Make mixer ioctls load from a memory buffer rather than a file. This is prep for uploading the memory buffer to IO to be processed there.

apps/systemlib/mixer/mixer_multirotor.cpp

@@ -54,6 +54,9 @@
 
 #include "mixer.h"
 
+#define debug(fmt, args...)	do { } while(0)
+//#define debug(fmt, args...)	do { printf("[mixer] " fmt "\n", ##args); } while(0)
+
 #define		CW		(-1.0f)
 #define		CCW		(1.0f)
 
@@ -151,6 +154,59 @@ MultirotorMixer::~MultirotorMixer()
 {
 }
 
+MultirotorMixer *
+MultirotorMixer::from_text(Mixer::ControlCallback control_cb, uintptr_t cb_handle, const char *buf, unsigned &buflen)
+{
+	MultirotorMixer::Geometry geometry;
+	char geomname[8];
+	int s[4];
+	int used;
+
+	if (sscanf(buf, "R: %s %d %d %d %d%n", geomname, &s[0], &s[1], &s[2], &s[3], &used) != 5) {
+		debug("multirotor parse failed on '%s'", buf);
+		return nullptr;
+	}
+	if (used > (int)buflen) {
+		debug("multirotor spec used %d of %u", used, buflen);
+		return nullptr;
+	}
+	buflen -= used;
+
+	if (!strcmp(geomname, "4+")) {
+		geometry = MultirotorMixer::QUAD_PLUS;
+
+	} else if (!strcmp(geomname, "4x")) {
+		geometry = MultirotorMixer::QUAD_X;
+
+	} else if (!strcmp(geomname, "6+")) {
+		geometry = MultirotorMixer::HEX_PLUS;
+
+	} else if (!strcmp(geomname, "6x")) {
+		geometry = MultirotorMixer::HEX_X;
+
+	} else if (!strcmp(geomname, "8+")) {
+		geometry = MultirotorMixer::OCTA_PLUS;
+
+	} else if (!strcmp(geomname, "8x")) {
+		geometry = MultirotorMixer::OCTA_X;
+
+	} else {
+		debug("unrecognised geometry '%s'", geomname);
+		return nullptr;
+	}
+
+	debug("adding multirotor mixer '%s'", geomname);
+
+	return new MultirotorMixer(
+		       control_cb,
+		       cb_handle,
+		       geometry,
+		       s[0] / 10000.0f,
+		       s[1] / 10000.0f,
+		       s[2] / 10000.0f,
+		       s[3] / 10000.0f);
+}
+
 unsigned
 MultirotorMixer::mix(float *outputs, unsigned space)
 {