It is simply defined as `f64` across every platform right now.
A use case hasn't been presented for a `float` type defined as the
highest precision floating point type implemented in hardware on the
platform. Performance-wise, using the smallest precision correct for the
use case greatly saves on cache space and allows for fitting more
numbers into SSE/AVX registers.
If there was a use case, this could be implemented as simply a type
alias or a struct thanks to `#[cfg(...)]`.
Closes#6592
The mailing list thread, for reference:
https://mail.mozilla.org/pipermail/rust-dev/2013-July/004632.html
It was a little ambiguous before how explicitl positional parameters and
implicit positional parameters intermingled, and this clarifies how the two
intermingle. This also updates a little bit of documentation/code examples
elsewhere as well.
It was a little ambiguous before how explicitl positional parameters and
implicit positional parameters intermingled, and this clarifies how the two
intermingle. This also updates a little bit of documentation/code examples
elsewhere as well.
std::vec: Sane implementations for connect_vec and concat_vec
Avoid unnecessary copying of subvectors, and calculate the needed space
beforehand. These implementations are simple but better than the
previous.
Also only implement it once, for all `Vector<T>` using:
impl<'self, T: Clone, V: Vector<T>> VectorVector<T> for &'self [V]
Closes#9581
Avoid unnecessary copying of subvectors, and calculate the needed space
beforehand. These implementations are simple but better than the
previous.
Also only implement it once, for all `Vector<T>` using:
impl<'self, T: Clone, V: Vector<T>> VectorVector<T> for &'self [V]
performance improved according to the bench test:
before
test vec::bench::concat ... bench: 74818 ns/iter (+/- 408)
test vec::bench::connect ... bench: 87066 ns/iter (+/- 376)
after
test vec::bench::concat ... bench: 17724 ns/iter (+/- 126)
test vec::bench::connect ... bench: 18353 ns/iter (+/- 691)
Closes#9581
std::vec: Use a valid value as lifetime dummy in iterator
The current implementation uses `&v[0]` for the lifetime struct field,
but that is a dangling pointer for iterators derived from zero-length
slices.
Example:
let v: [int, ..0] = []; println!("{:?}", v.iter())
std::vec::VecIterator<,int>{ptr: (0x7f3768626100 as *()), end: (0x7f3768626100 as *()), lifetime: &139875951207128}
To replace this parameter, use a field of type `Option<&'self ()>`
that is simply initialized with `None`, but still allows the iterator to
have a lifetime parameter.
This now makes it unsafe to save the pointer returned by .with_c_str
as that pointer now may be pointing at a stack allocated array.
I arbitrarily chose 32 bytes as the length of the stack vector, and
so it might not be the most optimal size.
before:
test c_str::bench::bench_with_c_str_long ... bench: 539 ns/iter (+/- 91)
test c_str::bench::bench_with_c_str_medium ... bench: 97 ns/iter (+/- 2)
test c_str::bench::bench_with_c_str_short ... bench: 70 ns/iter (+/- 5)
after:
test c_str::bench::bench_with_c_str_long ... bench: 542 ns/iter (+/- 13)
test c_str::bench::bench_with_c_str_medium ... bench: 53 ns/iter (+/- 6)
test c_str::bench::bench_with_c_str_short ... bench: 19 ns/iter (+/- 0)
The current implementation uses `&v[0]` for the lifetime struct field,
but that is a dangling pointer for iterators derived from zero-length
slices.
Example:
let v: [int, ..0] = []; println!("{:?}", v.iter())
std::vec::VecIterator<,int>{ptr: (0x7f3768626100 as *()), end: (0x7f3768626100 as *()), lifetime: &139875951207128}
To replace this parameter, use a field of type `Option<&'self ()>`
that is simply initialized with `None`, but still allows the iterator to
have a lifetime parameter.
This lifts various restrictions on the runtime, for example the character limit
when logging a message. Right now the old debug!-style macros still involve
allocating (because they use fmt! syntax), but the new debug2! macros don't
involve allocating at all (unless the formatter for a type requires allocation.
This also includes a fix for yielding from single-threaded schedulers where the scheduler would stop working before its work queue was empty. Fixes the deadlocks that this patch had previously.
Fix#7752.
~~(The glob API is a little funky; I tried to make a small test for it, which I'll add to the end of this description, and its not clear whether globfree is supposed to free solely the structure allocated by glob itself, or if it is going to try to free more than that.)~~ (The previous note was a user-error: I was misusing the CString API.)
Anyway, this seems to work in terms of calling errfunc where expected.)
```rust
#[allow(unused_imports)];
use std::libc::types::os::arch::c95::{c_char, c_int, size_t};
use std::libc::funcs::posix01::glob;
use std::libc::types::os::common::posix01::glob_t;
use std::libc::consts::os::posix01::{GLOB_APPEND, GLOB_DOOFFS, GLOB_ERR,
GLOB_MARK, GLOB_NOCHECK, GLOB_NOSORT,
GLOB_NOESCAPE, GLOB_NOSPACE,
GLOB_ABORTED, GLOB_NOMATCH};
use std::ptr;
use std::c_str;
#[fixed_stack_segment]
fn main() {
let mut g = glob_t {
gl_pathc: 0, // size_t,
__unused1: 0, // c_int,
gl_offs: 2, // size_t,
__unused2: 0, // c_int,
gl_pathv: ptr::null(), // **c_char,
__unused3: ptr::null(), // *c_void,
__unused4: ptr::null(), // *c_void,
__unused5: ptr::null(), // *c_void,
__unused6: ptr::null(), // *c_void,
__unused7: ptr::null(), // *c_void,
__unused8: ptr::null(), // *c_void,
};
extern "C" fn errfunc(_epath: *c_char, _errno: int) -> int {
println!("errfunc called");
return 0;
}
struct Reduced { pathc: size_t, offs: size_t, pathv: **c_char, }
impl Reduced {
fn from(g: &glob_t) -> Reduced {
Reduced {pathc: g.gl_pathc, offs: g.gl_offs, pathv: g.gl_pathv}
}
}
do ("*.rs/*").with_c_str |pat| {
println!("calling glob");
unsafe { glob::glob(pat, GLOB_DOOFFS, errfunc, &mut g); }
println!("After glob call");
println!("g: {:?}", Reduced::from(&g));
for i in range(0, g.gl_pathc as int) {
unsafe {
let p : **c_char = ptr::offset(g.gl_pathv, g.gl_offs as int + i);
let x = c_str::CString::new(*p, false);
match x.as_str() {
Some(s) => {
println!("gl_pathc[{:d}]: {:?}", i, s);
}
None => {
println!("gl_pathc[{:d}]: unvalid", i);
}
}
}
}
}
println!("calling globfree on g: {:?}", g);
unsafe { glob::globfree(&mut g); }
println!("after globfree call");
}
```
If there's no TLS key just yet, then there's nothing to unsafely borrow, so
continue returning None. This prevents causing the runtime to abort itself when
logging before the runtime is fully initialized.
Closes#9487
r? @brson
Moved OwnedStr doc comments from impl to trait.
Added a few #[inline] hints.
The doc comment changes make the source a bit harder to read, as
documentation and implementation no longer live right next to each
other. But this way they at least appear in the docs.
This lifts various restrictions on the runtime, for example the character limit
when logging a message. Right now the old debug!-style macros still involve
allocating (because they use fmt! syntax), but the new debug2! macros don't
involve allocating at all (unless the formatter for a type requires allocation.
