It turns out that the 32-bit toolchain for MSVC has many of these functions as
`static inline` functions in header files so there's not actually a symbol for
Rust to call. All of the implementations just cast floats to their 64-bit
variants and then cast back to 32-bit at the end, so the standard library now
takes this strategy.
Ensures that the same error type is propagated throughout. Unnecessary leakage
of the internals is prevented through the usage of stability attributes.
Closes#24748
This commit removes all the old casting/generic traits from `std::num` that are
no longer in use by the standard library. This additionally removes the old
`strconv` module which has not seen much use in quite a long time. All generic
functionality has been supplanted with traits in the `num` crate and the
`strconv` module is supplanted with the [rust-strconv crate][rust-strconv].
[rust-strconv]: https://github.com/lifthrasiir/rust-strconv
This is a breaking change due to the removal of these deprecated crates, and the
alternative crates are listed above.
[breaking-change]
This commit stabilizes the `std::num` module:
* The `Int` and `Float` traits are deprecated in favor of (1) the
newly-added inherent methods and (2) the generic traits available in
rust-lang/num.
* The `Zero` and `One` traits are reintroduced in `std::num`, which
together with various other traits allow you to recover the most
common forms of generic programming.
* The `FromStrRadix` trait, and associated free function, is deprecated
in favor of inherent implementations.
* A wide range of methods and constants for both integers and floating
point numbers are now `#[stable]`, having been adjusted for integer
guidelines.
* `is_positive` and `is_negative` are renamed to `is_sign_positive` and
`is_sign_negative`, in order to address #22985
* The `Wrapping` type is moved to `std::num` and stabilized;
`WrappingOps` is deprecated in favor of inherent methods on the
integer types, and direct implementation of operations on
`Wrapping<X>` for each concrete integer type `X`.
Closes#22985Closes#21069
[breaking-change]
This commit removes the reexports of `old_io` traits as well as `old_path` types
and traits from the prelude. This functionality is now all deprecated and needs
to be removed to make way for other functionality like `Seek` in the `std::io`
module (currently reexported as `NewSeek` in the io prelude).
Closes#23377Closes#23378
Building on #22076, I've added some tests for stable methods in f32 and f64 that didn't have any before.
Please let me know if there are any improvements I can make, and I am happy to make them! 📬
Rebase and follow-through on work done by @cmr and @aatch.
Implements most of rust-lang/rfcs#560. Errors encountered from the checks during building were fixed.
The checks for division, remainder and bit-shifting have not been implemented yet.
See also PR #20795
cc @Aatch ; cc @nikomatsakis
This changes the type of some public constants/statics in libunicode.
Notably some `&'static &'static [(char, char)]` have changed
to `&'static [(char, char)]`. The regexp crate seems to be the
sole user of these, yet this is technically a [breaking-change]
* `core::num`: adjust `UnsignedInt::is_power_of_two`,
`UnsignedInt::next_power_of_two`, `Int::pow`.
In particular for `Int::pow`: (1.) do not panic when `base`
overflows if `acc` never observes the overflowed `base`, and (2.)
if `acc` does observe the overflowed `base`, make sure we only
panic if we would have otherwise (e.g. during a computation of
`base * base`).
* also in `core::num`: avoid underflow during computation of `uint::MAX`.
* `std::num`: adjust tests `uint::test_uint_from_str_overflow`,
`uint::test_uint_to_str_overflow`, `strconv`
* `coretest::num`: adjust `test::test_int_from_str_overflow`.
Many of the core rust libraries have places that rely on integer
wrapping behaviour. These places have been altered to use the wrapping_*
methods:
* core:#️⃣:sip - A number of macros
* core::str - The `maximal_suffix` method in `TwoWaySearcher`
* rustc::util::nodemap - Implementation of FnvHash
* rustc_back::sha2 - A number of macros and other places
* rand::isaac - Isaac64Rng, changed to use the Wrapping helper type
Some places had "benign" underflow. This is when underflow or overflow
occurs, but the unspecified value is not used due to other conditions.
* collections::bit::Bitv - underflow when `self.nbits` is zero.
* collections:#️⃣:{map,table} - Underflow when searching an empty
table. Did cause undefined behaviour in this case due to an
out-of-bounds ptr::offset based on the underflowed index. However the
resulting pointers would never be read from.
* syntax::ext::deriving::encodable - Underflow when calculating the
index of the last field in a variant with no fields.
These cases were altered to avoid the underflow, often by moving the
underflowing operation to a place where underflow could not happen.
There was one case that relied on the fact that unsigned arithmetic and
two's complement arithmetic are identical with wrapping semantics. This
was changed to use the wrapping_* methods.
Finally, the calculation of variant discriminants could overflow if the
preceeding discriminant was `U64_MAX`. The logic in `rustc::middle::ty`
for this was altered to avoid the overflow completely, while the
remaining places were changed to use wrapping methods. This is because
`rustc::middle::ty::enum_variants` now throws an error when the
calculated discriminant value overflows a `u64`.
This behaviour can be triggered by the following code:
```
enum Foo {
A = U64_MAX,
B
}
```
This commit also implements the remaining integer operators for
Wrapped<T>.
* count_ones/zeros, trailing_ones/zeros return u32, not usize
* rotate_left/right take u32, not usize
* RADIX, MANTISSA_DIGITS, DIGITS, BITS, BYTES are u32, not usize
Doesn't touch pow because there's another PR for it.
[breaking-change]
This changes the type of some public constants/statics in libunicode.
Notably some `&'static &'static [(char, char)]` have changed
to `&'static [(char, char)]`. The regexp crate seems to be the
sole user of these, yet this is technically a [breaking-change]
Some function signatures have changed, so this is a [breaking-change].
In particular, radixes and numerical values of digits are represented by `u32` now.
Part of #22240
I was working on adding examples to the documentation in `std::num::Float`. I got to `exp2`, which says "Returns 2 raised to the power of the number, `2^(self)`."
So I tried running this code:
```
use std::num::Float;
#[test]
fn test_exp2() {
assert_eq!(32.0, 5.0.exp2());
}
```
and it resulted in a failure of `(left: `32`, right: `148.413159`)`. That 148.413159 is the value for e^5, which is `exp()`, not `exp2()`.
Sure enough, `exp2` is calling `exp` and shouldn't be, looks like a copy-paste error.
I haven't added any tests for this since it's unlikely to break again, but I will happily do so if people think that would be a good idea. The doc examples are coming :)
I scanned through the other functions in these files for similar sorts of errors and didn't notice any.
