diff --git a/src/tar.c b/src/tar.c
index 97d74bc..6de8961 100644
--- a/src/tar.c
+++ b/src/tar.c
@@ -48,10 +48,12 @@ split_long_name (const char *name, size_t length)
 {
   size_t i;
 
-  if (length > TARPREFIXSIZE)
-    length = TARPREFIXSIZE+2;
+  if (length > TARPREFIXSIZE + 1)
+    length = TARPREFIXSIZE + 1;
+  else if (ISSLASH (name[length - 1]))
+    length--;
   for (i = length - 1; i > 0; i--)
-    if (name[i] == '/')
+    if (ISSLASH (name[i]))
       break;
   return i;
 }