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
Branch
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REL9_2_STABLE
Details
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http://git.postgresql.org/pg/commitdiff/957b9c0c452ce166957c981c63c9a46fa32f64c1
Modified Files
--------------
src/backend/regex/regc_nfa.c | 314 +++++++++++++++++++++++++++--------
src/backend/regex/regcomp.c | 12 +-
src/test/regress/expected/regex.out | 20 +++
src/test/regress/sql/regex.sql | 7 +
4 files changed, 280 insertions(+), 73 deletions(-)