NF: add copy of OrderedDict for Python 2.6 compat

DICOM will need OrderedDict; copy in the external module until we
require Python 2.7

COPYING

@@ -122,37 +122,31 @@ Sphinx 0.6 doesn't work properly.
   OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
   DAMAGE.
 
-
-Lightunit module
-----------------
-
-Taken from IPython.
-
-::
-
-  Copyright (c) 2009 Fernando Perez and the IPython Development Team
-
-  Redistribution and use in source and binary forms, with or without
-  modification, are permitted provided that the following conditions are met:
-
-    a. Redistributions of source code must retain the above copyright notice,
-       this list of conditions and the following disclaimer.
-    b. Redistributions in binary form must reproduce the above copyright
-       notice, this list of conditions and the following disclaimer in the
-       documentation and/or other materials provided with the distribution.
-    c. Neither the name of the Enthought nor the names of its contributors
-       may be used to endorse or promote products derived from this software
-       without specific prior written permission.
-
-
-  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-  ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
-  ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
-  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
-  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
-  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
-  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
-  DAMAGE.
+Ordereddict
+-----------
+
+In ``nibabel/externals/ordereddict.py``
+
+Copied from: https://pypi.python.org/packages/source/o/ordereddict/ordereddict-1.1.tar.gz#md5=a0ed854ee442051b249bfad0f638bbec
+
+Copyright (c) 2009 Raymond Hettinger
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation files
+(the "Software"), to deal in the Software without restriction,
+including without limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of the Software,
+and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be
+    included in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+    OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+    HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+    WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+    OTHER DEALINGS IN THE SOFTWARE.

nibabel/externals/__init__.py

@@ -0,0 +1,5 @@
+# init for externals package
+try:
+    from collections import OrderedDict
+except ImportError: # < Python 2.7
+    from .ordereddict import OrderedDict

nibabel/externals/ordereddict.py

@@ -0,0 +1,132 @@
+# Copyright (c) 2009 Raymond Hettinger
+#
+# Permission is hereby granted, free of charge, to any person
+# obtaining a copy of this software and associated documentation files
+# (the "Software"), to deal in the Software without restriction,
+# including without limitation the rights to use, copy, modify, merge,
+# publish, distribute, sublicense, and/or sell copies of the Software,
+# and to permit persons to whom the Software is furnished to do so,
+# subject to the following conditions:
+#
+#     The above copyright notice and this permission notice shall be
+#     included in all copies or substantial portions of the Software.
+#
+#     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+#     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+#     OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+#     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+#     HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+#     WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+#     FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+#     OTHER DEALINGS IN THE SOFTWARE.
+
+# Allow Python3 to import module even though broken
+# The following import checks are a modification from the original ordereddict
+try:
+    from UserDict import DictMixin
+except ImportError:
+    pass
+else:
+    class OrderedDict(dict, DictMixin):
+
+        def __init__(self, *args, **kwds):
+            if len(args) > 1:
+                raise TypeError('expected at most 1 arguments, got %d' % len(args))
+            try:
+                self.__end
+            except AttributeError:
+                self.clear()
+            self.update(*args, **kwds)
+
+        def clear(self):
+            self.__end = end = []
+            end += [None, end, end]         # sentinel node for doubly linked list
+            self.__map = {}                 # key --> [key, prev, next]
+            dict.clear(self)
+
+        def __setitem__(self, key, value):
+            if key not in self:
+                end = self.__end
+                curr = end[1]
+                curr[2] = end[1] = self.__map[key] = [key, curr, end]
+            dict.__setitem__(self, key, value)
+
+        def __delitem__(self, key):
+            dict.__delitem__(self, key)
+            key, prev, next = self.__map.pop(key)
+            prev[2] = next
+            next[1] = prev
+
+        def __iter__(self):
+            end = self.__end
+            curr = end[2]
+            while curr is not end:
+                yield curr[0]
+                curr = curr[2]
+
+        def __reversed__(self):
+            end = self.__end
+            curr = end[1]
+            while curr is not end:
+                yield curr[0]
+                curr = curr[1]
+
+        def popitem(self, last=True):
+            if not self:
+                raise KeyError('dictionary is empty')
+            if last:
+                key = reversed(self).next()
+            else:
+                key = iter(self).next()
+            value = self.pop(key)
+            return key, value
+
+        def __reduce__(self):
+            items = [[k, self[k]] for k in self]
+            tmp = self.__map, self.__end
+            del self.__map, self.__end
+            inst_dict = vars(self).copy()
+            self.__map, self.__end = tmp
+            if inst_dict:
+                return (self.__class__, (items,), inst_dict)
+            return self.__class__, (items,)
+
+        def keys(self):
+            return list(self)
+
+        setdefault = DictMixin.setdefault
+        update = DictMixin.update
+        pop = DictMixin.pop
+        values = DictMixin.values
+        items = DictMixin.items
+        iterkeys = DictMixin.iterkeys
+        itervalues = DictMixin.itervalues
+        iteritems = DictMixin.iteritems
+
+        def __repr__(self):
+            if not self:
+                return '%s()' % (self.__class__.__name__,)
+            return '%s(%r)' % (self.__class__.__name__, self.items())
+
+        def copy(self):
+            return self.__class__(self)
+
+        @classmethod
+        def fromkeys(cls, iterable, value=None):
+            d = cls()
+            for key in iterable:
+                d[key] = value
+            return d
+
+        def __eq__(self, other):
+            if isinstance(other, OrderedDict):
+                if len(self) != len(other):
+                    return False
+                for p, q in  zip(self.items(), other.items()):
+                    if p != q:
+                        return False
+                return True
+            return dict.__eq__(self, other)
+
+        def __ne__(self, other):
+            return not self == other

nibabel/externals/tests/test_ordereddict.py

@@ -0,0 +1,21 @@
+# Test ordered dict loading
+
+from os.path import dirname, relpath, realpath
+import sys
+import inspect
+
+from .. import OrderedDict
+
+from nose.tools import assert_equal, assert_true
+
+MY_PATH = dirname(realpath(__file__))
+
+def test_right_version():
+    # If Python < 2.7, use our own copy, else use system copy
+    class_path = inspect.getfile(OrderedDict)
+    rel_dir = dirname(relpath(realpath(class_path), MY_PATH))
+    if sys.version_info[:2] < (2, 7):
+        assert_equal(rel_dir, '..')
+    else:
+        import collections
+        assert_true(collections.OrderedDict is OrderedDict)