The minimum (negative) value of a float is `-Bounded::max_value()`, not `Bounded::min_value()`.
Otherwise the following has an incorrect behavior:
```rust
let a = -1.0f64;
let b: f32 = NumCast::from(a); // incorrectly returns None
```
This changes an `assert_once_ever!` assertion to just a plain old assertion
around an atomic boolean to ensure that one particular runtime doesn't attempt
to exit twice.
Closes#9739
This changes an `assert_once_ever!` assertion to just a plain old assertion
around an atomic boolean to ensure that one particular runtime doesn't attempt
to exit twice.
Closes#9739
This disallows `str[0] = foo` along with `foo = &mut str[i]` to prevent strings
from being modified at runtime (except possibly through the `str` module)
Closes#8891
Fixes a bug that `rustc.exe -v` didn't show git revision hash.
The bug is caused by that `$(wildcard $(CFG_GIT))` requires
space-escaped inputs while `$(CFG_GIT)` is usually
`C:\Program Files (x86)\Gitin\git.exe`.
A pile of changes to `std::rand`:
- Add the 64-bit variant of the ISAAC Rng. This also splits the `Rng.next() -> u32` method into `Rng.next_u32() -> u32` and `Rng.next_u64() -> u64` to be able to actually take advantage of the wider numbers. They have default implementations in terms of each other. (This is ~2× faster than the 32 bit one for generating anything larger than a `u32` on 64-bit computers.)
- Add `ReaderRng` which just wraps a reader as an RNG, useful for `/dev/urandom`, `/dev/random`, `/dev/hwrng`, etc. This also adds the overrideable `fill_bytes` method to `Rng`, since readers can "generate" randomness more than just 8 bytes at a time.
- Add an interface to `/dev/urandom` (and the windows API) that implements `Rng` (`os::OSRng`) so that it is a first-class randomness source. This means that experimenting with things like seeding hashmaps from it will be much easier. It deletes most of the C++ supporting the old form, except for thin wrappers around the Windows API; I don't have access to a windows with Rust other than the try branch. ( **Note:** on unices, this means that `OSRng` requires the runtime, so it's not possible to use it to seed the scheduler RNG; I've replaced it with direct libc calls for reading from `/dev/urandom`.)
- Add the "blessed" `StdRng` which means users who just want a random number generator don't need to worry about the implementation details (which will make changing the underlying implementation from Isaac to something else will be easier, if this every happen). This actually changes between the 32 and 64-bit variants of Isaac depending on the platform at the moment.
- Add a `SeedableRng` trait for random number generators that can be explicitly seeded,
- Add the `ReseedingRng` wrapper for reseeding a RNG after a certain amount of randomness is emitted. (The method for reseeding is controlled via the `Reseeder` trait from the same module)
- changes to the task rng:
- uses `StdRng`
- it will reseed itself every 32KB, that is, after outputting 32KB of random data it will read new data from the OS (via `OSRng`)
- Implements `Rand` for `char`, and makes the `f32` and `f64` instances more reasonable (and more similar to most other languages I've looked at).
- Documentation, examples and tests
This lets the C++ code in the rt handle the (slightly) tricky parts of
random number generation: e.g. error detection/handling, and using the
values of the `#define`d options to the various functions.
It now:
- can be explicitly seeded from user code (`seed_task_rng`) or from the
environment (`RUST_SEED`, a positive integer)
- automatically reseeds itself from the OS *unless* it was seeded by
either method above
- has more documentation
This provides 2 methods: .reseed() and ::from_seed that modify and
create respecitively.
Implement this trait for the RNGs in the stdlib for which this makes
sense.
This is implemented as a wrapper around another RNG. It is designed
to allow the actual implementation to be changed without changing
the external API (e.g. it currently uses a 64-bit generator on 64-
bit platforms, and a 32-bit one on 32-bit platforms; but one could
imagine that the IsaacRng may be deprecated later, and having this
ability to switch algorithms without having to update the points of
use is convenient.)
This is the recommended general use RNG.
The former reads from e.g. /dev/urandom, the latter just wraps any
std::rt::io::Reader into an interface that implements Rng.
This also adds Rng.fill_bytes for efficient implementations of the above
(reading 8 bytes at a time is inefficient when you can read 1000), and
removes the dependence on src/rt (i.e. rand_gen_seed) although this last
one requires implementing hand-seeding of the XorShiftRng used in the
scheduler on Linux/unixes, since OSRng relies on a scheduler existing to
be able to read from /dev/urandom.
This is 2x faster on 64-bit computers at generating anything larger
than 32-bits.
It has been verified against the canonical C implementation from the
website of the creator of ISAAC64.
Also, move `Rng.next` to `Rng.next_u32` and add `Rng.next_u64` to
take full advantage of the wider word width; otherwise Isaac64 will
always be squeezed down into a u32 wasting half the entropy and
offering no advantage over the 32-bit variant.
Since lint check attributes are the preferred way of selectively
enabling/disabling lint checks, the output format of a failed
default check has been changed to reflect that.
When lint checks are being explicitly set by a command-line flag
or an attribute, the behavior is unchanged, so that the user can
quickly pinpoint the source.
Supersedes the patch suggested in #9778Closes#6580
Fixes a bug that `rustc.exe -v` didn't show git revision hash.
The bug is caused by that `$(wildcard $(CFG_GIT))` requires
space-escaped inputs while `$(CFG_GIT)` is usually
`C:\Program Files (x86)\Git\bin\git.exe`.
Since lint check attributes are the preferred way of selectively
enabling/disabling lint checks, the output format of a failed
default check has been changed to reflect that.
When lint checks are being explicitly set by a command-line flag
or an attribute, the behavior is unchanged, so that the user can
quickly pinpoint the source.
Closes#6580
It's unclear to me why these currently aren't allowed, and my best guess is that
a long time ago we didn't strip the ast of cfg nodes before syntax expansion.
Now that this is done, I'm not certain that we should continue to prohibit this
functionality.
This is a step in the right direction towards #5605, because now we can add an
empty `std::macros` module to the documentation with a bunch of empty macros
explaining how they're supposed to be used.
It's unclear to me why these currently aren't allowed, and my best guess is that
a long time ago we didn't strip the ast of cfg nodes before syntax expansion.
Now that this is done, I'm not certain that we should continue to prohibit this
functionality.
This is a step in the right direction towards #5605, because now we can add an
empty `std::macros` module to the documentation with a bunch of empty macros
explaining how they're supposed to be used.
