# HG changeset patch
# User Matti Hamalainen <ccr@tnsp.org>
# Date 1587933261 -10800
# Node ID b6b8e7249666296263e258bf6bb7c03a8eb8897d
# Parent  dbc71c0003765ae6eb9bd8cc25c5052e7b320678
Check that the buffer length is >= 1 before trying to access buf[len - 1]

diff -r dbc71c000376 -r b6b8e7249666 th_printf.c
--- a/th_printf.c	Sun Apr 26 23:30:17 2020 +0300
+++ b/th_printf.c	Sun Apr 26 23:34:21 2020 +0300
@@ -121,7 +121,7 @@
     (void) prec;
 
     // This is not very nice
-    if (buf[len - 1] != '0')
+    if (len < 1 || buf[len - 1] != '0')
     {
         if (*prec > 0)
             (*prec)--;