- Adds the `Sample` and `IndependentSample` traits for generating numbers where there are parameters (e.g. a list of elements to draw from, or the mean/variance of a normal distribution). The former takes `&mut self` and the latter takes `&self` (this is the only difference).
- Adds proper `Normal` and `Exp`-onential distributions
- Adds `Range` which generates `[lo, hi)` generically & properly (via a new trait) replacing the incorrect behaviour of `Rng.gen_integer_range` (this has become `Rng.gen_range` for convenience, it's far more efficient to use `Range` itself)
- Move the `Weighted` struct from `std::rand` to `std::rand::distributions` & improve it
- optimisations and docs
This reifies the computations required for uniformity done by
(the old) `Rng.gen_integer_range` (now Rng.gen_range), so that they can
be amortised over many invocations, if it is called in a loop.
Also, it makes it correct, but using a trait + impls for each type,
rather than trying to coerce `Int` + `u64` to do the right thing. This
also makes it more extensible, e.g. big integers could & should
implement SampleRange.
Also, documentation & general clean-up:
- remove `gen_char_from`: better served by `sample` or `choose`.
- `gen_bytes` generalised to `gen_vec`.
- `gen_int_range`/`gen_uint_range` merged into `gen_integer_range` and
made to be properly uniformly distributed. Fixes#8644.
Minor adjustments to other functions.
These functions have very few users since they are mostly replaced by
iterator-based constructions.
Convert a few remaining users in-tree, and reduce the number of
functions by basically renaming build_sized_opt to build, and removing
the other two. This for both the vec and the at_vec versions.
Encoding should really only be done from [u8]<->str. The extra
convenience implementations don't really have a place, especially since
they're so trivial.
Also improved error messages in FromBase64.
The overhead of str::push_char is high enough to cripple the performance
of these two functions. I've switched them to build the output in a
~[u8] and then convert to a string later. Since we know exactly the
bytes going into the vector, we can use the unsafe version to avoid the
is_utf8 check.
I could have riced it further with vec::raw::get, but it only added
~10MB/s so I didn't think it was worth it. ToHex is still ~30% slower
than FromHex, which is puzzling.
Before:
```
test base64::test::from_base64 ... bench: 1000 ns/iter (+/- 349) = 204 MB/s
test base64::test::to_base64 ... bench: 2390 ns/iter (+/- 1130) = 63 MB/s
...
test hex::tests::bench_from_hex ... bench: 884 ns/iter (+/- 220) = 341 MB/s
test hex::tests::bench_to_hex ... bench: 2453 ns/iter (+/- 919) = 61 MB/s
```
After:
```
test base64::test::from_base64 ... bench: 1271 ns/iter (+/- 600) = 160 MB/s
test base64::test::to_base64 ... bench: 759 ns/iter (+/- 286) = 198 MB/s
...
test hex::tests::bench_from_hex ... bench: 875 ns/iter (+/- 377) = 345 MB/s
test hex::tests::bench_to_hex ... bench: 593 ns/iter (+/- 240) = 254 MB/s
```
- Made naming schemes consistent between Option, Result and Either
- Changed Options Add implementation to work like the maybe monad (return None if any of the inputs is None)
- Removed duplicate Option::get and renamed all related functions to use the term `unwrap` instead
Change the former repetition::
for 5.times { }
to::
do 5.times { }
.times() cannot be broken with `break` or `return` anymore; for those
cases, use a numerical range loop instead.
There's now an enum to pick the character set instead of a url_safe
bool.
from_base64 now returns a Result<~[u8], ~str> and returns an Err instead
of killing the task when it is called on invalid input.
Fixed documentation examples.
The Base64 package previously had extremely basic functionality. It only
suported the standard encoding character set, didn't support line breaks
and always padded output. This commit makes it significantly more
powerful.
The FromBase64 impl now supports all of the standard variants of Base64.
It ignores newlines,interprets '-' and '_' as well as '+' and '/' and
doesn't require padding. It isn't incredibly pedantic and will
successfully parse strings that are not strictly valid, but I don't
think the extra complexity required to make it accept _only_ valid
strings is worth it.
The ToBase64 trait has been modified such that to_base64 now takes a
base64::Config struct which contains the output format configuration.
This currently includes the selection of character set (standard or
url safe), whether or not to pad and an optional line break width. The
package comes with three static Config structs for the RFC 4648
standard, RFC 4648 url safe and RFC 2045 MIME formats.
The other option for configuring ToBase64 output would be to have one
method with the configuration flags passed and other traits with default
impls for the common cases, but I think that's a little messier.
Previously, FromBase64 was only implemented on ~[u8] and ~str when
any pointer would do. The implementations of FromBase64 are now
consistent with the implementations of ToBase64.
