checksum

问题 I'm trying to quickly determine if two sets of schedules are identical and also generate a key which these unique schedules can be references by. I originally attempted to use HASHBYTES but quickly discovered that you are only able to hash 8000 characters and I have a significant number of datetimes which when concatenated are longer than 8000. So, I attempted to use Checksum and Checksum_Agg since they seem to be designed for this sort of thing. I'm aware that Checksum has a higher chance of

问题 Introduction Step 1 I tried to read the barcode (see image below) using a mobile barcode reader and online tools and got it: data - 30925018 , visualization algorithm - Code128C Step 2 Then I tried to generate a barcode from given data and got these images: Original barcode Generated barcode Step 3 As you can see, the images are different. So, I decided to decrypt it by myself. Here is the result: Original decrypted barcode Generated decrypted barcode Сlarifications As Wikipedia says (https:/

问题 I'm working on a project which includes verifying the checksum of an Int input with the Damm Algorithm. I've managed to create a the operational table and my method for accessing the value in the table involves passing an interim value and a digit to pass in as the column value. ex. self.tableToUse[interim,checkSumArray[i]] Unfortunately, I've run into a snag when I'm trying to pass the digits from my input into the the get/set method where I cannot find a way to convert the Characters into

问题 zlib's crc32_combine() takes crcA, crcB, and lengthB to calculate crcAB. # returns crcAB crc32_combine(crcA, crcB, lenB) Using concepts from Mark Adler's awesome posts here and here I was able to produce crc32_trim_trailing.pl which takes crcAB, crcB, and lengthB to calculate crcA (I use this to peel off padding of a known length and value). # prints crcA perl crc32_trim_trailing.pl $crcAB $crcB $lenB Unfortunately, this uses the principles of the slow method described, where each null byte

问题 I am writing a console application which iterates through a binary tree and searches for new or changed files based on their md5 checksums. The whole process is acceptable fast (14sec for ~70.000 files) but generating the checksums takes about 5min which is quite too slow... Any suggestions for improving this process? My hash function is the following: private string getMD5(string filename) { using (var md5 = new MD5CryptoServiceProvider()) { if (File.Exists(@filename)) { try { var buffer =

问题 How do you interpret this phrase? Checksum This is the value to make zero on the addition of the lower 8 bits from the header to the checksum. With this protocol description: Protocol Consist of header (1 byte) + data length (1 byte) + command data (13 bytes) + check sum (1 bytes) + connection ID (1 byte). (I literally copied this protocol description, so I'dont know why there is 1 bytes (in plural). But I can tell you it is only one byte) Here are some sample TCP packets of this protocol: HE

问题 I'm trying to implement a simple data transfer using UDP. I have a problem for the checksum, given a packet containing the data, how should I implement the checksum? also any idea how to implement the timeouts so it will trigger the retransmission ? Thanks 回答1: Why not try Reliable UDP, see http://en.wikipedia.org/wiki/Reliable_User_Datagram_Protocol It has a standard. 回答2: here's one approach for the internet checksum unsigned short checkSum() { unsigned long sum = 0; int i; for(i=0; i <

问题 I am suppose to create a checksum with MD5 Hash generator, and i am using the image "Image to create checksum" I have downloaded an image on both iOS and Andriod device and created MD5 hash as follows: For Andriod Device: Checksum : 09955F4875C8798FFEAF5EFD95FB3AA7 Image : For IOS Device: Checksum : 8C18C548188D68C086691BAC7C68DC35 Image : I have even cross checked creating checksum by downloading image on system as well which also gives "09955F4875C8798FFEAF5EFD95FB3AA7" which is matching

问题 I'm having trouble with creating a Maxim CRC-16 Algorithm that would match a specific output. I've listed the resources I've used to help me write the program below: Maxim App Note 27 Sanity-Free CRC-16 Computation Julia CRC Computation (By Andrew Cooke) CRC-16 Lookup Table (in C) Another CRC Lookup Table in C CRC Wiki Page With the above references, I wrote a simple program that would compute the CRC-16 using both a bit by bit approach, and a look-up table approach. The bit-by-bit approach

问题 I am using Arduino Mega 2560 to communicate with the server. I create a byte array, uses the first digit as a indicator (to tell the server this message is from a arduino device) and the last digit for check sum. // for creating msg void createmsg(){ int index = 0; memset(MSGpack,0,sizeof(MSGpack)); byte sum; MSGpack[0] = 0x23; // for identifing it is arduino // for current readings index = 14; for (int i = 0; i < 7; i++){ float voltage = readcurrent(i); injectByte(voltage, index); index =