Mercurial > vim
view README.md @ 34854:97b5457962ed v9.1.0296
patch 9.1.0296: regexp: engines do not handle case-folding well
Commit: https://github.com/vim/vim/commit/7a27c108e0509f3255ebdcb6558e896c223e4d23
Author: Christian Brabandt <cb@256bit.org>
Date: Tue Apr 9 22:53:19 2024 +0200
patch 9.1.0296: regexp: engines do not handle case-folding well
Problem: Regex engines do not handle case-folding well
Solution: Correctly calculate byte length of characters to skip
When the regexp engine compares two utf-8 codepoints case insensitively
it may match an adjacent character, because it assumes it can step over
as many bytes as the pattern contains.
This however is not necessarily true because of case-folding, a
multi-byte UTF-8 character can be considered equal to some single-byte
value.
Let's consider the pattern '?' and the string 's'. When comparing and
ignoring case, the single character 's' matches, and since it matches
Vim will try to step over the match (by the amount of bytes of the
pattern), assuming that since it matches, the length of both strings is
the same.
However in that case, it should only step over the single byte
value 's' so by 1 byte and try to start matching after it again. So for the
backtracking engine we need to ensure:
- we try to match the correct length for the pattern and the text
- in case of a match, we step over it correctly
The same thing can happen for the NFA engine, when skipping to the next
character to test for a match. We are skipping over the regstart
pointer, however we do not consider the case that because of
case-folding we may need to adjust the number of bytes to skip over. So
this needs to be adjusted in find_match_text() as well.
A related issue turned out, when prog->match_text is actually empty. In
that case we should try to find the next match and skip this condition.
fixes: #14294
closes: #14433
Signed-off-by: Christian Brabandt <cb@256bit.org>
author | Christian Brabandt <cb@256bit.org> |
---|---|
date | Tue, 09 Apr 2024 23:00:08 +0200 |
parents | fe206762c077 |
children | d0ba4d429256 |
line wrap: on
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# [![Vim The editor](https://github.com/vim/vim/raw/master/runtime/vimlogo.gif)](https://www.vim.org) [![Github Build status](https://github.com/vim/vim/workflows/GitHub%20CI/badge.svg)](https://github.com/vim/vim/actions?query=workflow%3A%22GitHub+CI%22) [![Appveyor Build status](https://ci.appveyor.com/api/projects/status/o2qht2kjm02sgghk?svg=true)](https://ci.appveyor.com/project/chrisbra/vim) [![Cirrus Build Status](https://api.cirrus-ci.com/github/vim/vim.svg)](https://cirrus-ci.com/github/vim/vim) [![Coverage Status](https://codecov.io/gh/vim/vim/coverage.svg?branch=master)](https://codecov.io/gh/vim/vim?branch=master) [![Coverity Scan](https://scan.coverity.com/projects/241/badge.svg)](https://scan.coverity.com/projects/vim) [![Debian CI](https://badges.debian.net/badges/debian/testing/vim/version.svg)](https://buildd.debian.org/vim) [![Packages](https://repology.org/badge/tiny-repos/vim.svg)](https://repology.org/metapackage/vim) [![Fossies codespell report](https://fossies.org/linux/test/vim-master.tar.gz/codespell.svg)](https://fossies.org/linux/test/vim-master.tar.gz/codespell.html) If you find a bug or want to discuss the best way to add a new feature, please [open an issue](https://github.com/vim/vim/issues/new/choose). If you have a question or want to discuss the best way to do something with Vim, you can use [StackExchange](https://vi.stackexchange.com/) or one of the [Maillists](https://www.vim.org/community.php). ## What is Vim? Vim is a greatly improved version of the good old UNIX editor [Vi](https://en.wikipedia.org/wiki/Vi). Many new features have been added: multi-level undo, syntax highlighting, command line history, on-line help, spell checking, filename completion, block operations, script language, etc. There is also a Graphical User Interface (GUI) available. Still, Vi compatibility is maintained, those who have Vi "in the fingers" will feel at home. See [`runtime/doc/vi_diff.txt`](runtime/doc/vi_diff.txt) for differences with Vi. This editor is very useful for editing programs and other plain text files. All commands are given with normal keyboard characters, so those who can type with ten fingers can work very fast. Additionally, function keys can be mapped to commands by the user, and the mouse can be used. Vim runs under MS-Windows (7, 8, 10, 11), macOS, Haiku, VMS and almost all flavours of UNIX. Porting to other systems should not be very difficult. Older versions of Vim run on MS-DOS, MS-Windows 95/98/Me/NT/2000/XP/Vista, Amiga DOS, Atari MiNT, BeOS, RISC OS and OS/2. These are no longer maintained. For Vim9 script see [README_VIM9](README_VIM9.md). ## Distribution You can often use your favorite package manager to install Vim. On Mac and Linux a small version of Vim is pre-installed, you still need to install Vim if you want more features. There are separate distributions for Unix, PC, Amiga and some other systems. This `README.md` file comes with the runtime archive. It includes the documentation, syntax files and other files that are used at runtime. To run Vim you must get either one of the binary archives or a source archive. Which one you need depends on the system you want to run it on and whether you want or must compile it yourself. Check https://www.vim.org/download.php for an overview of currently available distributions. Some popular places to get the latest Vim: * Check out the git repository from [GitHub](https://github.com/vim/vim). * Get the source code as an [archive](https://github.com/vim/vim/releases). * Get a Windows executable from the [vim-win32-installer](https://github.com/vim/vim-win32-installer/releases) repository. ## Compiling If you obtained a binary distribution you don't need to compile Vim. If you obtained a source distribution, all the stuff for compiling Vim is in the [`src`](./src/) directory. See [`src/INSTALL`](./src/INSTALL) for instructions. ## Installation See one of these files for system-specific instructions. Either in the [READMEdir directory](./READMEdir/) (in the repository) or the top directory (if you unpack an archive): ``` README_ami.txt Amiga README_unix.txt Unix README_dos.txt MS-DOS and MS-Windows README_mac.txt Macintosh README_haiku.txt Haiku README_vms.txt VMS ``` There are other `README_*.txt` files, depending on the distribution you used. ## Documentation The Vim tutor is a one hour training course for beginners. Often it can be started as `vimtutor`. See `:help tutor` for more information. The best is to use `:help` in Vim. If you don't have an executable yet, read [`runtime/doc/help.txt`](./runtime/doc/help.txt). It contains pointers to the other documentation files. The User Manual reads like a book and is recommended to learn to use Vim. See `:help user-manual`. ## Copying Vim is Charityware. You can use and copy it as much as you like, but you are encouraged to make a donation to help orphans in Uganda. Please read the file [`runtime/doc/uganda.txt`](./runtime/doc/uganda.txt) for details (do `:help uganda` inside Vim). Summary of the license: There are no restrictions on using or distributing an unmodified copy of Vim. Parts of Vim may also be distributed, but the license text must always be included. For modified versions, a few restrictions apply. The license is GPL compatible, you may compile Vim with GPL libraries and distribute it. ## Sponsoring Fixing bugs and adding new features takes a lot of time and effort. To show your appreciation for the work and motivate developers to continue working on Vim please send a donation. The money you donated will be mainly used to help children in Uganda. See [`runtime/doc/uganda.txt`](./runtime/doc/uganda.txt). But at the same time donations increase the development team motivation to keep working on Vim! For the most recent information about sponsoring look on the Vim web site: https://www.vim.org/sponsor/ ## Contributing If you would like to help make Vim better, see the [CONTRIBUTING.md](./CONTRIBUTING.md) file. ## Information If you are on macOS, you can use [MacVim](https://macvim.org). The latest news about Vim can be found on the Vim home page: https://www.vim.org/ If you have problems, have a look at the Vim documentation or tips: https://www.vim.org/docs.php https://vim.fandom.com/wiki/Vim_Tips_Wiki If you still have problems or any other questions, use one of the mailing lists to discuss them with Vim users and developers: https://www.vim.org/maillist.php If nothing else works, report bugs directly to the vim-dev mailing list: `<vim-dev@vim.org>` ## Main author Most of Vim was created by Bram Moolenaar `<Bram@vim.org>` [Bram-Moolenaar](https://vimhelp.org/version9.txt.html#Bram-Moolenaar) Send any other comments, patches, flowers and suggestions to the vim-dev mailing list: `<vim-dev@vim.org>` This is `README.md` for version 9.1 of Vim: Vi IMproved.