System.IO.BinaryReader.ReadInt64 C# (CSharp) Method

        public virtual long ReadInt64()
        {
            FillBuffer(8);
            uint lo = (uint)(_buffer[0] | _buffer[1] << 8 |
                             _buffer[2] << 16 | _buffer[3] << 24);
            uint hi = (uint)(_buffer[4] | _buffer[5] << 8 |
                             _buffer[6] << 16 | _buffer[7] << 24);
            return (long)((ulong)hi) << 32 | lo;
        }

 public IDictionary<byte[], IList<long>> Read(BinaryReader reader, int keyWidth)
 {
     var indexWidth = reader.ReadInt64();
     var buckets = new Dictionary<byte[], IList<long>>(new ByteArrayComparer());
     while (reader.BaseStream.Position < reader.BaseStream.Length)
     {
         var bucket = new List<long>();
         var index = reader.ReadBytes(keyWidth);
         for (int i = 0; i < indexWidth - keyWidth; i += sizeof (long))
         {
             var value = reader.ReadInt64();
             if (value != long.MaxValue)
             {
                 bucket.Add(value);
             }
             else
             {
                 reader.BaseStream.Seek(indexWidth - keyWidth - i - sizeof (long), SeekOrigin.Current);
                 break;
             }
         }
         buckets[index] = bucket;
     }
     return buckets;
 }