+def format_changeset(a, b, change):
+ return (a[0], filter_line(a[1]), b[0], filter_line(b[1]), change)
+
+
+def html_diff_table(la, lb, context=None):
+ all_changes = difflib._mdiff(la, lb)
+
+ if context is None:
+ changes = (format_changeset(*c) for c in all_changes)
+ else:
+ changes = []
+ q = deque()
+ after_change = False
+
+ for changeset in all_changes:
+ q.append(changeset)
+
+ if changeset[2]:
+ after_change = True
+ if not after_change:
+ changes.append((0, '-----', 0, '-----', False))
+ changes.extend(format_changeset(*c) for c in q)
+ q.clear()
+ else:
+ if len(q) == context and after_change:
+ changes.extend(format_changeset(*c) for c in q)
+ q.clear()
+ after_change = False
+ elif len(q) > context:
+ q.popleft()
+