From cccda38920288e53a70a60a44c7c17f2d7cb7413 Mon Sep 17 00:00:00 2001
From: Julien Lengrand-Lambert <julien@lengrand.fr>
Date: Thu, 21 Nov 2013 11:08:35 +0100
Subject: [PATCH] Finishes implementing hash method

---
 02_hash_maps/hm.py      | 13 ++++++++++++-
 02_hash_maps/hm_test.py |  6 +++++-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/02_hash_maps/hm.py b/02_hash_maps/hm.py
index 71c80f2..9cf3a4e 100644
--- a/02_hash_maps/hm.py
+++ b/02_hash_maps/hm.py
@@ -12,8 +12,19 @@ class HashMap():
 		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.
+		"""
 		if len(value) < 1:
 			raise Exception("Size of value must be greater than one")
-		return 1
+		
+		# hash function taken from HT3.
+		# We shift and add : << 4 is a *16
+		h = 0
+		for letter in value:
+			h = (h << 4) + ord(letter)
+			
+		return h
 
 	
diff --git a/02_hash_maps/hm_test.py b/02_hash_maps/hm_test.py
index 1561125..5f16779 100644
--- a/02_hash_maps/hm_test.py
+++ b/02_hash_maps/hm_test.py
@@ -17,8 +17,12 @@ 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("test"), 1)
+		self.assertEqual(hm._hash(value), 502948)
 
 		value = ""
 		self.assertRaises(Exception, lambda x : hm._hash(value))