]> granicus.if.org Git - postgresql/commit
Fix infinite-loop risk in fixempties() stage of regex compilation.
authorTom Lane <tgl@sss.pgh.pa.us>
Thu, 7 Mar 2013 16:51:03 +0000 (11:51 -0500)
committerTom Lane <tgl@sss.pgh.pa.us>
Thu, 7 Mar 2013 16:51:03 +0000 (11:51 -0500)
commita7b61d4f5af37344f8973b2dfce47e2ba2680061
tree0af6a1de63f305d5d5b1830369692d422d3a2c57
parent7ccefe8610db8b339bad2c5b51abc07448a32947
Fix infinite-loop risk in fixempties() stage of regex compilation.

The previous coding of this function could get into situations where it
would never terminate, because successive passes would re-add EMPTY arcs
that had been removed by the previous pass.  Rewrite the function
completely using a new algorithm that is guaranteed to terminate, and
also seems to be usually faster than the old one.  Per Tcl bugs 3604074
and 3606683.

Tom Lane and Don Porter
src/backend/regex/regc_nfa.c
src/backend/regex/regcomp.c
src/test/regress/expected/regex.out
src/test/regress/sql/regex.sql