hashing function

01-data-structures/04-hashes-part-1/hash_item.rb

@@ -3,5 +3,7 @@ class HashItem
   attr_accessor :value
 
   def initialize(key, value)
+    @key = key
+    @value = value
   end
-end
+end

01-data-structures/04-hashes-part-1/hashclass.rb

@@ -1,27 +1,56 @@
+require_relative 'hash_item'
+
 class HashClass
 
   def initialize(size)
     @items = Array.new(size)
   end
 
   def []=(key, value)
+    i = index(key, size())
+    new_item = @items[i]
+    if new_item == nil
+      @items[i] = HashItem.new(key,value)
+    elsif new_item.key != key
+      while @items[index(key, size())].key != nil && @items[index(key, size())].key != key
+        resize()
+        j = index(key, size())
+        break if @items[j] == nil
+      end
+      self[key] = value
+    elsif new_item.key == key && new_item.value != value
+      resize()
+      new_item.value = value
+    end
   end
 
 
   def [](key)
+    i = index(key, size())
+    @items[i].value
   end
 
   def resize
+    @size = @items.length * 2
+    resized_hash = Array.new(@size)
+    @items.each do |item|
+      if item != nil
+        resized_hash[index(item.key, @size)] = item
+      end
+    end
+    @items = resized_hash
   end
 
   # Returns a unique, deterministically reproducible index into an array
   # We are hashing based on strings, let's use the ascii value of each string as
   # a starting point.
   def index(key, size)
+    key.sum % size
   end
 
   # Simple method to return the number of items in the hash
   def size
+    @items.length
   end
 
-end
+end