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authorSiddharth Ravikumar <sravik@bgsu.edu>2015-01-12 17:31:54 -0500
committerSiddharth Ravikumar <sravik@bgsu.edu>2015-01-12 17:31:54 -0500
commit92633ad0d4cd4c7ff7a811460b9691842af15276 (patch)
tree8d548c5c34521ddf3b36c54fbef4f2dd0441a2bd
parent666b0e5fcfd6157ca8606bf2a429e50004773fdc (diff)
added back combox/file.py
-rw-r--r--combox/file.py127
1 files changed, 127 insertions, 0 deletions
diff --git a/combox/file.py b/combox/file.py
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+++ b/combox/file.py
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+# Copyright (C) 2014 Combox author(s). See AUTHORS.
+#
+# This file is part of Combox.
+#
+# Combox 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.
+#
+# Combox 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 Combox (see COPYING). If not, see
+# <http://www.gnu.org/licenses/>.
+
+from os import path
+from sys import exit
+from glob import glob
+
+
+def split_data(data, n):
+ """Split data into `n' parts and return them as an array.
+
+ data: Stream of bytes or string
+ n: Number of parts the file has to be split.
+ """
+
+ d_parts = []
+ # File size in bytes.
+ data_size = len(data)
+ # No. of bytes for each data part.
+ part_size = data_size / n
+ # Take note of remaining bytes; this is non-zero when data_size is
+ # not divisible by `n'.
+ rem_bytes = data_size % n
+
+ start = 0
+ end = part_size
+ while end <= data_size:
+ d_parts.append(data[start:end])
+ start = end
+ end = end + part_size
+
+ # read the remaining bytes into the last data part.
+ end += start + rem_bytes
+ d_parts[n-1] += data[start:end]
+
+ return d_parts
+
+
+def glue_data(d_parts):
+ """Glue different parts of the data to one.
+
+ d_parts: Array containing different parts of the data. Each part
+ is a sequence of bytes.
+ """
+
+ data = ''
+ for part in d_parts:
+ data += part
+
+ return data
+
+
+def read_file(filename):
+ """Read file and return it as a string.
+
+ filename: Absolute pathname of the file.
+ """
+ file_ = None
+ try:
+ file_ = open(filename, 'rb')
+ except IOError:
+ print "ERROR: opening %s" % (filename)
+ exit(1)
+
+ return file_.read()
+
+
+def write_file(filename, filecontent):
+ """Write `filecontent' to `filename'.
+
+ filename: Absolute pathname of the file.
+ filecontent: String/bytstream to write to filename.
+ """
+ file_ = None
+ try:
+ file_ = open(filename, 'wb')
+ file_.write(filecontent)
+ except IOError:
+ print "ERROR: creating and writing content to %s" % (filename)
+ exit(1)
+
+def write_shards(shards, directory, shard_basename):
+ """Write shards to respective files respective files.
+
+ shard: list of strings (ciphers or data).
+ directory: absolute path of directory to which it shards must be written to.
+ shard_basename: base name of the shard.
+ """
+
+ # partial filename of the shard
+ p_filename = path.join(directory, shard_basename)
+ shard_no = 0
+ for shard in shards:
+ shard_name = "%s.shard%s" % (p_filename, shard_no)
+ write_file(shard_name, shard)
+ shard_no += 1
+
+def read_shards(directory, shard_basename):
+ """Read the shards from directory and return it as a list.
+
+ directory: absolute path of directory from which to read the shards.
+ shard_basename: base name of the shard.
+ """
+
+ shards = []
+ # partial filename of the shard
+ p_filename = "%s.shard*" % path.join(directory, shard_basename)
+ for shard_file in sorted(glob(p_filename)):
+ shard_content = read_file(shard_file)
+ shards.append(shard_content)
+
+ return shards