CRC | Fastest CRC32 for x86 , Intel and AMD , +
kandi X-RAY | CRC Summary
kandi X-RAY | CRC Summary
computing is just the process of transforming and moving data. when data is moved through a channel or stored in a medium, there is some possibility of corruption: the chance that when the data is read back out on the receiving end, it's wrong - different than what was sent/stored. if we care enough about the data, we may want to perform some kind of verification to at least detect, if not correct, errors. we often do care about our data's correctness, so the problem of verifying integrity proves quite ubiquitous. this very text likely made its way through many such verifications on its way to you - the data transfer mechanisms of wi-fi, ethernet, and hdmi all verify every bit of data sent through them, for example. modern game engines and development tools are so complex that it should be no surprise that the problem is applicable to them in multiple ways. saved games are one such example. when we write out your progress to a disk drive, we might want to verify that it was written successfully. and when we load it, we might want to verify that it's still intact, lest we load bad data and cause crashes or
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QUESTION
I have the following document.
...ANSWER
Answered 2022-Apr-08 at 19:48If you use remove all the interference from markdown, you are more flexible with the placement of the bibliography:
QUESTION
I am using SPI communication to communicate between Raspberry Pi and a microcontroller. I am sending a value of "32" (a 32-bit integer) or "0x00000020" with CRC value calculated by the microcontroller as "2613451423". I am running CRC32 on this 32-bit integer. Polynomial being used on MCU is "0x04C11DB7". Below is the snippet of code I am using on microcontroller:
...ANSWER
Answered 2022-Mar-30 at 04:52I was able to figure out the issues. I used this https://crccalc.com/?crc=C5&method=crc32&datatype=hex&outtype=0 to confirm CRC values that I was getting on microcontroller and RPi.
First issue was on microcontroller, where I was not even performing the CRC on the data, instead I was performing on the address where that data was stored.
Second issue was that MCU was performing CRC on the value which was stored in the little-endian form. On RPi also, CRC was being performed on values stored in little-endian form. Hence, since the endianness was same on both the devices, I did not have to reverse the bits or bytes.
After doing these changes, I was able to get correct and same CRC values on both RPi and microcontroller.
QUESTION
I wrote a dataframe to a csv in Pyspark. And I got the output files in the directory as:
._SUCCESS.crc
.part-00000-6cbfdcfd-afff-4ded-802c-6ccd67f3804a-c000.csv.crc
part-00000-6cbfdcfd-afff-4ded-802c-6ccd67f3804a-c000.csv
How do I keep only the CSV file in the directory and delete rest of the files, using Python?
...ANSWER
Answered 2022-Feb-09 at 10:00import os
directory = "/path/to/directory/with/files"
files_in_directory = os.listdir(directory)
filtered_files = [file for file in files_in_directory if not file.endswith(".csv")]
for file in filtered_files:
path_to_file = os.path.join(directory, file)
os.remove(path_to_file)
QUESTION
This is a follow up question from: : LP_c_long instance instead of list but is a different issue so I am posting a new question here.
I am using ctypes to invoke a c function from python script. The c function which is being invoked is:
...ANSWER
Answered 2022-Mar-27 at 04:00As @Mark's suggested in comments, you would have to store the data into another variable/list, for example: recv = spi.xfer2(data)
. Then you would need to use this recv in your unpack function.
Further, you could also use a python library called zlib instead of using a c library (there are other python libraries as well).
Another point, since zlib takes only bytes as input, you would need to convert recv into bytes (here recv is a list; check my code). I modified some of your code.
QUESTION
I am sending messages from an ATMEGA644 to a Linux machine, and the CRC32 routine gives a different result on the two machines. The CRC algorithm is from MIT.
The ATMEGA version is compiled with avr-gcc and the Linux version with cc. The Linux compilation produces two warnings about the size of the printf parameters in the test harness, but even if you eliminate these warnings, the result is the same.
Here is the crc32 routine, together with a main() test harness that shows the problem:
...ANSWER
Answered 2022-Mar-22 at 15:29The two different systems you are comparing have int
types of different sizes, and although your code does not use int
explicitly, it is used implicitly by the rules of the C language.
On the AVR, ~0U
has the type unsigned int
(i.e. uint16_t
) and a value of 0xFFFF.
On a normal PC, ~0U
has the type unsigned int
(i.e. uint32_t
) and a value of 0xFFFFFFFF.
Like Tom Karzes said, you should just use ~crc
if you want to invert all the bits in the crc
variable in a simple, cross-platform way.
QUESTION
I am in a project and I have to comply with ISO26262 so I need to verify my CAN frame. I am going to check my frame using the CRC calculation. My question is: Should I do this calculation in my program or does the CAN protocol already do it automatically?
...ANSWER
Answered 2022-Mar-10 at 08:00CAN contains a 15 bit CRC on the data-link layer. It is handled by the CAN controller and you don't need to do a thing in software, other than checking for errors reported by the controller.
Application layer CRC could be use in some special cases like when you are transferring large amounts of data such as bootloaders. But it isn't necessary for ordinary communication.
QUESTION
I am fairly new to OpenShift and have been using CRC (Code Ready Containers) for a little while, and now decided to install the single server OpenShift on bare metal using the Assisted-Installer method from https://cloud.redhat.com/blog/deploy-openshift-at-the-edge-with-single-node-openshift and https://console.redhat.com/openshift/assisted-installer/clusters/. This has worked well and I have a functional single-server.
As a single server in a test environment (without NFS available) I need/want to create PersistentVolumes with hostPath (localhost storage) - these work flawlessly in CRC. However on the full install, I run into an issue when mounting PVC's to pods as the pods were not running privileged. I edited the deployment config and added the lines below (within the containers hash)
...ANSWER
Answered 2021-Oct-04 at 07:55The short answer to this is: don't use hostPath.
You are using hostPath to make use of arbitrary disk space available on the underlying host's volume. hostPath can also be used to read/write any directory path on the underlying host's volume -- which, as you can imagine, should be used with great care.
Have a look at this as an alternative -- https://docs.openshift.com/container-platform/4.8/storage/persistent_storage/persistent-storage-local.html
QUESTION
I'm trying to write a PCLMULQDQ-optimized CRC-32 implementation. The specific CRC-32 variant is for one that I don't own, but am trying to support in library form. In crcany model form, it has the following parameters:
width=32 poly=0xaf init=0xffffffff refin=false refout=false xorout=0x00000000 check=0xa5fd3138
(Omitted residue which I believe is 0x00000000
but honestly don't know what it is)
A basic non-table-based/bitwise implementation of the algorithm (as generated by crcany
) is:
ANSWER
Answered 2022-Mar-07 at 15:47I have 6 sets of code for 16, 32, 64 bit crc, non-reflected and reflected here. The code is setup for Visual Studio. Comments have been added to the constants which were missing from Intel's github site.
https://github.com/jeffareid/crc
32 bit non-relfected is here:
https://github.com/jeffareid/crc/tree/master/crc32f
You'll need to change the polynomial in crc32fg.cpp, which generates the constants. The polynomial you want is actually:
QUESTION
I am unsure why this fails to demangle symbols:
...ANSWER
Answered 2022-Mar-06 at 16:29For one thing, you are not calling __cxa_demangle
correctly. Documentation says:
output_buffer
A region of memory, allocated with malloc, of*length
bytes, into which the demangled name is stored. Ifoutput_buffer
is not long enough, it is expanded usingrealloc
.output_buffer
may instead beNULL
; in that case, the demangled name is placed in a region of memory allocated withmalloc
.
You are passing a stack buffer
instead. Get rid of it (and the pointless memset
), and do this instead:
QUESTION
I´ve got the following example:
...ANSWER
Answered 2022-Feb-16 at 21:46The following parameters produce the desired result 280ACDA5:
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