diff options
Diffstat (limited to 'vm.c')
| -rw-r--r-- | vm.c | 30 |
1 files changed, 19 insertions, 11 deletions
@@ -157,9 +157,10 @@ static match_t *_match(grammar_t *g, file_t *f, const char *str, vm_op_t *op, un m->op = op; match_t **dest = &m->child; - const char *prev = str; size_t reps = 0; - for (;;) { + ssize_t max = op->args.repetitions.max; + for (reps = 0; max == -1 || reps < (size_t)max; ++reps) { + const char *start = str; // Separator match_t *sep = NULL; if (op->args.repetitions.sep != NULL && reps > 0) { @@ -168,9 +169,23 @@ static match_t *_match(grammar_t *g, file_t *f, const char *str, vm_op_t *op, un str = sep->end; } match_t *p = _match(g, f, str, op->args.repetitions.repeat_pat, flags, rec); - if (p == NULL || (p->end == prev && reps > 0)) { // Prevent infinite loops + if (p == NULL) { + destroy_match(&sep); + break; + } + if (p->end == start && reps > 0) { + // Since no forward progress was made on either `pat` or + // `sep` and BPEG does not have mutable state, it's + // guaranteed that no progress will be made on the next + // loop either. We know that this will continue to loop + // until reps==max, so let's just cut to the chase instead + // of looping infinitely. destroy_match(&sep); destroy_match(&p); + if (op->args.repetitions.max == -1) + reps = ~(size_t)0; + else + reps = (size_t)op->args.repetitions.max; break; } if (sep) { @@ -180,16 +195,9 @@ static match_t *_match(grammar_t *g, file_t *f, const char *str, vm_op_t *op, un *dest = p; dest = &p->nextsibling; str = p->end; - prev = str; - - ++reps; - if (op->args.repetitions.max != -1 && reps > (size_t)op->args.repetitions.max) { - destroy_match(&m); - return NULL; - } } - if ((ssize_t)reps < op->args.repetitions.min) { + if (reps < (size_t)op->args.repetitions.min) { destroy_match(&m); return NULL; } |