763 lines
23 KiB
Rust
763 lines
23 KiB
Rust
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};
|
|
|
|
use float::FloatCore;
|
|
|
|
/// 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().as_ref().and_then(ToPrimitive::to_isize)
|
|
}
|
|
|
|
/// Converts the value of `self` to an `i8`.
|
|
#[inline]
|
|
fn to_i8(&self) -> Option<i8> {
|
|
self.to_i64().as_ref().and_then(ToPrimitive::to_i8)
|
|
}
|
|
|
|
/// Converts the value of `self` to an `i16`.
|
|
#[inline]
|
|
fn to_i16(&self) -> Option<i16> {
|
|
self.to_i64().as_ref().and_then(ToPrimitive::to_i16)
|
|
}
|
|
|
|
/// Converts the value of `self` to an `i32`.
|
|
#[inline]
|
|
fn to_i32(&self) -> Option<i32> {
|
|
self.to_i64().as_ref().and_then(ToPrimitive::to_i32)
|
|
}
|
|
|
|
/// Converts the value of `self` to an `i64`.
|
|
fn to_i64(&self) -> Option<i64>;
|
|
|
|
/// Converts the value of `self` to an `i128`.
|
|
///
|
|
/// 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<i128> {
|
|
self.to_i64().map(From::from)
|
|
}
|
|
|
|
/// Converts the value of `self` to a `usize`.
|
|
#[inline]
|
|
fn to_usize(&self) -> Option<usize> {
|
|
self.to_u64().as_ref().and_then(ToPrimitive::to_usize)
|
|
}
|
|
|
|
/// Converts the value of `self` to an `u8`.
|
|
#[inline]
|
|
fn to_u8(&self) -> Option<u8> {
|
|
self.to_u64().as_ref().and_then(ToPrimitive::to_u8)
|
|
}
|
|
|
|
/// Converts the value of `self` to an `u16`.
|
|
#[inline]
|
|
fn to_u16(&self) -> Option<u16> {
|
|
self.to_u64().as_ref().and_then(ToPrimitive::to_u16)
|
|
}
|
|
|
|
/// Converts the value of `self` to an `u32`.
|
|
#[inline]
|
|
fn to_u32(&self) -> Option<u32> {
|
|
self.to_u64().as_ref().and_then(ToPrimitive::to_u32)
|
|
}
|
|
|
|
/// Converts the value of `self` to an `u64`.
|
|
#[inline]
|
|
fn to_u64(&self) -> Option<u64>;
|
|
|
|
/// Converts the value of `self` to an `u128`.
|
|
///
|
|
/// 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<u128> {
|
|
self.to_u64().map(From::from)
|
|
}
|
|
|
|
/// Converts the value of `self` to an `f32`.
|
|
#[inline]
|
|
fn to_f32(&self) -> Option<f32> {
|
|
self.to_f64().as_ref().and_then(ToPrimitive::to_f32)
|
|
}
|
|
|
|
/// Converts the value of `self` to an `f64`.
|
|
#[inline]
|
|
fn to_f64(&self) -> Option<f64> {
|
|
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! { $T:
|
|
fn to_usize -> usize;
|
|
fn to_u8 -> u8;
|
|
fn to_u16 -> u16;
|
|
fn to_u32 -> u32;
|
|
fn to_u64 -> u64;
|
|
#[cfg(has_i128)]
|
|
fn to_u128 -> u128;
|
|
}
|
|
|
|
#[inline]
|
|
fn to_f32(&self) -> Option<f32> {
|
|
Some(*self as f32)
|
|
}
|
|
#[inline]
|
|
fn to_f64(&self) -> Option<f64> {
|
|
Some(*self as f64)
|
|
}
|
|
}
|
|
};
|
|
}
|
|
|
|
impl_to_primitive_int!(isize);
|
|
impl_to_primitive_int!(i8);
|
|
impl_to_primitive_int!(i16);
|
|
impl_to_primitive_int!(i32);
|
|
impl_to_primitive_int!(i64);
|
|
#[cfg(has_i128)]
|
|
impl_to_primitive_int!(i128);
|
|
|
|
macro_rules! impl_to_primitive_uint_to_int {
|
|
($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! { $T:
|
|
fn to_usize -> usize;
|
|
fn to_u8 -> u8;
|
|
fn to_u16 -> u16;
|
|
fn to_u32 -> u32;
|
|
fn to_u64 -> u64;
|
|
#[cfg(has_i128)]
|
|
fn to_u128 -> u128;
|
|
}
|
|
|
|
#[inline]
|
|
fn to_f32(&self) -> Option<f32> {
|
|
Some(*self as f32)
|
|
}
|
|
#[inline]
|
|
fn to_f64(&self) -> Option<f64> {
|
|
Some(*self as f64)
|
|
}
|
|
}
|
|
};
|
|
}
|
|
|
|
impl_to_primitive_uint!(usize);
|
|
impl_to_primitive_uint!(u8);
|
|
impl_to_primitive_uint!(u16);
|
|
impl_to_primitive_uint!(u32);
|
|
impl_to_primitive_uint!(u64);
|
|
#[cfg(has_i128)]
|
|
impl_to_primitive_uint!(u128);
|
|
|
|
macro_rules! impl_to_primitive_float_to_float {
|
|
($SrcT:ident : $( fn $method:ident -> $DstT:ident ; )*) => {$(
|
|
#[inline]
|
|
fn $method(&self) -> Option<$DstT> {
|
|
// Only finite values that are reducing size need to worry about overflow.
|
|
if size_of::<$SrcT>() > size_of::<$DstT>() && FloatCore::is_finite(*self) {
|
|
let n = *self as f64;
|
|
if n < $DstT::MIN as f64 || n > $DstT::MAX as f64 {
|
|
return None;
|
|
}
|
|
}
|
|
// We can safely cast NaN, +-inf, and finite values in range.
|
|
Some(*self as $DstT)
|
|
}
|
|
)*}
|
|
}
|
|
|
|
macro_rules! impl_to_primitive_float_to_signed_int {
|
|
($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(*self as $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(*self as $i);
|
|
}
|
|
}
|
|
None
|
|
}
|
|
)*}
|
|
}
|
|
|
|
macro_rules! impl_to_primitive_float_to_unsigned_int {
|
|
($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(*self as $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(*self as $u);
|
|
}
|
|
}
|
|
None
|
|
}
|
|
)*}
|
|
}
|
|
|
|
macro_rules! impl_to_primitive_float {
|
|
($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.
|
|
pub trait FromPrimitive: Sized {
|
|
/// Convert an `isize` to return an optional value of this type. If the
|
|
/// value cannot be represented by this value, then `None` is returned.
|
|
#[inline]
|
|
fn from_isize(n: isize) -> Option<Self> {
|
|
n.to_i64().and_then(FromPrimitive::from_i64)
|
|
}
|
|
|
|
/// Convert an `i8` to return an optional value of this type. If the
|
|
/// type cannot be represented by this value, then `None` is returned.
|
|
#[inline]
|
|
fn from_i8(n: i8) -> Option<Self> {
|
|
FromPrimitive::from_i64(From::from(n))
|
|
}
|
|
|
|
/// Convert an `i16` to return an optional value of this type. If the
|
|
/// type cannot be represented by this value, then `None` is returned.
|
|
#[inline]
|
|
fn from_i16(n: i16) -> Option<Self> {
|
|
FromPrimitive::from_i64(From::from(n))
|
|
}
|
|
|
|
/// Convert an `i32` to return an optional value of this type. If the
|
|
/// type cannot be represented by this value, then `None` is returned.
|
|
#[inline]
|
|
fn from_i32(n: i32) -> Option<Self> {
|
|
FromPrimitive::from_i64(From::from(n))
|
|
}
|
|
|
|
/// Convert an `i64` to return an optional value of this type. If the
|
|
/// type cannot be represented by this value, then `None` is returned.
|
|
fn from_i64(n: i64) -> Option<Self>;
|
|
|
|
/// Convert an `i128` to return an optional value of this type. If the
|
|
/// type cannot be represented by this value, 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<Self> {
|
|
n.to_i64().and_then(FromPrimitive::from_i64)
|
|
}
|
|
|
|
/// Convert a `usize` to return an optional value of this type. If the
|
|
/// type cannot be represented by this value, then `None` is returned.
|
|
#[inline]
|
|
fn from_usize(n: usize) -> Option<Self> {
|
|
n.to_u64().and_then(FromPrimitive::from_u64)
|
|
}
|
|
|
|
/// Convert an `u8` to return an optional value of this type. If the
|
|
/// type cannot be represented by this value, then `None` is returned.
|
|
#[inline]
|
|
fn from_u8(n: u8) -> Option<Self> {
|
|
FromPrimitive::from_u64(From::from(n))
|
|
}
|
|
|
|
/// Convert an `u16` to return an optional value of this type. If the
|
|
/// type cannot be represented by this value, then `None` is returned.
|
|
#[inline]
|
|
fn from_u16(n: u16) -> Option<Self> {
|
|
FromPrimitive::from_u64(From::from(n))
|
|
}
|
|
|
|
/// Convert an `u32` to return an optional value of this type. If the
|
|
/// type cannot be represented by this value, then `None` is returned.
|
|
#[inline]
|
|
fn from_u32(n: u32) -> Option<Self> {
|
|
FromPrimitive::from_u64(From::from(n))
|
|
}
|
|
|
|
/// Convert an `u64` to return an optional value of this type. If the
|
|
/// type cannot be represented by this value, then `None` is returned.
|
|
fn from_u64(n: u64) -> Option<Self>;
|
|
|
|
/// Convert an `u128` to return an optional value of this type. If the
|
|
/// type cannot be represented by this value, 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<Self> {
|
|
n.to_u64().and_then(FromPrimitive::from_u64)
|
|
}
|
|
|
|
/// Convert a `f32` to return an optional value of this type. If the
|
|
/// type cannot be represented by this value, then `None` is returned.
|
|
#[inline]
|
|
fn from_f32(n: f32) -> Option<Self> {
|
|
FromPrimitive::from_f64(From::from(n))
|
|
}
|
|
|
|
/// Convert a `f64` to return an optional value of this type. If the
|
|
/// type cannot be represented by this value, then `None` is returned.
|
|
#[inline]
|
|
fn from_f64(n: f64) -> Option<Self> {
|
|
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).$method()
|
|
}
|
|
)*}
|
|
}
|
|
|
|
impl<T: ToPrimitive> ToPrimitive for Wrapping<T> {
|
|
impl_to_primitive_wrapping! {
|
|
fn to_isize -> isize;
|
|
fn to_i8 -> i8;
|
|
fn to_i16 -> i16;
|
|
fn to_i32 -> i32;
|
|
fn to_i64 -> i64;
|
|
#[cfg(has_i128)]
|
|
fn to_i128 -> i128;
|
|
|
|
fn to_usize -> usize;
|
|
fn to_u8 -> u8;
|
|
fn to_u16 -> u16;
|
|
fn to_u32 -> u32;
|
|
fn to_u64 -> u64;
|
|
#[cfg(has_i128)]
|
|
fn to_u128 -> u128;
|
|
|
|
fn to_f32 -> f32;
|
|
fn to_f64 -> f64;
|
|
}
|
|
}
|
|
|
|
macro_rules! impl_from_primitive_wrapping {
|
|
($( $(#[$cfg:meta])* fn $method:ident ( $i:ident ); )*) => {$(
|
|
#[inline]
|
|
$(#[$cfg])*
|
|
fn $method(n: $i) -> Option<Self> {
|
|
T::$method(n).map(Wrapping)
|
|
}
|
|
)*}
|
|
}
|
|
|
|
impl<T: FromPrimitive> FromPrimitive for Wrapping<T> {
|
|
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<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);
|
|
#[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<T: NumCast> NumCast for Wrapping<T> {
|
|
fn from<U: ToPrimitive>(n: U) -> Option<Self> {
|
|
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
|
|
///
|
|
/// Currently, some uses of the `as` operator are not entirely safe.
|
|
/// In particular, it is undefined behavior if:
|
|
///
|
|
/// - A truncated floating point value cannot 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
|
|
/// ```
|
|
///
|
|
/// - Or a floating point value does not fit in another floating
|
|
/// point type ([#15536](https://github.com/rust-lang/rust/issues/15536)).
|
|
///
|
|
/// ```ignore
|
|
/// # use num_traits::AsPrimitive;
|
|
/// let x: f32 = (1e300f64).as_(); // UB
|
|
/// ```
|
|
///
|
|
pub trait AsPrimitive<T>: '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 => {});
|