From 20713324f5dd5ea000b99a46e70b4378a1521f2b Mon Sep 17 00:00:00 2001
From: "Richard M. Stallman" <rms@gnu.org>
Date: Mon, 18 Aug 1997 18:56:07 +0000
Subject: [PATCH] (Fchar_before): Do range check before decrement.

---
 src/editfns.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/editfns.c b/src/editfns.c
index c8a6506e49..c12ea5ac3b 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -610,18 +610,17 @@ is returned as a character.")
       n = XINT (pos);
     }
 
+  if (n <= BEGV || n > ZV)
+    return Qnil;
+
   if (!NILP (current_buffer->enable_multibyte_characters))
     {
       DEC_POS (n);
-      if (n < BEGV || n >= ZV)
-	return Qnil;
       XSETFASTINT (val, FETCH_CHAR (n));
     }
   else
     {
       n--;
-      if (n < BEGV || n >= ZV)
-	return Qnil;
       XSETFASTINT (val, FETCH_BYTE (n));
     }
    return val;
-- 
2.20.1