Simplify _asn1_append_value() and avoid memcpy's with zero length

Based on patch of Pascal Cuoq <pascal.cuoq@trust-in-soft.com>

1 files changed, 19 insertions, 9 deletions

diff --git a/lib/parser_aux.c b/lib/parser_aux.c
index 0a1f645..a42cdd2 100644
--- a/lib/parser_aux.c
+++ b/lib/parser_aux.c
@@ -316,39 +316,49 @@ _asn1_append_value (asn1_node node, const void *value, unsigned int len)
 {
   if (node == NULL)
     return node;
-  if (node->value != NULL && node->value != node->small_value)
+
+  if (node->value == NULL)
+    return _asn1_set_value (node, value, len);
+
+  if (len == 0)
+    return node;
+
+  if (node->value == node->small_value)
     {
-      /* value is allocated */
+      /* value is in node */
       int prev_len = node->value_len;
       node->value_len += len;
-      node->value = _asn1_realloc (node->value, node->value_len);
+      node->value = malloc (node->value_len);
       if (node->value == NULL)
 	{
 	  node->value_len = 0;
 	  return NULL;
 	}
+
+      if (prev_len > 0)
+        memcpy (node->value, node->small_value, prev_len);
+
       memcpy (&node->value[prev_len], value, len);
 
       return node;
     }
-  else if (node->value == node->small_value)
+  else /* if (node->value != NULL && node->value != node->small_value) */
     {
-      /* value is in node */
+      /* value is allocated */
       int prev_len = node->value_len;
       node->value_len += len;
-      node->value = malloc (node->value_len);
+
+      node->value = _asn1_realloc (node->value, node->value_len);
       if (node->value == NULL)
 	{
 	  node->value_len = 0;
 	  return NULL;
 	}
-      memcpy (node->value, node->small_value, prev_len);
+
       memcpy (&node->value[prev_len], value, len);
 
       return node;
     }
-  else				/* node->value == NULL */
-    return _asn1_set_value (node, value, len);
 }
 
 /******************************************************************/