Merge pull request #814 from dscheg/dev

Fix displayLevel overflow

lib/dictBuilder/cover.c

@@ -969,7 +969,7 @@ ZDICTLIB_API size_t ZDICT_optimizeTrainFromBuffer_cover(
   /* Initialization */
   COVER_best_init(&best);
   /* Turn down global display level to clean up display at level 2 and below */
-  g_displayLevel = parameters->zParams.notificationLevel - 1;
+  g_displayLevel = displayLevel == 0 ? 0 : displayLevel - 1;
   /* Loop through d first because each new value needs a new context */
   LOCALDISPLAYLEVEL(displayLevel, 2, "Trying %u different sets of parameters\n",
                     kIterations);