cleanup: use const for struct Location pointers and references

this allows the compiler to generate more efficient code

APMrover2/Log.pde

@@ -300,7 +300,7 @@ struct log_Cmd {
 };
 
 // Write a command processing packet. Total length : 19 bytes
-static void Log_Write_Cmd(uint8_t num, struct Location *wp)
+static void Log_Write_Cmd(uint8_t num, const struct Location *wp)
 {
     struct log_Cmd pkt = {
         LOG_PACKET_HEADER_INIT(LOG_CMD_MSG),
@@ -655,7 +655,7 @@ static void log_callback(uint8_t msgid)
 // dummy functions
 static void Log_Write_Mode(uint8_t mode) {}
 static void Log_Write_Startup(uint8_t type) {}
-static void Log_Write_Cmd(uint8_t num, struct Location *wp) {}
+static void Log_Write_Cmd(uint8_t num, const struct Location *wp) {}
 static void Log_Write_Current() {}
 static void Log_Write_Nav_Tuning() {}
 static void Log_Write_GPS(	uint32_t log_Time, int32_t log_Lattitude, int32_t log_Longitude, int32_t log_gps_alt, int32_t log_mix_alt,

APMrover2/commands.pde

@@ -100,7 +100,7 @@ static void set_cmd_with_index(struct Location temp, int i)
 This function stores waypoint commands
 It looks to see what the next command type is and finds the last command.
 */
-static void set_next_WP(struct Location *wp)
+static void set_next_WP(const struct Location *wp)
 {
 	// copy the current WP into the OldWP slot
 	// ---------------------------------------

APMrover2/test.pde

@@ -304,7 +304,7 @@ test_wp(uint8_t argc, const Menu::arg *argv)
 }
 
 static void
-test_wp_print(struct Location *cmd, uint8_t wp_index)
+test_wp_print(const struct Location *cmd, uint8_t wp_index)
 {
 	cliSerial->printf_P(PSTR("command #: %d id:%d options:%d p1:%d p2:%ld p3:%ld p4:%ld \n"),
 		(int)wp_index,

ArduCopter/Log.pde

@@ -685,7 +685,7 @@ struct log_Cmd {
 };
 
 // Write a command processing packet.  Total length : 21 bytes
-static void Log_Write_Cmd(uint8_t num, struct Location *wp)
+static void Log_Write_Cmd(uint8_t num, const struct Location *wp)
 {
     struct log_Cmd pkt = {
         LOG_PACKET_HEADER_INIT(LOG_CMD_MSG),
@@ -1354,7 +1354,7 @@ static void log_callback(uint8_t msgid)
 
 void print_latlon(AP_HAL::BetterStream *s, int32_t lat_or_lon) {}
 static void Log_Write_Startup() {}
-static void Log_Write_Cmd(uint8_t num, struct Location *wp) {}
+static void Log_Write_Cmd(uint8_t num, const struct Location *wp) {}
 static void Log_Write_Mode(uint8_t mode) {}
 static void Log_Write_IMU() {}
 static void Log_Write_GPS() {}

ArduCopter/commands.pde

@@ -124,7 +124,7 @@ static int32_t get_RTL_alt()
  *  It precalculates all the necessary stuff.
  */
 
-static void set_next_WP(struct Location *wp)
+static void set_next_WP(const struct Location *wp)
 {
     // copy the current WP into the OldWP slot
     // ---------------------------------------

ArduCopter/setup.pde

@@ -1416,7 +1416,7 @@ init_esc()
     }
 }
 
-static void print_wp(struct Location *cmd, uint8_t index)
+static void print_wp(const struct Location *cmd, uint8_t index)
 {
    	//float t1 = (float)cmd->lat / t7;
     //float t2 = (float)cmd->lng / t7;

ArduPlane/Log.pde

@@ -298,7 +298,7 @@ struct log_Cmd {
 };
 
 // Write a command processing packet. Total length : 19 bytes
-static void Log_Write_Cmd(uint8_t num, struct Location *wp)
+static void Log_Write_Cmd(uint8_t num, const struct Location *wp)
 {
     struct log_Cmd pkt = {
         LOG_PACKET_HEADER_INIT(LOG_CMD_MSG),
@@ -702,7 +702,7 @@ static void log_callback(uint8_t msgid)
 // dummy functions
 static void Log_Write_Mode(uint8_t mode) {}
 static void Log_Write_Startup(uint8_t type) {}
-static void Log_Write_Cmd(uint8_t num, struct Location *wp) {}
+static void Log_Write_Cmd(uint8_t num, const struct Location *wp) {}
 static void Log_Write_Current() {}
 static void Log_Write_Nav_Tuning() {}
 static void Log_Write_GPS() {}

ArduPlane/commands.pde

@@ -147,7 +147,7 @@ static int32_t read_alt_to_hold()
  *  This function stores waypoint commands
  *  It looks to see what the next command type is and finds the last command.
  */
-static void set_next_WP(struct Location *wp)
+static void set_next_WP(const struct Location *wp)
 {
     // copy the current WP into the OldWP slot
     // ---------------------------------------

ArduPlane/commands_logic.pde

@@ -263,7 +263,7 @@ static void do_land()
     set_next_WP(&next_nav_command);
 }
 
-static void loiter_set_direction_wp(struct Location *nav_command) 
+static void loiter_set_direction_wp(const struct Location *nav_command)
 {
     if (nav_command->options & MASK_OPTIONS_LOITER_DIRECTION) {
         loiter_direction = -1;

ArduPlane/test.pde

@@ -334,7 +334,7 @@ test_wp(uint8_t argc, const Menu::arg *argv)
 }
 
 static void
-test_wp_print(struct Location *cmd, uint8_t wp_index)
+test_wp_print(const struct Location *cmd, uint8_t wp_index)
 {
     cliSerial->printf_P(PSTR("command #: %d id:%d options:%d p1:%d p2:%ld p3:%ld p4:%ld \n"),
                     (int)wp_index,

libraries/AP_Limits/AP_Limit_Altitude.cpp

@@ -45,11 +45,12 @@ const AP_Param::GroupInfo AP_Limit_Altitude::var_info[] PROGMEM = {
     AP_GROUPEND
 };
 
-AP_Limit_Altitude::AP_Limit_Altitude(struct Location *current_loc) :
+AP_Limit_Altitude::AP_Limit_Altitude(const struct Location *current_loc) :
-    AP_Limit_Module(AP_LIMITS_ALTITUDE)     // enabled and required
+    AP_Limit_Module(AP_LIMITS_ALTITUDE),     // enabled and required
+    _current_loc(current_loc)
 {
     AP_Param::setup_object_defaults(this, var_info);
-    _current_loc = current_loc;
+    //_current_loc = current_loc;
 }
 
 bool AP_Limit_Altitude::triggered()

libraries/AP_Limits/AP_Limit_Altitude.h

@@ -16,7 +16,7 @@
 class AP_Limit_Altitude : public AP_Limit_Module {
 
 public:
-    AP_Limit_Altitude(struct Location *current_loc);
+    AP_Limit_Altitude(const struct Location *current_loc);
 
     AP_Int32        min_alt();
     AP_Int32        max_alt();
@@ -27,7 +27,7 @@ public:
     static const struct AP_Param::GroupInfo         var_info[];
 
 protected:
-    struct Location *                               _current_loc;
+    const struct Location *                               _current_loc;
     AP_Int32        _min_alt;
     AP_Int32        _max_alt;
 

libraries/AP_Limits/AP_Limit_Geofence.cpp

@@ -56,8 +56,8 @@ const AP_Param::GroupInfo AP_Limit_Geofence::var_info[] PROGMEM = {
 
 
 AP_Limit_Geofence::AP_Limit_Geofence(uint16_t efs, uint8_t f_wp_s,
-        uint8_t max_fp, GPS *&gps, struct Location *h_loc,
+        uint8_t max_fp, GPS *&gps, const struct Location *h_loc,
-        struct Location *c_loc) :
+        const struct Location *c_loc) :
     AP_Limit_Module(AP_LIMITS_GEOFENCE),
     _gps(gps),
     _current_loc(c_loc),

libraries/AP_Limits/AP_Limit_Geofence.h

@@ -20,7 +20,7 @@
 class AP_Limit_Geofence : public AP_Limit_Module {
 
 public:
-    AP_Limit_Geofence(uint16_t eeprom_fence_start, uint8_t fpsize, uint8_t max_fp, GPS *&gps, struct Location *home_loc, struct Location *current_loc);
+    AP_Limit_Geofence(uint16_t eeprom_fence_start, uint8_t fpsize, uint8_t max_fp, GPS *&gps, const struct Location *home_loc, const struct Location *current_loc);
     bool        init();
     bool        triggered();
 
@@ -38,8 +38,8 @@ protected:
 
     // pointers to gps, current location and home
     GPS *&                  _gps;
-    struct Location *       _current_loc;
+    const struct Location *       _current_loc;
-    struct Location *       _home;
+    const struct Location *       _home;
 
 
     // Simple mode, just radius

libraries/AP_Math/AP_Math.h

@@ -70,9 +70,9 @@ int32_t                 get_bearing_cd(const struct Location *loc1, const struct
 // our previous waypoint and point2 is our target waypoint
 // then this function returns true if we have flown past
 // the target waypoint
-bool        location_passed_point(struct Location & location,
+bool        location_passed_point(const struct Location & location,
-                                  struct Location & point1,
+                                  const struct Location & point1,
-                                  struct Location & point2);
+                                  const struct Location & point2);
 
 //  extrapolate latitude/longitude given bearing and distance
 void        location_update(struct Location *loc, float bearing, float distance);

libraries/AP_Math/examples/location/location.pde

@@ -64,7 +64,7 @@ static void test_passed_waypoint(void)
     hal.console->println("waypoint tests OK");
 }
 
-static void test_one_offset(struct Location &loc,
+static void test_one_offset(const struct Location &loc,
                             float ofs_north, float ofs_east,
                             float dist, float bearing)
 {

libraries/AP_Math/location.cpp

@@ -72,9 +72,9 @@ int32_t get_bearing_cd(const struct Location *loc1, const struct Location *loc2)
 // our previous waypoint and point2 is our target waypoint
 // then this function returns true if we have flown past
 // the target waypoint
-bool location_passed_point(struct Location &location,
+bool location_passed_point(const struct Location &location,
-                           struct Location &point1,
+                           const struct Location &point1,
-                           struct Location &point2)
+                           const struct Location &point2)
 {
     // the 3 points form a triangle. If the angle between lines
     // point1->point2 and location->point2 is greater than 90

libraries/AP_Mount/AP_Mount.cpp

@@ -533,7 +533,7 @@ void AP_Mount::status_msg(mavlink_message_t *msg)
 }
 
 /// Set mount point/region of interest, triggered by mission script commands
-void AP_Mount::set_roi_cmd(struct Location *target_loc)
+void AP_Mount::set_roi_cmd(const struct Location *target_loc)
 {
 #if MNT_GPSPOINT_OPTION == ENABLED
     // set the target gps location
@@ -571,7 +571,7 @@ AP_Mount::angle_input_rad(RC_Channel* rc, int16_t angle_min, int16_t angle_max)
 }
 
 void
-AP_Mount::calc_GPS_target_angle(struct Location *target)
+AP_Mount::calc_GPS_target_angle(const struct Location *target)
 {
     float GPS_vector_x = (target->lng-_current_loc->lng)*cosf(ToRad((_current_loc->lat+target->lat)*0.00000005f))*0.01113195f;
     float GPS_vector_y = (target->lat-_current_loc->lat)*0.01113195f;

libraries/AP_Mount/AP_Mount.h

@@ -46,7 +46,7 @@ public:
     void                    configure_msg(mavlink_message_t* msg);
     void                    control_msg(mavlink_message_t* msg);
     void                    status_msg(mavlink_message_t* msg);
-    void                    set_roi_cmd(struct Location *target_loc);
+    void                    set_roi_cmd(const struct Location *target_loc);
     void                    configure_cmd();
     void                    control_cmd();
 
@@ -72,7 +72,7 @@ private:
     void                            set_GPS_target_location(Location targetGPSLocation); ///< used to tell the mount to track GPS location
 
     // internal methods
-    void                            calc_GPS_target_angle(struct Location *target);
+    void                            calc_GPS_target_angle(const struct Location *target);
     void                            stabilize();
     int16_t                         closest_limit(int16_t angle, int16_t* angle_min, int16_t* angle_max);
     void                            move_servo(uint8_t rc, int16_t angle, int16_t angle_min, int16_t angle_max);