From 45b981b6a4b19ce9d16ab7735ccb02fa646b40b3 Mon Sep 17 00:00:00 2001
From: Kyryl Melekhin <k.melekhin@gmail.com>
Date: Thu, 2 Sep 2021 22:55:03 +0000
Subject: [PATCH] fix pathological cases

---
 pike.c  | 13 ++++++-------
 test.sh | 24 ++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/pike.c b/pike.c
index 1801ab1..37f659a 100644
--- a/pike.c
+++ b/pike.c
@@ -427,10 +427,10 @@ int re_comp(rcode *prog, const char *re, int nsubs)
 #define _return(state) \
 { prog->gen = gen + 1; return state; } \
 
-#define newsub(init) \
+#define newsub(init, copy) \
 s1 = freesub; \
 if (s1) \
-	freesub = (rsub*)s1->sub[0]; \
+	{ freesub = (rsub*)s1->sub[0]; copy } \
 else \
 	{ s1 = (rsub*)&nsubs[rsubsize * subidx++]; init } \
 
@@ -454,12 +454,11 @@ subs[i++] = sub; \
 goto next##nn; \
 
 #define save1() \
-newsub(for (j = nsubp / 2; j < nsubp; j++) s1->sub[j] = NULL;) \
-for (j = 0; j < nsubp / 2; j++) \
-	s1->sub[j] = sub->sub[j]; \
+newsub(for (j = 0; j < nsubp; j++) s1->sub[j] = sub->sub[j];, \
+for (j = 0; j < nsubp / 2; j++) s1->sub[j] = sub->sub[j];) \
 
 #define save2() \
-newsub(/*nop*/) \
+newsub(/*nop*/, /*nop*/) \
 for (j = 0; j < nsubp; j++) \
 	s1->sub[j] = sub->sub[j]; \
 
@@ -586,7 +585,7 @@ int re_pikevm(rcode *prog, const char *s, const char **subp, int nsubp)
 		nlistidx = 0;
 		if (!matched) {
 			jmp_start:
-			newsub(for (i = 1; i < nsubp; i++) s1->sub[i] = NULL;)
+			newsub(for (i = 1; i < nsubp; i++) s1->sub[i] = NULL;, /*nop*/)
 			s1->ref = 1;
 			s1->sub[0] = _sp;
 			addthread(1, clist, clistidx, insts, s1)
diff --git a/test.sh b/test.sh
index 6486070..443e2f5 100755
--- a/test.sh
+++ b/test.sh
@@ -106,6 +106,14 @@ qwerty.*$
 (aaaa|aaa|a){3,4}
 (a)(a)
 (a){2}
+(a|bcdef|g|ab|c|d|e|efg|fg)*
+(.*) (.*) (.*) (.*) (.*)
+(.+?)(.+?)
+(a?)(a?)(a?)aaa
+(ab)?(ab)?(ab)?aaa
+(.+)(.+)
+a(?:b|c|d){4,5}(.)
+(?:c|d)(?:)(?:a(?:)(?:b)(?:b(?:))(?:b(?:)(?:b)))
 "
 input="\
 abcdef
@@ -213,6 +221,14 @@ aaaaaa
 aaaaaaaaaa
 aaaa
 aaaa
+abcdefg
+a  c d ee fff
+abcd
+aaa
+abaaa
+abcd
+acdbcdbe
+cabbbb
 "
 expect="\
 (0,3)
@@ -320,6 +336,14 @@ expect="\
 (0,10)(9,10)
 (0,2)(0,1)(1,2)
 (0,2)(1,2)
+(0,7)(6,7)
+(0,13)(0,2)(3,4)(5,6)(7,9)(10,13)
+(0,2)(0,1)(1,2)
+(0,3)(0,0)(0,0)(0,0)
+(0,5)(0,2)(?,?)(?,?)
+(0,4)(0,3)(3,4)
+(0,7)(6,7)
+(0,6)
 (0,0)
 "