cw_pagination_helper.py

import math
class PaginationHelper:

	# The constructor takes in an array of items and a integer indicating
	# how many items fit within a single page
	def __init__(self, collection, items_per_page):
			self.collection = collection
			self.items_per_page = items_per_page
			self.local = locals()
	
	# returns the number of items within the entire collection
	def item_count(self):
			return len(self.collection)
	
	# returns the number of pages
	def page_count(self):
			return int(math.ceil(1.0 * self.item_count() / self.items_per_page))			
	
	# returns the number of items on the current page. page_index is zero based
	# this method should return -1 for page_index values that are out of range
	def page_item_count(self,page_index):
			if (page_index+1) * self.items_per_page <= self.item_count():
					return self.items_per_page
			if page_index*self.items_per_page<self.item_count() and (page_index+1) * self.items_per_page > self.item_count():
					return self.item_count()%self.items_per_page
			return -1
	
	# determines what page an item is on. Zero based indexes.
	# this method should return -1 for item_index values that are out of range
	def page_index(self,item_index):
			if item_index < self.item_count() and item_index >= 0 :
					return item_index/self.items_per_page
			return -1