一、在FileStream流和byte[]中查找(搜索)指定字符串

        /// <summary>
        /// 在当前流中搜索指定的 byte[]
        /// </summary>
        /// <param name="arr"></param>
        /// <param name="key">搜索关键字</param>
        /// <param name="beginPosition">搜索开始位置</param>
        /// <returns>如果存在则返回byte[]在流中首次出现的位置，否则返回 -1</returns>
        private static List<long> Search(FileStream stream, long beginPosition, long endPosition, byte[] key)
        {
            //FileStream stream = File.Open(path, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);
            List<long> position = new List<long>();

            if (stream == null || stream.Length <= beginPosition)
            {
                return null;
            }

            if (key == null || stream.Length < key.Length)
            {
                return null;
            }

            long i = -1;
            long j = -1;
            int currentByte = int.MinValue;
            //for (i = beginPosition; i < stream.Length; i++)
            for (i = beginPosition; i < endPosition; i++)
            {
                if (stream.Length < key.Length + i)
                {
                    break;
                }
                stream.Seek(i, SeekOrigin.Begin);
                for (j = 0; j < key.Length; j++)
                {
                    currentByte = stream.ReadByte();
                    if (currentByte != key[j])
                    {
                        break;
                    }
                }
                if (j == key.Length)
                {
                    //return i;
                    position.Add(i);
                }

                if (currentByte == -1)
                {
                    break;
                }
            }
            return position;
        }

参考：https://blog.csdn.net/lonelyenvoy/article/details/52416529