# HG changeset patch
# User Henry S. Thompson <ht@inf.ed.ac.uk>
# Date 1618597680 0
# Node ID d48537c4cbae45a9e98ae735ddd3ba28edac3818
# Parent  1a4c5fdc29238af65c44b964d9ed798af6e47181
triple args checked, filename opened

diff -r 1a4c5fdc2923 -r d48537c4cbae bin/ix.py
--- a/bin/ix.py	Fri Apr 16 13:15:23 2021 +0000
+++ b/bin/ix.py	Fri Apr 16 18:28:00 2021 +0000
@@ -52,11 +52,17 @@
                     nargs='?')
 parser.add_argument('filename',
                     help='name of gzipped Common Crawl WARC-format file',
-                    nargs='?')
+                    nargs='?',
+                    type=argparse.FileType('rb',0))
 # Hack the order of optional and positional in the help output
 parser._action_groups.sort(key=lambda g:g.title)
 #parser.print_help()
 pa=parser.parse_args(sys.argv[1:])
 # We have to enforce our own check..
-print(pa)
+print(pa,file=sys.stderr)
+if pa.length is not None and (
+  pa.offset is None or pa.filename is None):
+  parser.error("length, offset and filename must all be supplied together")
+  
+buf=bytearray(1024*1024)