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/*
* 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) 2013-2018 by the GPSD project
* SPDX-License-Identifier: BSD-2-clause
*/
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "gpsd.h"
#include "bits.h"
#include <stdint.h>
#ifdef AIVDM_ENABLE
#define AIS_MSG_PART2_FLAG 0x100
static unsigned char convtab[] = {"0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVW`abcdefghijklmnopqrstuvw"};
static unsigned char contab1[] = {0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27,0x28,0x29,0x2a,0x2b,0x2c,0x2d,0x2e,0x2f,
0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0x3a,0x3b,0x3c,0x3d,0x3e,0x3f,
0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f,
0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1e,0x1f,
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff};
static void ais_addbits(unsigned char *bits,
unsigned int start,
unsigned int len,
uint64_t data)
{
unsigned int l;
unsigned int pos;
uint64_t mask;
unsigned int mask1;
mask = 0x1;
pos = (start+len-1) / 6;
mask1 = 0x20;
mask1 = mask1 >> ((start+len-1) % 6);
if (len == 0) {
return;
}
for(l=0;l<len;l++) {
if (data & mask) {
bits[pos] |= mask1;
}
mask <<= 1;
mask1 <<= 1;
if (mask1 == 0x40) {
pos -= 1;
mask1 = 0x1;
}
}
return;
}
static void ais_addchar(unsigned char *bits,
unsigned int start,
unsigned int len,
char *data)
{
unsigned int l;
unsigned int flag;
for(l=0,flag=0;l<len;l++) {
unsigned char a, b;
a = (unsigned char) data[l];
if (a == (unsigned char)'\0') {
flag = 1;
}
if (flag == 0) {
b = contab1[a & 0x7f];
} else {
b = (unsigned char) '\0';
}
ais_addbits(bits, start+6*l, 6, (uint64_t)b);
}
return;
}
static void ais_adddata(unsigned char *bits,
unsigned int start,
unsigned int len,
char *data)
{
unsigned int l;
for(l=0;l<len;l++) {
ais_addbits(bits, start+6*l, 6, (uint64_t)data[l]);
}
return;
}
static void ais_binary_to_ascii(unsigned char *bits, unsigned int len)
{
unsigned int l;
if (len == 0) {
bits[0] = '\0';
return;
}
for (l=0;l<len;l+=6) {
bits[l/6] = convtab[bits[l/6] & 0x3f];
}
return;
}
unsigned int ais_binary_encode(struct ais_t *ais,
unsigned char *bits,
int flag)
{
unsigned int len;
len = 0;
if (flag != 0) {
flag = AIS_MSG_PART2_FLAG;
}
ais_addbits(bits, 0, 6, (uint64_t)ais->type);
ais_addbits(bits, 6, 2, (uint64_t)ais->repeat);
ais_addbits(bits, 8, 30, (uint64_t)ais->mmsi);
switch (flag | ais->type) {
case 1: /* Position Report */
case 2:
case 3:
ais_addbits(bits, 38, 4, (uint64_t)ais->type1.status);
ais_addbits(bits, 42, 8, (uint64_t)ais->type1.turn);
ais_addbits(bits, 50, 10, (uint64_t)ais->type1.speed);
ais_addbits(bits, 60, 1, (uint64_t)ais->type1.accuracy);
ais_addbits(bits, 61, 28, (uint64_t)ais->type1.lon);
ais_addbits(bits, 89, 27, (uint64_t)ais->type1.lat);
ais_addbits(bits, 116, 12, (uint64_t)ais->type1.course);
ais_addbits(bits, 128, 9, (uint64_t)ais->type1.heading);
ais_addbits(bits, 137, 6, (uint64_t)ais->type1.second);
ais_addbits(bits, 143, 2, (uint64_t)ais->type1.maneuver);
/* ais_addbits(bits, 145, 3, (uint64_t)ais->type1.spare); */
ais_addbits(bits, 148, 1, (uint64_t)ais->type1.raim);
ais_addbits(bits, 149, 19, (uint64_t)ais->type1.radio);
len = 149 + 19;
break;
case 4: /* Base Station Report */
case 11: /* UTC/Date Response */
ais_addbits(bits, 38, 14, (uint64_t)ais->type4.year);
ais_addbits(bits, 52, 4, (uint64_t)ais->type4.month);
ais_addbits(bits, 56, 5, (uint64_t)ais->type4.day);
ais_addbits(bits, 61, 5, (uint64_t)ais->type4.hour);
ais_addbits(bits, 66, 6, (uint64_t)ais->type4.minute);
ais_addbits(bits, 72, 6, (uint64_t)ais->type4.second);
ais_addbits(bits, 78, 1, (uint64_t)ais->type4.accuracy);
ais_addbits(bits, 79, 28, (uint64_t)ais->type4.lon);
ais_addbits(bits, 107, 27, (uint64_t)ais->type4.lat);
ais_addbits(bits, 134, 4, (uint64_t)ais->type4.epfd);
/* ais_addbits(bits, 138, 10, (uint64_t)ais->type4.spare); */
ais_addbits(bits, 148, 1, (uint64_t)ais->type4.raim);
ais_addbits(bits, 149, 19, (uint64_t)ais->type4.radio);
len = 149 + 19;
break;
case 5: /* Ship static and voyage related data */
ais_addbits(bits, 38, 2, (uint64_t)ais->type5.ais_version);
ais_addbits(bits, 40, 30, (uint64_t)ais->type5.imo);
ais_addchar(bits, 70, 7, ais->type5.callsign);
ais_addchar(bits, 112, 20, ais->type5.shipname);
ais_addbits(bits, 232, 8, (uint64_t)ais->type5.shiptype);
ais_addbits(bits, 240, 9, (uint64_t)ais->type5.to_bow);
ais_addbits(bits, 249, 9, (uint64_t)ais->type5.to_stern);
ais_addbits(bits, 258, 6, (uint64_t)ais->type5.to_port);
ais_addbits(bits, 264, 6, (uint64_t)ais->type5.to_starboard);
ais_addbits(bits, 270, 4, (uint64_t)ais->type5.epfd);
ais_addbits(bits, 274, 4, (uint64_t)ais->type5.month);
ais_addbits(bits, 278, 5, (uint64_t)ais->type5.day);
ais_addbits(bits, 283, 5, (uint64_t)ais->type5.hour);
ais_addbits(bits, 288, 6, (uint64_t)ais->type5.minute);
ais_addbits(bits, 294, 8, (uint64_t)ais->type5.draught);
ais_addchar(bits, 302, 20, ais->type5.destination);
ais_addbits(bits, 422, 1, (uint64_t)ais->type5.dte);
/* ais_addbits(bits, 423, 1, (uint64_t)ais->type5.spare); */
len = 423 + 1;
break;
case 9: /* Standard SAR Aircraft Position Report */
ais_addbits(bits, 38, 12, (uint64_t)ais->type9.alt);
ais_addbits(bits, 50, 10, (uint64_t)ais->type9.speed);
ais_addbits(bits, 60, 1, (uint64_t)ais->type9.accuracy);
ais_addbits(bits, 61, 28, (uint64_t)ais->type9.lon);
ais_addbits(bits, 89, 27, (uint64_t)ais->type9.lat);
ais_addbits(bits, 116, 12, (uint64_t)ais->type9.course);
ais_addbits(bits, 128, 6, (uint64_t)ais->type9.second);
ais_addbits(bits, 134, 8, (uint64_t)ais->type9.regional);
ais_addbits(bits, 142, 1, (uint64_t)ais->type9.dte);
/* ais_addbits(bits, 143, 3, (uint64_t)ais->type9.spare); */
ais_addbits(bits, 146, 1, (uint64_t)ais->type9.assigned);
ais_addbits(bits, 147, 1, (uint64_t)ais->type9.raim);
ais_addbits(bits, 148, 19, (uint64_t)ais->type9.radio);
len = 148 + 19;
break;
case 18: /* Standard Class B CS Position Report */
ais_addbits(bits, 38, 8, (uint64_t)ais->type18.reserved);
ais_addbits(bits, 46, 10, (uint64_t)ais->type18.speed);
ais_addbits(bits, 56, 1, (uint64_t)ais->type18.accuracy);
ais_addbits(bits, 57, 28, (uint64_t)ais->type18.lon);
ais_addbits(bits, 85, 27, (uint64_t)ais->type18.lat);
ais_addbits(bits, 112, 12, (uint64_t)ais->type18.course);
ais_addbits(bits, 124, 9, (uint64_t)ais->type18.heading);
ais_addbits(bits, 133, 6, (uint64_t)ais->type18.second);
ais_addbits(bits, 139, 2, (uint64_t)ais->type18.regional);
ais_addbits(bits, 141, 1, (uint64_t)ais->type18.cs);
ais_addbits(bits, 142, 1, (uint64_t)ais->type18.display);
ais_addbits(bits, 143, 1, (uint64_t)ais->type18.dsc);
ais_addbits(bits, 144, 1, (uint64_t)ais->type18.band);
ais_addbits(bits, 145, 1, (uint64_t)ais->type18.msg22);
ais_addbits(bits, 146, 1, (uint64_t)ais->type18.assigned);
ais_addbits(bits, 147, 1, (uint64_t)ais->type18.raim);
ais_addbits(bits, 148, 20, (uint64_t)ais->type18.radio);
len = 148 + 20;
break;
case 19: /* Extended Class B CS Position Report */
ais_addbits(bits, 38, 8, (uint64_t)ais->type19.reserved);
ais_addbits(bits, 46, 10, (uint64_t)ais->type19.speed);
ais_addbits(bits, 56, 1, (uint64_t)ais->type19.accuracy);
ais_addbits(bits, 57, 28, (uint64_t)ais->type19.lon);
ais_addbits(bits, 85, 27, (uint64_t)ais->type19.lat);
ais_addbits(bits, 112, 12, (uint64_t)ais->type19.course);
ais_addbits(bits, 124, 9, (uint64_t)ais->type19.heading);
ais_addbits(bits, 133, 6, (uint64_t)ais->type19.second);
ais_addbits(bits, 139, 4, (uint64_t)ais->type19.regional);
ais_addchar(bits, 143, 20, ais->type19.shipname);
ais_addbits(bits, 263, 8, (uint64_t)ais->type19.shiptype);
ais_addbits(bits, 271, 9, (uint64_t)ais->type19.to_bow);
ais_addbits(bits, 280, 9, (uint64_t)ais->type19.to_stern);
ais_addbits(bits, 289, 6, (uint64_t)ais->type19.to_port);
ais_addbits(bits, 295, 6, (uint64_t)ais->type19.to_starboard);
ais_addbits(bits, 299, 4, (uint64_t)ais->type19.epfd);
ais_addbits(bits, 302, 1, (uint64_t)ais->type19.raim);
ais_addbits(bits, 305, 1, (uint64_t)ais->type19.dte);
ais_addbits(bits, 306, 1, (uint64_t)ais->type19.assigned);
/* ais_addbits(bits, 307, 5, (uint64_t)ais->type19.spare); */
len = 307 + 5;
break;
case 21: /* Aid-to-Navigation Report */
ais_addbits(bits, 38, 5, (uint64_t)ais->type21.aid_type);
ais_addchar(bits, 43, 20, ais->type21.name);
ais_addbits(bits, 163, 1, (uint64_t)ais->type21.accuracy);
ais_addbits(bits, 164, 28, (uint64_t)ais->type21.lon);
ais_addbits(bits, 192, 27, (uint64_t)ais->type21.lat);
ais_addbits(bits, 219, 9, (uint64_t)ais->type21.to_bow);
ais_addbits(bits, 228, 9, (uint64_t)ais->type21.to_stern);
ais_addbits(bits, 237, 6, (uint64_t)ais->type21.to_port);
ais_addbits(bits, 243, 6, (uint64_t)ais->type21.to_starboard);
ais_addbits(bits, 249, 4, (uint64_t)ais->type21.epfd);
ais_addbits(bits, 253, 6, (uint64_t)ais->type21.second);
ais_addbits(bits, 259, 1, (uint64_t)ais->type21.off_position);
ais_addbits(bits, 260, 8, (uint64_t)ais->type21.regional);
ais_addbits(bits, 268, 1, (uint64_t)ais->type21.raim);
ais_addbits(bits, 269, 1, (uint64_t)ais->type21.virtual_aid);
ais_addbits(bits, 270, 1, (uint64_t)ais->type21.assigned);
/* ais_addbits(bits, 271, 1, (uint64_t)ais->type21.spare); */
len = 271 + 1;
if (strlen(ais->type21.name) > 20) {
unsigned int extralen = (unsigned int)(strlen(ais->type21.name) - 20);
ais_addchar(bits, 272, extralen, ais->type21.name + 20);
len += extralen * 6;
}
break;
case 24: /* Class B CS Static Data Report Part 1 */
if (ais->type24.part == part_a) {
ais_addbits(bits, 38, 2, (uint64_t)0);
ais_addchar(bits, 40, 20, ais->type24.shipname);
/* ais_addbits(bits, 160, 8, (uint64_t)ais->type24.a.spare); */
len = 160;
}
break;
case 24 | AIS_MSG_PART2_FLAG: /* Class B CS Static Data Report Part 2 */
if ((ais->type24.part == part_b) || (ais->type24.part == both)) {
ais_addbits(bits, 38, 2, (uint64_t)1);
ais_addbits(bits, 40, 8, (uint64_t)ais->type24.shiptype);
ais_addchar(bits, 48, 3, &ais->type24.vendorid[0]);
ais_adddata(bits, 66, 3, &ais->type24.vendorid[3]);
ais_addchar(bits, 90, 7, ais->type24.callsign);
if (AIS_AUXILIARY_MMSI(ais->mmsi)) {
ais_addbits(bits, 132, 30, (uint64_t)ais->type24.mothership_mmsi);
} else {
ais_addbits(bits, 132, 9, (uint64_t)ais->type24.dim.to_bow);
ais_addbits(bits, 141, 9, (uint64_t)ais->type24.dim.to_stern);
ais_addbits(bits, 150, 6, (uint64_t)ais->type24.dim.to_port);
ais_addbits(bits, 156, 6, (uint64_t)ais->type24.dim.to_starboard);
}
/* ais_addbits(bits, 162, 6, ais->type24.b.spare); */
len = 162 + 6;
}
break;
case 27: /* Long Range AIS Broadcast message */
ais_addbits(bits, 38, 1, (uint64_t)ais->type27.accuracy);
ais_addbits(bits, 39, 1, (uint64_t)ais->type27.raim);
ais_addbits(bits, 40, 4, (uint64_t)ais->type27.status);
ais_addbits(bits, 44, 18, (uint64_t)ais->type27.lon);
ais_addbits(bits, 62, 17, (uint64_t)ais->type27.lat);
ais_addbits(bits, 79, 6, (uint64_t)ais->type27.speed);
ais_addbits(bits, 85, 9, (uint64_t)ais->type27.course);
ais_addbits(bits, 94, 1, (uint64_t)ais->type27.gnss);
break;
}
ais_binary_to_ascii(bits, len);
return len;
}
#endif /* AIVDM_ENABLE */
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