3 files changed, 78 insertions, 0 deletions
diff --git a/src/plugins/unittest/CMakeLists.txt b/src/plugins/unittest/CMakeLists.txt
index 0af0dea250c..5c8825f4f3f 100644
--- a/src/plugins/unittest/CMakeLists.txt
+++ b/src/plugins/unittest/CMakeLists.txt
@@ -28,5 +28,6 @@ add_vpp_plugin(unittest
   session_test.c
   string_test.c
   tcp_test.c
+  sparse_vec_test.c
   unittest.c
 )
diff --git a/src/plugins/unittest/sparse_vec_test.c b/src/plugins/unittest/sparse_vec_test.c
new file mode 100644
index 00000000000..bb875452cdf
--- /dev/null
+++ b/src/plugins/unittest/sparse_vec_test.c
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2018 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <vlib/vlib.h>
+#include <vppinfra/sparse_vec.h>
+
+static clib_error_t *
+test_sparse_vec_command_fn (vlib_main_t * vm,
+			    unformat_input_t * input,
+			    vlib_cli_command_t * cmd)
+{
+  /* A sparse vector ... */
+  int *spv = 0;
+  int i, c0, c1;
+  u32 i0, i1;
+
+  /* set one member */
+  sparse_vec_validate (spv, 42)[0] = 0x4242;
+  /* count how many times we can find it */
+  c0 = 0;
+  for (i = 0; i <= 0xffff; i++)
+    {
+      c0 += (sparse_vec_index (spv, i) != 0);
+    }
+
+  if (c0 != 1)
+    vlib_cli_output (vm, "sparse_vec_index failed: c0 is %d != 1", c0);
+
+  c0 = 0;
+  c1 = 0;
+  for (i = 0; i <= 0xffff; i++)
+    {
+      sparse_vec_index2 (spv, i, 0xffff ^ i, &i0, &i1);
+      c0 += (i0 != 0);
+      c1 += (i1 != 0);
+    }
+
+  if (c0 != 1)
+    vlib_cli_output (vm, "sparse_vec_index2 failed: c0 is %d != 1", c0);
+  if (c1 != 1)
+    vlib_cli_output (vm, "sparse_vec_index2 failed: c1 is %d != 1", c1);
+
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (test_sparse_vec_command, static) =
+{
+  .path = "test sparse_vec",
+  .short_help = "test sparse_vec",
+  .function = test_sparse_vec_command_fn,
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vppinfra/sparse_vec.h b/src/vppinfra/sparse_vec.h
index cfa5778e290..54a92ce7a84 100644
--- a/src/vppinfra/sparse_vec.h
+++ b/src/vppinfra/sparse_vec.h
@@ -115,6 +115,10 @@ sparse_vec_index_internal (void *v,
 
   w = h->is_member_bitmap[i];
 
+  /* count_trailing_zeros(0) == 0, take care of that case */
+  if (PREDICT_FALSE (maybe_range == 0 && insert == 0 && w == 0))
+    return 0;
+
   if (PREDICT_TRUE (maybe_range == 0 && insert == 0 &&
 		    count_trailing_zeros (w) == b))
     return h->member_counts[i] + 1;