1 files changed, 120 insertions, 0 deletions
diff --git a/webapp/django/core/paginator.py b/webapp/django/core/paginator.py
new file mode 100644
index 0000000000..495cdf2d76
--- /dev/null
+++ b/webapp/django/core/paginator.py
@@ -0,0 +1,120 @@
+from math import ceil
+
+class InvalidPage(Exception):
+    pass
+
+class PageNotAnInteger(InvalidPage):
+    pass
+
+class EmptyPage(InvalidPage):
+    pass
+
+class Paginator(object):
+    def __init__(self, object_list, per_page, orphans=0, allow_empty_first_page=True):
+        self.object_list = object_list
+        self.per_page = per_page
+        self.orphans = orphans
+        self.allow_empty_first_page = allow_empty_first_page
+        self._num_pages = self._count = None
+
+    def validate_number(self, number):
+        "Validates the given 1-based page number."
+        try:
+            number = int(number)
+        except ValueError:
+            raise PageNotAnInteger('That page number is not an integer')
+        if number < 1:
+            raise EmptyPage('That page number is less than 1')
+        if number > self.num_pages:
+            if number == 1 and self.allow_empty_first_page:
+                pass
+            else:
+                raise EmptyPage('That page contains no results')
+        return number
+
+    def page(self, number):
+        "Returns a Page object for the given 1-based page number."
+        number = self.validate_number(number)
+        bottom = (number - 1) * self.per_page
+        top = bottom + self.per_page
+        if top + self.orphans >= self.count:
+            top = self.count
+        return Page(self.object_list[bottom:top], number, self)
+
+    def _get_count(self):
+        "Returns the total number of objects, across all pages."
+        if self._count is None:
+            try:
+                self._count = self.object_list.count()
+            except (AttributeError, TypeError):
+                # AttributeError if object_list has no count() method.
+                # TypeError if object_list.count() requires arguments
+                # (i.e. is of type list).
+                self._count = len(self.object_list)
+        return self._count
+    count = property(_get_count)
+
+    def _get_num_pages(self):
+        "Returns the total number of pages."
+        if self._num_pages is None:
+            if self.count == 0 and not self.allow_empty_first_page:
+                self._num_pages = 0
+            else:
+                hits = max(1, self.count - self.orphans)
+                self._num_pages = int(ceil(hits / float(self.per_page)))
+        return self._num_pages
+    num_pages = property(_get_num_pages)
+
+    def _get_page_range(self):
+        """
+        Returns a 1-based range of pages for iterating through within
+        a template for loop.
+        """
+        return range(1, self.num_pages + 1)
+    page_range = property(_get_page_range)
+
+QuerySetPaginator = Paginator # For backwards-compatibility.
+
+class Page(object):
+    def __init__(self, object_list, number, paginator):
+        self.object_list = object_list
+        self.number = number
+        self.paginator = paginator
+
+    def __repr__(self):
+        return '<Page %s of %s>' % (self.number, self.paginator.num_pages)
+
+    def has_next(self):
+        return self.number < self.paginator.num_pages
+
+    def has_previous(self):
+        return self.number > 1
+
+    def has_other_pages(self):
+        return self.has_previous() or self.has_next()
+
+    def next_page_number(self):
+        return self.number + 1
+
+    def previous_page_number(self):
+        return self.number - 1
+
+    def start_index(self):
+        """
+        Returns the 1-based index of the first object on this page,
+        relative to total objects in the paginator.
+        """
+        # Special case, return zero if no items.
+        if self.paginator.count == 0:
+            return 0
+        return (self.paginator.per_page * (self.number - 1)) + 1
+
+    def end_index(self):
+        """
+        Returns the 1-based index of the last object on this page,
+        relative to total objects found (hits).
+        """
+        # Special case for the last page because there can be orphans.
+        if self.number == self.paginator.num_pages:
+            return self.paginator.count
+        return self.number * self.paginator.per_page