atrf-path: option -P to load a min/max profile; pass/fail indication in GUI

- sweep.h (MIN_DIFF, MAX_DIFF, struct sweep): added min/max profile
- sweep.h (do_sweep), atrf-path.c (do_half_sweep, do_sweep): compare
  result against limits and return pass/fail decision
- sweep.h (N_CHAN), atrf-path.c (do_half_sweep, do_sweeps), gui.c
  (N_CHAN): declare number of channels in one central place instead of
  scattering it all around the program
- atrf-path.c (do_read_profile, read_profile, usage, main): new option -P
  to read a min/max profile
- gui.c (indicate, main): moved indicator to separate function and
  improved blink logic
- gui.c (OVER_RGBA, UNDER_RGBA, indicate, main): change color to indicate
  pass/fail

tools/atrf-path/sweep.h

@@ -19,6 +19,12 @@
 #include "atrf.h"
 
 
+#define	N_CHAN	16
+
+#define	MIN_DIFF	-97.0	/* RSSI(min)-TX(max) = -94 - 3		*/
+#define	MAX_DIFF	7.0	/* RSSI(max)-TX(min) = -10 - (-17)	*/
+
+
 struct sweep {
 	struct atrf_dsc *tx;
 	struct atrf_dsc *rx;
@@ -27,6 +33,8 @@ struct sweep {
 	int power;
 	uint8_t cont_tx;
 	int samples;
+	double min[N_CHAN];
+	double max[N_CHAN];
 };
 
 struct sample {
@@ -35,6 +43,14 @@ struct sample {
 };
 
 
-void do_sweep(const struct sweep *sweep, struct sample *res);
+/*
+ * do_sweep returns whether the signal is within the limits:
+ *
+ *  1: at least one sample is above the maximum
+ *  0: all samples are between minimum and maximum
+ * -1: at least one sample below the minimum, and none above the maximum
+ */
+
+int do_sweep(const struct sweep *sweep, struct sample *res);
 
 #endif /* !SWEEP_H */