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Miscellaneous cleanup of regular-expression compiler.

Browse Source 
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.
This commit is contained in:
Tom Lane
2015-10-16 15:52:12 -04:00
parent 538b3b8b35
commit afdfcd3f76
5 changed files with 153 additions and 54 deletions
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55
src/backend/regex/regc_nfa.c
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@@ -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);