Miscellaneous cleanup of regular-expression compiler.

Revert our previous addition of "all" flags to copyins() and copyouts();
they're no longer needed, and were never anything but an unsightly hack.

Improve a couple of infelicities in the REG_DEBUG code for dumping
the NFA data structure, including adding code to count the total
number of states and arcs.

Add a couple of missed error checks.

Add some more documentation in the README file, and some regression tests
illustrating cases that exceeded the state-count limit and/or took
unreasonable amounts of time before this set of patches.

Back-patch to all supported branches.

diff --git a/src/backend/regex/regc_nfa.c b/src/backend/regex/regc_nfa.c
index fe8a4a12d1783a870e782667fb5cfb055bdd5b9b..6f04321cd357822f76bbb58b8dd75f883d220be3 100644 (file)
--- a/src/backend/regex/regc_nfa.c
+++ b/src/backend/regex/regc_nfa.c
@@ -823,14 +823,11 @@ moveins(struct nfa * nfa,
 
 /*
  * copyins - copy in arcs of a state to another state
- *
- * Either all arcs, or only non-empty ones as determined by all value.
  */
 static void
 copyins(struct nfa * nfa,
                struct state * oldState,
-               struct state * newState,
-               int all)
+               struct state * newState)
 {
        assert(oldState != newState);
 
@@ -840,8 +837,7 @@ copyins(struct nfa * nfa,
                struct arc *a;
 
                for (a = oldState->ins; a != NULL; a = a->inchain)
-                       if (all || a->type != EMPTY)
-                               cparc(nfa, a, a->from, newState);
+                       cparc(nfa, a, a->from, newState);
        }
        else
        {
@@ -873,12 +869,6 @@ copyins(struct nfa * nfa,
                {
                        struct arc *a = oa;
 
-                       if (!all && a->type == EMPTY)
-                       {
-                               oa = oa->inchain;
-                               continue;
-                       }
-
                        switch (sortins_cmp(&oa, &na))
                        {
                                case -1:
@@ -904,12 +894,6 @@ copyins(struct nfa * nfa,
                        /* newState does not have anything matching oa */
                        struct arc *a = oa;
 
-                       if (!all && a->type == EMPTY)
-                       {
-                               oa = oa->inchain;
-                               continue;
-                       }
-
                        oa = oa->inchain;
                        createarc(nfa, a->type, a->co, a->from, newState);
                }
@@ -1107,14 +1091,11 @@ moveouts(struct nfa * nfa,
 
 /*
  * copyouts - copy out arcs of a state to another state
- *
- * Either all arcs, or only non-empty ones as determined by all value.
  */
 static void
 copyouts(struct nfa * nfa,
                 struct state * oldState,
-                struct state * newState,
-                int all)
+                struct state * newState)
 {
        assert(oldState != newState);
 
@@ -1124,8 +1105,7 @@ copyouts(struct nfa * nfa,
                struct arc *a;
 
                for (a = oldState->outs; a != NULL; a = a->outchain)
-                       if (all || a->type != EMPTY)
-                               cparc(nfa, a, newState, a->to);
+                       cparc(nfa, a, newState, a->to);
        }
        else
        {
@@ -1157,12 +1137,6 @@ copyouts(struct nfa * nfa,
                {
                        struct arc *a = oa;
 
-                       if (!all && a->type == EMPTY)
-                       {
-                               oa = oa->outchain;
-                               continue;
-                       }
-
                        switch (sortouts_cmp(&oa, &na))
                        {
                                case -1:
@@ -1188,12 +1162,6 @@ copyouts(struct nfa * nfa,
                        /* newState does not have anything matching oa */
                        struct arc *a = oa;
 
-                       if (!all && a->type == EMPTY)
-                       {
-                               oa = oa->outchain;
-                               continue;
-                       }
-
                        oa = oa->outchain;
                        createarc(nfa, a->type, a->co, newState, a->to);
                }
@@ -1452,6 +1420,10 @@ optimize(struct nfa * nfa,
                fprintf(f, "\nfinal cleanup:\n");
 #endif
        cleanup(nfa);                           /* final tidying */
+#ifdef REG_DEBUG
+       if (verbose)
+               dumpnfa(nfa, f);
+#endif
        return analyze(nfa);            /* and analysis */
 }
 
@@ -1568,7 +1540,7 @@ pull(struct nfa * nfa,
                s = newstate(nfa);
                if (NISERR())
                        return 0;
-               copyins(nfa, from, s, 1);               /* duplicate inarcs */
+               copyins(nfa, from, s);  /* duplicate inarcs */
                cparc(nfa, con, s, to); /* move constraint arc */
                freearc(nfa, con);
                if (NISERR())
@@ -1735,7 +1707,7 @@ push(struct nfa * nfa,
                s = newstate(nfa);
                if (NISERR())
                        return 0;
-               copyouts(nfa, to, s, 1);        /* duplicate outarcs */
+               copyouts(nfa, to, s);   /* duplicate outarcs */
                cparc(nfa, con, from, s);               /* move constraint arc */
                freearc(nfa, con);
                if (NISERR())
@@ -2952,6 +2924,8 @@ dumpnfa(struct nfa * nfa,
 {
 #ifdef REG_DEBUG
        struct state *s;
+       int                     nstates = 0;
+       int                     narcs = 0;
 
        fprintf(f, "pre %d, post %d", nfa->pre->no, nfa->post->no);
        if (nfa->bos[0] != COLORLESS)
@@ -2964,7 +2938,12 @@ dumpnfa(struct nfa * nfa,
                fprintf(f, ", eol [%ld]", (long) nfa->eos[1]);
        fprintf(f, "\n");
        for (s = nfa->states; s != NULL; s = s->next)
+       {
                dumpstate(s, f);
+               nstates++;
+               narcs += s->nouts;
+       }
+       fprintf(f, "total of %d states, %d arcs\n", nstates, narcs);
        if (nfa->parent == NULL)
                dumpcolors(nfa->cm, f);
        fflush(f);

diff --git a/src/backend/regex/regcomp.c b/src/backend/regex/regcomp.c
index 9e04a4f298acfdbb25df0d49f9f68fd7639e3a7b..f4eebf84d7b678f805747b70124e291e08a6277d 100644 (file)
--- a/src/backend/regex/regcomp.c
+++ b/src/backend/regex/regcomp.c
@@ -136,10 +136,10 @@ static int        sortins_cmp(const void *, const void *);
 static void sortouts(struct nfa *, struct state *);
 static int     sortouts_cmp(const void *, const void *);
 static void moveins(struct nfa *, struct state *, struct state *);
-static void copyins(struct nfa *, struct state *, struct state *, int);
+static void copyins(struct nfa *, struct state *, struct state *);
 static void mergeins(struct nfa *, struct state *, struct arc **, int);
 static void moveouts(struct nfa *, struct state *, struct state *);
-static void copyouts(struct nfa *, struct state *, struct state *, int);
+static void copyouts(struct nfa *, struct state *, struct state *);
 static void cloneouts(struct nfa *, struct state *, struct state *, struct state *, int);
 static void delsub(struct nfa *, struct state *, struct state *);
 static void deltraverse(struct nfa *, struct state *, struct state *);
@@ -181,7 +181,6 @@ static void dumpnfa(struct nfa *, FILE *);
 #ifdef REG_DEBUG
 static void dumpstate(struct state *, FILE *);
 static void dumparcs(struct state *, FILE *);
-static int     dumprarcs(struct arc *, struct state *, FILE *, int);
 static void dumparc(struct arc *, struct state *, FILE *);
 static void dumpcnfa(struct cnfa *, FILE *);
 static void dumpcstate(int, struct cnfa *, FILE *);
@@ -613,7 +612,9 @@ makesearch(struct vars * v,
        for (s = slist; s != NULL; s = s2)
        {
                s2 = newstate(nfa);
-               copyouts(nfa, s, s2, 1);
+               NOERR();
+               copyouts(nfa, s, s2);
+               NOERR();
                for (a = s->ins; a != NULL; a = b)
                {
                        b = a->inchain;
@@ -1997,7 +1998,7 @@ dump(regex_t *re,
        dumpcolors(&g->cmap, f);
        if (!NULLCNFA(g->search))
        {
-               printf("\nsearch:\n");
+               fprintf(f, "\nsearch:\n");
                dumpcnfa(&g->search, f);
        }
        for (i = 1; i < g->nlacons; i++)