/// <summary>
        ///     Obtains a stream which can be used to read and write a cache file's meta in realtime.
        ///     The stream will be set up such that offsets in the stream correspond to meta pointers in the cache file.
        /// </summary>
        /// <param name="cacheFile">The cache file to get a stream for.</param>
        /// <returns>The stream if it was opened successfully, or null otherwise.</returns>
        public override IStream GetMetaStream(ICacheFile cacheFile)
        {
            if (!CheckBuildInfo())
            {
                return(null);
            }

            Process gameProcess = FindGameProcess();

            if (gameProcess == null)
            {
                return(null);
            }

            PokingInformation info = RetrieveInformation(gameProcess);

            if (!info.HeaderAddress.HasValue)
            {
                throw new NotImplementedException("Second Generation poking requires a HeaderAddress value.");
            }
            if (!info.MagicAddress.HasValue)
            {
                throw new NotImplementedException("Second Generation poking requires a MagicAddress value.");
            }
            if (!info.SharedMagicAddress.HasValue)
            {
                throw new NotImplementedException("Second Generation poking requires a SharedMagicAddress value.");
            }

            var gameMemory = new ProcessModuleMemoryStream(gameProcess, _buildInfo.GameModule);
            var mapInfo    = new SecondGenMapPointerReader(gameMemory, _buildInfo, info);

            long metaAddress;

            if (cacheFile.Type != CacheFileType.Shared)
            {
                metaAddress = mapInfo.CurrentCacheAddress;

                // The map isn't shared, so make sure the map names match
                if (mapInfo.MapName != cacheFile.InternalName)
                {
                    gameMemory.Close();
                    return(null);
                }
            }
            else
            {
                metaAddress = mapInfo.SharedCacheAddress;

                // Make sure the shared and current map pointers are different,
                // or that the current map is the shared map
                if (mapInfo.MapType != CacheFileType.Shared && mapInfo.CurrentCacheAddress == mapInfo.SharedCacheAddress)
                {
                    gameMemory.Close();
                    return(null);
                }
            }

            var metaStream = new OffsetStream(gameMemory, metaAddress - cacheFile.MetaArea.BasePointer);

            return(new EndianStream(metaStream, BitConverter.IsLittleEndian ? Endian.LittleEndian : Endian.BigEndian));
        }
        /// <summary>
        ///     Obtains a stream which can be used to read and write a cache file's meta in realtime.
        ///     The stream will be set up such that offsets in the stream correspond to meta pointers in the cache file.
        /// </summary>
        /// <param name="cacheFile">The cache file to get a stream for.</param>
        /// <returns>The stream if it was opened successfully, or null otherwise.</returns>
        public IStream GetMetaStream(ICacheFile cacheFile)
        {
            if (string.IsNullOrEmpty(_buildInfo.GameExecutable))
            {
                throw new InvalidOperationException("No gameExecutable value found in Engines.xml for engine " + _buildInfo.Name + ".");
            }
            if (_buildInfo.Poking == null)
            {
                throw new InvalidOperationException("No poking definitions found in Engines.xml for engine " + _buildInfo.Name + ".");
            }

            Process gameProcess = FindGameProcess();

            if (gameProcess == null)
            {
                return(null);
            }

            string version = gameProcess.MainModule.FileVersionInfo.FileVersion;

            PokingInformation info = _buildInfo.Poking.RetrieveInformation(version);

            if (info == null)
            {
                throw new InvalidOperationException("Game version " + version + " does not have poking information defined in the Formats folder.");
            }

            if (!info.HeaderAddress.HasValue)
            {
                throw new NotImplementedException("Second Generation poking requires a HeaderAddress value.");
            }
            if (!info.MagicAddress.HasValue)
            {
                throw new NotImplementedException("Second Generation poking requires a MagicAddress value.");
            }
            if (!info.SharedMagicAddress.HasValue)
            {
                throw new NotImplementedException("Second Generation poking requires a SharedMagicAddress value.");
            }

            var gameMemory = new ProcessMemoryStream(gameProcess);
            var mapInfo    = new SecondGenMapPointerReader(gameMemory, _buildInfo, info);

            long metaAddress;

            if (cacheFile.Type != CacheFileType.Shared)
            {
                metaAddress = mapInfo.CurrentCacheAddress;

                // The map isn't shared, so make sure the map names match
                if (mapInfo.MapName != cacheFile.InternalName)
                {
                    gameMemory.Close();
                    return(null);
                }
            }
            else
            {
                metaAddress = mapInfo.SharedCacheAddress;

                // Make sure the shared and current map pointers are different,
                // or that the current map is the shared map
                if (mapInfo.MapType != CacheFileType.Shared && mapInfo.CurrentCacheAddress == mapInfo.SharedCacheAddress)
                {
                    gameMemory.Close();
                    return(null);
                }
            }

            var metaStream = new OffsetStream(gameMemory, metaAddress - cacheFile.MetaArea.BasePointer);

            return(new EndianStream(metaStream, BitConverter.IsLittleEndian ? Endian.LittleEndian : Endian.BigEndian));
        }