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sdrtrunk/src/test/java/io/github/dsheirer
Christopher Smith fbc54a38dd LRRP: decode request token values as 7-bit varints and correct request token names (#2507)
Motorola LRRP request tokens that carry an integer (trigger interval
0x31, trigger distance 0x78 and the unknown parameters 0x42 / 0x44)
encode it as a 7-bit variable length integer: each byte holds seven
value bits, most significant group first, and the high bit of a byte
flags a continuation byte.  The parser read a single byte, so a real
triggered location start request

  09 11 22 03 FF FF EE 52 44 64 42 9C 10 62 57 34 31 84 58

was logged as

  ID:15663103 TRIGGER ON GPIO TRIGGER EVERY:132 SECS REQUESTED TOKENS
  [TIME,REQUEST-64,REQUEST-62,HORIZONTAL DIRECTION,TIMESTAMP,
  UNRECOGNIZED(10,44,58,9C)]

and now decodes to

  ID:FFFFEE PERIODIC INTERVAL:600 SECS PARAM-42:3600 PARAM-44:100
  REQUESTED TOKENS [TIME,HORIZONTAL SPEED,HORIZONTAL DIRECTION]

The encoding and the token names follow node-dmr-lib (LRRP.js
parseLRRPInt/toLRRPInt and its quoted TRBONet captures, DMRConst.js)
and Moto.Net (LRRPPacket.cs "using VLQ for most of the fields").

- Add VarInt, a shared 7-bit varint reader, and VarIntToken, a token
  base class whose byte length is measured from the value and bounded
  by the remaining payload.  Use them for 0x31, 0x78, 0x42 and 0x44.
- Add TokenType.fromRequestValue(): 0x34 is the periodic trigger flag
  in a request and the timestamp in a response.  TokenFactory accepts
  the resolved TokenType so the request path is not re-resolved.
- Rename request tokens: 0x31 TRIGGER_INTERVAL (TriggerInterval),
  0x4A TRIGGER_CONDITION (TriggerCondition: 02 emergency, 42 pin
  status change, 50 PTT, 51 PTT emergency), 0x78 TRIGGER_DISTANCE
  (TriggerDistance), 0x62 HORIZONTAL_SPEED.  0x42 and 0x44 become
  REQUEST_PARAMETER_42/44 (RequestParameter) with an optional varint
  value; their meaning is unknown (observed 3600 and 100).  Remove
  TriggerGpio and TriggerOnMove.
- Identity: assemble the request id big-endian (it was accumulated
  LSB-first), render it in hex, and clamp the read to the message.
- RequestedTokens: keep a list that holds only unrecognized ids; add
  getters for the recognized and unrecognized lists.
- Remove leftover debug locals from LRRPPacket.parseTokens().
- Add LRRPPacketTest (both captured bodies plus two copies with a
  corrupted type byte) and VarIntTest.

Built with the project's Gradle build (JDK 27 toolchain, in Docker);
compileJava, compileTestJava and the 9 new tests pass.

Co-authored-by: csmith_ai <carrottop@gmail.com>
Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>
2026-11-13 02:33:52 -05:00
..
2026-11-08 06:03:13 -05:00