Issue #99: Added HyperLogLogLength that takes array of HLL keys

StackExchange.Redis/StackExchange/Redis/IDatabase.cs

@@ -182,6 +182,13 @@ public interface IDatabase : IRedis, IDatabaseAsync
         /// <remarks>http://redis.io/commands/pfcount</remarks>
         long HyperLogLogLength(RedisKey key, CommandFlags flags = CommandFlags.None);
 
+        /// <summary>
+        /// Returns the approximated cardinality of the union of the HyperLogLogs passed, by internally merging the HyperLogLogs stored at the provided keys into a temporary hyperLogLog, or 0 if the variable does not exist.
+        /// </summary>
+        /// <returns>The approximated number of unique elements observed via HyperLogLogAdd.</returns>
+        /// <remarks>http://redis.io/commands/pfcount</remarks>
+        long HyperLogLogLength(RedisKey[] keys, CommandFlags flags = CommandFlags.None);
+
         /// <summary>
         /// Merge multiple HyperLogLog values into an unique value that will approximate the cardinality of the union of the observed Sets of the source HyperLogLog structures.
         /// </summary>

StackExchange.Redis/StackExchange/Redis/IDatabaseAsync.cs

@@ -147,6 +147,13 @@ public interface IDatabaseAsync : IRedisAsync
         /// <remarks>http://redis.io/commands/pfcount</remarks>
         Task<long> HyperLogLogLengthAsync(RedisKey key, CommandFlags flags = CommandFlags.None);
 
+        /// <summary>
+        /// Returns the approximated cardinality of the union of the HyperLogLogs passed, by internally merging the HyperLogLogs stored at the provided keys into a temporary hyperLogLog, or 0 if the variable does not exist.
+        /// </summary>
+        /// <returns>The approximated number of unique elements observed via HyperLogLogAdd.</returns>
+        /// <remarks>http://redis.io/commands/pfcount</remarks>
+        Task<long> HyperLogLogLengthAsync(RedisKey[] keys, CommandFlags flags = CommandFlags.None);
+
         /// <summary>
         /// Merge multiple HyperLogLog values into an unique value that will approximate the cardinality of the union of the observed Sets of the source HyperLogLog structures.
         /// </summary>

StackExchange.Redis/StackExchange/Redis/KeyspaceIsolation/DatabaseWrapper.cs

@@ -121,6 +121,11 @@ public long HyperLogLogLength(RedisKey key, CommandFlags flags = CommandFlags.No
             return this.Inner.HyperLogLogLength(this.ToInner(key), flags);
         }
 
+        public long HyperLogLogLength(RedisKey[] keys, CommandFlags flags = CommandFlags.None)
+        {
+            return this.Inner.HyperLogLogLength(this.ToInner(keys), flags);
+        }
+
         public void HyperLogLogMerge(RedisKey destination, RedisKey[] sourceKeys, CommandFlags flags = CommandFlags.None)
         {
             this.Inner.HyperLogLogMerge(this.ToInner(destination), this.ToInner(sourceKeys), flags);

StackExchange.Redis/StackExchange/Redis/KeyspaceIsolation/WrapperBase.cs

@@ -127,6 +127,11 @@ public Task<long> HyperLogLogLengthAsync(RedisKey key, CommandFlags flags = Comm
             return this.Inner.HyperLogLogLengthAsync(this.ToInner(key), flags);
         }
 
+        public Task<long> HyperLogLogLengthAsync(RedisKey[] keys, CommandFlags flags = CommandFlags.None)
+        {
+            return this.Inner.HyperLogLogLengthAsync(this.ToInner(keys), flags);
+        }
+
         public Task HyperLogLogMergeAsync(RedisKey destination, RedisKey[] sourceKeys, CommandFlags flags = CommandFlags.None)
         {
             return this.Inner.HyperLogLogMergeAsync(this.ToInner(destination), this.ToInner(sourceKeys), flags);

StackExchange.Redis/StackExchange/Redis/RedisDatabase.cs

@@ -281,12 +281,28 @@ public long HyperLogLogLength(RedisKey key, CommandFlags flags = CommandFlags.No
             return ExecuteSync(cmd, ResultProcessor.Int64);
         }
 
+        public long HyperLogLogLength(RedisKey[] keys, CommandFlags flags = CommandFlags.None)
+        {
+            if (keys == null) throw new ArgumentNullException("keys");
+
+            var cmd = Message.Create(Db, flags, RedisCommand.PFCOUNT, keys);
+            return ExecuteSync(cmd, ResultProcessor.Int64);
+        }
+
         public Task<long> HyperLogLogLengthAsync(RedisKey key, CommandFlags flags = CommandFlags.None)
         {
             var cmd = Message.Create(Db, flags, RedisCommand.PFCOUNT, key);
             return ExecuteAsync(cmd, ResultProcessor.Int64);
         }
 
+        public Task<long> HyperLogLogLengthAsync(RedisKey[] keys, CommandFlags flags = CommandFlags.None)
+        {
+            if (keys == null) throw new ArgumentNullException("keys");
+
+            var cmd = Message.Create(Db, flags, RedisCommand.PFCOUNT, keys);
+            return ExecuteAsync(cmd, ResultProcessor.Int64);
+        }
+
         public void HyperLogLogMerge(RedisKey destination, RedisKey first, RedisKey second, CommandFlags flags = CommandFlags.None)
         {
             var cmd = Message.Create(Db, flags, RedisCommand.PFMERGE, destination, first, second);