RCMapper: simple mapping object for primary input channels

allows arbitrary mapping of first 4 channels

libraries/AP_RCMapper/AP_RCMapper.cpp

@@ -0,0 +1,43 @@
+/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
+
+#include <AP_HAL.h>
+#include <AP_RCMapper.h>
+
+const AP_Param::GroupInfo RCMapper::var_info[] PROGMEM = {
+    // @Param: ROLL
+    // @DisplayName: Roll channel
+    // @Description: Roll channel number
+    // @Range: 1 8
+    // @Increment: 1
+    // @User: Advanced
+    AP_GROUPINFO("ROLL",        0, RCMapper, _ch_roll, 1),
+
+    // @Param: PITCH
+    // @DisplayName: Pitch channel
+    // @Description: Pitch channel number
+    // @Range: 1 8
+    // @Increment: 1
+    AP_GROUPINFO("PITCH",       1, RCMapper, _ch_pitch, 2),
+
+    // @Param: THROTTLE
+    // @DisplayName: Throttle channel
+    // @Description: Throttle channel number
+    // @Range: 1 8
+    // @Increment: 1
+    AP_GROUPINFO("THROTTLE",    2, RCMapper, _ch_throttle, 3),
+
+    // @Param: YAW
+    // @DisplayName: Yaw channel
+    // @Description: Yaw channel number
+    // @Range: 1 8
+    // @Increment: 1
+    AP_GROUPINFO("YAW",         3, RCMapper, _ch_yaw, 4),
+
+    AP_GROUPEND
+};
+
+// object constructor.
+RCMapper::RCMapper(void)
+{
+    AP_Param::setup_object_defaults(this, var_info);
+}

libraries/AP_RCMapper/AP_RCMapper.h

@@ -0,0 +1,37 @@
+/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
+#ifndef AP_RCMAPPER_H
+#define AP_RCMAPPER_H
+
+#include <inttypes.h>
+#include <AP_Common.h>
+#include <AP_Param.h>
+
+class RCMapper
+{
+public:
+    /// Constructor
+    ///
+    RCMapper();
+
+    /// roll - return input channel number for roll / aileron input
+    uint8_t roll() const { return _ch_roll; }
+
+    /// pitch - return input channel number for pitch / elevator input
+    uint8_t pitch() const { return _ch_pitch; }
+
+    /// throttle - return input channel number for throttle input
+    uint8_t throttle() const { return _ch_throttle; }
+
+    /// yaw - return input channel number for yaw / rudder input
+    uint8_t yaw() const { return _ch_yaw; }
+
+    static const struct AP_Param::GroupInfo var_info[];
+
+private:
+    // channel mappings
+    AP_Int8 _ch_roll;
+    AP_Int8 _ch_pitch;
+    AP_Int8 _ch_yaw;
+    AP_Int8 _ch_throttle;
+};
+#endif