From a10640c60c524a158eacfdaf6a98440236415430 Mon Sep 17 00:00:00 2001
From: Wojciech Kaczmarski <w.kaczmarski@teletra.pl>
Date: Mon, 18 Aug 2025 14:20:03 +0200
Subject: [PATCH] decoder: added message output

src, dst, type, meta
---
 .gitignore                      |  1 +
 examples/m17_loopback_noisy.grc | 24 ++++++++++++++++++++----
 grc/m17_m17_decoder.block.yml   |  5 +++++
 lib/m17_decoder_impl.cc         | 23 ++++++++++++++++++++---
 4 files changed, 46 insertions(+), 7 deletions(-)

diff --git a/.gitignore b/.gitignore
index ee61bf2..4a034c1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@
 *.pyo
 build*/
 examples/*.py
+.vscode/*
diff --git a/examples/m17_loopback_noisy.grc b/examples/m17_loopback_noisy.grc
index 79e84e1..75942a9 100644
--- a/examples/m17_loopback_noisy.grc
+++ b/examples/m17_loopback_noisy.grc
@@ -178,9 +178,24 @@ blocks:
     bus_sink: false
     bus_source: false
     bus_structure: null
-    coordinate: [960, 228.0]
+    coordinate: [960, 212.0]
     rotation: 0
     state: disabled
+- name: blocks_message_debug_0
+  id: blocks_message_debug
+  parameters:
+    affinity: ''
+    alias: ''
+    comment: ''
+    en_uvec: 'True'
+    log_level: info
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [960, 304.0]
+    rotation: 0
+    state: enabled
 - name: blocks_null_sink_0
   id: blocks_null_sink
   parameters:
@@ -195,7 +210,7 @@ blocks:
     bus_sink: false
     bus_source: false
     bus_structure: null
-    coordinate: [960, 192.0]
+    coordinate: [960, 168.0]
     rotation: 0
     state: enabled
 - name: blocks_throttle2_0
@@ -294,8 +309,8 @@ blocks:
     alias: ''
     callsign: 'True'
     comment: ''
-    debug_ctrl: 'True'
-    debug_data: 'True'
+    debug_ctrl: 'False'
+    debug_data: 'False'
     encr_type: '0'
     key: ''
     maxoutbuf: '0'
@@ -417,6 +432,7 @@ connections:
 - [m17_m17_coder_0, '0', blocks_add_xx_0, '0']
 - [m17_m17_decoder_0, '0', blocks_file_sink_0, '0']
 - [m17_m17_decoder_0, '0', blocks_null_sink_0, '0']
+- [m17_m17_decoder_0, fields, blocks_message_debug_0, print]
 
 metadata:
   file_format: 1
diff --git a/grc/m17_m17_decoder.block.yml b/grc/m17_m17_decoder.block.yml
index 4b16f8f..4fe941b 100644
--- a/grc/m17_m17_decoder.block.yml
+++ b/grc/m17_m17_decoder.block.yml
@@ -79,6 +79,11 @@ outputs:
   dtype: byte
   vlen: 1
   optional: 0
+- label: fields
+  domain: message
+  id: fields
+  type: message
+  optional: true
 
 documentation: |-
      The decoder block accepts two boolean debugging flags defining which messages are displayed in the console when messages are received, and a threshold parameter. The threshold defines a value below which the incoming message is detected. It is based on the Euclidean distance (L^2 norm) between the received symbol stream and protocol-defined syncronization patterns. Ideally, the distance would reach 0.0 for an ideal match. A default threshold value of 2.0 is selected.
diff --git a/lib/m17_decoder_impl.cc b/lib/m17_decoder_impl.cc
index 2d106cd..d4dd9f4 100644
--- a/lib/m17_decoder_impl.cc
+++ b/lib/m17_decoder_impl.cc
@@ -67,6 +67,8 @@ namespace gr
 			set_key(key);
 			set_encr_type(encr_type);
 			_expected_next_fn = 0;
+
+			message_port_register_out(pmt::mp("fields"));
 		}
 
 		/*
@@ -216,7 +218,7 @@ namespace gr
 		m17_decoder_impl::forecast(int noutput_items,
 								   gr_vector_int &ninput_items_required)
 		{
-			ninput_items_required[0] = 1; //  noutput_items;
+			ninput_items_required[0] = 1; // do work only if there is at least one symbol available
 		}
 
 		// this is generating a correct seed value based on the fn value,
@@ -541,10 +543,25 @@ namespace gr
 							// debug - dump LICH
 							if (lich_chunks_rcvd == 0x3F) // all 6 chunks received?
 							{
+								// handle message output
+								pmt::pmt_t msg;
+								decode_callsign_bytes(d_dst, _lsf.dst);
+								decode_callsign_bytes(d_src, _lsf.src);
+
+								pmt::pmt_t dict = pmt::make_dict();
+								dict = pmt::dict_add(dict, pmt::mp("src"), pmt::intern((char *)d_src));
+								dict = pmt::dict_add(dict, pmt::mp("dst"), pmt::intern((char *)d_dst));
+
+								msg = pmt::init_u8vector(2, _lsf.type);
+								dict = pmt::dict_add(dict, pmt::mp("type"), msg);
+								msg = pmt::init_u8vector(14, _lsf.meta);
+								dict = pmt::dict_add(dict, pmt::mp("meta"), msg);
+
+								message_port_pub(pmt::mp("fields"), dict);
+
+								// debug data display
 								if (_callsign == true)
 								{
-									decode_callsign_bytes(d_dst, _lsf.dst);
-									decode_callsign_bytes(d_src, _lsf.src);
 									if (_debug_ctrl == true)
 									{
 										printf("DST: %-9s ", d_dst); // DST