From: Neale Ranns <neale@graphiant.com>
Date: Sun, 9 Jan 2022 13:24:47 +0000 (+0000)
Subject: vppinfra: Check for NULL vec before the backwards iteration
X-Git-Tag: v22.06-rc0~46
X-Git-Url: https://gerrit.fd.io/r/gitweb?a=commitdiff_plain;h=9d33cfc0bc1928f0b4c8aa95c170cf91ee8011a0;p=vpp.git

vppinfra: Check for NULL vec before the backwards iteration

Type: improvement

'vec_end(v) - 1' does not yield a good starting point. Check for NULL vec before the loop, so the user does not have to.

Signed-off-by: Neale Ranns <neale@graphiant.com>
Change-Id: Ia174ec8095bc476853cce709a7048d7a3e3b377d
---

diff --git a/src/vppinfra/vec_bootstrap.h b/src/vppinfra/vec_bootstrap.h
index 5cf5d3b76a1..e14c4be8e52 100644
--- a/src/vppinfra/vec_bootstrap.h
+++ b/src/vppinfra/vec_bootstrap.h
@@ -213,15 +213,17 @@ u32 vec_len_not_inline (void *v);
 #define vec_foreach(var,vec) for (var = (vec); var < vec_end (vec); var++)
 
 /** \brief Vector iterator (reverse) */
-#define vec_foreach_backwards(var,vec) \
-for (var = vec_end (vec) - 1; var >= (vec); var--)
+#define vec_foreach_backwards(var, vec)                                       \
+  if (vec)                                                                    \
+    for (var = vec_end (vec) - 1; var >= (vec); var--)
 
 /** \brief Iterate over vector indices. */
 #define vec_foreach_index(var,v) for ((var) = 0; (var) < vec_len (v); (var)++)
 
 /** \brief Iterate over vector indices (reverse). */
-#define vec_foreach_index_backwards(var,v) \
-  for ((var) = vec_len((v)) - 1; (var) >= 0; (var)--)
+#define vec_foreach_index_backwards(var, v)                                   \
+  if (v)                                                                      \
+    for ((var) = vec_len ((v)) - 1; (var) >= 0; (var)--)
 
 /** \brief return the NUMA index for a vector */
 always_inline uword