diff options
Diffstat (limited to 'src/backend/regex/regc_color.c')
| -rw-r--r-- | src/backend/regex/regc_color.c | 34 |
1 files changed, 30 insertions, 4 deletions
diff --git a/src/backend/regex/regc_color.c b/src/backend/regex/regc_color.c index 0864011cce1..30bda0e5ad0 100644 --- a/src/backend/regex/regc_color.c +++ b/src/backend/regex/regc_color.c @@ -936,7 +936,16 @@ okcolors(struct nfa *nfa, } else if (cd->nschrs == 0 && cd->nuchrs == 0) { - /* parent empty, its arcs change color to subcolor */ + /* + * Parent is now empty, so just change all its arcs to the + * subcolor, then free the parent. + * + * It is not obvious that simply relabeling the arcs like this is + * OK; it appears to risk creating duplicate arcs. We are + * basically relying on the assumption that processing of a + * bracket expression can't create arcs of both a color and its + * subcolor between the bracket's endpoints. + */ cd->sub = NOSUB; scd = &cm->cd[sco]; assert(scd->nschrs > 0 || scd->nuchrs > 0); @@ -1062,6 +1071,7 @@ colorcomplement(struct nfa *nfa, struct colordesc *cd; struct colordesc *end = CDEND(cm); color co; + struct arc *a; assert(of != from); @@ -1069,10 +1079,26 @@ colorcomplement(struct nfa *nfa, if (findarc(of, PLAIN, RAINBOW) != NULL) return; + /* Otherwise, transiently mark the colors that appear in of's out-arcs */ + for (a = of->outs; a != NULL; a = a->outchain) + { + if (a->type == PLAIN) + { + assert(a->co >= 0); + cd = &cm->cd[a->co]; + assert(!UNUSEDCOLOR(cd)); + cd->flags |= COLMARK; + } + } + + /* Scan colors, clear transient marks, add arcs for unmarked colors */ for (cd = cm->cd, co = 0; cd < end && !CISERR(); cd++, co++) - if (!UNUSEDCOLOR(cd) && !(cd->flags & PSEUDO)) - if (findarc(of, PLAIN, co) == NULL) - newarc(nfa, type, co, from, to); + { + if (cd->flags & COLMARK) + cd->flags &= ~COLMARK; + else if (!UNUSEDCOLOR(cd) && !(cd->flags & PSEUDO)) + newarc(nfa, type, co, from, to); + } } |