Add `Regexp.linear_time?` (#6901)

1 files changed, 15 insertions, 1 deletions

diff --git a/regexec.c b/regexec.c
index a9822ee064..a52ed800c5 100644
--- a/regexec.c
+++ b/regexec.c
@@ -694,7 +694,21 @@ unexpected_bytecode_error:
 bytecode_error:
   return ONIGERR_UNDEFINED_BYTECODE;
 }
-#endif /* USE_MATCH_CACHE */
+#else /* USE_MATCH_CACHE */
+static OnigPosition count_num_cache_opcode(regex_t* reg, long* num, long* table_size)
+{
+  *num = NUM_CACHE_OPCODE_FAIL;
+  return 0;
+}
+#endif
+
+extern int
+onig_check_linear_time(OnigRegexType* reg)
+{
+  long num = 0, table_size = 0;
+  count_num_cache_opcode(reg, &num, &table_size);
+  return num != NUM_CACHE_OPCODE_FAIL;
+}
 
 extern void
 onig_region_clear(OnigRegion* region)