Add a '-c' flag to the command line

Author: rhpvorderman

src/isal/igzip.py

@@ -276,6 +276,8 @@ def main():
         "-d", "--decompress", action="store_false",
         dest="compress",
         help="Decompress the file instead of compressing.")
+    parser.add_argument("-c", "--stdout", action="store_true",
+                        help="write on standard output")
     args = parser.parse_args()
 
     compresslevel = args.compresslevel or _COMPRESS_LEVEL_TRADEOFF
@@ -291,14 +293,21 @@ def main():
     else:
         if args.compress:
             in_file = io.open(args.file, mode="rb")
-            out_file = open(args.file + ".gz", mode="wb",
-                            compresslevel=compresslevel)
+            if args.stdout:
+                out_file = IGzipFile(mode="wb", compresslevel=compresslevel,
+                                     fileobj=sys.stdout.buffer)
+            else:
+                out_file = open(args.file + ".gz", mode="wb",
+                                compresslevel=compresslevel)
         else:
             base, extension = os.path.splitext(args.file)
             if extension != ".gz":
                 raise ValueError(f"filename doesn't end in .gz: {args.file}")
             in_file = open(args.file, "rb")
-            out_file = io.open(base, "wb")
+            if args.stdout:
+                out_file = sys.stdout.buffer
+            else:
+                out_file = io.open(base, "wb")
     try:
         while True:
             block = in_file.read(BUFFER_SIZE)

tests/test_igzip_cli.py

@@ -91,3 +91,23 @@ def test_decompress_infile_outfile_error(capsysbinary):
     assert error.match("filename doesn't end")
     out, err = capsysbinary.readouterr()
     assert out == b''
+
+
+def test_decompress_infile_stdout(capsysbinary, tmp_path):
+    test_gz = tmp_path / "test.gz"
+    test_gz.write_bytes(gzip.compress(DATA))
+    sys.argv = ['', '-cd', str(test_gz)]
+    igzip.main()
+    out, err = capsysbinary.readouterr()
+    assert out == DATA
+    assert err == b''
+
+
+def test_compress_infile_stdout(capsysbinary, tmp_path):
+    test = tmp_path / "test"
+    test.write_bytes(DATA)
+    sys.argv = ['', '-c', str(test)]
+    igzip.main()
+    out, err = capsysbinary.readouterr()
+    assert gzip.decompress(out) == DATA
+    assert err == b''