1 files changed, 74 insertions, 0 deletions
diff --git a/bzrlib/_btree_serializer_py.py b/bzrlib/_btree_serializer_py.py
new file mode 100644
index 0000000..21d00e6
--- /dev/null
+++ b/bzrlib/_btree_serializer_py.py
@@ -0,0 +1,74 @@
+# Copyright (C) 2008, 2009, 2010 Canonical Ltd
+#
+# 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 2 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, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+#
+
+"""B+Tree index parsing."""
+
+from __future__ import absolute_import
+
+from bzrlib import static_tuple
+
+
+def _parse_leaf_lines(bytes, key_length, ref_list_length):
+    lines = bytes.split('\n')
+    nodes = []
+    as_st = static_tuple.StaticTuple.from_sequence
+    stuple = static_tuple.StaticTuple
+    for line in lines[1:]:
+        if line == '':
+            return nodes
+        elements = line.split('\0', key_length)
+        # keys are tuples
+        key = as_st(elements[:key_length]).intern()
+        line = elements[-1]
+        references, value = line.rsplit('\0', 1)
+        if ref_list_length:
+            ref_lists = []
+            for ref_string in references.split('\t'):
+                ref_list = as_st([as_st(ref.split('\0')).intern()
+                                  for ref in ref_string.split('\r') if ref])
+                ref_lists.append(ref_list)
+            ref_lists = as_st(ref_lists)
+            node_value = stuple(value, ref_lists)
+        else:
+            node_value = stuple(value, stuple())
+        # No need for StaticTuple here as it is put into a dict
+        nodes.append((key, node_value))
+    return nodes
+
+
+def _flatten_node(node, reference_lists):
+    """Convert a node into the serialized form.
+
+    :param node: A tuple representing a node (key_tuple, value, references)
+    :param reference_lists: Does this index have reference lists?
+    :return: (string_key, flattened)
+        string_key  The serialized key for referencing this node
+        flattened   A string with the serialized form for the contents
+    """
+    if reference_lists:
+        # TODO: Consider turning this back into the 'unoptimized' nested loop
+        #       form. It is probably more obvious for most people, and this is
+        #       just a reference implementation.
+        flattened_references = ['\r'.join(['\x00'.join(reference)
+                                           for reference in ref_list])
+                                for ref_list in node[3]]
+    else:
+        flattened_references = []
+    string_key = '\x00'.join(node[1])
+    line = ("%s\x00%s\x00%s\n" % (string_key,
+        '\t'.join(flattened_references), node[2]))
+    return string_key, line