regex: change old-style definitions

[oI0ck]

We use a regex implementation from one of BSD's, and it contains old-style definitions which are being slowly dropped from newer compilers.

JIRA: RTOS-1233

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (refactoring, style fixes, git/CI config, submodule management, no code logic changes)

How Has This Been Tested?

• Already covered by automatic testing.
• New test added: (add PR link here).
• Tested by hand on: (list targets here).

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing linter checks and tests passed.
• My changes generate no new compilation warnings for any of the targets.

Special treatment

• This PR needs additional PRs to work (list the PRs, preferably in merge-order).
• I will merge this PR by myself when appropriate.

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request refactors the C function declarations within the regex library to adhere to contemporary ANSI C standards. The primary goal is to improve code maintainability and ensure compatibility with modern compilers, preventing potential build failures or warnings related to deprecated syntax. This change systematically updates function signatures to include parameter types directly in the function declaration, moving away from the older K&R style.

Highlights

• Code Modernization: Updated numerous function definitions and prototypes from old-style K&R C to modern ANSI C style across the regex implementation files.
• Compiler Compatibility: Addressed compatibility issues with newer compilers that are gradually dropping support for old-style C definitions.

Changelog

• regex/collate.c
  • Updated function definitions for __collate_load_tables, __collate_substitute, __collate_lookup, and __collate_strdup to ANSI C style.
• regex/collate.h
  • Updated function prototypes for __collate_strdup, __collate_substitute, __collate_load_tables, and __collate_lookup to ANSI C style.
• regex/collcmp.c
  • Updated the function definition for __collate_range_cmp to ANSI C style.
• regex/engine.c
  • Updated function definitions for matcher, dissect, backref, fast, slow, step, print, at, and pchar to ANSI C style.
• regex/fnmatch.c
  • Updated function definitions for fnmatch and rangematch to ANSI C style.
• regex/glob.c
  • Updated function definitions and prototypes for compare, g_Ctoc, g_lstat, g_opendir, g_strchr, g_stat, glob0, glob1, glob2, glob3, globextend, globtilde, globexp1, globexp2, match, qprintf, glob, and globfree to ANSI C style.
• regex/regcomp.c
  • Updated numerous function definitions including regcomp, p_ere, p_ere_exp, p_str, p_bre, p_simp_re, p_count, p_bracket, p_b_term, p_b_cclass, p_b_eclass, p_b_symbol, p_b_coll_elem, othercase, bothcases, ordinary, nonnewline, repeat, seterr, allocset, freeset, freezeset, firstch, nch, mcadd, mcsub, mcin, mcfind, mcinvert, mccase, isinsets, samesets, categorize, dupl, doemit, doinsert, dofwd, enlarge, stripsnug, findmust, altoffset, computejumps, computematchjumps, and pluscount to ANSI C style.
• regex/regerror.c
  • Updated function definitions for regerror and regatoi to ANSI C style.
• regex/regexec.c
  • Updated the function definition for regexec to ANSI C style.
• regex/regfree.c
  • Updated the function definition for regfree to ANSI C style.

Activity

• Associated with JIRA ticket RTOS-1233.
• Automatic testing has already covered these changes.

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[gemini-code-assist]

Code Review

This pull request is a great initiative to modernize the codebase by converting old-style K&R C function definitions to ANSI C prototypes. The changes across the various files in the regex directory are largely correct and improve compatibility with modern compilers. I've identified a few areas in glob.c where function signature formatting is inconsistent, leading to long lines that are hard to read. My review comments provide specific suggestions to address these for better code consistency and readability. Overall, a valuable and well-executed refactoring.

[github-actions]

Unit Test Results

9 525 tests   8 933 ✅  52m 31s ⏱️
  583 suites    592 💤
    1 files        0 ❌

Results for commit 176a6a4.

♻️ This comment has been updated with latest results.

[julianuziemblo]

Small nits. I'd consider adding a (nearly) empty .clang-format file to this directory so that the CI doesn't shout at us every time we have make fixes here. Other than those, LGTM.

[julianuziemblo]

LGTM

[adamgreloch]

Do we need to keep this? Was there any deeper meaning to previous #ifdef notdef of this declaration other than that it was not defined?

[oI0ck]

We don't and there wasn't.
I'm just thinking that it's better not to deviate much from the original code, in case we want to pull changes from upstream implementation.

[adamgreloch]

If we don't want to deviate, then maybe let's revert to the original?

Quick look suggests that the notdef seems to be a common pattern in FreeBSD source used instead of if 0:

• https://github.com/freebsd/freebsd-src/blob/2c5cd07828ad76c332e3bedc29fc641809e85396/lib/libc/gen/glob.c#L157
• https://github.com/search?q=repo%3Afreebsd%2Ffreebsd-src%20notdef&type=code