blob: 8949834a1e61a0997bb4cf1c67f1c0f7cb697dc8 [file] [log] [blame]
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()));
}
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]
fn wrapping_to_primitive() {
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));
}