add conversion checks based on feedback from KelseyCreekSoftware

Author: Teque5

docs/source/converters.rst

@@ -97,10 +97,10 @@ BLUE Converter
 
 The BLUE converter handles CDIF (.cdif) recordings while placing BLUE header information into the following global fields:
 
-* ``blue:fixed`` - fixed header information (at start of file)
-* ``blue:adjunct`` - adjunct header information (after fixed header)
-* ``blue:extended`` - extended header information (at end of file)
-* ``blue:keywords`` - user-defined key-value pairs
+* ``blue:fixed`` - Fixed header information (at start of file).
+* ``blue:adjunct`` - Adjunct header information (after fixed header).
+* ``blue:extended`` - Extended header information (at end of file). Note any duplicate fields will have a suffix like ``_1``, ``_2``, etc appended.
+* ``blue:keywords`` - User-defined key-value pairs.
 
 .. autofunction:: sigmf.convert.blue.blue_to_sigmf
 

sigmf/convert/__main__.py

@@ -35,8 +35,9 @@ def main() -> None:
     parser.add_argument("input", type=str, help="Input recording path")
     parser.add_argument("output", type=str, help="Output SigMF path (no extension)")
     parser.add_argument("-v", "--verbose", action="count", default=0, help="Increase verbosity level")
-    parser.add_argument("-a", "--archive", action="store_true", help="Output .sigmf archive only")
-    parser.add_argument(
+    exclusive_group = parser.add_mutually_exclusive_group()
+    exclusive_group.add_argument("-a", "--archive", action="store_true", help="Output .sigmf archive only")
+    exclusive_group.add_argument(
         "--ncd", action="store_true", help="Output .sigmf-meta only and process as a Non-Conforming Dataset (NCD)"
     )
     parser.add_argument("--version", action="version", version=f"%(prog)s v{toolversion}")
@@ -52,16 +53,19 @@ def main() -> None:
     input_path = Path(args.input)
     output_path = Path(args.output)
 
-    # validate that ncd files are in same directory as input
+    # for ncd check that input & output files are in same directory
     if args.ncd and input_path.parent.resolve() != output_path.parent.resolve():
         raise SigMFConversionError(
             f"NCD files must be in the same directory as input file. "
             f"Input: {input_path.parent.resolve()}, Output: {output_path.parent.resolve()}"
         )
 
+    # check that the output path is a file and not a directory
+    if output_path.is_dir():
+        raise SigMFConversionError(f"Output path must be a filename, not a directory: {output_path}")
+
     # detect file type using magic bytes (same logic as fromfile())
     magic_bytes = get_magic_bytes(input_path, count=4, offset=0)
-
     if magic_bytes == b"RIFF":
         # WAV file
         _ = wav_to_sigmf(wav_path=input_path, out_path=output_path, create_archive=args.archive, create_ncd=args.ncd)