feat(dmr): decode CACH and slot type

DMRDecoder.pas

@@ -18,7 +18,7 @@ unit DMRDecoder;
 interface
 
 uses
-  Classes, SysUtils, SyncObjs, Math, DMRBindings;
+  Classes, SysUtils, SyncObjs, Math, DMRBindings, DMRProtocol;
 
 const
   DMR_INPUT_RATE       = 48000;
@@ -49,6 +49,13 @@ type
     SignalRMS: Single;
     LastSyncAgeMs: QWord;
     VocoderAvailable: Boolean;
+    CACHValid: Boolean;
+    Slot: Integer;
+    LCSS: Integer;
+    SlotTypeValid: Boolean;
+    ColorCode: Integer;
+    DataType: Integer;
+    SlotTypeCorrectedBits: Integer;
   end;
 
   TDMRDecoder = class;
@@ -90,9 +97,10 @@ type
     FMagSum: array[0..DMR_SAMPLES_PER_SYM - 1] of Double;
     FBestSyncQuality: Double;
     FTrackPhase: Integer;
-    FCurrentBurst: array[0..DMR_BURST_DIBITS - 1] of Byte;
+    FCurrentBurst: TDMRDibitBurst;
     FCurrentBurstPos: Integer;
-    FLastBurst: array[0..DMR_BURST_DIBITS - 1] of Byte;
+    FLastBurst: TDMRDibitBurst;
+    FLastBurstInfo: TDMRBurstInfo;
     FBurstCount: QWord;
     FRMSSq: Double;
 
@@ -250,6 +258,7 @@ begin
     FBestSyncQuality := 0;
     FillChar(FCurrentBurst, SizeOf(FCurrentBurst), 0);
     FillChar(FLastBurst, SizeOf(FLastBurst), 0);
+    FillChar(FLastBurstInfo, SizeOf(FLastBurstInfo), 0);
     FTrackPhase := -1;
     FCurrentBurstPos := 0;
     FBurstCount := 0;
@@ -435,6 +444,7 @@ end;
 procedure TDMRDecoder.CompleteBurst;
 begin
   Move(FCurrentBurst[0], FLastBurst[0], SizeOf(FLastBurst));
+  DMRParseBurst(FLastBurst, FLastBurstInfo);
   Inc(FBurstCount);
   FCurrentBurstPos := 0;
 end;
@@ -494,6 +504,21 @@ begin
                   (S.LastSyncAgeMs <= DMR_SYNC_HOLD_MS);
       S.SignalRMS := Sqrt(FRMSSq);
       S.VocoderAvailable := FMbe <> nil;
+      // CACH exists on base-station bursts. On MS/direct bursts the same
+      // positions are payload/guard symbols and can accidentally form a
+      // syntactically valid Hamming word.
+      S.CACHValid := FLastBurstInfo.CACH.Valid and
+                     (FSyncKind in [dskBSData, dskBSVoice]);
+      S.Slot := FLastBurstInfo.CACH.Slot;
+      S.LCSS := FLastBurstInfo.CACH.LCSS;
+      // Voice sync replaces the centre Slot Type field. Do not expose a
+      // chance Golay match from AMBE bits as a real colour/data type.
+      S.SlotTypeValid := FLastBurstInfo.SlotType.Valid and
+                         (FSyncKind in [dskBSData, dskMSData,
+                          dskDirectTS1Data, dskDirectTS2Data]);
+      S.ColorCode := FLastBurstInfo.SlotType.ColorCode;
+      S.DataType := FLastBurstInfo.SlotType.DataType;
+      S.SlotTypeCorrectedBits := FLastBurstInfo.SlotType.CorrectedBits;
     finally
       FStatusLock.Leave;
     end;