Puedo GPGSA outputs 12 SATs and NaNs as empty.

GPGSA is commonly taken to be 12 sats.  Prevent ublox and TSIP drivers
from outputting more.  No regressions had more than 12 anyway.

DOPs that were NaNs were output as 0.0.  Now output as blanks.
Too easy for a user to take 0.0 as a real number.

1 files changed, 30 insertions, 12 deletions

diff --git a/pseudonmea.c b/pseudonmea.c
index 2b9bf7c3..4dcc663f 100644
--- a/pseudonmea.c
+++ b/pseudonmea.c
@@ -156,31 +156,48 @@ static void gpsd_binary_quality_dump(struct gps_device_t *session,
 
     if (session->device_type != NULL && (session->gpsdata.set & MODE_SET) != 0) {
 	int i, j;
+	int max_channels = session->device_type->channels;
+
+	/* GPGSA commonly has exactly 12 channels, enforce that as a MAX */
+	if ( 12 < max_channels ) {
+	    /* what to do with the excess channels? */
+	    max_channels = 12;
+	}
 
 	bufp2 = bufp + strlen(bufp);
 	(void)snprintf(bufp, len,
 		       "$GPGSA,%c,%d,", 'A', session->gpsdata.fix.mode);
 	j = 0;
-	for (i = 0; i < session->device_type->channels; i++) {
+	for (i = 0; i < max_channels; i++) {
 	    if (session->gpsdata.skyview[i].used == true){
-		str_appendf(bufp, len,
-			       "%d,",
-			       session->gpsdata.skyview[i].PRN);
+		str_appendf(bufp, len, "%d,", session->gpsdata.skyview[i].PRN);
 	        j++;
 	    }
 	}
-	for (i = j; i < session->device_type->channels; i++) {
+	for (i = j; i < max_channels; i++) {
+	    /* fill out the empty slots */
 	    (void)strlcat(bufp, ",", len);
 	}
-#define ZEROIZE(x)	(isnan(x)!=0 ? 0.0 : x)
 	if (session->gpsdata.fix.mode == MODE_NO_FIX)
 	    (void)strlcat(bufp, ",,,", len);
-	else
-	    str_appendf(bufp, len,
-			   "%.1f,%.1f,%.1f*",
-			   ZEROIZE(session->gpsdata.dop.pdop),
-			   ZEROIZE(session->gpsdata.dop.hdop),
-			   ZEROIZE(session->gpsdata.dop.vdop));
+	else {
+            /* output the DOPs, NaN as blanks */
+	    if ( 0 == isnan( session->gpsdata.dop.pdop ) ) {
+		str_appendf(bufp, len, "%.1f,", session->gpsdata.dop.pdop);
+	    } else {
+		(void)strlcat(bufp, ",", len);
+	    }
+	    if ( 0 == isnan( session->gpsdata.dop.hdop ) ) {
+		str_appendf(bufp, len, "%.1f,", session->gpsdata.dop.hdop);
+	    } else {
+		(void)strlcat(bufp, ",", len);
+	    }
+	    if ( 0 == isnan( session->gpsdata.dop.vdop ) ) {
+		str_appendf(bufp, len, "%.1f*", session->gpsdata.dop.vdop);
+	    } else {
+		(void)strlcat(bufp, "*", len);
+	    }
+	}
 	nmea_add_checksum(bufp2);
     }
     if (isfinite(session->gpsdata.fix.epx)!=0
@@ -196,6 +213,7 @@ static void gpsd_binary_quality_dump(struct gps_device_t *session,
 	    (void)gmtime_r(&intfixtime, &tm);
 	}
 	bufp2 = bufp + strlen(bufp);
+#define ZEROIZE(x)      (isnan(x)!=0 ? 0.0 : x)
 	str_appendf(bufp, len,
 		       "$GPGBS,%02d%02d%02d,%.2f,M,%.2f,M,%.2f,M",
 		       tm.tm_hour, tm.tm_min, tm.tm_sec,