These intrinsics are synthesized, so maybe they should be in another
file. But since they are just a single line of code each, based on the
bswap intrinsics and aren't really intended for public consumption (they should be exposed as a
single function / trait) I thought they would fit here.
It can sometimes be useful to have maps/sets of floating point values.
Doing arithmetic with floats and then using them as keys is, of course, not a good idea.
This allows mass-initialization of large structs without having to specify all the fields.
I'm a bit hesitant, but I wanted to get this out there. I don't really like using the `Zero` trait, because it doesn't really make sense for a type like `HashMap` to use `Zero` as the 'blank allocation' trait. In theory there'd be a new trait, but then that's adding cruft to the language which may not necessarily need to be there.
I do think that this can be useful, but I only implemented `Zero` on the basic types where I thought it made sense, so it may not be all that usable yet. (opinions?)
Moves all the remaining functions that could reasonably be methods to be methods, except for some FFI ones (which I believe @erickt is working on, possibly) and `each_split_within`, since I'm not really sure the details of it (I believe @kimundi wrote the current implementation, so maybe he could convert it to an external iterator method on `StrSlice`, e.g. `word_wrap_iter(&self) -> WordWrapIterator<'self>`, where `WordWrapIterator` impls `Iterator<&'self str>`. It probably won't be too hard, since it's already a state machine.)
This also cleans up the comparison impls for the string types, except I'm not sure how the lang items `eq_str` and `eq_str_uniq` need to be handled, so they (`eq_slice` and `eq`) remain stand-alone functions.
This moves them all into the traits submodule, and delegates Ord
to the TotalOrd instance. It also deletes the stand-alone lt, gt,
ge and le functions.
This is caused by StrVector having a generic implementation for &[S]
and so #5898 means that method resolution of ~[~[1]].concat() sees that
both StrVector and VectorVector have methods that (superficially) match.
They are now connect_vec and concat_vec, which means that they can actually be
called.
r? @brson
links to issues: #7065 the race that's fixed; #7066 the perf improvement I added. There are also some minor cleanup commits here.
To measure the performance improvement from replacing the exclusive with an atomic uint, I edited the ```msgsend-ring-rw-arcs``` bench test to do a ```write_downgrade``` instead of just a ```write```, so that it stressed the code paths that accessed ```read_count```. (At first I was still using ```write``` and saw no performance difference whatsoever, whoooops.)
The bench test measures how long it takes to send 1,000,000 messages by using rwarcs to emulate pipes. I also measured the performance difference imposed by the fix to the ```access_lock``` race (which involves taking an extra semaphore in the ```cond.wait()``` path). The net result is that fixing the race imposes a 4% to 5% slowdown, but doing the atomic uint optimization gives a 6% to 8% speedup.
Note that this speedup will be most visible in read- or downgrade-heavy workloads. If an RWARC's only users are writers, the optimization doesn't matter. All the same, I think this more than justifies the extra complexity I mentioned in #7066.
The raw numbers are:
```
with xadd read count
before write_cond fix
4.18 to 4.26 us/message
with write_cond fix
4.35 to 4.39 us/message
with exclusive read count
before write_cond fix
4.41 to 4.47 us/message
with write_cond fix
4.65 to 4.76 us/message
```
The code compiles and runs under windows now, but I couldn't look up any
symbol from the current executable (dlopen(NULL)), and calling looked
up external function handles doesn't seem to work correctly under windows.
This is caused by StrVector having a generic implementation for &[S]
and so #5898 means that method resolution of ~[~[1]].concat() sees that
both StrVector and VectorVector have methods that (superficially) match.
They are now connect_vec and concat_vec, which means that they can actually be
called.
