crc

问题 Will using only 2 upper/lower bytes of a crc32 sum make it weaker than crc16? Background: I'm currently implementing a wireless protocol. I have chunks of 64byte each, and according to Data Length vs CRC Length I would need at most crc16. Using crc16 instead of crc32 would free up bandwidth for use in Forward error correction (64byte is one block in FEC). However, my hardware is quite low powered but has hardware support for CRC32. So my idea was to use the hardware crc32 engine and just

问题 From this answer I adapted the code below: function _makeCRCTable() { const CRCTable = new Uint32Array(256); for (let i = 256; i--;) { let char = i; for (let j = 8; j--;) { char = char & 1 ? 3988292384 ^ char >>> 1 : char >>> 1; } CRCTable[i] = char; } return CRCTable; } This code generates table as here, but for Ogg I need another table - as here. From Ogg documentation: 32 bit CRC value (direct algorithm, initial val and final XOR = 0, generator polynomial=0x04c11db7) parseInt('04c11db7',

问题 It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center. Closed 9 years ago . Can someone please code me the CRC64 Reverse Algorithm in C#? I am unable to code it, can't understand anything. Thanks, I have copied the CRC64 Checksum code from C++ and converted it into C# .NET. The entire

问题 I'm trying to convert PHP snippet into Python3 code but outputs of print and echo are different. You can see it in the step 1. Do you know where is the problem? I'm attaching input arrays too but I think they are equal. �W2+ vs ee7523b2 EDIT When I switch raw from TRUE to FALSE, outputs of 1st step are the same. $d = strrev(hash("crc32b", $d, FALSE)) . $d But the problem is that I have to convert PHP to Python, not the opposite because, then I'm usit in the step 2 which I need to have equal

问题 I'm using ubuntu 12.04 and I wanted to enable ubuntu one at first. So I ran ubuntuone-control-panel-qt . Then it said ImportError: No module named pkg_resources . The solutions I found on Internet said it could be fixed by reinstalling the python distribute package. So I used curl -O http://python-distribute.org/distribute_setup.yp and then python distribute_setup.py But an annoying message appeared, saying that IOError: CRC check failed 0x77057d99 != 0xec0a9eeL I was almost driven crazy. How

问题 I've been struggling with the intrinsics. In particular I don't get the same results using the standard CRC calculation and the supposedly equivalent intel intrinsics. I'd like to move to using _mm_crc32_u16 , and _mm_crc32_u32 but if I can't get the 8 bit operation to work there's no point. static UINT32 g_ui32CRC32Table[256] = { 0x00000000L, 0x77073096L, 0xEE0E612CL, 0x990951BAL, 0x076DC419L, 0x706AF48FL, 0xE963A535L, 0x9E6495A3L, 0x0EDB8832L, 0x79DCB8A4L, 0xE0D5E91EL, 0x97D2D988L, .... //

问题 I'm looking at designing a low-level radio communications protocol, and am trying to decide what sort of checksum/crc to use. The hardware provides a CRC-8; each packet has 6 bytes of overhead in addition to the data payload. One of the design goals is to minimize transmission overhead. For some types of data, the CRC-8 should be adequate, for for other types it would be necessary to supplement that to avoid accepting erroneous data. If I go with a single-byte supplement, what would be the

问题 How do I calculate CRC16 in Python? In Perl I would write something like: use Digest::CRC "crc16"; $result = crc16($str); How do I do same thing in Python? 回答1: There is a library for calculating CRC16 here http://pypi.python.org/pypi/crc16/0.1.0 来源： https://stackoverflow.com/questions/5292290/crc16-in-python

问题 I tried to find out how to calculate the error detection capabilities of arbitrary CRC polynomials. I know that there are various error detection capabilities that may (or may not) apply to an arbitrary polynomial: Detection of a single bit error: All CRCs can do this since this only requires a CRC width >= 1. Detection of burst errors: All CRCs can detect burst errors up to a size that equals their width. Detection of odd numbers of bit errors: CRC with polynomials with an even number of

问题 What is CRC? And how does it help in error detection? 回答1: CRC stands for Cyclic Redundancy Check. it helps in error detection.. It consists of the following b(x)-> transmitted code word q(x)-> quotient i(x)-> information polynomial r(x)-> remainder polynomial g(x)-> generated polynomial step 1: x^(n-k) * i(x) step 2: r(x) = (x^(n-k) * i(x))%g(x) step 3: b(x) = (x^(n-k) * i(x)) XOR with r(x) which results in a transmitted code word. this b(x) is send to the reciever end from the sender and if