Wrote utility to create empty files.

1 files changed, 89 insertions, 0 deletions

diff --git a/create-file b/create-file
new file mode 100755
index 0000000..dd41073
--- /dev/null
+++ b/create-file
@@ -0,0 +1,89 @@
+#!/usr/bin/python
+#
+# create-file -- create a file full of zeroes
+# Copyright (C) 2009  Lars Wirzenius
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+import optparse
+import os
+
+
+def parse_size(size):
+    sizes = (
+        ("k", 1000),
+        ("m", 1000**2),
+        ("g", 1000**3),
+
+        ("kb", 1000),
+        ("mb", 1000**2),
+        ("gb", 1000**3),
+
+        ("kib", 1024),
+        ("mib", 1024**2),
+        ("gib", 1024**3),
+        )
+    size = size.lower()
+    for suffix, x in sizes:
+        if size.endswith(suffix):
+            amount = int(size[:-len(suffix)].strip())
+            return amount * x
+    return int(size.strip())
+
+
+def parse_args():
+    parser = optparse.OptionParser()
+    
+    parser.epilog = ("SIZE is a size. Default is in bytes, use suffixes "
+                     "kB/MB/GB for multiples of 1000, KiB/MiB/GiB for "
+                     "multiples of 1024. Only integers supported.")
+    
+    parser.add_option("--sparse", action="store_true",
+                      help="create a sparse file")
+                     
+    parser.add_option("--size", metavar="SIZE", default="0",
+                      help="create a file of size SIZE")
+
+    options, filenames = parser.parse_args()
+    options.size = parse_size(options.size)
+
+    return options, filenames
+
+
+def create_file(filename, options):
+    fd = os.open(filename, os.O_WRONLY | os.O_CREAT | os.O_EXCL, 0666)
+    if options.sparse:
+        if options.size > 0:
+            os.lseek(fd, options.size - 1, os.SEEK_SET)
+            os.write(fd, "\0")
+    else:
+        bytes = options.size
+        data = "\0" * 1024**2
+        while bytes >= len(data):
+            os.write(fd, data)
+            bytes -= len(data)
+        if bytes > 0:
+            os.write(fd, data[:bytes])
+    os.close(fd)
+
+
+def main():
+    options, filenames = parse_args()
+    for filename in filenames:
+        create_file(filename, options)
+
+
+if __name__ == "__main__":
+    main()