From 3474da6c97972019c2b4b5c49e655e6ef3b4a6da Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <tridge@samba.org>
Date: Mon, 21 Jul 2014 09:37:41 +1000
Subject: [PATCH] AP_Param: added a method for example programs to set
 parameters in objects

---
 libraries/AP_Param/AP_Param.cpp | 18 ++++++++++++++++++
 libraries/AP_Param/AP_Param.h   |  6 ++++++
 2 files changed, 24 insertions(+)

diff --git a/libraries/AP_Param/AP_Param.cpp b/libraries/AP_Param/AP_Param.cpp
index 9791632fa5..fa7b2eebe3 100644
--- a/libraries/AP_Param/AP_Param.cpp
+++ b/libraries/AP_Param/AP_Param.cpp
@@ -819,6 +819,24 @@ void AP_Param::setup_object_defaults(const void *object_pointer, const struct Gr
     }
 }
 
+// set a value directly in an object. This should only be used by
+// example code, not by mainline vehicle code
+void AP_Param::set_object_value(const void *object_pointer, 
+                                const struct GroupInfo *group_info, 
+                                const char *name, float value)
+{
+    uintptr_t base = (uintptr_t)object_pointer;
+    uint8_t type;
+    for (uint8_t i=0;
+         (type=PGM_UINT8(&group_info[i].type)) != AP_PARAM_NONE;
+         i++) {
+        if (strcmp(name, group_info[i].name) == 0 && type <= AP_PARAM_FLOAT) {
+            void *ptr = (void *)(base + PGM_UINT16(&group_info[i].offset));
+            set_value((enum ap_var_type)type, ptr, value);
+        }
+    }
+}
+
 
 // load default values for all scalars in a sketch. This does not
 // recurse into sub-objects
diff --git a/libraries/AP_Param/AP_Param.h b/libraries/AP_Param/AP_Param.h
index c836843ca3..4c5eadc5a5 100644
--- a/libraries/AP_Param/AP_Param.h
+++ b/libraries/AP_Param/AP_Param.h
@@ -199,6 +199,12 @@ public:
     // load default values for scalars in a group
     static void         setup_object_defaults(const void *object_pointer, const struct GroupInfo *group_info);
 
+    // set a value directly in an object. This should only be used by
+    // example code, not by mainline vehicle code
+    static void set_object_value(const void *object_pointer, 
+                                 const struct GroupInfo *group_info, 
+                                 const char *name, float value);
+
     // load default values for all scalars in the main sketch. This
     // does not recurse into the sub-objects    
     static void         setup_sketch_defaults(void);