Add Check Hex String block

Checks data from input port from "Starting Position" on for a "Hex String".

    If the incoming string matches the entered string, data will be passed to output port "ok", else to "fail".

    Example for a match:

    Entered block parameters:
    "Hex String" = 4450304E4641	(ASCII for DP0NFA)
    "Starting Position" = 10		(Starts counting from 0 on)

    Data coming into input port: "02300400000000003D0E4450304E4641000100C300B7142EF90F9C06290000000"

(cherry picked from commit e191a1e)

grc/CMakeLists.txt

@@ -36,6 +36,7 @@ install(FILES
     satellites_check_crc16_ccitt_false.block.yml
     satellites_check_crc.block.yml
     satellites_check_eseo_crc.block.yml
+    satellites_check_hex_string.block.yml
     satellites_check_swiatowid_crc.block.yml
     satellites_check_tt64_crc.block.yml
     satellites_convolutional_encoder.block.yml

grc/satellites_check_hex_string.block.yml

@@ -0,0 +1,48 @@
+# auto-generated by grc.converter
+
+id: satellites_check_hex_string
+label: Check Hex String
+category: '[Satellites]/Misc'
+
+parameters:
+-   id: hexstring
+    label: Hex String
+    dtype: string
+    default: "c0ffee"
+
+-   id: startindex
+    label: Starting Position
+    dtype: int
+    default: 0
+
+inputs:
+-   domain: message
+    id: in
+
+outputs:
+-   domain: message
+    id: ok
+    optional: true
+-   domain: message
+    id: fail
+    optional: true
+
+templates:
+    imports: import satellites
+    make: satellites.check_hex_string(${hexstring}, ${startindex})
+
+documentation: |-
+    Checks data from input port from "Starting Position" on for a "Hex String".
+
+    If the incoming string matches the entered string, data will be passed to output port "ok", else to "fail".
+
+    Example for a match:
+
+    Entered block parameters:
+    "Hex String" = 4450304E4641	(ASCII for DP0NFA)
+    "Starting Position" = 10		(Starts counting from 0 on)
+
+    Data coming into input port: "02300400000000003D0E4450304E4641000100C300B7142EF90F9C06290000000"
+    
+
+file_format: 1

python/CMakeLists.txt

@@ -51,6 +51,7 @@ GR_PYTHON_INSTALL(
     check_crc16_ccitt_false.py
     check_crc.py
     check_eseo_crc.py
+    check_hex_string.py
     check_swiatowid_crc.py
     check_tt64_crc.py
     crc32c.py

python/__init__.py

@@ -61,6 +61,7 @@
 from .check_crc16_ccitt_false import check_crc16_ccitt_false
 from .check_crc import check_crc
 from .check_eseo_crc import check_eseo_crc
+from .check_hex_string import check_hex_string
 from .check_swiatowid_crc import check_swiatowid_crc
 from .check_tt64_crc import check_tt64_crc
 from .eseo_line_decoder import eseo_line_decoder

python/check_hex_string.py

@@ -0,0 +1,50 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+# Copyright 2024 DL7NDR Daniel (https://www.qrz.com/db/DL7NDR)
+#
+# This file is part of gr-satellites
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+
+
+from gnuradio import gr
+import pmt
+
+
+class check_hex_string(gr.basic_block):
+    """
+    Checks incoming hex string from a specified position
+    for a given hex string.
+    """
+    def __init__(self, hexstring, startindex=0):
+        gr.basic_block.__init__(
+            self,
+            name='check_hex_string',
+            in_sig=[],
+            out_sig=[])
+
+        self.hexstring = bytes.fromhex(hexstring)
+        self.startindex = startindex
+
+        self.message_port_register_in(pmt.intern('in'))
+        self.set_msg_handler(pmt.intern('in'), self.handle_msg)
+        self.message_port_register_out(pmt.intern('ok'))
+        self.message_port_register_out(pmt.intern('fail'))
+
+    def handle_msg(self, msg_pmt):
+        msg = pmt.cdr(msg_pmt)
+        if not pmt.is_u8vector(msg):
+            print('[ERROR] Received invalid message type. Expected u8vector')
+            return
+        packet = bytes(pmt.u8vector_elements(msg))
+
+        hex_str = packet[self.startindex:self.startindex + len(self.hexstring)]
+
+        if hex_str == self.hexstring:
+            # match
+            self.message_port_pub(pmt.intern('ok'), msg_pmt)
+        else:
+            # no match
+            self.message_port_pub(pmt.intern('fail'), msg_pmt)