In perl.git, the branch smoke-me/khw-5.21 has been created
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at eb0d74007d325667397855e20e46fc27949222f8 (commit)
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commit eb0d74007d325667397855e20e46fc27949222f8
Author: Karl Williamson <[email protected]>
Date: Mon Sep 22 13:59:39 2014 -0600
Tighten uses of regex synthetic start class
A synthetic start class (SSC) is generated by the regular expression
pattern compiler to give a consolidation of all the possible things that
can match at the beginning of where a pattern can possibly match.
For example
qr/a?bfoo/;
requires the match to begin with either an 'a' or a 'b'. There are no
other possibilities. We can set things up to quickly scan for either of
these in the target string, and only when one of these is found do we
need to look for 'foo'.
In many patterns, no SSC is generated; and with the advent of tries,
SSC's have become less important.
There is an overhead associated with using SSCs. If the number of
possibilities that the SSC excludes is relatively small, it can be
counter-productive to use them.
This patch creates a crude sieve to decide whether to use an SSC or not.
If the SSC doesn't exclude at least half the "likely" possiblities, it
is discarded. This is a starting point, and can be refined if
necessary as we gain experience.
See thread beginning with
http://nntp.perl.org/group/perl.perl5.porters/212644
M embed.fnc
M embed.h
M ext/re/t/regop.t
M proto.h
M regcomp.c
M regen/unicode_constants.pl
M t/re/pat.t
M unicode_constants.h
commit 77a96660bcf89f1153151235099e889d4a309f2b
Author: Karl Williamson <[email protected]>
Date: Sat Sep 20 10:20:11 2014 -0600
regcomp.c: Use strnEQ instead of series of tests
At some point it is more efficient and certainly clearer to call a
library function to do a strcmp than to test each individual byte.
Based on irc discussion with the original coder of this, I changed this
sequence of 6 comparisions to a strnEQ. At the same time, this adds an
buffer overlflow check. I was unable to cause the previous code to
overflow, but I believe it was possible. And this changes the magic
number 6 in the code to a mnemonic giving its meaning.
M regcomp.c
commit 1b13d3055a217e4ff4a7f4f3dd368511bf248eb6
Author: Karl Williamson <[email protected]>
Date: Thu Aug 28 13:59:01 2014 -0600
XXXcharbits
M regcomp.h
commit 8c8885c1bfaee9b8900625bd02fc0327c24c7866
Author: Karl Williamson <[email protected]>
Date: Tue Jun 17 18:49:53 2014 -0600
XXX partial perlapi text
M perlvars.h
commit 66ccb51be3c2819dfcdd4725f7430f29209a2a20
Author: Karl Williamson <[email protected]>
Date: Sat May 17 19:37:06 2014 -0600
XXX Don't push. attempt to tell tries everything at compile time
But, it appears this is thrown away, have to consult with Yves to see if
is worth pursuing
M embed.fnc
M embed.h
M perl.h
M proto.h
M regcomp.c
M regcomp.h
M regcomp.sym
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