[core] perf: simplify buffer_move()

require src and dest to be non-NULL

change no longer releases large swapped buffers with buffer_reset()

src/buffer.c

@@ -66,14 +66,10 @@ void buffer_reset(buffer *b) {
 
 void buffer_move(buffer *b, buffer *src) {
 	buffer tmp;
+	force_assert(NULL != b);
+	force_assert(NULL != src);
 
-	if (NULL == b) {
-		buffer_reset(src);
-		return;
-	}
-	buffer_reset(b);
-	if (NULL == src) return;
-
+	buffer_clear(b);
 	tmp = *src; *src = *b; *b = tmp;
 }
 

src/configparser.y

@@ -317,9 +317,11 @@ value(A) ::= key(B). {
 }
 
 value(A) ::= STRING(B). {
+  buffer *b;
   A = (data_unset *)data_string_init();
-  buffer_move(((data_string *)(A))->value, B);
-  buffer_free(B);
+  b = ((data_string *)(A))->value;
+  buffer_free(b);
+  ((data_string *)(A))->value = B;
   B = NULL;
 }