记录：8583规范位图的简单实现

8583规范使用位图来标识报文包含的域，就是用8个或16个字节中每一位代表一个域，相应从1到64或从1到128域，这里是用c#把一个包含域的数组转换成位图的简单实现：

 

        /// <summary>

        /// 生成bit-map

        /// </summary>

        /// <param name="len">8或16</param>

        /// <param name="indexs">域数组{2,4,6,8,9}</param>

        /// <returns></returns>

        public static byte[] getBitMap(int len, int[] indexs)

        {

            byte[] temp = new byte[len];

            int t1, t2;

            byte t3;

            for (int i = 0; i < len; i++)

            {

                temp[i] = 0x00;

            }

            for (int k = 0; k < indexs.Length; k++)

            {

                if (indexs[k] > 8 * len || indexs[k] <= 0)

                {

                    continue;

                }

                t1 = indexs[k] / 8;

                t2 = indexs[k] % 8;

                if (t2 == 0)

                {

                    t3 = 0x01;

                    temp[t1 - 1] |= t3;

                }

                else

                {

                    t3 = 0x80;

                    t3 = (byte)(t3 >> (t2 - 1));

                    temp[t1] |= t3;

                }

            }

            return temp;

        }