Groundbreaking for AIVDM messages in nmea mode.

1 files changed, 119 insertions, 0 deletions

diff --git a/pseudoais.c b/pseudoais.c
new file mode 100644
index 00000000..ff2c5a6d
--- /dev/null
+++ b/pseudoais.c
@@ -0,0 +1,119 @@
+/*
+ * Encode AIS messages.
+ *
+ * See the file AIVDM.txt on the GPSD website for documentation and references.
+ *
+ * This file is build from driver_ais.c
+ *
+ * This file is Copyright (c) 2013 by the GPSD project
+ * BSD terms apply: see the file COPYING in the distribution root for details.
+ */
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+
+#include "gpsd.h"
+#include "bits.h"
+#include <stdint.h>
+
+static unsigned char convtab[] = {"0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVW`abcdefghijklmnopqrstuvw"};
+
+static unsigned int ais_addbits(unsigned char *bits,
+				unsigned int   start,
+				unsigned int   len,
+				uint64_t       data)
+{
+    unsigned int  l;
+    unsigned int  pos;
+    uint64_t      mask;
+    unsigned char mask1;
+
+    mask  = 0x1;
+    pos   = (start+len-1) / 6;
+    mask1 = 0x20;
+    mask1 = mask1 >> ((start+len-1) % 6);
+
+    if (len == 0) {
+        return 0;
+    }
+
+    for(l=0;l<len;l++) {
+        if (data & mask) {
+	    bits[pos] |= mask1; 
+	}
+	mask  <<= 1;
+	mask1 <<= 1;
+	if (mask1 == 0x40) {
+	    pos   -= 1;
+	    mask1  = 0x1;
+	}
+    }
+    return 0;
+}
+
+
+static unsigned int ais_binary_to_ascii(unsigned char *bits, unsigned int len)
+{
+    unsigned int l;
+
+    if (len == 0) {
+        bits[0] = 0;
+        return 0;
+    }
+
+    for (l=0;l<len;l+=6) {
+        bits[l/6] = convtab[bits[l/6] & 0x3f];
+    }
+}
+
+
+unsigned int ais_binary_encode(struct ais_t *ais,
+			       unsigned char *bits)
+{
+    unsigned int len;
+
+    len = 0;
+
+    ais_addbits(bits,  0,  6, ais->type);
+    ais_addbits(bits,  6,  2, ais->repeat);
+    ais_addbits(bits,  8, 30, ais->mmsi);
+    switch (ais->type) {
+    case 1:	/* Position Report */
+    case 2:
+    case 3:
+        ais_addbits(bits,  38,  4, ais->type1.status);
+        ais_addbits(bits,  42,  8, ais->type1.turn);
+        ais_addbits(bits,  50, 10, ais->type1.speed);
+	ais_addbits(bits,  60,  1, ais->type1.accuracy);
+	ais_addbits(bits,  61, 28, ais->type1.lon);
+	ais_addbits(bits,  89, 27, ais->type1.lat);
+	ais_addbits(bits, 116, 12, ais->type1.course);
+	ais_addbits(bits, 128,  9, ais->type1.heading);
+	ais_addbits(bits, 137,  6, ais->type1.second);
+	ais_addbits(bits, 143,  2, ais->type1.maneuver);
+	/* ais->type1.spare	        = UBITS(145, 3); */
+	ais_addbits(bits, 148,  1, ais->type1.raim);
+	ais_addbits(bits, 149, 19, ais->type1.radio);
+	len = 149 + 19;
+	break;
+    case 4: 	/* Base Station Report */
+    case 11:	/* UTC/Date Response */
+        break;
+    case 5:     /* Ship static and voyage related data */
+        break;
+    case 9:     /* Standard SAR Aircraft Position Report */
+        break;
+    case 18:	/* Standard Class B CS Position Report */
+        break;
+    case 19:	/* Extended Class B CS Position Report */
+        break;
+    case 21:	/* Aid-to-Navigation Report */
+        break;
+    case 24:	/* Class B CS Static Data Report */
+        break;
+    case 27:	/* Long Range AIS Broadcast message */
+        break;
+    }
+    ais_binary_to_ascii(bits, len);
+    return len;
+}