Add simple example program.

1 files changed, 86 insertions, 0 deletions

diff --git a/example.py b/example.py
new file mode 100644
index 0000000..9feb5e3
--- /dev/null
+++ b/example.py
@@ -0,0 +1,86 @@
+# Copyright 2010  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 hashlib
+import os
+import sys
+
+import btree
+
+
+def compute(filename):
+    f = open(filename)
+    md5 = hashlib.md5()
+    while True:
+        data = f.read(1024)
+        if not data:
+            break
+        md5.update(data)
+    f.close()
+    return md5.hexdigest()
+
+
+def open_tree(dirname):
+    key_size = len(compute('/dev/null'))
+    node_size = 4096
+    
+    codec = btree.NodeCodec(key_size)
+    ns = btree.NodeStoreDisk(dirname, node_size, codec)
+    forest = btree.Forest(ns)
+    if forest.trees:
+        tree = forest.trees[0]
+    else:
+        tree = forest.new_tree()
+    return forest, tree
+
+
+def add(filenames):
+    forest, tree = open_tree('example.tree')
+    for filename in filenames:
+        checksum = compute(filename)
+        tree.insert(checksum, filename)
+    forest.commit()
+
+
+def find(checksums):
+    forest, tree = open_tree('example.tree')
+    for checksum in checksums:
+        filename = tree.lookup(checksum)
+        print checksum, filename
+
+
+def list_checksums():
+    forest, tree = open_tree('example.tree')
+    key_size = len(compute('/dev/null'))
+    minkey = '00' * key_size
+    maxkey = 'ff' * key_size
+    for checksum, filename in tree.lookup_range(minkey, maxkey):
+        print checksum, filename
+
+
+def main():
+    if sys.argv[1] == 'add':
+        add(sys.argv[2:])
+    elif sys.argv[1] == 'find':
+        find(sys.argv[2:])
+    elif sys.argv[1] == 'list':
+        list_checksums()
+    else:
+        raise Exception('Unknown operation %s' % sys.argv[1])
+
+
+if __name__ == '__main__':
+    main()