2b82c072c7
The innermost loop of TwoWaySearcher checks the boundary of the haystack vs position + needle.len(), and it checks the last byte of the needle against the byteset. If these two steps are combined by using the indexing of the last needle byte's position as bounds check, the algorithm improves its throughput. We improve the innermost loop by reducing the number of instructions used, and elminating the panic case for the checked indexing that was previously used. Selected benchmarks from the external/workspace testsuite. Benchmarks improve across the board. ``` before: test bb_in_aa::twoway_find ... bench: 4,229 ns/iter (+/- 1,305) = 23646 MB/s test bb_in_aa::twoway_rfind ... bench: 3,873 ns/iter (+/- 101) = 25819 MB/s test short_1let_long::twoway_find ... bench: 7,075 ns/iter (+/- 29) = 360 MB/s test short_1let_long::twoway_rfind ... bench: 6,640 ns/iter (+/- 79) = 384 MB/s test short_2let_long::twoway_find ... bench: 3,823 ns/iter (+/- 16) = 667 MB/s test short_2let_long::twoway_rfind ... bench: 3,774 ns/iter (+/- 44) = 675 MB/s test short_3let_long::twoway_find ... bench: 3,582 ns/iter (+/- 47) = 712 MB/s test short_3let_long::twoway_rfind ... bench: 3,616 ns/iter (+/- 34) = 705 MB/s with this commit: test bb_in_aa::twoway_find ... bench: 2,952 ns/iter (+/- 20) = 33875 MB/s test bb_in_aa::twoway_rfind ... bench: 2,939 ns/iter (+/- 99) = 34025 MB/s test short_1let_long::twoway_find ... bench: 4,593 ns/iter (+/- 4) = 555 MB/s test short_1let_long::twoway_rfind ... bench: 4,592 ns/iter (+/- 76) = 555 MB/s test short_2let_long::twoway_find ... bench: 2,804 ns/iter (+/- 3) = 909 MB/s test short_2let_long::twoway_rfind ... bench: 2,807 ns/iter (+/- 40) = 908 MB/s test short_3let_long::twoway_find ... bench: 3,105 ns/iter (+/- 120) = 821 MB/s test short_3let_long::twoway_rfind ... bench: 3,019 ns/iter (+/- 50) = 844 MB/s ``` - `bb_in_aa`: fast skip due to byteset filter loop improves. - 1/2/3let: Searches for 1, 2, or 3 ascii bytes improves.
The Rust Programming Language
Rust is a fast systems programming language that guarantees memory safety and offers painless concurrency (no data races). It does not employ a garbage collector and has minimal runtime overhead.
This repo contains the code for the compiler (rustc), as well
as standard libraries, tools and documentation for Rust.
Quick Start
Read "Installing Rust" from The Book.
Building from Source
-
Make sure you have installed the dependencies:
g++4.7 orclang++3.xpython2.6 or later (but not 3.x)- GNU
make3.81 or later curlgit
-
Clone the source with
git:$ git clone https://github.com/rust-lang/rust.git $ cd rust
-
Build and install:
$ ./configure $ make && make installNote: You may need to use
sudo make installif you do not normally have permission to modify the destination directory. The install locations can be adjusted by passing a--prefixargument toconfigure. Various other options are also supported – pass--helpfor more information on them.When complete,
make installwill place several programs into/usr/local/bin:rustc, the Rust compiler, andrustdoc, the API-documentation tool. This install does not include Cargo, Rust's package manager, which you may also want to build.
Building on Windows
MSYS2 can be used to easily build Rust on Windows:
-
Grab the latest MSYS2 installer and go through the installer.
-
From the MSYS2 terminal, install the
mingw64toolchain and other required tools.# Choose one based on platform: $ pacman -S mingw-w64-i686-toolchain $ pacman -S mingw-w64-x86_64-toolchain $ pacman -S base-devel -
Run
mingw32_shell.batormingw64_shell.batfrom wherever you installed MSYS2 (i.e.C:\msys), depending on whether you want 32-bit or 64-bit Rust. -
Navigate to Rust's source code, configure and build it:
$ ./configure $ make && make install
Notes
Since the Rust compiler is written in Rust, it must be built by a precompiled "snapshot" version of itself (made in an earlier state of development). As such, source builds require a connection to the Internet, to fetch snapshots, and an OS that can execute the available snapshot binaries.
Snapshot binaries are currently built and tested on several platforms:
| Platform \ Architecture | x86 | x86_64 |
|---|---|---|
| Windows (7, 8, Server 2008 R2) | ✓ | ✓ |
| Linux (2.6.18 or later) | ✓ | ✓ |
| OSX (10.7 Lion or later) | ✓ | ✓ |
You may find that other platforms work, but these are our officially supported build environments that are most likely to work.
Rust currently needs about 1.5 GiB of RAM to build without swapping; if it hits swap, it will take a very long time to build.
There is more advice about hacking on Rust in CONTRIBUTING.md.
Getting Help
The Rust community congregates in a few places:
- Stack Overflow - Direct questions about using the language.
- users.rust-lang.org - General discussion and broader questions.
- /r/rust - News and general discussion.
Contributing
To contribute to Rust, please see CONTRIBUTING.
Rust has an IRC culture and most real-time collaboration happens in a variety of channels on Mozilla's IRC network, irc.mozilla.org. The most popular channel is #rust, a venue for general discussion about Rust, and a good place to ask for help.
License
Rust is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0), with portions covered by various BSD-like licenses.
See LICENSE-APACHE, LICENSE-MIT, and COPYRIGHT for details.