1 files changed, 4 insertions, 3 deletions
diff --git a/lzf_c.c b/lzf_c.c
index 99dab09..0b5d816 100644
--- a/lzf_c.c
+++ b/lzf_c.c
@@ -170,12 +170,13 @@ lzf_compress (const void *const in_data, unsigned int in_len,
           unsigned int maxlen = in_end - ip - len;
           maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
 
+          if (expect_false (op + 3 + 1 >= out_end)) /* first a faster conservative test */
+            if (op - !lit + 3 + 1 >= out_end) /* second the exact but rare test */
+              return 0;
+
           op [- lit - 1] = lit - 1; /* stop run */
           op -= !lit; /* undo run if length is zero */
 
-          if (expect_false (op + 3 + 1 >= out_end))
-            return 0;
-
           for (;;)
             {
               if (expect_true (maxlen > 16))