1 files changed, 131 insertions, 0 deletions
diff --git a/Lib/fontTools/merge/util.py b/Lib/fontTools/merge/util.py
new file mode 100644
index 00000000..66cea4d5
--- /dev/null
+++ b/Lib/fontTools/merge/util.py
@@ -0,0 +1,131 @@
+# Copyright 2013 Google, Inc. All Rights Reserved.
+#
+# Google Author(s): Behdad Esfahbod, Roozbeh Pournader
+
+from fontTools.misc.timeTools import timestampNow
+from fontTools.ttLib.tables.DefaultTable import DefaultTable
+from functools import reduce
+import operator
+import logging
+
+
+log = logging.getLogger("fontTools.merge")
+
+
+# General utility functions for merging values from different fonts
+
+def equal(lst):
+	lst = list(lst)
+	t = iter(lst)
+	first = next(t)
+	assert all(item == first for item in t), "Expected all items to be equal: %s" % lst
+	return first
+
+def first(lst):
+	return next(iter(lst))
+
+def recalculate(lst):
+	return NotImplemented
+
+def current_time(lst):
+	return timestampNow()
+
+def bitwise_and(lst):
+	return reduce(operator.and_, lst)
+
+def bitwise_or(lst):
+	return reduce(operator.or_, lst)
+
+def avg_int(lst):
+	lst = list(lst)
+	return sum(lst) // len(lst)
+
+def onlyExisting(func):
+	"""Returns a filter func that when called with a list,
+	only calls func on the non-NotImplemented items of the list,
+	and only so if there's at least one item remaining.
+	Otherwise returns NotImplemented."""
+
+	def wrapper(lst):
+		items = [item for item in lst if item is not NotImplemented]
+		return func(items) if items else NotImplemented
+
+	return wrapper
+
+def sumLists(lst):
+	l = []
+	for item in lst:
+		l.extend(item)
+	return l
+
+def sumDicts(lst):
+	d = {}
+	for item in lst:
+		d.update(item)
+	return d
+
+def mergeBits(bitmap):
+
+	def wrapper(lst):
+		lst = list(lst)
+		returnValue = 0
+		for bitNumber in range(bitmap['size']):
+			try:
+				mergeLogic = bitmap[bitNumber]
+			except KeyError:
+				try:
+					mergeLogic = bitmap['*']
+				except KeyError:
+					raise Exception("Don't know how to merge bit %s" % bitNumber)
+			shiftedBit = 1 << bitNumber
+			mergedValue = mergeLogic(bool(item & shiftedBit) for item in lst)
+			returnValue |= mergedValue << bitNumber
+		return returnValue
+
+	return wrapper
+
+
+class AttendanceRecordingIdentityDict(object):
+	"""A dictionary-like object that records indices of items actually accessed
+	from a list."""
+
+	def __init__(self, lst):
+		self.l = lst
+		self.d = {id(v):i for i,v in enumerate(lst)}
+		self.s = set()
+
+	def __getitem__(self, v):
+		self.s.add(self.d[id(v)])
+		return v
+
+class GregariousIdentityDict(object):
+	"""A dictionary-like object that welcomes guests without reservations and
+	adds them to the end of the guest list."""
+
+	def __init__(self, lst):
+		self.l = lst
+		self.s = set(id(v) for v in lst)
+
+	def __getitem__(self, v):
+		if id(v) not in self.s:
+			self.s.add(id(v))
+			self.l.append(v)
+		return v
+
+class NonhashableDict(object):
+	"""A dictionary-like object mapping objects to values."""
+
+	def __init__(self, keys, values=None):
+		if values is None:
+			self.d = {id(v):i for i,v in enumerate(keys)}
+		else:
+			self.d = {id(k):v for k,v in zip(keys, values)}
+
+	def __getitem__(self, k):
+		return self.d[id(k)]
+
+	def __setitem__(self, k, v):
+		self.d[id(k)] = v
+
+	def __delitem__(self, k):
+		del self.d[id(k)]