On 10/3/22 03:43, Yi-yo Chiang wrote: > On Thu, Sep 29, 2022 at 1:20 PM Rob Landley <r...@landley.net > <mailto:r...@landley.net>> wrote: > > All '^' and '$' do is say the zero length match occurs just once at the > start or > end of every line, but the -o logic discards all zero length matches and > the > non-o logic just cares that there IS a match. UNLESS you're producing > colored > output, but the colored output mostly piggybacks on -o. There is a sort of > terrible corner case though, which oddly enough makes this corner case > visible! > > $ echo potato | grep --color=always '' | hd > 00000000 70 6f 74 61 74 6f 0a |potato.| > 00000007 > $ echo potato | toybox grep --color=always '' | hd > 00000000 1b 5b 6d 1b 5b 31 3b 33 31 6d 1b 5b 6d 70 6f 74 > |.[m.[1;31m.[mpot| > 00000010 61 74 6f 0a |ato.| > 00000014 > $ echo potato | toybox grep --color=always '$' | hd > 00000000 1b 5b 6d 70 6f 74 61 74 6f 1b 5b 31 3b 33 31 6d > |.[mpotato.[1;31m| > 00000010 1b 5b 6d 0a |.[m.| > 00000014 > > Yeah, I have a todo item to try to optimize the color escape generation > for > toybox but last time I sat down and looked at it I just didn't have the > spoons. > > I have some optimizations related to color output, not sure if these are what > you had in mind?
NI was just talking about making it not emit unnecessary color escapes that do nothing but cancel each other out. > * If not showing color (no --color) or not showing matched part (-v) and (-o, > -w, -x) are not given, then call regcomp() with REG_NOSUB. (could potentially > improve the compiled regex) > * If regex pattern was compiled with REG_NOSUB (we are not > printing/highlighting > matched part), then we can stop pattern matching as soon as we found first hit > (no need to loop through all patterns to find longest match nor all matches) > (break this loop early > https://github.com/landley/toybox/blob/b17dc8e111dd408db04ea7ae70c410fd3054a751/toys/posix/grep.c#L218 *shrug* Sure, sounds like a good idea. > I can send you these patches after I rebase my local tree on top of the recent > bucket sort optimizations. > > > that a simplified case based on the real-world build break caused by > ... > > merging zero jar files into one instead of all the jar files :-) > > Acknowledged. Try commit 193009855266? > > > Still had problems when matching Fixed patterns: > > $ echo '\.zip' | ./old-toybox grep -F '\.zip' > \.zip > $ echo '\.zip' | ./toybox grep -F '\.zip' > $ > > I think what's happening is the fixed string pattern '\.zip' gets put into the > '.' bucket (should be '\' bucket instead?), thus '\.zip' never matches > anything. Sigh, you're right. Try commit b26689f95065 Rob _______________________________________________ Toybox mailing list Toybox@lists.landley.net http://lists.landley.net/listinfo.cgi/toybox-landley.net
