(#37) Add Random.NextInt64

Uses an internal Random instance to generate a second sample which is
OR'd with the first to produce a 64-bit integer

X10D/src/RandomExtensions/RandomExtensions.cs

@@ -163,6 +163,87 @@ namespace X10D.RandomExtensions
             return list[random.Next(list.Count)];
         }
 
+        /// <summary>
+        ///     Returns a random 64-bit integer.
+        /// </summary>
+        /// <param name="random">The <see cref="System.Random" /> instance.</param>
+        /// <returns>
+        ///     A 64-bit signed integer greater than or equal to 0 and less than <see cref="long.MaxValue" />.
+        /// </returns>
+        /// <exception cref="ArgumentNullException"><paramref name="random" /> is <see langword="null" />.</exception>
+        public static long NextInt64(this Random random)
+        {
+            if (random is null)
+            {
+                throw new ArgumentNullException(nameof(random));
+            }
+
+            var sample = random.Next();
+            var sampledRandom = new Random(sample);
+            return (long)sample << 32 | sampledRandom.Next();
+        }
+
+        /// <summary>
+        ///     Returns a non-negative random 64-bit integer that is less than the specified maximum.
+        /// </summary>
+        /// <param name="random">The <see cref="System.Random" /> instance.</param>
+        /// <param name="maxValue">The exclusive upper bound of the random number returned.</param>
+        /// <returns>
+        ///     A 64-bit signed integer that is greater than or equal to 0, and less than <paramref name="maxValue" />; that is,
+        ///     the range of return values ordinarily includes 0 but not <paramref name="maxValue" />. However, if
+        ///     <paramref name="maxValue" /> equals 0, <paramref name="maxValue"/> is returned.
+        /// </returns>
+        /// <remarks><paramref name="maxValue" /> must be greater than or equal to 0.</remarks>
+        /// <exception cref="ArgumentNullException"><paramref name="random" /> is <see langword="null" />.</exception>
+        /// <exception cref="ArgumentOutOfRangeException"><paramref name="maxValue" /> is less than 0.</exception>
+        public static long NextInt64(this Random random, long maxValue)
+        {
+            if (random is null)
+            {
+                throw new ArgumentNullException(nameof(random));
+            }
+
+            if (maxValue < 0)
+            {
+                throw new ArgumentOutOfRangeException(nameof(maxValue), ExceptionMessages.MaxValueGreaterThanEqualTo0);
+            }
+
+            return random.NextInt64(0, maxValue);
+        }
+
+        /// <summary>
+        ///     Returns a random 64-bit integer that is within a specified range.
+        /// </summary>
+        /// <param name="random">The <see cref="System.Random" /> instance.</param>
+        /// <param name="minValue">The inclusive lower bound of the random number returned.</param>
+        /// <param name="maxValue">The exclusive upper bound of the random number returned.</param>
+        /// <returns>
+        ///     A 64-bit signed integer greater than or equal to <paramref name="minValue" /> and less than
+        ///     <paramref name="maxValue" />; that is, the range of return values includes <paramref name="minValue" /> but not
+        ///     <paramref name="maxValue" />. If <paramref name="minValue" /> equals <paramref name="maxValue" />,
+        ///     <paramref name="minValue" /> is returned.
+        /// </returns>
+        /// <remarks><paramref name="maxValue" /> must be greater than or equal to <paramref name="minValue" />.</remarks>
+        /// <exception cref="ArgumentNullException"><paramref name="random" /> is <see langword="null" />.</exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="maxValue" /> is less than <paramref name="minValue" />.
+        /// </exception>
+        public static long NextInt64(this Random random, long minValue, long maxValue)
+        {
+            if (random is null)
+            {
+                throw new ArgumentNullException(nameof(random));
+            }
+
+            if (maxValue < minValue)
+            {
+                throw new ArgumentOutOfRangeException(ExceptionMessages.MaxValueGreaterThanEqualToMinValue);
+            }
+
+            var sample = random.NextInt64();
+            return (sample % (maxValue - minValue)) + minValue;
+        }
+
         /// <summary>
         ///     Returns a random single-precision floating point number between 0 and 1.
         /// </summary>