From 832c5e996e8fb492b078a4612428745e18b70dcd Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <tridge@samba.org>
Date: Thu, 20 Sep 2012 07:42:46 +1000
Subject: [PATCH] APM: make it possible to fetch parameters by index

---
 ArduPlane/GCS_Mavlink.pde | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/ArduPlane/GCS_Mavlink.pde b/ArduPlane/GCS_Mavlink.pde
index 9d9f4fd168..15b80b37fa 100644
--- a/ArduPlane/GCS_Mavlink.pde
+++ b/ArduPlane/GCS_Mavlink.pde
@@ -1328,16 +1328,20 @@ void GCS_MAVLINK::handleMessage(mavlink_message_t* msg)
         mavlink_param_request_read_t packet;
         mavlink_msg_param_request_read_decode(msg, &packet);
         if (mavlink_check_target(packet.target_system,packet.target_component)) break;
-        if (packet.param_index != -1) {
-            gcs_send_text_P(SEVERITY_LOW, PSTR("Param by index not supported"));
-            break;
-        }
-
         enum ap_var_type p_type;
-        AP_Param *vp = AP_Param::find(packet.param_id, &p_type);
-        if (vp == NULL) {
-            gcs_send_text_fmt(PSTR("Unknown parameter %s"), packet.param_id);
-            break;
+        AP_Param *vp;
+        if (packet.param_index != -1) {
+            vp = AP_Param::find_by_index(packet.param_index, &p_type);
+            if (vp == NULL) {
+                gcs_send_text_fmt(PSTR("Unknown parameter index %d"), packet.param_index);
+                break;
+            }
+        } else {
+            vp = AP_Param::find(packet.param_id, &p_type);
+            if (vp == NULL) {
+                gcs_send_text_fmt(PSTR("Unknown parameter /%s"), packet.param_id);
+                break;
+            }
         }
         char param_name[ONBOARD_PARAM_NAME_LENGTH];
         vp->copy_name(param_name, sizeof(param_name), true);