~ chicken-core (chicken-5) 2b13db1b147433427a972a57b325f99fa06532c9

commit 2b13db1b147433427a972a57b325f99fa06532c9
Author:     siiky <github-siiky@net-c.cat>
AuthorDate: Sat Apr 27 01:41:18 2024 +0100
Commit:     Peter Bex <peter@more-magic.net>
CommitDate: Fri May 3 08:46:43 2024 +0200

    Fix bounds check in substring[-ci]=?
    
    It should be permitted to start comparing at the end of a string.
    
    Signed-off-by: felix <felix@call-with-current-continuation.org>
    Signed-off-by: Peter Bex <peter@more-magic.net>

diff --git a/data-structures.scm b/data-structures.scm
index ad09d26b..1c3f063d 100644
--- a/data-structures.scm
+++ b/data-structures.scm
@@ -155,8 +155,8 @@
 (define (##sys#substring=? s1 s2 start1 start2 n)
   (##sys#check-string s1 'substring=?)
   (##sys#check-string s2 'substring=?)
-  (##sys#check-range start1 0 (##sys#size s1) 'substring=?)
-  (##sys#check-range start2 0 (##sys#size s2) 'substring=?)
+  (##sys#check-range start1 0 (fx+ (##sys#size s1) 1) 'substring=?)
+  (##sys#check-range start2 0 (fx+ (##sys#size s2) 1) 'substring=?)
   (let* ((maxlen (fxmin (fx- (##sys#size s1) start1)
                         (fx- (##sys#size s2) start2)))
          (len (if n
@@ -170,8 +170,8 @@
 (define (##sys#substring-ci=? s1 s2 start1 start2 n)
   (##sys#check-string s1 'substring-ci=?)
   (##sys#check-string s2 'substring-ci=?)
-  (##sys#check-range start1 0 (##sys#size s1) 'substring-ci=?)
-  (##sys#check-range start2 0 (##sys#size s2) 'substring-ci=?)
+  (##sys#check-range start1 0 (fx+ (##sys#size s1) 1) 'substring-ci=?)
+  (##sys#check-range start2 0 (fx+ (##sys#size s2) 1) 'substring-ci=?)
   (let* ((maxlen (fxmin (fx- (##sys#size s1) start1)
                         (fx- (##sys#size s2) start2)))
          (len (if n
diff --git a/tests/data-structures-tests.scm b/tests/data-structures-tests.scm
index eb779531..a81b87b6 100644
--- a/tests/data-structures-tests.scm
+++ b/tests/data-structures-tests.scm
@@ -46,6 +46,14 @@
 (assert (= 2 (substring-index-ci "o\x00bar" "foo\x00BAR")))
 (assert (not (substring=? "foo\x00a" "foo\x00b" 1 1)))
 (assert (not (substring-ci=? "foo\x00a" "foo\x00b" 1 1)))
+(assert (substring=? "" "" 0 0 0))
+(assert (substring-ci=? "" "" 0 0 0))
+(assert (substring=? "" "abc"))
+(assert (substring-ci=? "" "abc"))
+(assert (substring=? "abc" ""))
+(assert (substring-ci=? "abc" ""))
+(assert-error (substring=? "" "" 0 0 1))
+(assert-error (substring-ci=? "" "" 0 0 1))
 (assert (substring=? "foo" "foo" 0 0 3))
 (assert (substring-ci=? "foo" "foo" 0 0 3))
 (assert (not (substring-index "o\x00bar" "foo\x00baz")))