Mercurial > hg
view README.rst @ 48671:f1ed5c304f45
encoding: fix trim() to be O(n) instead of O(n^2)
`encoding.trim()` iterated over the possible lengths smaller than the
input and created a slice for each. It then calculated the column
width of the result, which is of course O(n), so the overall algorithm
was O(n). This patch rewrites it to iterate over the unicode
characters, keeping track of the length so far. Also, the old
algorithm started from the end of the string, which made it much worse
when the input is large and the limit is small (such as the typical 72
we pass to it).
You can time it by running something like this:
```
time python3 -c 'from mercurial.utils import stringutil; print(stringutil.ellipsis(b"0123456789" * 1000, 5))'
```
That drops from 4.05 s to 83 ms with this patch (and most of that is
of course startup time).
Differential Revision: https://phab.mercurial-scm.org/D12089
author | Martin von Zweigbergk <martinvonz@google.com> |
---|---|
date | Wed, 26 Jan 2022 10:11:01 -0800 |
parents | c5912e35d06d |
children |
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Mercurial ========= Mercurial is a fast, easy to use, distributed revision control tool for software developers. Basic install:: $ make # see install targets $ make install # do a system-wide install $ hg debuginstall # sanity-check setup $ hg # see help Running without installing:: $ make local # build for inplace usage $ ./hg --version # should show the latest version See https://mercurial-scm.org/ for detailed installation instructions, platform-specific notes, and Mercurial user information. Notes for packagers =================== Mercurial ships a copy of the python-zstandard sources. This is used to provide support for zstd compression and decompression functionality. The module is not intended to be replaced by the plain python-zstandard nor is it intended to use a system zstd library. Patches can result in hard to diagnose errors and are explicitly discouraged as unsupported configuration.