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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; version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  16  */
  17
  18 package org.altusmetrum.altoslib_1;
  19
  20 import java.text.*;
  21
  22 /*
  23  * Telemetry data contents
  24  */
  25
  26 public abstract class AltosTelemetry implements AltosStateUpdate {
  27
  28         /* All telemetry packets have these fields */
  29         public int      tick;
  30         public int      serial;
  31         public int      rssi;
  32         public int      status;
  33
  34         /* Mark when we received the packet */
  35         long            received_time;
  36
  37         static boolean cksum(int[] bytes) {
  38                 int     sum = 0x5a;
  39                 for (int i = 1; i < bytes.length - 1; i++)
  40                         sum += bytes[i];
  41                 sum &= 0xff;
  42                 return sum == bytes[bytes.length - 1];
  43         }
  44
  45         public void update_state(AltosState state) {
  46                 state.set_serial(serial);
  47                 state.set_tick(tick);
  48                 state.set_rssi(rssi, status);
  49                 state.set_received_time(received_time);
  50         }
  51
  52         final static int PKT_APPEND_STATUS_1_CRC_OK             = (1 << 7);
  53         final static int PKT_APPEND_STATUS_1_LQI_MASK           = (0x7f);
  54         final static int PKT_APPEND_STATUS_1_LQI_SHIFT          = 0;
  55
  56         final static int packet_type_TM_sensor = 0x01;
  57         final static int packet_type_Tm_sensor = 0x02;
  58         final static int packet_type_Tn_sensor = 0x03;
  59         final static int packet_type_configuration = 0x04;
  60         final static int packet_type_location = 0x05;
  61         final static int packet_type_satellite = 0x06;
  62         final static int packet_type_companion = 0x07;
  63         final static int packet_type_mega_sensor = 0x08;
  64         final static int packet_type_mega_data = 0x09;
  65         final static int packet_type_metrum_sensor = 0x0a;
  66         final static int packet_type_metrum_data = 0x0b;
  67         final static int packet_type_mini = 0x10;
  68
  69         static AltosTelemetry parse_hex(String hex)  throws ParseException, AltosCRCException {
  70                 AltosTelemetry  telem = null;
  71
  72                 int[] bytes;
  73                 try {
  74                         bytes = AltosLib.hexbytes(hex);
  75                 } catch (NumberFormatException ne) {
  76                         throw new ParseException(ne.getMessage(), 0);
  77                 }
  78
  79                 /* one for length, one for checksum */
  80                 if (bytes[0] != bytes.length - 2)
  81                         throw new ParseException(String.format("invalid length %d != %d\n",
  82                                                                bytes[0],
  83                                                                bytes.length - 2), 0);
  84                 if (!cksum(bytes))
  85                         throw new ParseException(String.format("invalid line \"%s\"", hex), 0);
  86
  87                 int     rssi = AltosLib.int8(bytes, bytes.length - 3) / 2 - 74;
  88                 int     status = AltosLib.uint8(bytes, bytes.length - 2);
  89
  90                 if ((status & PKT_APPEND_STATUS_1_CRC_OK) == 0)
  91                         throw new AltosCRCException(rssi);
  92
  93                 /* length, data ..., rssi, status, checksum -- 4 bytes extra */
  94                 switch (bytes.length) {
  95                 case AltosLib.ao_telemetry_standard_len + 4:
  96                         telem = AltosTelemetryStandard.parse_hex(bytes);
  97                         break;
  98                 case AltosLib.ao_telemetry_0_9_len + 4:
  99                         telem = new AltosTelemetryLegacy(bytes);
 100                         break;
 101                 case AltosLib.ao_telemetry_0_8_len + 4:
 102                         telem = new AltosTelemetryLegacy(bytes);
 103                         break;
 104                 default:
 105                         throw new ParseException(String.format("Invalid packet length %d", bytes.length), 0);
 106                 }
 107                 if (telem != null) {
 108                         telem.received_time = System.currentTimeMillis();
 109                         telem.rssi = rssi;
 110                         telem.status = status;
 111                 }
 112                 return telem;
 113         }
 114
 115         public static AltosTelemetry parse(String line) throws ParseException, AltosCRCException {
 116                 String[] word = line.split("\\s+");
 117                 int i =0;
 118
 119                 if (word[i].equals("CRC") && word[i+1].equals("INVALID")) {
 120                         i += 2;
 121                         AltosParse.word(word[i++], "RSSI");
 122                         throw new AltosCRCException(AltosParse.parse_int(word[i++]));
 123                 }
 124
 125                 AltosTelemetry telem;
 126
 127                 if (word[i].equals("TELEM")) {
 128                         telem = parse_hex(word[i+1]);
 129                 } else {
 130                         telem = new AltosTelemetryLegacy(line);
 131                 }
 132                 return telem;
 133         }
 134 }