Adds hm implementation with items. Currently, this is just a copy paste from the bare simple hm implementation

02_hash_maps/hm.py

@@ -129,6 +129,57 @@ class HMTableCollision(HashMap):
 
 		return h % self._hash_size
 
+class HashMapWithItem():
+	"""
+	This implementation USES _HashMapItems
+	Also, this implementation will return an error in case of a collision.
+	Data will not be lost, but another key will have to be used.
+	"""
+	def __init__(self, hash_size=513):
+		self._hash_size = hash_size
+		self._size = 0
+		self.hmap = [None] * self._hash_size
+
+	def add(self, key, value):
+		"""
+		Adds the provided value to the hashmap.
+		Raises an Exception if a collision is detected
+		"""
+		my_key = self._hash(key)
+		if self.hmap[my_key] == None:
+			self.hmap[my_key] = value
+			self._size += 1
+		else:
+			raise Exception("Collision detected at index %d", key)
+
+	def get(self, key):
+		"""
+		Finds the element in the hash table that may contain the id for
+		the string we are looking for
+		"""
+		my_key = self._hash(key)
+		return self.hmap[my_key]
+
+	def size(self):
+		return self._size
+
+	def _hash(self, value):
+		"""
+		Generates a hash for the given value.
+		The input is expected to be a String, with only ASCII characters.
+
+		# hash function taken from HT3.
+		# We shift and add : << 4 is a *16
+		"""
+		if len(value) < 1:
+			raise Exception("Size of value must be greater than one")
+
+		h = 0
+		for letter in value:
+			h = (h << 4) + ord(letter)
+
+		return h % self._hash_size
+
 class HMNeighbourCollision():
 	def __init__(self, hash_size=513):
 		self._hash_size = hash_size

02_hash_maps/hm_test.py

@@ -14,62 +14,62 @@ class test_hash_map_neighbour_collision(unittest.TestCase):
 
 	def test__find_free_idx(self):
 		hm = HMNeighbourCollision()
-		
+
 		key = "One"
 		value = "Ibiza"
-		
+
 		my_key = hm._hash(key)
 		idx = hm._find_free_idx(my_key)
 		self.assertEqual(my_key, idx)
-		
+
 		hm.add(key, value)
 		self.assertEqual(hm.size(), 1)
-		
+
 		# We move one up
-		idx = hm._find_free_idx(my_key)		
+		idx = hm._find_free_idx(my_key)
 		self.assertEqual(my_key - 1, idx)
-		
+
 		hm.add(key, "Ibiza2")
-		self.assertEqual(hm.size(), 2)	
+		self.assertEqual(hm.size(), 2)
 
 		# We move one down
-		idx = hm._find_free_idx(my_key)		
+		idx = hm._find_free_idx(my_key)
 		self.assertEqual(my_key + 1, idx)
 
 		hm.add(key, "Ibiza3")
-		self.assertEqual(hm.size(), 3)	
+		self.assertEqual(hm.size(), 3)
 
 		# We move two up
-		idx = hm._find_free_idx(my_key)		
+		idx = hm._find_free_idx(my_key)
 		self.assertEqual(my_key - 2, idx)
 
 class test_hash_map_table_collision(unittest.TestCase):
 
 	def test_add(self):
 		hm = HMTableCollision()
-		
+
 		hm.add("a", "Ibiza")
 		self.assertEqual(hm.size(), 1)
-		
+
 		hm.add("a", "Ibiza2")
-		self.assertEqual(hm.size(), 2)	
+		self.assertEqual(hm.size(), 2)
 
 	def test_get(self):
-		
+
 		hm = HMTableCollision()
 		value = ""
 		self.assertRaises(Exception, lambda x : hm.get(value))
-		
+
 		key = "One"
 		value = "Ibiza"
 		hm.add(key, value)
 
 		key2 = "Two"
-		value2 = "NY"		
+		value2 = "NY"
 		hm.add(key2, value2)
 		hm.add("Three", "Berlin")
 		hm.add("Four", "Chicago")
-		
+
 		value3 = "Ibiza2"
 		hm.add(key, value3)
 
@@ -81,15 +81,15 @@ class test_hash_map_table_collision(unittest.TestCase):
 		self.assertEqual(hm.get(key), [value, value3])
 
 
-class test_hash_map(unittest.TestCase):
+class test_hash_map_with_item(unittest.TestCase):
 
 	def test_hash_size(self):
 		hm = HashMap()
 		self.assertEqual(hm._hash_size, 513)
-		
+
 		hm = HashMap(1025)
 		self.assertEqual(hm._hash_size, 1025)
-		
+
 
 	def test_size(self):
 		hm = HashMap()
@@ -97,10 +97,10 @@ class test_hash_map(unittest.TestCase):
 
 	def test__hash(self):
 		hm = HashMap()
-		
+
 		value = "a"
 		self.assertEqual(hm._hash(value), ord(value))
-		
+
 		value = "test"
 		self.assertEqual(hm._hash(value), 208)
 
@@ -110,7 +110,7 @@ class test_hash_map(unittest.TestCase):
 
 	def test_add(self):
 		hm = HashMap()
-		
+
 		hm.add("a", "Ibiza")
 		self.assertEqual(hm.size(), 1)
 
@@ -119,23 +119,79 @@ class test_hash_map(unittest.TestCase):
 		self.assertEqual(hm.size(), 1)
 
 	def test_get(self):
-		
+
 		hm = HashMap()
 		value = ""
 		self.assertRaises(Exception, lambda x : hm.get(value))
-		
+
 		key = "One"
 		value = "Ibiza"
 		hm.add(key, value)
-		
+
 		hm.add("Two", "NY")
 		hm.add("Three", "Berlin")
 		hm.add("Four", "Chicago")
-		
+
 		self.assertEqual(hm.size(), 4)
 
 		self.assertEqual(hm.get(key), value)
 		self.assertEqual(hm.get("Five"), None)
-		
+
+class test_hash_map(unittest.TestCase):
+
+	def test_hash_size(self):
+		hm = HashMap()
+		self.assertEqual(hm._hash_size, 513)
+
+		hm = HashMap(1025)
+		self.assertEqual(hm._hash_size, 1025)
+
+
+	def test_size(self):
+		hm = HashMap()
+		self.assertEqual(hm.size(), 0)
+
+	def test__hash(self):
+		hm = HashMap()
+
+		value = "a"
+		self.assertEqual(hm._hash(value), ord(value))
+
+		value = "test"
+		self.assertEqual(hm._hash(value), 208)
+
+		value = ""
+		self.assertRaises(Exception, lambda x : hm._hash(value))
+
+
+	def test_add(self):
+		hm = HashMap()
+
+		hm.add("a", "Ibiza")
+		self.assertEqual(hm.size(), 1)
+
+		# Tests Collision
+		self.assertRaises(Exception, lambda x : hm.add("a", "Ibiza"))
+		self.assertEqual(hm.size(), 1)
+
+	def test_get(self):
+
+		hm = HashMap()
+		value = ""
+		self.assertRaises(Exception, lambda x : hm.get(value))
+
+		key = "One"
+		value = "Ibiza"
+		hm.add(key, value)
+
+		hm.add("Two", "NY")
+		hm.add("Three", "Berlin")
+		hm.add("Four", "Chicago")
+
+		self.assertEqual(hm.size(), 4)
+
+		self.assertEqual(hm.get(key), value)
+		self.assertEqual(hm.get("Five"), None)
+
 if __name__ == "__main__":
 	unittest.main()