Added (simplified) zinterstore

lib/redis/connection/memory.rb

@@ -1,3 +1,4 @@
+require 'set'
 require 'redis/connection/registry'
 require 'redis/connection/command_helper'
 
@@ -783,6 +784,29 @@ def zrevrangebyscore(key, max, min, with_scores = nil)
         end.flatten.map(&:to_s)
       end
 
+      def zinterstore(out, _, *keys)
+        fail_unless_zset(out)
+
+        hashes = keys.map do |src|
+          case @data[src]
+          when Set
+            Hash[@data[src].zip([0] * @data[src].size)]
+          when Hash
+            @data[src]
+          else
+            nil
+          end
+        end.compact
+
+        @data[out] = ZSet.new
+        values = hashes.inject([]) {|r, h| r.empty? ? h.keys : r & h.keys }
+        values.each do |value|
+          @data[out][value] = hashes.inject(0) {|n, h| n + h[value].to_i }
+        end
+
+        @data[out].size
+      end
+
       private
 
         def is_a_set?(key)

spec/sorted_sets_spec.rb

@@ -106,6 +106,25 @@ module FakeRedis
       @client.zrevrank("key", "four").should be_nil
     end
 
+    it "should create untersections between multiple (sorted) sets and store the resulting sorted set in a new key" do
+      @client.zadd("key1", 1, "one")
+      @client.zadd("key1", 2, "two")
+      @client.zadd("key1", 3, "three")
+      @client.zadd("key2", 5, "two")
+      @client.zadd("key2", 7, "three")
+      @client.sadd("key3", 'one')
+      @client.sadd("key3", 'two')
+
+      @client.zinterstore("out", ["key1", "key2"]).should == 2
+      @client.zrange("out", 0, 100, :with_scores => true).should == ['two', '7', 'three', '10']
+
+      @client.zinterstore("out", ["key1", "key3"]).should == 2
+      @client.zrange("out", 0, 100, :with_scores => true).should == ['one', '1', 'two', '2']
+
+      @client.zinterstore("out", ["key1", "key2", "key3"]).should == 1
+      @client.zrange("out", 0, 100, :with_scores => true).should == ['two', '7']
+    end
+
     #it "should remove all members in a sorted set within the given indexes"
 
     #it "should remove all members in a sorted set within the given scores"