65ce08f38c
Replace state enum with a cached hash code which has the same memory overhead and locality as the enum, but can really speed things up with non-integer-like keys (keys for which either hash() or == take more than couple cycles, or where the key data is "indirect" and might incur another cache miss). To function as both empty/filled state and a hash code cache, it only needs to be ensured that hash codes are non-zero for any real key. That is done at the one place in the whole file hash() is called. Keep convention clear via isFilled() & isEmpty(). An isDeleted state will no longer be necessary as per below excl/inf loop fix. Since some use sites know hc and some do not, re-factor rawGet into two forms - one with known hash code and one with an unknown HC that returns it. Both forms still return <0 on missing, but returns the much more informative "-1 - index". That return can be quickly inverted by -1 - result to recover the index where insert should happen, provided no modifications are made to the table in the meantime. This protocol retains the prior <0 interface and also makes it easy to avoid unnecessary duplicate search work in procs like containsOrInclImpl (which formerly searched in the initial get and AGAIN in rawInsert). Strip the searching part out of rawInsert to "make it even more raw". swap(s.data, n) a bit earlier so rawGet and rawGetKnownHC can have similar parameter lists and integrate well with rawInsert/code sharing between Set and OrderedSet impls. This PR also fixes infinite looping upon too many deletes. [ The deleted state (aka "tombstone") approach is vulnerable to the table filling up with deleted items which forces giant scans for missing keys which could be anywhere. In the version prior to this PR, table wraparound wasn't even detected yielding infinite loops. ] This PR changes excl() from marking slots as deleted to Knuth algo 6.4R, "local/incremental moveback rehashing" - adapted from Knuth's h->h-1 to the cache-friendlier h->h+1 probe sequence and adapted from "gotos" to a new doWhile template. This method restores the table to a state that would have resulted from pure inserts (in some order). Update nextTry accordingly. Since linear probing can degrade a little faster, 50% rather than 66% may be a better default growth threshold, but users should be able to adjust threshold anyway. Old unit tests all pass. More extensive testing in this module is probably warranted before taking similar enhancements over to collections.tables.
Nim Compiler
This repo contains the Nim compiler, Nim's stdlib, tools and documentation.
Compiling
Compiling the Nim compiler is quite straightforward. Because the Nim compiler itself is written in the Nim programming language the C source of an older version of the compiler are needed to bootstrap the latest version. The C sources are available in a separate repo here.
Pre-compiled snapshots of the compiler are also available on Nimbuild. Your platform however may not currently be built for.
The compiler currently supports the following platform and architecture combinations:
- Windows (Windows XP or greater) - x86 and x86_64
- Linux (most, if not all, distributions) - x86, x86_64, ppc64 and armv6l
- Mac OS X 10.04 or higher - x86, x86_64 and ppc64
In reality a lot more are supported, however they are not tested regularly.
To build from source you will need:
- gcc 3.x or later recommended. Other alternatives which may work are: clang, Visual C++, Intel's C++ compiler
- git or wget
If you are on a fairly modern *nix system, the following steps should work:
$ git clone git://github.com/Araq/Nim.git
$ cd Nim
$ git clone --depth 1 git://github.com/nim-lang/csources
$ cd csources && sh build.sh
$ cd ..
$ bin/nim c koch
$ ./koch boot -d:release
koch install [dir] may then be used to install Nim, or you can simply
add it to your PATH. More koch related options are documented in
doc/koch.txt.
The above steps can be performed on Windows in a similar fashion, the
build.bat and build64.bat (for x86_64 systems) are provided to be used
instead of build.sh.
Getting help
A forum is available if you have any questions, and you can also get help in the IRC channel on Freenode in #nim. If you ask questions on StackOverflow use the nim tag.
License
The compiler and the standard library are licensed under the MIT license, except for some modules where the documentation suggests otherwise. This means that you can use any license for your own programs developed with Nim, allowing you to create commercial applications.
Read copying.txt for more details.
Copyright (c) 2006-2014 Andreas Rumpf. All rights reserved.
Build Status
| Linux | Windows | Mac | |
|---|---|---|---|
| x86 | |||
| x86_64 | |||
| arm |