Exemple #1
0
        /// <summary>计算数据流校验码</summary>
        /// <param name="stream"></param>
        /// <param name="count"></param>
        /// <returns></returns>
        public static UInt32 Compute(Stream stream, Int32 count = -1)
        {
            var crc = new Crc32Util();

            crc.Update(stream, count);
            return(crc.Value);
        }
Exemple #2
0
        /// <summary>计算校验码</summary>
        /// <param name="buf"></param>
        /// <param name="offset"></param>
        /// <param name="count"></param>
        /// <returns></returns>
        public static UInt32 Compute(Byte[] buf, Int32 offset = 0, Int32 count = -1)
        {
            var crc = new Crc32Util();

            crc.Update(buf, offset, count);
            return(crc.Value);
        }
Exemple #3
0
        /// <summary>计算数据流校验码,指定起始位置和字节数偏移量</summary>
        /// <remarks>
        /// 一般用于计算数据包校验码,需要回过头去开始校验,并且可能需要跳过最后的校验码长度。
        /// position小于0时,数据流从当前位置开始计算校验;
        /// position大于等于0时,数据流移到该位置开始计算校验,最后由count决定可能差几个字节不参与计算;
        /// </remarks>
        /// <param name="stream"></param>
        /// <param name="position">如果大于等于0,则表示从该位置开始计算</param>
        /// <param name="count">字节数偏移量,一般用负数表示</param>
        /// <returns></returns>
        public static UInt32 ComputeRange(Stream stream, Int64 position = -1, Int32 count = -1)
        {
            if (position >= 0)
            {
                if (count > 0)
                {
                    count = -count;
                }
                count += (Int32)(stream.Position - position);
                if (count == 0)
                {
                    return(0);
                }

                stream.Position = position;
            }

            var crc = new Crc32Util();

            crc.Update(stream, count);
            return(crc.Value);
        }