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   1 /*
   2  * Copyright © 2011 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;
  19 import java.text.*;
  20
  21 public abstract class AltosTelemetryRecord {
  22
  23         long    received_time;
  24         abstract public AltosRecord update_state(AltosRecord previous);
  25
  26         static boolean cksum(int[] bytes) {
  27                 int     sum = 0x5a;
  28                 for (int i = 1; i < bytes.length - 1; i++)
  29                         sum += bytes[i];
  30                 sum &= 0xff;
  31                 return sum == bytes[bytes.length - 1];
  32         }
  33
  34         final static int PKT_APPEND_STATUS_1_CRC_OK             = (1 << 7);
  35         final static int PKT_APPEND_STATUS_1_LQI_MASK           = (0x7f);
  36         final static int PKT_APPEND_STATUS_1_LQI_SHIFT          = 0;
  37
  38         final static int packet_type_TM_sensor = 0x01;
  39         final static int packet_type_Tm_sensor = 0x02;
  40         final static int packet_type_Tn_sensor = 0x03;
  41         final static int packet_type_configuration = 0x04;
  42         final static int packet_type_location = 0x05;
  43         final static int packet_type_satellite = 0x06;
  44         final static int packet_type_companion = 0x07;
  45         final static int packet_type_MM_sensor = 0x08;
  46
  47         static AltosTelemetryRecord parse_hex(String hex)  throws ParseException, AltosCRCException {
  48                 AltosTelemetryRecord    r;
  49
  50                 int[] bytes;
  51                 try {
  52                         bytes = AltosLib.hexbytes(hex);
  53                 } catch (NumberFormatException ne) {
  54                         throw new ParseException(ne.getMessage(), 0);
  55                 }
  56
  57                 /* one for length, one for checksum */
  58                 if (bytes[0] != bytes.length - 2)
  59                         throw new ParseException(String.format("invalid length %d != %d\n",
  60                                                                bytes[0],
  61                                                                bytes.length - 2), 0);
  62                 if (!cksum(bytes))
  63                         throw new ParseException(String.format("invalid line \"%s\"", hex), 0);
  64
  65                 int     rssi = AltosLib.int8(bytes, bytes.length - 3) / 2 - 74;
  66                 int     status = AltosLib.uint8(bytes, bytes.length - 2);
  67
  68                 if ((status & PKT_APPEND_STATUS_1_CRC_OK) == 0)
  69                         throw new AltosCRCException(rssi);
  70
  71                 /* length, data ..., rssi, status, checksum -- 4 bytes extra */
  72                 switch (bytes.length) {
  73                 case AltosLib.ao_telemetry_standard_len + 4:
  74                         int     type = AltosLib.uint8(bytes, 4 + 1);
  75                         switch (type) {
  76                         case packet_type_TM_sensor:
  77                         case packet_type_Tm_sensor:
  78                         case packet_type_Tn_sensor:
  79                         case packet_type_MM_sensor:
  80                                 r = new AltosTelemetryRecordSensor(bytes, rssi);
  81                                 break;
  82                         case packet_type_configuration:
  83                                 r = new AltosTelemetryRecordConfiguration(bytes);
  84                                 break;
  85                         case packet_type_location:
  86                                 r = new AltosTelemetryRecordLocation(bytes);
  87                                 break;
  88                         case packet_type_satellite:
  89                                 r = new AltosTelemetryRecordSatellite(bytes);
  90                                 break;
  91                         case packet_type_companion:
  92                                 r = new AltosTelemetryRecordCompanion(bytes);
  93                                 break;
  94                         default:
  95                                 r = new AltosTelemetryRecordRaw(bytes);
  96                                 break;
  97                         }
  98                         break;
  99                 case AltosLib.ao_telemetry_0_9_len + 4:
 100                         r = new AltosTelemetryRecordLegacy(bytes, rssi, status);
 101                         break;
 102                 case AltosLib.ao_telemetry_0_8_len + 4:
 103                         r = new AltosTelemetryRecordLegacy(bytes, rssi, status);
 104                         break;
 105                 default:
 106                         throw new ParseException(String.format("Invalid packet length %d", bytes.length), 0);
 107                 }
 108                 r.received_time = System.currentTimeMillis();
 109                 return r;
 110         }
 111
 112         public static AltosTelemetryRecord parse(String line) throws ParseException, AltosCRCException {
 113                 AltosTelemetryRecord    r;
 114
 115                 String[] word = line.split("\\s+");
 116                 int i =0;
 117                 if (word[i].equals("CRC") && word[i+1].equals("INVALID")) {
 118                         i += 2;
 119                         AltosParse.word(word[i++], "RSSI");
 120                         throw new AltosCRCException(AltosParse.parse_int(word[i++]));
 121                 }
 122
 123                 if (word[i].equals("TELEM"))
 124                         r = parse_hex(word[i+1]);
 125                 else
 126                         r = new AltosTelemetryRecordLegacy(line);
 127                 return r;
 128         }
 129 }