Move libXtest into libX/tests
This change moves:
1. `libcoretest` into `libcore/tests`
2. `libcollectionstest` into `libcollections/tests`
This is a follow-up to #39561.
r? @alexcrichton
Let .rev()'s find use the underlying rfind and vice versa
- Connect the plumbing in an obvious way from Rev's find → underlying rfind and vice versa
- A style change in the provided implementation for Iterator::rfind, using simple next_back when it is enough
Add ptr::offset_to
This PR adds a method to calculate the signed distance (in number of elements) between two pointers. The resulting value can then be passed to `offset` to get one pointer from the other. This is similar to pointer subtraction in C/C++.
There are 2 special cases:
- If the distance is not a multiple of the element size then the result is rounded towards zero. (in C/C++ this is UB)
- ZST return `None`, while normal types return `Some(isize)`. This forces the user to handle the ZST case in unsafe code. (C/C++ doesn't have ZSTs)
Reduce a table used for `Debug` impl of `str`.
This commit shrinks the size of the aforementioned table from 2,102 bytes to 1,197 bytes. This is achieved by an observation that most `u16` entries are common in its upper byte. Specifically:
- `SINGLETONS` now uses two tables, one for (upper byte, lower count) and another for a series of lower bytes. For each upper byte given number of lower bytes are read and compared.
- `NORMAL` now uses a variable length format for the count of "true" codepoints and "false" codepoints (one byte with MSB unset, or two big-endian bytes with the first MSB set).
The code size and relative performance roughly remains same as this commit tries to optimize for both. The new table and algorithm has been verified for the equivalence to older ones.
In my x86-64 macOS laptop with `rustc 1.17.0-nightly (0aeb9c129 2017-03-15)`, `-C opt-level=3 -C lto` gives the following:
* The old routine compiles to 2,102 bytes of data and 416 bytes of code.
* The new routine compiles to 1,197 bytes of data and 448 bytes of code.
Counting a number of all printable Unicode scalar values (128,003, if you wonder) by filtering `0..0x110000` with `std::char::from_u32` and `is_printable` took 50±7ms for both. This can be surprising as the new routine *has* to do more calculations; this is partly explained by the fact that a linear search of `SINGLETONS` has been replaced by *two* linear searches for upper and lower bytes, which greatly reduces the iteration count.
Added links to types in from_utf8 description
References #29375. Link to types mentioned in the documentation for `from_utf8` (`str`, `&[u8`], etc). Paragraphs were reformatted to keep any one line from being excessively long, but are otherwise unchanged.
Added links to from_utf8 methods in Utf8Error
Referencing #29375. Linked the `from_utf8` methods for both `String` and `str` in the description. Also linked the `u8` to its documentation
This commit shrinks the size of the aforementioned table from
2,102 bytes to 1,197 bytes. This is achieved by an observation that
most u16 entries are common in its upper byte. Specifically:
- SINGLETONS now uses two tables, one for (upper byte, lower count)
and another for a series of lower bytes. For each upper byte given
number of lower bytes are read and compared.
- NORMAL now uses a variable length format for the count of "true"
codepoints and "false" codepoints (one byte with MSB unset, or
two big-endian bytes with the first MSB set).
The code size and relative performance roughly remains same as this
commit tries to optimize for both. The new table and algorithm has
been verified for the equivalence to older ones.
Improve the docs for the write and writeln macros
This change reduces duplication by linking the documentation for
`writeln!` to `write!`. It also restructures the `write!` documentation
to read in a more logical manner (I hope; feedback would be welcome).
Updates #29329, #29381
Implement all PartialOrd methods for Reverse
When making a forwarding wrapper we must in general forward all methods,
so that we use the type's own `lt` for example instead of the default.
Example important case: f32's partial_cmp does several operations but
its lt is a primitive.
Follow up on #40720
This change reduces duplication by linking the documentation for
`writeln!` to `write!`. It also restructures the `write!` documentation
to read in a more logical manner.
Updates #29329, #29381
When making a forwarding wrapper we must in general forward all methods,
so that we use the type's own `lt` for example instead of the default.
Example important case: f32's partial_cmp does several operations but
its lt is a primitive.
libcore: fix compilation on 16bit target (MSP430).
Since PR #40601 has been merged, libcore no longer compiles on MSP430.
The reason is this code in `break_patterns`:
```rust
let mut random = len;
random ^= random << 13;
random ^= random >> 17;
random ^= random << 5;
random &= modulus - 1;
```
It assumes that `len` is at least a 32 bit integer.
As a workaround replace `break_patterns` with an empty function for 16bit targets.
cc @stjepang
cc @alexcrichton
Added core::cmp::Reverse for sort_by_key reverse sorting
I'm not sure if this is the best way to go about proposing this feature but it's pretty useful. It allows you to use `sort_by_key` and return tuples where a single item is then reversed to how it normally sorts.
I quite miss something like this in Rust currently though I'm not sure if this is the best way to implement it.
