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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2015-10-16 15:11:49 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2015-10-16 15:11:49 -0400 |
| commit | 2a8d6e4d06d6ea2e1323aeab79bbb867d0f816c5 (patch) | |
| tree | 7542e029b63a38b188105481bc7bb4352c3b0269 /src/backend/regex/regcomp.c | |
| parent | 677e64cb8042ff6002069f1b587d933f4cdee925 (diff) | |
Improve performance of pullback/pushfwd in regular-expression compiler.
The previous coding would create a new intermediate state every time it
wanted to interchange the ordering of two constraint arcs. Certain regex
features such as \Y can generate large numbers of parallel constraint arcs,
and if we needed to reorder the results of that, we created unreasonable
numbers of intermediate states. To improve matters, keep a list of
already-created intermediate states associated with the state currently
being considered by the outer loop; we can re-use such states to place all
the new arcs leading to the same destination or source.
I also took the trouble to redefine push() and pull() to have a less risky
API: they no longer delete any state or arc that the caller might possibly
have a pointer to, except for the specifically-passed constraint arc.
This reduces the risk of re-introducing the same type of error seen in
the failed patch for CVE-2007-4772.
Back-patch to all supported branches.
Diffstat (limited to 'src/backend/regex/regcomp.c')
| -rw-r--r-- | src/backend/regex/regcomp.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/src/backend/regex/regcomp.c b/src/backend/regex/regcomp.c index e3bdf283b41..4e44a8c15ad 100644 --- a/src/backend/regex/regcomp.c +++ b/src/backend/regex/regcomp.c @@ -149,9 +149,9 @@ static void cleartraverse(struct nfa *, struct state *); static void specialcolors(struct nfa *); static long optimize(struct nfa *, FILE *); static void pullback(struct nfa *, FILE *); -static int pull(struct nfa *, struct arc *); +static int pull(struct nfa *, struct arc *, struct state **); static void pushfwd(struct nfa *, FILE *); -static int push(struct nfa *, struct arc *); +static int push(struct nfa *, struct arc *, struct state **); #define INCOMPATIBLE 1 /* destroys arc */ #define SATISFIED 2 /* constraint satisfied */ |