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   1 /*
   2  * Copyright © 2010 Keith Packard <keithp@keithp.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  17  */
  18
  19 package org.altusmetrum.altoslib_11;
  20
  21 import java.text.*;
  22
  23 /*
  24  * Telemetry data contents
  25  */
  26
  27 public abstract class AltosTelemetry implements AltosStateUpdate {
  28
  29         /* All telemetry packets have these fields */
  30         public int      tick;
  31         public int      serial;
  32         public int      rssi;
  33         public int      status;
  34
  35         /* Mark when we received the packet */
  36         long            received_time;
  37
  38         static boolean cksum(int[] bytes) {
  39                 int     sum = 0x5a;
  40                 for (int i = 1; i < bytes.length - 1; i++)
  41                         sum += bytes[i];
  42                 sum &= 0xff;
  43                 return sum == bytes[bytes.length - 1];
  44         }
  45
  46         public void update_state(AltosState state) {
  47                 state.set_serial(serial);
  48                 if (state.state() == AltosLib.ao_flight_invalid)
  49                         state.set_state(AltosLib.ao_flight_startup);
  50                 state.set_tick(tick);
  51                 state.set_rssi(rssi, status);
  52                 state.set_received_time(received_time);
  53         }
  54
  55         final static int PKT_APPEND_STATUS_1_CRC_OK             = (1 << 7);
  56         final static int PKT_APPEND_STATUS_1_LQI_MASK           = (0x7f);
  57         final static int PKT_APPEND_STATUS_1_LQI_SHIFT          = 0;
  58
  59         final static int packet_type_TM_sensor = 0x01;
  60         final static int packet_type_Tm_sensor = 0x02;
  61         final static int packet_type_Tn_sensor = 0x03;
  62         final static int packet_type_configuration = 0x04;
  63         final static int packet_type_location = 0x05;
  64         final static int packet_type_satellite = 0x06;
  65         final static int packet_type_companion = 0x07;
  66         final static int packet_type_mega_sensor = 0x08;
  67         final static int packet_type_mega_data = 0x09;
  68         final static int packet_type_metrum_sensor = 0x0a;
  69         final static int packet_type_metrum_data = 0x0b;
  70         final static int packet_type_mini = 0x10;
  71
  72         static AltosTelemetry parse_hex(String hex)  throws ParseException, AltosCRCException {
  73                 AltosTelemetry  telem = null;
  74
  75                 int[] bytes;
  76                 try {
  77                         bytes = AltosLib.hexbytes(hex);
  78                 } catch (NumberFormatException ne) {
  79                         throw new ParseException(ne.getMessage(), 0);
  80                 }
  81
  82                 /* one for length, one for checksum */
  83                 if (bytes[0] != bytes.length - 2)
  84                         throw new ParseException(String.format("invalid length %d != %d\n",
  85                                                                bytes[0],
  86                                                                bytes.length - 2), 0);
  87                 if (!cksum(bytes))
  88                         throw new ParseException(String.format("invalid line \"%s\"", hex), 0);
  89
  90                 int     rssi = AltosLib.int8(bytes, bytes.length - 3) / 2 - 74;
  91                 int     status = AltosLib.uint8(bytes, bytes.length - 2);
  92
  93                 if ((status & PKT_APPEND_STATUS_1_CRC_OK) == 0)
  94                         throw new AltosCRCException(rssi);
  95
  96                 /* length, data ..., rssi, status, checksum -- 4 bytes extra */
  97                 switch (bytes.length) {
  98                 case AltosLib.ao_telemetry_standard_len + 4:
  99                         telem = AltosTelemetryStandard.parse_hex(bytes);
 100                         break;
 101                 case AltosLib.ao_telemetry_0_9_len + 4:
 102                         telem = new AltosTelemetryLegacy(bytes);
 103                         break;
 104                 case AltosLib.ao_telemetry_0_8_len + 4:
 105                         telem = new AltosTelemetryLegacy(bytes);
 106                         break;
 107                 default:
 108                         throw new ParseException(String.format("Invalid packet length %d", bytes.length), 0);
 109                 }
 110                 if (telem != null) {
 111                         telem.received_time = System.currentTimeMillis();
 112                         telem.rssi = rssi;
 113                         telem.status = status;
 114                 }
 115                 return telem;
 116         }
 117
 118         public static int extend_height(AltosState state, int height_16) {
 119                 double  compare_height;
 120                 int     height = height_16;
 121
 122                 if (state.gps != null && state.gps.alt != AltosLib.MISSING) {
 123                         compare_height = state.gps_height();
 124                 } else {
 125                         compare_height = state.height();
 126                 }
 127
 128                 if (compare_height != AltosLib.MISSING) {
 129                         int     high_bits = (int) Math.floor (compare_height / 65536.0);
 130
 131                         height = (high_bits << 16) | (height_16 & 0xffff);
 132
 133                         if (Math.abs(height + 65536 - compare_height) < Math.abs(height - compare_height))
 134                                 height += 65536;
 135                         else if (Math.abs(height - 65536 - compare_height) < Math.abs(height - compare_height))
 136                                 height -= 65536;
 137                 }
 138                 return height;
 139         }
 140
 141         public static AltosTelemetry parse(String line) throws ParseException, AltosCRCException {
 142                 String[] word = line.split("\\s+");
 143                 int i =0;
 144
 145                 if (word[i].equals("CRC") && word[i+1].equals("INVALID")) {
 146                         i += 2;
 147                         AltosParse.word(word[i++], "RSSI");
 148                         throw new AltosCRCException(AltosParse.parse_int(word[i++]));
 149                 }
 150
 151                 AltosTelemetry telem;
 152
 153                 if (word[i].equals("TELEM")) {
 154                         telem = parse_hex(word[i+1]);
 155                 } else {
 156                         telem = new AltosTelemetryLegacy(line);
 157                 }
 158                 return telem;
 159         }
 160 }