrom; |
| |
| try_from_upper_bounded!(usize, u8, u16); |
| try_from_unbounded!(usize, u32, u64, u128); |
| try_from_upper_bounded!(usize, i8, i16, i32); |
| try_from_unbounded!(usize, i64, i128); |
| |
| try_from_both_bounded!(isize, u8, u16); |
| try_from_lower_bounded!(isize, u32, u64, u128); |
| try_from_both_bounded!(isize, i8, i16); |
| try_from_unbounded!(isize, i32, i64, i128); |
| |
| rev!(try_from_unbounded, usize, u32); |
| rev!(try_from_upper_bounded, usize, u64, u128); |
| rev!(try_from_lower_bounded, usize, i8, i16, i32); |
| rev!(try_from_both_bounded, usize, i64, i128); |
| |
| rev!(try_from_unbounded, isize, u16); |
| rev!(try_from_upper_bounded, isize, u32, u64, u128); |
| rev!(try_from_unbounded, isize, i32); |
| rev!(try_from_both_bounded, isize, i64, i128); |
| } |
| |
| #[cfg(target_pointer_width = "64")] |
| mod ptr_try_from_impls { |
| use super::TryFromIntError; |
| use crate::convert::TryFrom; |
| |
| try_from_upper_bounded!(usize, u8, u16, u32); |
| try_from_unbounded!(usize, u64, u128); |
| try_from_upper_bounded!(usize, i8, i16, i32, i64); |
| try_from_unbounded!(usize, i128); |
| |
| try_from_both_bounded!(isize, u8, u16, u32); |
| try_from_lower_bounded!(isize, u64, u128); |
| try_from_both_bounded!(isize, i8, i16, i32); |
| try_from_unbounded!(isize, i64, i128); |
| |
| rev!(try_from_unbounded, usize, u32, u64); |
| rev!(try_from_upper_bounded, usize, u128); |
| rev!(try_from_lower_bounded, usize, i8, i16, i32, i64); |
| rev!(try_from_both_bounded, usize, i128); |
| |
| rev!(try_from_unbounded, isize, u16, u32); |
| rev!(try_from_upper_bounded, isize, u64, u128); |
| rev!(try_from_unbounded, isize, i32, i64); |
| rev!(try_from_both_bounded, isize, i128); |
| } |
