From bbbc2bd1d7719070d9765def3dc7a11a42cd9797 Mon Sep 17 00:00:00 2001 From: Josh Stone Date: Mon, 7 May 2018 12:28:53 -0700 Subject: [PATCH] impl 128-bit numeric casts This includes new conditional methods `ToPrimitive::{to_i128,to_u128}` and `FromPrimitive::{from_i128,from_u128}`. Since features can only be additive, these methods must not cause a breaking change to anyone when enabled -- thus they have a default implementation that converts through 64-bit values. Types that can do better with a full 128-bit integer, like bigint or floating-point, will probably want to override these. --- src/cast.rs | 478 ++++++++++++++++++++------------------------------ tests/cast.rs | 319 +++++++++++++++++++++++++++++++++ 2 files changed, 508 insertions(+), 289 deletions(-) create mode 100644 tests/cast.rs diff --git a/src/cast.rs b/src/cast.rs index 6e89961..ce21c81 100644 --- a/src/cast.rs +++ b/src/cast.rs @@ -3,6 +3,8 @@ use core::{u8, u16, u32, u64, usize}; use core::{f32, f64}; use core::mem::size_of; use core::num::Wrapping; +#[cfg(feature = "i128")] +use core::{i128, u128}; use float::FloatCore; @@ -35,6 +37,18 @@ pub trait ToPrimitive { /// Converts the value of `self` to an `i64`. fn to_i64(&self) -> Option; + /// 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(feature = "i128")] + fn to_i128(&self) -> Option { + self.to_i64().map(From::from) + } + /// Converts the value of `self` to a `usize`. #[inline] fn to_usize(&self) -> Option { @@ -63,6 +77,18 @@ pub trait ToPrimitive { #[inline] fn to_u64(&self) -> Option; + /// 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(feature = "i128")] + fn to_u128(&self) -> Option { + self.to_u64().map(From::from) + } + /// Converts the value of `self` to an `f32`. #[inline] fn to_f32(&self) -> Option { @@ -77,8 +103,9 @@ pub trait ToPrimitive { } macro_rules! impl_to_primitive_int_to_int { - ($SrcT:ident : $( fn $method:ident -> $DstT:ident ; )*) => {$( + ($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 $SrcT; @@ -92,11 +119,12 @@ macro_rules! impl_to_primitive_int_to_int { } macro_rules! impl_to_primitive_int_to_uint { - ($SrcT:ident : $( fn $method:ident -> $DstT:ident ; )*) => {$( + ($SrcT:ident : $( $(#[$cfg:meta])* fn $method:ident -> $DstT:ident ; )*) => {$( #[inline] + $(#[$cfg])* fn $method(&self) -> Option<$DstT> { - let max = $DstT::MAX as u64; - if 0 <= *self && (size_of::<$SrcT>() < size_of::<$DstT>() || *self as u64 <= max) { + let max = $DstT::MAX as $SrcT; + if 0 <= *self && (size_of::<$SrcT>() <= size_of::<$DstT>() || *self <= max) { Some(*self as $DstT) } else { None @@ -114,6 +142,8 @@ macro_rules! impl_to_primitive_int { fn to_i16 -> i16; fn to_i32 -> i32; fn to_i64 -> i64; + #[cfg(feature = "i128")] + fn to_i128 -> i128; } impl_to_primitive_int_to_uint! { $T: @@ -122,6 +152,8 @@ macro_rules! impl_to_primitive_int { fn to_u16 -> u16; fn to_u32 -> u32; fn to_u64 -> u64; + #[cfg(feature = "i128")] + fn to_u128 -> u128; } #[inline] @@ -137,13 +169,16 @@ impl_to_primitive_int!(i8); impl_to_primitive_int!(i16); impl_to_primitive_int!(i32); impl_to_primitive_int!(i64); +#[cfg(feature = "i128")] +impl_to_primitive_int!(i128); macro_rules! impl_to_primitive_uint_to_int { - ($SrcT:ident : $( fn $method:ident -> $DstT:ident ; )*) => {$( + ($SrcT:ident : $( $(#[$cfg:meta])* fn $method:ident -> $DstT:ident ; )*) => {$( #[inline] + $(#[$cfg])* fn $method(&self) -> Option<$DstT> { - let max = $DstT::MAX as u64; - if size_of::<$SrcT>() < size_of::<$DstT>() || *self as u64 <= max { + let max = $DstT::MAX as $SrcT; + if size_of::<$SrcT>() < size_of::<$DstT>() || *self <= max { Some(*self as $DstT) } else { None @@ -153,8 +188,9 @@ macro_rules! impl_to_primitive_uint_to_int { } macro_rules! impl_to_primitive_uint_to_uint { - ($SrcT:ident : $( fn $method:ident -> $DstT:ident ; )*) => {$( + ($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 { @@ -175,6 +211,8 @@ macro_rules! impl_to_primitive_uint { fn to_i16 -> i16; fn to_i32 -> i32; fn to_i64 -> i64; + #[cfg(feature = "i128")] + fn to_i128 -> i128; } impl_to_primitive_uint_to_uint! { $T: @@ -183,6 +221,8 @@ macro_rules! impl_to_primitive_uint { fn to_u16 -> u16; fn to_u32 -> u32; fn to_u64 -> u64; + #[cfg(feature = "i128")] + fn to_u128 -> u128; } #[inline] @@ -198,6 +238,8 @@ impl_to_primitive_uint!(u8); impl_to_primitive_uint!(u16); impl_to_primitive_uint!(u32); impl_to_primitive_uint!(u64); +#[cfg(feature = "i128")] +impl_to_primitive_uint!(u128); macro_rules! impl_to_primitive_float_to_float { ($SrcT:ident : $( fn $method:ident -> $DstT:ident ; )*) => {$( @@ -217,8 +259,9 @@ macro_rules! impl_to_primitive_float_to_float { } macro_rules! impl_to_primitive_float_to_signed_int { - ($f:ident : $( fn $method:ident -> $i:ident ; )*) => {$( + ($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)`. @@ -246,8 +289,9 @@ macro_rules! impl_to_primitive_float_to_signed_int { } macro_rules! impl_to_primitive_float_to_unsigned_int { - ($f:ident : $( fn $method:ident -> $u:ident ; )*) => {$( + ($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)`. @@ -260,6 +304,7 @@ macro_rules! impl_to_primitive_float_to_unsigned_int { } 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); @@ -279,6 +324,8 @@ macro_rules! impl_to_primitive_float { fn to_i16 -> i16; fn to_i32 -> i32; fn to_i64 -> i64; + #[cfg(feature = "i128")] + fn to_i128 -> i128; } impl_to_primitive_float_to_unsigned_int! { $T: @@ -287,6 +334,8 @@ macro_rules! impl_to_primitive_float { fn to_u16 -> u16; fn to_u32 -> u32; fn to_u64 -> u64; + #[cfg(feature = "i128")] + fn to_u128 -> u128; } impl_to_primitive_float_to_float! { $T: @@ -334,6 +383,19 @@ pub trait FromPrimitive: Sized { /// type cannot be represented by this value, the `None` is returned. fn from_i64(n: i64) -> Option; + /// Convert an `i128` to return an optional value of this type. If the + /// type cannot be represented by this value, the `None` is returned. + /// + /// This method is only available with feature `i128` enabled on Rust >= 1.26. + /// + /// The default implementation converts through `from_i64()`. Types implementing + /// this trait should override this method if they can represent a greater range. + #[inline] + #[cfg(feature = "i128")] + fn from_i128(n: i128) -> Option { + n.to_i64().and_then(FromPrimitive::from_i64) + } + /// Convert a `usize` to return an optional value of this type. If the /// type cannot be represented by this value, the `None` is returned. #[inline] @@ -366,6 +428,19 @@ pub trait FromPrimitive: Sized { /// type cannot be represented by this value, the `None` is returned. fn from_u64(n: u64) -> Option; + /// Convert an `u128` to return an optional value of this type. If the + /// type cannot be represented by this value, the `None` is returned. + /// + /// This method is only available with feature `i128` enabled on Rust >= 1.26. + /// + /// The default implementation converts through `from_u64()`. Types implementing + /// this trait should override this method if they can represent a greater range. + #[inline] + #[cfg(feature = "i128")] + fn from_u128(n: u128) -> Option { + n.to_u64().and_then(FromPrimitive::from_u64) + } + /// Convert a `f32` to return an optional value of this type. If the /// type cannot be represented by this value, the `None` is returned. #[inline] @@ -389,11 +464,15 @@ macro_rules! impl_from_primitive { #[inline] fn from_i16(n: i16) -> Option<$T> { n.$to_ty() } #[inline] fn from_i32(n: i32) -> Option<$T> { n.$to_ty() } #[inline] fn from_i64(n: i64) -> Option<$T> { n.$to_ty() } + #[cfg(feature = "i128")] + #[inline] fn from_i128(n: i128) -> Option<$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.$to_ty() } + #[cfg(feature = "i128")] + #[inline] fn from_u128(n: u128) -> Option<$T> { n.$to_ty() } #[inline] fn from_f32(n: f32) -> Option<$T> { n.$to_ty() } #[inline] fn from_f64(n: f64) -> Option<$T> { n.$to_ty() } @@ -406,22 +485,83 @@ impl_from_primitive!(i8, to_i8); impl_from_primitive!(i16, to_i16); impl_from_primitive!(i32, to_i32); impl_from_primitive!(i64, to_i64); +#[cfg(feature = "i128")] +impl_from_primitive!(i128, to_i128); impl_from_primitive!(usize, to_usize); impl_from_primitive!(u8, to_u8); impl_from_primitive!(u16, to_u16); impl_from_primitive!(u32, to_u32); impl_from_primitive!(u64, to_u64); +#[cfg(feature = "i128")] +impl_from_primitive!(u128, to_u128); impl_from_primitive!(f32, to_f32); impl_from_primitive!(f64, to_f64); -impl ToPrimitive for Wrapping { - fn to_i64(&self) -> Option { self.0.to_i64() } - fn to_u64(&self) -> Option { self.0.to_u64() } +macro_rules! impl_to_primitive_wrapping { + ($( $(#[$cfg:meta])* fn $method:ident -> $i:ident ; )*) => {$( + #[inline] + $(#[$cfg])* + fn $method(&self) -> Option<$i> { + (self.0).$method() + } + )*} } + +impl ToPrimitive for Wrapping { + impl_to_primitive_wrapping! { + fn to_isize -> isize; + fn to_i8 -> i8; + fn to_i16 -> i16; + fn to_i32 -> i32; + fn to_i64 -> i64; + #[cfg(feature = "i128")] + fn to_i128 -> i128; + + fn to_usize -> usize; + fn to_u8 -> u8; + fn to_u16 -> u16; + fn to_u32 -> u32; + fn to_u64 -> u64; + #[cfg(feature = "i128")] + fn to_u128 -> u128; + + fn to_f32 -> f32; + fn to_f64 -> f64; + } +} + +macro_rules! impl_from_primitive_wrapping { + ($( $(#[$cfg:meta])* fn $method:ident ( $i:ident ); )*) => {$( + #[inline] + $(#[$cfg])* + fn $method(n: $i) -> Option { + T::$method(n).map(Wrapping) + } + )*} +} + impl FromPrimitive for Wrapping { - fn from_u64(n: u64) -> Option { T::from_u64(n).map(Wrapping) } - fn from_i64(n: i64) -> Option { T::from_i64(n).map(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(feature = "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(feature = "i128")] + fn from_u128(u128); + + fn from_f32(f32); + fn from_f64(f64); + } } @@ -465,11 +605,15 @@ 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(feature = "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(feature = "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); @@ -524,284 +668,40 @@ where } macro_rules! impl_as_primitive { - ($T: ty => $( $U: ty ),* ) => { - $( + (@ $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(feature = "i128")] impl u128); + impl_as_primitive!(@ $T => { i8, i16, i32, i64, isize }); + impl_as_primitive!(@ $T => #[cfg(feature = "i128")] impl i128); }; } -impl_as_primitive!(u8 => char, u8, i8, u16, i16, u32, i32, u64, isize, usize, i64, f32, f64); -impl_as_primitive!(i8 => u8, i8, u16, i16, u32, i32, u64, isize, usize, i64, f32, f64); -impl_as_primitive!(u16 => u8, i8, u16, i16, u32, i32, u64, isize, usize, i64, f32, f64); -impl_as_primitive!(i16 => u8, i8, u16, i16, u32, i32, u64, isize, usize, i64, f32, f64); -impl_as_primitive!(u32 => u8, i8, u16, i16, u32, i32, u64, isize, usize, i64, f32, f64); -impl_as_primitive!(i32 => u8, i8, u16, i16, u32, i32, u64, isize, usize, i64, f32, f64); -impl_as_primitive!(u64 => u8, i8, u16, i16, u32, i32, u64, isize, usize, i64, f32, f64); -impl_as_primitive!(i64 => u8, i8, u16, i16, u32, i32, u64, isize, usize, i64, f32, f64); -impl_as_primitive!(usize => u8, i8, u16, i16, u32, i32, u64, isize, usize, i64, f32, f64); -impl_as_primitive!(isize => u8, i8, u16, i16, u32, i32, u64, isize, usize, i64, f32, f64); -impl_as_primitive!(f32 => u8, i8, u16, i16, u32, i32, u64, isize, usize, i64, f32, f64); -impl_as_primitive!(f64 => u8, i8, u16, i16, u32, i32, u64, isize, usize, i64, f32, f64); -impl_as_primitive!(char => char, u8, i8, u16, i16, u32, i32, u64, isize, usize, i64); -impl_as_primitive!(bool => u8, i8, u16, i16, u32, i32, u64, isize, usize, i64); +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(feature = "i128")] +impl_as_primitive!(u128 => { f32, f64 }); +#[cfg(feature = "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 => {}); -#[test] -fn to_primitive_float() { - use core::f32; - use core::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) {} - require_toprimitive(&Wrapping(42)); -} - -#[test] -fn wrapping_is_fromprimitive() { - fn require_fromprimitive(_: &T) {} - require_fromprimitive(&Wrapping(42)); -} - -#[test] -fn wrapping_is_numcast() { - fn require_numcast(_: &T) {} - require_numcast(&Wrapping(42)); -} - -#[test] -fn as_primitive() { - let x: f32 = (1.625f64).as_(); - assert_eq!(x, 1.625f32); - - let x: f32 = (3.14159265358979323846f64).as_(); - assert_eq!(x, 3.1415927f32); - - let x: u8 = (768i16).as_(); - assert_eq!(x, 0); -} - -#[test] -fn float_to_integer_checks_overflow() { - // This will overflow an i32 - let source: f64 = 1.0e+123f64; - - // Expect the overflow to be caught - assert_eq!(cast::(source), None); -} - -#[test] -fn cast_to_int_checks_overflow() { - let big_f: f64 = 1.0e123; - let normal_f: f64 = 1.0; - let small_f: f64 = -1.0e123; - assert_eq!(None, cast::(big_f)); - assert_eq!(None, cast::(big_f)); - assert_eq!(None, cast::(big_f)); - assert_eq!(None, cast::(big_f)); - assert_eq!(None, cast::(big_f)); - - assert_eq!(Some(normal_f as isize), cast::(normal_f)); - assert_eq!(Some(normal_f as i8), cast::(normal_f)); - assert_eq!(Some(normal_f as i16), cast::(normal_f)); - assert_eq!(Some(normal_f as i32), cast::(normal_f)); - assert_eq!(Some(normal_f as i64), cast::(normal_f)); - - assert_eq!(None, cast::(small_f)); - assert_eq!(None, cast::(small_f)); - assert_eq!(None, cast::(small_f)); - assert_eq!(None, cast::(small_f)); - assert_eq!(None, cast::(small_f)); -} - -#[test] -fn cast_to_unsigned_int_checks_overflow() { - let big_f: f64 = 1.0e123; - let normal_f: f64 = 1.0; - let small_f: f64 = -1.0e123; - assert_eq!(None, cast::(big_f)); - assert_eq!(None, cast::(big_f)); - assert_eq!(None, cast::(big_f)); - assert_eq!(None, cast::(big_f)); - assert_eq!(None, cast::(big_f)); - - assert_eq!(Some(normal_f as usize), cast::(normal_f)); - assert_eq!(Some(normal_f as u8), cast::(normal_f)); - assert_eq!(Some(normal_f as u16), cast::(normal_f)); - assert_eq!(Some(normal_f as u32), cast::(normal_f)); - assert_eq!(Some(normal_f as u64), cast::(normal_f)); - - assert_eq!(None, cast::(small_f)); - assert_eq!(None, cast::(small_f)); - assert_eq!(None, cast::(small_f)); - assert_eq!(None, cast::(small_f)); - assert_eq!(None, cast::(small_f)); -} - -#[cfg(all(test, feature = "std"))] -fn dbg(args: ::core::fmt::Arguments) { - println!("{}", args); -} - -#[cfg(all(test, not(feature = "std")))] -fn dbg(_: ::core::fmt::Arguments) {} - -// Rust 1.8 doesn't handle cfg on macros correctly -// #[cfg(test)] -#[allow(unused)] -macro_rules! dbg { ($($tok:tt)*) => { dbg(format_args!($($tok)*)) } } - -#[test] -fn cast_float_to_int_edge_cases() { - use core::mem::transmute; - - trait RawOffset: Sized { - type Raw; - fn raw_offset(self, offset: Self::Raw) -> Self; - } - impl RawOffset for f32 { - type Raw = i32; - fn raw_offset(self, offset: Self::Raw) -> Self { - unsafe { - let raw: Self::Raw = transmute(self); - transmute(raw + offset) - } - } - } - impl RawOffset for f64 { - type Raw = i64; - fn raw_offset(self, offset: Self::Raw) -> Self { - unsafe { - let raw: Self::Raw = transmute(self); - transmute(raw + offset) - } - } - } - - macro_rules! test_edge { - ($f:ident -> $($t:ident)+) => { $({ - dbg!("testing cast edge cases for {} -> {}", stringify!($f), stringify!($t)); - - let small = if $t::MIN == 0 || size_of::<$t>() < size_of::<$f>() { - $t::MIN as $f - 1.0 - } else { - ($t::MIN as $f).raw_offset(1).floor() - }; - let fmin = small.raw_offset(-1); - dbg!(" testing min {}\n\tvs. {:.16}\n\tand {:.16}", $t::MIN, fmin, small); - assert_eq!(Some($t::MIN), cast::<$f, $t>($t::MIN as $f)); - assert_eq!(Some($t::MIN), cast::<$f, $t>(fmin)); - assert_eq!(None, cast::<$f, $t>(small)); - - let (max, large) = if size_of::<$t>() < size_of::<$f>() { - ($t::MAX, $t::MAX as $f + 1.0) - } else { - let large = $t::MAX as $f; // rounds up! - let max = large.raw_offset(-1) as $t; // the next smallest possible - assert_eq!(max.count_ones(), $f::MANTISSA_DIGITS); - (max, large) - }; - let fmax = large.raw_offset(-1); - dbg!(" testing max {}\n\tvs. {:.16}\n\tand {:.16}", max, fmax, large); - assert_eq!(Some(max), cast::<$f, $t>(max as $f)); - assert_eq!(Some(max), cast::<$f, $t>(fmax)); - assert_eq!(None, cast::<$f, $t>(large)); - - dbg!(" testing non-finite values"); - assert_eq!(None, cast::<$f, $t>($f::NAN)); - assert_eq!(None, cast::<$f, $t>($f::INFINITY)); - assert_eq!(None, cast::<$f, $t>($f::NEG_INFINITY)); - })+} - } - - test_edge!(f32 -> isize i8 i16 i32 i64); - test_edge!(f32 -> usize u8 u16 u32 u64); - test_edge!(f64 -> isize i8 i16 i32 i64); - test_edge!(f64 -> usize u8 u16 u32 u64); -} - -#[test] -fn cast_int_to_int_edge_cases() { - use core::cmp::Ordering::*; - - macro_rules! test_edge { - ($f:ident -> $($t:ident)+) => { $({ - fn test_edge() { - dbg!("testing cast edge cases for {} -> {}", stringify!($f), stringify!($t)); - - match ($f::MIN as i64).cmp(&($t::MIN as i64)) { - Greater => { - assert_eq!(Some($f::MIN as $t), cast::<$f, $t>($f::MIN)); - } - Equal => { - assert_eq!(Some($t::MIN), cast::<$f, $t>($f::MIN)); - } - Less => { - let min = $t::MIN as $f; - assert_eq!(Some($t::MIN), cast::<$f, $t>(min)); - assert_eq!(None, cast::<$f, $t>(min - 1)); - } - } - - match ($f::MAX as u64).cmp(&($t::MAX as u64)) { - Greater => { - let max = $t::MAX as $f; - assert_eq!(Some($t::MAX), cast::<$f, $t>(max)); - assert_eq!(None, cast::<$f, $t>(max + 1)); - } - Equal => { - assert_eq!(Some($t::MAX), cast::<$f, $t>($f::MAX)); - } - Less => { - assert_eq!(Some($f::MAX as $t), cast::<$f, $t>($f::MAX)); - } - } - } - test_edge(); - })+}; - ($( $from:ident )+) => { $({ - test_edge!($from -> isize i8 i16 i32 i64); - test_edge!($from -> usize u8 u16 u32 u64); - })+} - } - - test_edge!(isize i8 i16 i32 i64); - test_edge!(usize u8 u16 u32 u64); -} diff --git a/tests/cast.rs b/tests/cast.rs new file mode 100644 index 0000000..773cc24 --- /dev/null +++ b/tests/cast.rs @@ -0,0 +1,319 @@ +//! Tests of `num_traits::cast`. + +#![no_std] + +#[cfg(feature = "std")] +#[macro_use] +extern crate std; + +extern crate num_traits; + +use num_traits::cast::*; + +use core::{i8, i16, i32, i64, isize}; +use core::{u8, u16, u32, u64, usize}; +use core::{f32, f64}; +#[cfg(feature = "i128")] +use core::{i128, u128}; + +use core::mem; +use core::num::Wrapping; + +#[test] +fn to_primitive_float() { + let f32_toolarge = 1e39f64; + assert_eq!(f32_toolarge.to_f32(), None); + assert_eq!((f32::MAX as f64).to_f32(), Some(f32::MAX)); + assert_eq!((-f32::MAX as f64).to_f32(), Some(-f32::MAX)); + assert_eq!(f64::INFINITY.to_f32(), Some(f32::INFINITY)); + assert_eq!((f64::NEG_INFINITY).to_f32(), Some(f32::NEG_INFINITY)); + assert!((f64::NAN).to_f32().map_or(false, |f| f.is_nan())); +} + +#[test] +fn wrapping_to_primitive() { + macro_rules! test_wrapping_to_primitive { + ($($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) {} + require_toprimitive(&Wrapping(42)); +} + +#[test] +fn wrapping_is_fromprimitive() { + fn require_fromprimitive(_: &T) {} + require_fromprimitive(&Wrapping(42)); +} + +#[test] +fn wrapping_is_numcast() { + fn require_numcast(_: &T) {} + require_numcast(&Wrapping(42)); +} + +#[test] +fn as_primitive() { + let x: f32 = (1.625f64).as_(); + assert_eq!(x, 1.625f32); + + let x: f32 = (3.14159265358979323846f64).as_(); + assert_eq!(x, 3.1415927f32); + + let x: u8 = (768i16).as_(); + assert_eq!(x, 0); +} + +#[test] +fn float_to_integer_checks_overflow() { + // This will overflow an i32 + let source: f64 = 1.0e+123f64; + + // Expect the overflow to be caught + assert_eq!(cast::(source), None); +} + +#[test] +fn cast_to_int_checks_overflow() { + let big_f: f64 = 1.0e123; + let normal_f: f64 = 1.0; + let small_f: f64 = -1.0e123; + assert_eq!(None, cast::(big_f)); + assert_eq!(None, cast::(big_f)); + assert_eq!(None, cast::(big_f)); + assert_eq!(None, cast::(big_f)); + assert_eq!(None, cast::(big_f)); + + assert_eq!(Some(normal_f as isize), cast::(normal_f)); + assert_eq!(Some(normal_f as i8), cast::(normal_f)); + assert_eq!(Some(normal_f as i16), cast::(normal_f)); + assert_eq!(Some(normal_f as i32), cast::(normal_f)); + assert_eq!(Some(normal_f as i64), cast::(normal_f)); + + assert_eq!(None, cast::(small_f)); + assert_eq!(None, cast::(small_f)); + assert_eq!(None, cast::(small_f)); + assert_eq!(None, cast::(small_f)); + assert_eq!(None, cast::(small_f)); +} + +#[test] +fn cast_to_unsigned_int_checks_overflow() { + let big_f: f64 = 1.0e123; + let normal_f: f64 = 1.0; + let small_f: f64 = -1.0e123; + assert_eq!(None, cast::(big_f)); + assert_eq!(None, cast::(big_f)); + assert_eq!(None, cast::(big_f)); + assert_eq!(None, cast::(big_f)); + assert_eq!(None, cast::(big_f)); + + assert_eq!(Some(normal_f as usize), cast::(normal_f)); + assert_eq!(Some(normal_f as u8), cast::(normal_f)); + assert_eq!(Some(normal_f as u16), cast::(normal_f)); + assert_eq!(Some(normal_f as u32), cast::(normal_f)); + assert_eq!(Some(normal_f as u64), cast::(normal_f)); + + assert_eq!(None, cast::(small_f)); + assert_eq!(None, cast::(small_f)); + assert_eq!(None, cast::(small_f)); + assert_eq!(None, cast::(small_f)); + assert_eq!(None, cast::(small_f)); +} + +#[test] +#[cfg(feature = "i128")] +fn cast_to_i128_checks_overflow() { + let big_f: f64 = 1.0e123; + let normal_f: f64 = 1.0; + let small_f: f64 = -1.0e123; + assert_eq!(None, cast::(big_f)); + assert_eq!(None, cast::(big_f)); + + assert_eq!(Some(normal_f as i128), cast::(normal_f)); + assert_eq!(Some(normal_f as u128), cast::(normal_f)); + + assert_eq!(None, cast::(small_f)); + assert_eq!(None, cast::(small_f)); +} + +#[cfg(feature = "std")] +fn dbg(args: ::core::fmt::Arguments) { + println!("{}", args); +} + +#[cfg(not(feature = "std"))] +fn dbg(_: ::core::fmt::Arguments) {} + +// Rust 1.8 doesn't handle cfg on macros correctly +macro_rules! dbg { ($($tok:tt)*) => { dbg(format_args!($($tok)*)) } } + +macro_rules! float_test_edge { + ($f:ident -> $($t:ident)+) => { $({ + dbg!("testing cast edge cases for {} -> {}", stringify!($f), stringify!($t)); + + let small = if $t::MIN == 0 || mem::size_of::<$t>() < mem::size_of::<$f>() { + $t::MIN as $f - 1.0 + } else { + ($t::MIN as $f).raw_offset(1).floor() + }; + let fmin = small.raw_offset(-1); + dbg!(" testing min {}\n\tvs. {:.0}\n\tand {:.0}", $t::MIN, fmin, small); + assert_eq!(Some($t::MIN), cast::<$f, $t>($t::MIN as $f)); + assert_eq!(Some($t::MIN), cast::<$f, $t>(fmin)); + assert_eq!(None, cast::<$f, $t>(small)); + + let (max, large) = if mem::size_of::<$t>() < mem::size_of::<$f>() { + ($t::MAX, $t::MAX as $f + 1.0) + } else { + let large = $t::MAX as $f; // rounds up! + let max = large.raw_offset(-1) as $t; // the next smallest possible + assert_eq!(max.count_ones(), $f::MANTISSA_DIGITS); + (max, large) + }; + let fmax = large.raw_offset(-1); + dbg!(" testing max {}\n\tvs. {:.0}\n\tand {:.0}", max, fmax, large); + assert_eq!(Some(max), cast::<$f, $t>(max as $f)); + assert_eq!(Some(max), cast::<$f, $t>(fmax)); + assert_eq!(None, cast::<$f, $t>(large)); + + dbg!(" testing non-finite values"); + assert_eq!(None, cast::<$f, $t>($f::NAN)); + assert_eq!(None, cast::<$f, $t>($f::INFINITY)); + assert_eq!(None, cast::<$f, $t>($f::NEG_INFINITY)); + })+} +} + +trait RawOffset: Sized { + type Raw; + fn raw_offset(self, offset: Self::Raw) -> Self; +} + +impl RawOffset for f32 { + type Raw = i32; + fn raw_offset(self, offset: Self::Raw) -> Self { + unsafe { + let raw: Self::Raw = mem::transmute(self); + mem::transmute(raw + offset) + } + } +} + +impl RawOffset for f64 { + type Raw = i64; + fn raw_offset(self, offset: Self::Raw) -> Self { + unsafe { + let raw: Self::Raw = mem::transmute(self); + mem::transmute(raw + offset) + } + } +} + +#[test] +fn cast_float_to_int_edge_cases() { + float_test_edge!(f32 -> isize i8 i16 i32 i64); + float_test_edge!(f32 -> usize u8 u16 u32 u64); + float_test_edge!(f64 -> isize i8 i16 i32 i64); + float_test_edge!(f64 -> usize u8 u16 u32 u64); +} + +#[test] +#[cfg(feature = "i128")] +fn cast_float_to_i128_edge_cases() { + float_test_edge!(f32 -> i128 u128); + float_test_edge!(f64 -> i128 u128); +} + +macro_rules! int_test_edge { + ($f:ident -> { $($t:ident)+ } with $BigS:ident $BigU:ident ) => { $({ + fn test_edge() { + dbg!("testing cast edge cases for {} -> {}", stringify!($f), stringify!($t)); + + match ($f::MIN as $BigS).cmp(&($t::MIN as $BigS)) { + Greater => { + assert_eq!(Some($f::MIN as $t), cast::<$f, $t>($f::MIN)); + } + Equal => { + assert_eq!(Some($t::MIN), cast::<$f, $t>($f::MIN)); + } + Less => { + let min = $t::MIN as $f; + assert_eq!(Some($t::MIN), cast::<$f, $t>(min)); + assert_eq!(None, cast::<$f, $t>(min - 1)); + } + } + + match ($f::MAX as $BigU).cmp(&($t::MAX as $BigU)) { + Greater => { + let max = $t::MAX as $f; + assert_eq!(Some($t::MAX), cast::<$f, $t>(max)); + assert_eq!(None, cast::<$f, $t>(max + 1)); + } + Equal => { + assert_eq!(Some($t::MAX), cast::<$f, $t>($f::MAX)); + } + Less => { + assert_eq!(Some($f::MAX as $t), cast::<$f, $t>($f::MAX)); + } + } + } + test_edge(); + })+} +} + +#[test] +fn cast_int_to_int_edge_cases() { + use core::cmp::Ordering::*; + + macro_rules! test_edge { + ($( $from:ident )+) => { $({ + int_test_edge!($from -> { isize i8 i16 i32 i64 } with i64 u64); + int_test_edge!($from -> { usize u8 u16 u32 u64 } with i64 u64); + })+} + } + + test_edge!(isize i8 i16 i32 i64); + test_edge!(usize u8 u16 u32 u64); +} + +#[test] +#[cfg(feature = "i128")] +fn cast_int_to_128_edge_cases() { + use core::cmp::Ordering::*; + + macro_rules! test_edge { + ($( $t:ident )+) => { + $( + int_test_edge!($t -> { i128 u128 } with i128 u128); + )+ + int_test_edge!(i128 -> { $( $t )+ } with i128 u128); + int_test_edge!(u128 -> { $( $t )+ } with i128 u128); + } + } + + test_edge!(isize i8 i16 i32 i64 i128); + test_edge!(usize u8 u16 u32 u64 u128); +} +