num-traits/tests/cast.rs

320 lines
9.7 KiB
Rust

//! 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(has_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: 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));
}
#[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::<f64, i32>(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::<f64, isize>(big_f));
assert_eq!(None, cast::<f64, i8>(big_f));
assert_eq!(None, cast::<f64, i16>(big_f));
assert_eq!(None, cast::<f64, i32>(big_f));
assert_eq!(None, cast::<f64, i64>(big_f));
assert_eq!(Some(normal_f as isize), cast::<f64, isize>(normal_f));
assert_eq!(Some(normal_f as i8), cast::<f64, i8>(normal_f));
assert_eq!(Some(normal_f as i16), cast::<f64, i16>(normal_f));
assert_eq!(Some(normal_f as i32), cast::<f64, i32>(normal_f));
assert_eq!(Some(normal_f as i64), cast::<f64, i64>(normal_f));
assert_eq!(None, cast::<f64, isize>(small_f));
assert_eq!(None, cast::<f64, i8>(small_f));
assert_eq!(None, cast::<f64, i16>(small_f));
assert_eq!(None, cast::<f64, i32>(small_f));
assert_eq!(None, cast::<f64, i64>(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::<f64, usize>(big_f));
assert_eq!(None, cast::<f64, u8>(big_f));
assert_eq!(None, cast::<f64, u16>(big_f));
assert_eq!(None, cast::<f64, u32>(big_f));
assert_eq!(None, cast::<f64, u64>(big_f));
assert_eq!(Some(normal_f as usize), cast::<f64, usize>(normal_f));
assert_eq!(Some(normal_f as u8), cast::<f64, u8>(normal_f));
assert_eq!(Some(normal_f as u16), cast::<f64, u16>(normal_f));
assert_eq!(Some(normal_f as u32), cast::<f64, u32>(normal_f));
assert_eq!(Some(normal_f as u64), cast::<f64, u64>(normal_f));
assert_eq!(None, cast::<f64, usize>(small_f));
assert_eq!(None, cast::<f64, u8>(small_f));
assert_eq!(None, cast::<f64, u16>(small_f));
assert_eq!(None, cast::<f64, u32>(small_f));
assert_eq!(None, cast::<f64, u64>(small_f));
}
#[test]
#[cfg(has_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::<f64, i128>(big_f));
assert_eq!(None, cast::<f64, u128>(big_f));
assert_eq!(Some(normal_f as i128), cast::<f64, i128>(normal_f));
assert_eq!(Some(normal_f as u128), cast::<f64, u128>(normal_f));
assert_eq!(None, cast::<f64, i128>(small_f));
assert_eq!(None, cast::<f64, u128>(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(has_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!($from -> { usize u8 u16 u32 u64 } with i64 u64);
})+}
}
test_edge!(isize i8 i16 i32 i64);
test_edge!(usize u8 u16 u32 u64);
}
#[test]
#[cfg(has_i128)]
fn cast_int_to_128_edge_cases() {
use core::cmp::Ordering::*;
macro_rules! test_edge {
($( $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);
}