+ /* Parameter validation */
+
+ if (!buffer || !required_length) {
+ return (AE_BAD_PARAMETER);
+ }
+
+ /*
+ * Buffer->Length is used as both an input and output parameter. Get the
+ * input actual length and set the output required buffer length.
+ */
+ input_buffer_length = buffer->length;
+ buffer->length = required_length;
+
+ /*
+ * The input buffer length contains the actual buffer length, or the type
+ * of buffer to be allocated by this routine.
+ */
+ switch (input_buffer_length) {