Serialise dict int values specially

Dir objects are mostly integers. This encodes them specially.
./serialise-speed went from 97/s to 104/s.

1 files changed, 20 insertions, 1 deletions

diff --git a/obnamlib/obj_serialiser.py b/obnamlib/obj_serialiser.py
index 0eb70b5a..ccc0a722 100644
--- a/obnamlib/obj_serialiser.py
+++ b/obnamlib/obj_serialiser.py
@@ -147,9 +147,14 @@ def _next_object(pos, length):
 
 def _serialise_dict(obj):
     keys = obj.keys()
+    int_keys = [key for key in keys if type(obj[key]) in (int, long)]
     str_keys = [key for key in keys if type(obj[key]) is str]
-    other_keys = [key for key in keys if key not in str_keys]
+    special_keys = set(int_keys).union(set(str_keys))
+    other_keys = [key for key in keys if key not in special_keys]
+
     parts = []
+    parts.append(_serialise_str_list(int_keys))
+    parts.append(_serialise_int_list([obj[key] for key in int_keys]))
     parts.append(_serialise_str_list(str_keys))
     parts.append(_serialise_str_list([obj[key] for key in str_keys]))
     parts.append(_serialise_str_list(other_keys))
@@ -164,6 +169,10 @@ def _deserialise_dict(serialised):
     result = {}
     pos = 0
 
+    int_keys, pos = _deserialise_str_list(serialised, pos)
+    int_values, pos = _deserialise_int_list(serialised, pos)
+    result.update(zip(int_keys, int_values))
+
     str_keys, pos = _deserialise_str_list(serialised, pos)
     str_values, pos = _deserialise_str_list(serialised, pos)
     result.update(zip(str_keys, str_values))
@@ -194,6 +203,16 @@ def _deserialise_str_list(serialised, pos):
     return strings, pos
 
 
+def _serialise_int_list(ints):
+    return _serialise_str_list([str(i) for i in ints])
+
+
+def _deserialise_int_list(serialised, pos):
+    strings, pos = _deserialise_str_list(serialised, pos)
+    ints = [int(s) for s in strings]
+    return ints, pos
+
+
 def _deserialise_prefix(serialised, pos):
     length = _extract_length(serialised, pos)
     end = _next_object(pos, length)